Biopharmconsortium Blog

Expert commentary from Haberman Associates biotechnology and pharmaceutical consulting.

Posts filed under: Stem Cells

Strimvelis (GSK2696273), a gene therapy for a deadly immunodeficiency in children, expected to reach the European market in mid-2016

Adenosine deaminase

Adenosine deaminase

Our recent book-length report, Gene Therapy: Moving Toward Commercialization was published by Cambridge Healthtech Institute in November 2015. As indicated by its title, the report focuses on clinical-stage gene therapy programs that are aimed at commercialization, and the companies that are carrying out these programs.

Until recently, gene therapy was thought of as a scientifically-premature field with little prospect of near-term commercialization. However, as outlined in our report, numerous companies have been pursuing clinical programs aimed at regulatory approval and commercialization. These efforts have attracted the interest of investors and of large pharma and biotech companies. As a result, several gene therapy specialty companies have gone public, and some companies in this sector have attracted large pharma or biotech partnerships.

A key question addressed in our report is whether any gene therapies might be expected to reach the U.S. and/or European markets in the near term. In the last chapter (Chapter 9) of the report, we included a table (Table 9.1) of eight gene therapy products that we deemed to be likely to reach the market before 2020.

One of these products, uniQure/Chiesi’s Glybera (alipogene tiparvovec), a treatment for the ultra-rare condition lipoprotein lipase deficiency (LPLD), was approved in Europe in 2012. It is thus the “first commercially available gene therapy” in a regulated market. However, uniQure has dropped plans to seek FDA approval for Glybera.

As we discussed in our December 17, 2015 article on this blog, another product listed in Table 9.1, Spark Therapeutics’ SPK-RPE65, is expected to reach the U.S. market by 2017. SPK-RPE65 is a gene therapy for the rare retinal diseases Leber congenital amaurosis and retinitis pigmentosa type 20. As of March 9, 2016, Spark is preparing to file a Biologics License Application (BLA) for SPK-RPE65 in the second half of 2016. SPK-RPE65 may be the first gene therapy approved in the U.S. Spark also plans to file a marketing authorization application (MAA) in Europe in early 2017.

Now comes an announcement of the impending European marketing of a third product listed in Table 9.1, GlaxoSmithKline/San Raffaele Telethon Institute for Gene Therapy (TIGET)’s GSK2696273, now called Strimvelis. On April 1, 2016, the The European Medicines Agency (EMA) recommended the approval of Strimvelis in Europe, for the treatment of children with ADA severe combined immune deficiency (ADA-SCID) for whom no matching bone marrow donor is available. ADA-SCID is a type of SCID caused by mutations in the gene for adenosine deaminase (ADA).

Approximately 15 children per year are born in Europe with ADA-SCID, which leaves them unable to make certain white blood cell that are involved in the immune system. ADA-SCID is an autosomal recessive condition that accounts for about 15% of cases of SCID. ADA deficiency results in the intracellular buildup of toxic metabolites that are especially deleterious to the highly metabolically active T and B cells. These cells thus fail to mature, resulting in life-threatening immune deficiency. Children with ADA-SCID rarely survive beyond two years unless their immune function is rescued via bone marrow transplant from a compatible donor. Thus Strimvelis is indicated for children for whom no compatible donor is available.

As we discussed in our report, the development of therapies for ADA-SCID goes back to the earliest days of gene therapy, in 1990. Interestingly, Strimvelis (GSK2696273) is based on a Moloney murine leukemia virus (MoMuLV) gammaretrovirus vector carrying a functional gene for ADA. In other applications (for example, gene therapy for another type of SCID called SCID-X1), the use of MoMuLV vectors resulted in a high level of leukemia induction. As a result, researchers have developed other types of retroviral vectors (such as those based on  lentiviruses) that do not have this issue. Nevertheless, Strimvelis Mo-MuLV-ADA gene therapy has been show to be safe over 13 years of clinical testing, with no leukemia induction. As discussed in our report, researchers hypothesize that ADA deficiency may create an unfavorable environment for leukemogenesis.

Delivery of Strimvelis requires the isolation of hematopoietic stem cells (HSCs) from each patient, followed by ex vivo infection of the cells with the MoMuLV-ADA construct. The transformed cells are then infused into the patient, resulting in restoration of a functional immune system.

With the EMA recommendation of approval for Strimvelis, it is expected that the therapy will be approved by the European Commission approval in July 2016.

Strimvelis is the result of a 2010 partnership between GSK and Italy’s San Raffaele Telethon Institute for Gene Therapy (TIGET), and the biotechnology company MolMed, which is based at TIGET in Milan. MolMed is currently the only approved site in the world for production of and ex vivo therapy with Strimvelis. However, GSK is looking into ways of expanding the numbers of sites that will be capable of and approved for administration of the therapy. GSK’s plans will include seeking FDA approval for expansion into the U.S. market.

Moreover, as discussed in our report, under the GSK/TIGET agreement,  GSK has exclusive options to develop six further applications of ex vivo stem cell therapy, using gene transfer technology developed at TIGET. GSK has already exercised its option to develop two further programs in two other rare diseases. Both are currently in clinical trials. Because of the issue of leukemogenesis with most gammaretrovirus-based gene therapies, these other gene therapy products are based on the use of lentiviral vectors.

Given the tiny size of the market for each of these therapies, pricing is an important—and tricky—issue. For example, treatment with UniQure’s Glybera, as of 2014, cost $1 million. As of now, GSK is not putting a price on Stremvelis, but reportedly the therapy will cost “very significantly less than $1 million” if and when it is approved.

Conclusions

The success of researchers and companies in moving three of the eight gene therapies listed in Table 9.1 toward regulatory approval suggests that gene therapy will attain at least some degree of near term commercial success. However, Glybera and Strimvelis are for ultra-rare diseases, and are thus not expected to command large markets.

However, as discussed in our previous blog article, SPK-RPE65 may achieve peak sales ranging from $350 million to $900 million. And as discussed in our report, some of the remaining therapies listed in Table 9.1, especially those involved in treatment of blood diseases or cancer, may achieve sales in the billions of dollars. Thus, depending on the timing and success of clinical trials and regulatory submissions of these therapies, gene therapy may demonstrate a degree of near-term commercial success that few thought was possible just five years ago.

Meanwhile, even therapies that address rare or ultra-rare diseases will be expected to save the lives or the sight of patients who receive these products.

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As the producers of this blog, and as consultants to the biotechnology and pharmaceutical industry, Haberman Associates would like to hear from you. If you are in a biotech or pharmaceutical company, and would like a 15-20-minute, no-obligation telephone discussion of issues raised by this or other blog articles, or of other issues that are important to your company, please contact us by phone or e-mail. We also welcome your comments on this or any other article on this blog.

Our New Year’s 2015 article: Notable researchers and breakthrough research of 2014

 

Pre-1917 Russian Happy Christmas and Happy New Year card

Pre-1917 Russian Happy Christmas and Happy New Year card

As is their customary practice, both Nature and Science ran end-of-year specials. The Nature special (in their 18 December issue) is entitled “365 days: Nature’s 10. Ten people who mattered this year.” The Science special (in their 19 December issue) is entitled, as usual “2014 Breakthrough of the Year.” As is also usual, there is a section for “Runners Up” to the year’s “Breakthrough”.

From the point of view of a consulting group—and a blog—that focuses on effective drug discovery and development strategies, we were disappointed with both end-of-year specials. Most of the material in these articles was irrelevant to our concerns.

Science chose the Rosetta/Philae comet-chasing mission as the “Breakthrough of the Year”, and its “runners up” included several robotics and space-technology items, as well as new “letters” to the DNA “alphabet” that don’t code for anything.

Nature also focused on comet chasers, robot makers, and space technologists, as well as cosmologist and mathematicians, and a fundraising gimmick—“the ice-bucket challenge”. Moreover, Nature was much too restrictive in titling its article “Ten people who mattered”. Every human being matters!

Nevertheless, these two special sections do contain a few gems that are both relevant to effective drug discovery and development, and are worthy of highlighting as “notable researchers of 2014” and “breakthrough research of 2014”. We discuss these in the remainder of this article.

Suzanne Topalian, M.D.

Suzanne Topalian is one of the researchers profiled in “Nature’s 10”. She is a long-time cancer immunotherapy clinical researcher who began her career in 1985 in the laboratory of cancer immunotherapy pioneer Steven Rosenberg at the National Cancer Institute (Bethesda MD). In the early days of the field, when cancer immunotherapy was scientifically premature, there was a great deal of skepticism that these types of treatments would even work. However, both Dr. Rosenberg and Dr. Topalian persevered in their research.

In 2006, Dr. Topalian moved to Johns Hopkins University (Baltimore, MD) to help launch clinical trials of Medarex/Bristol-Myers Squibb/Ono’s nivolumab, a PD-1 inhibitor. As noted in the Nature article, her work “led to a landmark publication in 2012 showing that nivolumab produced dramatic responses not only in some people with advanced melanoma but also in those with lung cancer [specifically, non–small-cell lung cancer, NSCLC].” We also discussed that publication on the Biopharmconsortium Blog, and in our recently published book-length Insight Pharma Report, Cancer Immunotherapy: immune checkpoint inhibitors, cancer vaccines, and adoptive T-cell therapies. Our report also includes discussions of Dr. Rosenberg’s more recent work in cellular immunotherapy.

As discussed in our report, nivolumab was approved in Japan as Ono’s Opdivo in July 2014 for treatment of unresectable melanoma, and a competitive PD-1 inhibitor, pembrolizumab (Merck’s Keytruda) was approved in the United States for advanced melanoma on September 5, 2014. More recently, on December 22, 2014, the FDA also approved nivolumab (BMS’ Opdivo) for advanced melanoma in the U.S. There are thus now two FDA-approved PD-1 inhibitors [in addition to the CTLA-4 inhibitor ipilimumab (BMS’ Yervoy)] available for treatment of advanced melanoma in the U.S.

Meanwhile, researchers continue to test both nivolumab and pembrolizumab for treatment of NSCLC and other cancers. And some analysts project that both of these agents are likely to be approved by the FDA for treatment of various populations of patients with NSCLC before the middle of 2015. Researchers are also testing combination therapies that include nivolumab or pembrolizumab in various cancers. And clinical trials of Genentech/Roche’s PD-L1 blocking agent MPDL3280A are also in progress.

Science’s 2013 Breakthrough of the Year was cancer immunotherapy, as we highlighted in our New Year’s 2014 blog article. Science could not make cancer immunotherapy the Breakthrough of the Year for 2014, too. Thus it chose to give physical scientists a turn in the limelight by highlighting the comet-chasing mission instead. Nevertheless, 2014 was the year in which cancer immunotherapy demonstrated its maturity by the regulatory approval of the two most advanced checkpoint inhibitor agents, pembrolizumab and nivolumab.

Implications for patients with terminal cancers

The clinically-promising results of cancer immunotherapy in a wide variety of cancers, coupled with the very large numbers of clinical trials in progress in this area, has also changed the situation for patients who have terminal cancers. Researchers who are conducting clinical trials of immunotherapies for these cancers are actively recruiting patients, of whom there are limited numbers at any one time. For example, there are now numerous clinical trials—mainly of immunotherapies—in pancreatic cancer, and most of these trials are recruiting patients. There are also active clinical trials of promising immunotherapies in the brain tumor glioblastoma. These are only two of many examples.

Recently, a 29-year-old woman with terminal glioblastoma ended her life using Oregon’s physician-assisted suicide law. Prior to her suicide, she became an advocate for “terminally ill patients who want to end their own lives”. We, however, are advocating that patients with glioblastoma and other types of terminal cancer for which there are promising immunotherapies seek out clinical trials that are actively recruiting patients. There is the possibility that some of these patients will receive treatments that will result in regression of their tumors or long-term remissions. (See, for example, the case highlighted in our September 16, 2014 blog article. There are many other such cases.) And it is highly likely that patients who participate in these trials will help researchers to learn how to better treat cancers that are now considered “incurable” or “terminal”, and thus help patients who contract these diseases in the future. From our point of view, that is a lot better than taking one’s own life via assisted suicide, and/or becoming an euthanasia advocate.

Masayo Takahashi, M.D., Ph.D.

Another researcher profiled in “Nature’s 10” is Masayo Takahashi, an ophthalmologist at the RIKEN Center for Developmental Biology (CDB) in Kobe, Japan who has been carrying out pioneering human stem cell clinical studies. We also discussed Dr. Takahashi’s research in our March 14, 2013 article on this blog.

At the time of our article, Dr. Takahashi and her colleagues planned to submit an application to the Japanese health ministry for a clinical study of induced pluripotent stem cell (iPS)-derived cells, which would constitute the first human study of such cells. They planned to treat approximately six people with severe age-related macular degeneration (AMD). The researchers planned to take an upper arm skin sample the size of a peppercorn, and transform the cells from this sample into iPS cells by using specific proteins. They were then to add other factors to induce differentiation of the iPS cells into retinal cells. Then a small sheet of these retinal cells were to be placed under the damaged area of the retina, where they were expected to grow and repair the damaged retinal pigment epithelium (RPE). Although the researchers would like to demonstrate efficacy of this treatment, the main focus of the initial studies was to be on safety.

According to the “Nature’s 10” article, such an autologous iPS-derived implant was transplanted into the back of a the damaged retina of one patient in September 2014. This patient, a woman in her 70s, had already lost most of her vision, and the treatment is unlikely to restore it. However, Dr. Takahashi and her colleagues are determining whether the transplant is safe and prevents further retinal deterioration. So far, everything has gone smoothly, and the transplant appears to have retained its integrity. However, the researchers will not reveal whether the study has been a success until a year after the transplantation.

The “Nature’s 10” article discusses how this technology might be moved forward into clinical use if the initial study is successful. It also discusses how Dr. Takahashi has been carrying her research forward in the face of a major setback that has plagued stem cell research at the CDB in 2014, as the result of the withdrawal of two once highly-regarded papers and the suicide of one of their authors.

Generation of insulin-producing human pancreatic β cells from embryonic stem (ES) cells or iPS

Another stem cell-related item, which was covered in Science’s end-of-2014 “Runners Up” article, concerned the in vitro generation of human pancreatic β cells from embryonic stem (ES) cells or iPS. For over a decade, researchers have been attempting to accomplish this feat, in order to have access to autologous β cells to treat type 1 diabetes, in which an autoimmune attack destroys a patient’s own β cells. In vitro generated β cells might also be used to screen for drugs that can improve β cell function, survival, and/or proliferation in patients with type 2 diabetes.

As reported in the Science article, two research groups—one led by Douglas A. Melton, Ph.D. (Harvard Stem Cell Institute, Cambridge, MA), and the other by Alireza Rezania, Ph.D. at BetaLogics Venture, a division of Janssen Research & Development, LLC.–developed protocols to produce unlimited quantities of β cells, in the first case from IPS cells, and in the other from ES cells.

However, in order to use the β cells to treat type 1 diabetes patients, researchers need to develop means (for example, some type of encapsulation) to protect the cells from the autoimmune reaction that killed patients’ own natural β cells in the first place. For example, Dr. Melton is collaborating with the laboratory of Daniel Anderson, Ph.D. (MIT Koch Institute for Integrative Cancer Research). Dr. Anderson and his colleagues have developed a chemically modified alginate that can be used to coat and protects clusters of β cells, thus forming artificial islets. Dr. Melton estimates that such implants would be about the size of a credit card.

The 2014 Boston biotech IPO boom

Meanwhile, the Boston area biotechnology community has seen a boom in young companies holding their initial public offerings (IPOs). 17 such companies were listed in a December 24 article in the Boston Business Journal. Among these companies are three that have been covered in the Biopharmconsortium Blog—Zafgen, Dicerna, and Sage Therapeutics.

We hope that 2015 will see at least the level of key discoveries, drug approvals, and financings seen in 2014.


As the producers of this blog, and as consultants to the biotechnology and pharmaceutical industry, Haberman Associates would like to hear from you. If you are in a biotech or pharmaceutical company, and would like a 15-20-minute, no-obligation telephone discussion of issues raised by this or other blog articles, or of other issues that are important to your company, please contact us by phone or e-mail. We also welcome your comments on this or any other article on this blog.

Chemokine receptor inhibitors for prevention of cancer metastasis

CXCR-1 N-terminal peptide bound to IL-8

CXCR-1 N-terminal peptide bound to IL-8

In our October 31, 2013 blog article, we discussed recent structural studies of the chemokine receptors CCR5 and CXCR4. We discussed the implications of these studies for the treatment of HIV/AIDS, especially using the CCR5 inhibitor maraviroc (Pfizer’s Selzentry/Celsentri). As discussed in the article, researchers are utilizing the structural studies of CCR5 and CXCR4 to develop improved HIV entry inhibitors that target these chemokine receptors.

Meanwhile, other researchers have been studying the role of chemokine receptors in cancer biology, and the potential use of chemokine receptor antagonists in cancer treatment.

CCR5 antagonists as potential treatments for metastatic breast cancer

One group of researchers, led by Richard G. Pestell, M.D., Ph.D. (Thomas Jefferson University, Philadelphia, PA) has been studying expression of CCR5 and its ligand CCL5 (also known as RANTES) and their role in breast cancer biology and pathogenesis. Their report of this study was published in the August 1, 2012 issue of Cancer Research.

These researchers first studied the combined expression of CCL5 and CCR5 in various subtypes of breast cancer, by analyzing a microarray database of over 2,000 human breast cancer samples. (The database was compiled from 27 independent studies). They found that CCL5/CCR5 expression was preferentially expressed in the basal and HER-2 positive subpopulations of human breast cancer.

Because of the high level of unmet medical need in treatment of basal breast cancer, the authors chose to focus their study on this breast cancer subtype. As the researchers point out, patients with basal breast cancer have increased risk of metastasis and low survival rates. Basal tumors in most cases do not express either androgen receptors, estrogen receptors (ERs), or HER-2. They thus cannot be treated with such standard receptor-targeting breast cancer therapeutics as tamoxifen, aromatase inhibitors, or trastuzumab. The only treatment options are cytotoxic chemotherapy, radiation, and/or surgery. However, these treatments typically results in early relapse and metastasis.

The basal breast cancer subpopulation shows a high degree of overlap with triple-negative (TN) breast cancer. We discussed TN breast cancer, and research aimed at defining subtypes and driver signaling pathways, in our August 2, 2011 article on this blog. In that article, we noted that TN breast cancers include two basal-like subtypes, at least according to one study. Other researchers found that 71% of TN breast cancers are of basal-like subtype, and that 77% of basal-like tumors are TN. A good part of the problem is that there is no accepted definition of basal-like breast cancers, and how best to define such tumors is controversial. However, both the TN and the basal subpopulations are very difficult to treat and have poor prognoses. It is thus crucial to find novel treatment strategies for these subpopulations of breast cancer.

Dr. Pestell and his colleagues therefore investigated the role of CCL5/CCR5 signaling in three human basal breast cancer cell lines that express CCR5. They found that CCL5 promoted intracellular calcium (Ca2+) signaling in these cells. The researchers then determined the effects of CCL5/CCR5 signaling in promoting in vitro cell invasion in a 3-dimensional invasion assay. For this assay, the researchers assessed the ability of cells to move from the bottom well of a Transwell chamber, across a membrane and through a collagen plug, in response to CCL5 as a chemoattractant. The researchers found that CCR5-positive cells, but not CCR5-negative cells, showed CCL5-dependent invasion.

The researchers then studied the ability of CCR5 inhibitors to block calcium signaling and in vitro invasion. The agents that they investigated were maraviroc and vicriviroc. Maraviroc (Pfizer’s Selzentry/Celsentri) is the marketed HIV-1 entry inhibitor that we discussed in our October 31, 2013 articleVicriviroc is an experimental HIV-1 inhibitor originally developed by Schering-Plough. Schering-Plough was acquired by Merck in 2009. Merck discontinued development of vicriviroc because the drug failed to meet primary efficacy endpoints in late stage trials.

Pestell et al. found that maraviroc and vicriviroc inhibited calcium responses by 65% and 90%, respectively in one of their CCR5-positive basal cell breast cancer lines, and gave similar results in another cell line. The researchers then found that  in two different CCR5-positive basal breast cancer cell lines, both maraviroc and vicriviroc inhibited in vitro invasion.

The researchers then studied the effect of maraviroc in blocking in vivo metastasis of a CCR5-positive basal cell breast cancer line, which had been genetically labeled with a fluorescent marker to facilitate noninvasive visualization by in vivo bioluminescence imaging (BLI). They used a standard in vivo lung metastasis assay, in which cells were injected into the tail veins of immunodeficient mice, and mice were treated by oral administration with either maraviroc or vehicle. The researchers then looked for lung metastases. They found that maraviroc-treated mice showed a significant reduction in both the number and the size of lung metastases, as compared to vehicle-treated mice.

In both in vitro and in vivo studies, the researchers showed that maraviroc did not affect cell viability or proliferation. In mice with established lung metastases, maraviroc did not affect tumor growth. Maraviroc inhibits only metastasis and homing of CCR5-positive basal cell breast cancer cells, but not their viability or proliferation.

As the result of their study, the researchers propose that CCR5 antagonists such as maraviroc and vicriviroc may be useful as adjuvant antimetastatic therapies for breast basal tumors with CCR5 overexpression.  They may also be useful as adjuvant antimetastatic treatments for other tumor types where CCR5 promotes metastasis, such as prostate and gastric cancer.

As usual, it must be emphasized that although this study is promising, it is only a preclinical proof-of-principle study in mice, which must be confirmed by human clinical trials.

In an October 25, 2013 Reuters news story, it was revealed that Citi analysts believe that Merck will take vicriviroc into the clinic  in cancer patients in 2014. Citi said that it expected vicriviroc to be tested in combination with “a Merck cancer immunotherapy” across multiple cancer types, including melanoma, colorectal, breast, prostate and liver cancer. (We discussed Merck’s promising cancer immunotherapy agent lambrolizumab/MK-3475 in our June 25, 2013 blog article. But the Merck agent to be tested together with vicriviroc was not disclosed in the Reuters news story.)

Despite this news story, Merck said that it had not disclosed any plans for clinical trials of vicriviroc in cancer.

The CXCR1 antagonist reparixin as a potential treatment for breast cancer

In our In April 2012 book-length report, “Advances in the Discovery of Protein-Protein Interaction Modulators” (published by Informa’s Scrip Insights), we discussed the case of the allosteric chemokine receptor antagonist reparixin (formerly known as repertaxin). Reparixin has been under developed by Dompé Farmaceutici (Milan, Italy). This agent targets both CXCR1 and CXCR2, which are receptors for interleukin-8 (IL-8). IL-8 is a well-known proinflammatory chemokine that is a major mediator of inflammation. As we discussed in our report, reparixin had been in Phase 2 development for the prevention of primary graft dysfunction after lung and kidney transplantation. However, it failed in clinical trials.

Meanwhile, researchers at the University of Michigan (led by Max S. Wicha, M.D., the Director of the University of Michigan Comprehensive Cancer Center) and at the Institut National de la Santé et de la Recherche Médicale (INSERM) in France were working to define a breast cancer stem cell signature using gene expression profiling. They found that CXCR1 was among the genes almost exclusively expressed in breast cancer stem cells, as compared with its expression in the bulk tumor.

IL-8 promoted invasion by the cancer stem cells, as demonstrated in an in vitro invasion assay. The CXCR1-positive, IL-8 sensitive cancer stem cell population was also found to give rise to many more metastases in mice than non-stem cell breast tumor cells isolate from the same cell line. This suggested the hypothesis that a CXCR1 inhibitor such as reparixin might be used as an anti-stem cell, antimetastatic agent in the treatment of breast cancer.

Dr. Wicha and his colleagues then studied the effects of blockade of CXCR1 by either reparixin or a CXCR1-specific blocking antibody on  bulk tumor and cancer stem cells in two breast cancer cell lines. The researchers found in in vitro studies that treatment with either of these two CXCR1 antagonists selectively depleted the cell lines of cancer stem cells (which represented 2% of the tumor cell population in both cell lines).

This depletion was followed by the induction of massive apoptosis of the bulk, non-stem tumor cells. This was mediated via a bystander effect, in which CXCR1-inhibited stem cells produce the soluble death mediator FASL (FAS ligand). FASL binds to FAS receptors on the bulk tumor cells, and induces an apoptotic pathway in these cells that results in their death.

In in vivo breast cancer xenograft models, the researchers treated tumor-bearing mice with either the cytotoxic agent docetaxel, reparixin, or a combination of both agents. Docetaxel treatment–with or without reparixin–resulted in a significant inhibition of tumor growth, while reparixin alone gave only a modest reduction in tumor growth. However, treatment with docetaxel alone gave no reduction (or an increase) in the percentage of stem cells in the tumors, while reparixin–either alone or in combination with docetaxel–gave a 75% reduction in the percentage of cancer stem cells. Moreover, in in vivo metastasis studies in mice, reparixin treatment gave a major reduction in systemic metastases. These results suggest that reparixin may be useful in eliminating breast cancer stem cells and in inhibiting metastasis and thus preventing recurrence of cancer in patients treated with chemotherapy.

As we discussed in our 2012 report, Dr. Wicha’s research on reperixin might represent an opportunity for Dompé to repurpose reperixin for cancer treatment. Since the publication of the 2012 report, Dompé has been carrying out a Phase 2 pilot study of reparixin in patients diagnosed with early, operable breast cancer, prior to their treatment via surgery. The goal of this study is to investigate if cancer stem cells decrease in two early breast cancer subgroups (estrogen receptor-positive and/or progesterone receptor positive/HER-2-negative, and estrogen receptor negative/progesterone receptor negative/HER-2-negative). The goal is to compare any differences between the two subgroups in order to better identify a target population.

Dompé has thus begun the process of clinical evaluation of reparixin for the new indication–treatment of breast cancer in order to inhibit metastasis and prevent recurrence.

Conclusions

Researchers have found promising evidence that at least two chemokine/chemokine receptor combinations may be involved in cancer stem cell biology and thus in the processes of metastasis and cancer recurrence. In at least one case–and perhaps both–companies are in the early stages of developing small-molecule chemokine receptor antagonists for inhibiting breast cancer metastasis and recurrence. Such a strategy might be applicable to other types of cancer as well.

As discussed by Wicha et al., in immune and inflammatory processes, chemokines serve to facilitate the homing and migration of immune cells. In the case of cancer, chemokines may act as “stemokines”, by facilitating the homing of cancer stem cells in the process of metastasis. Other chemokines and their receptors than those discussed in this article may be involved in other types of cancer, and may carry out similar “stemokine” functions.

Since around 90% of cancer deaths are due to metastasis, and since effective treatments for metastatic cancers are few, this is a potentially important area of cancer research and drug development.

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As the producers of this blog, and as consultants to the biotechnology and pharmaceutical industry, Haberman Associates would like to hear from you. If you are in a biotech or pharmaceutical company, and would like a 15-20-minute, no-obligation telephone discussion of issues raised by this or other blog articles, or of other issues that are important to  your company,  please contact us by phone or e-mail. We also welcome your comments on this or any other article on this blog.

Japanese group to take induced pluripotent stem (iPS) cell-derived retinal cells into the clinic

 

Stem cells. Source: http://bit.ly/ZnYuFS

Stem cells. Source: http://bit.ly/ZnYuFS

As reported in Nature News on 27 February 2013 ophthalmologist Masayo Takahashi M.D., Ph.D. and her colleagues at the RIKEN Center for Developmental Biology (Kobe, Japan), plan to submit an application to the Japanese health ministry for a clinical study of induced pluripotent stem cell (iPS)-derived cells. The researchers planned to submit their application in March 2013; if approved, they could begin recruiting patients as early as September.

The author of the Nature News article is Nature‘s Asian-Pacific Correspondent, David Cyranoski, who is based in Tokyo.

The researchers plan to treat approximately six people with severe age-related macular degeneration (AMD). Specifically, the researchers are targeting “wet” AMD, in which angiogenic blood vessels invade the retina, destroying the retinal pigment epithelium (RPE) that supports the light-sensitive photoreceptors.

AMD is a common cause of blindness that affects at least 1% of adults over 50. Wet AMD can be treated with anti-vascular endothelial growth factor (anti-VEGF) agents such as ranibizumab (Genentech/Novartis’ Lucentis), pegaptanib (Gilead/OSI/Pfizer’s Macugen), aflibercept (Sanofi/Regeneron’s Eylea), and–off-label–small doses of the anticancer agent bevacizumab (Genentech/Roche’s Avastin). However, the use of these agents requires that they be injected repeatedly into the eye.

According to the Nature News article, Dr. Takahashi and her colleagues will take an upper arm skin sample the size of a peppercorn, and transform the cells from this sample into iPS cells by using specific proteins. They will then add other factors that will induce differentiation of the iPS cells into retinal cells. Then a small sheet of these retinal cells will be placed under the damaged area of the retina, where they are expected to grow and repair the damaged RPE.

Although the researchers would like to demonstrate efficacy of this treatment in ameliorating the disease, the main focus of these studies will be on safety. Safety concerns include immunogenicity of the transplanted cells, and formation of tumors if the transplanted cells multiply uncontrollably. Another concern is that the transplanted cells might fail to engraft, and to integrate with the host tissue. It is also possible that the RPE identity of the transplanted and differentiated cells might not be stable over time.

With respect to these concerns, studies published by Japanese researchers in 2013 (Araki et al.) and reviewed in a recent Nature News article contradicted the original mouse studies that suggested that syngeneic or autologous iPS cells might be immunogenic.

With respect to tumor formation, Dr. Takahashi’s proposed studies will involve using only a few iPS cells, thus reducing the probability of forming tumors. Moreover, since the eye is relatively accessible, any tumors would be relatively easy to remove.

In addition, Dr, Takahashi has presented preclinical studies at conferences, which indicate that her iPS cells do not form tumors in mice and are safe in non-human primates. (Dr. Takahashi’s preclinical studies have also been submitted for publication.) The studies have provided reassurance of the cells’ safety to at least some leading researchers, such as Martin Pera (University of Melbourne, Australia) and George Daley (Harvard Medical School, Boston MA).

However, other researchers believe that to take iPS cell-derived tissue into the clinic at this time is premature. Robert Lanza, M.D., the chief scientific officer at Advanced Cell Technology (ACT) (Santa Monica CA) says that he cannot imagine regulatory agencies permitting studies such as Dr. Takahashi’s without years of preclinical testing.

As mentioned in the Nature News article, ACT has a program involving human embryonic stem cell (hES cell) and iPS-derived platelets for transfusion. This program is in the preclinical stage. Since platelets lack a nucleus and cannot form tumors, it is inherently less risky that clinical programs of stem-cell (and especially iPS cell) derived differentiated cells that have nuclei.

Dr. Takahashi’s proposed study of her therapy in humans is considered a “clinical study”, not a clinical trial. In Japan’s regulatory system, clinical studies are less tightly regulated than clinical trials. However, a clinical study cannot by itself lead to approval of a potential therapeutic for clinical use as a treatment. If Dr. Takahashi’s clinical study data is positive, that might attract investors or help her to get approval for a formal clinical trial. As in the U.S. or Europe, successful clinical trials will be required if Dr. Takahashi’s cellular therapy is ever to be used to treat patients.

Dr. Takahashi’s clinical study was approved by institutional review boards at both the natural sciences institute RIKEN in Wako and the Institute of Biomedical Research and Innovation in Kobe, where the surgical procedures will be carried out. Final approval will depend on the action of a committee of the Japanese Ministry of Health, Labour and Welfare. If Dr. Takahashi wins approval by September 2013 as expected, it will take another eight months to produce the tissue implants needed for her clinical study.

Other retinal repair programs involving human embryonic stem cell-derived RPE cells

Dr. Takahashi’s research does not represent the only RPE cell-based retinal repair program now being developed. There are at least two others, both of which are based on hES cells, not iPS cells.

As was not mentioned in the Nature News article, ACT has Phase 1 trials underway in its own RPE retinal repair program. ACT’s RPE cells are derived from human embryonic stem cells (hES cells). The company’s Phase 1 safety studies are in Stargardt’s Macular Dystrophy (SMD) and in dry AMD (which results from atrophy of the RPE layer, and causes vision loss through loss of photoreceptors in the central part of the eye. Dry AMD does not involve angiogenesis.). SMG is a rare inherited juvenile macular degeneration.

In February 2012, Dr. Lanza and his academic collaborators at the University of California at Los Angeles published a preliminary report of their clinical studies in dry AMD and SMG. In this study, one patient with each of the two conditions was treated with hES cell-derived RPE cells. The hES cell-derived RPE cells showed no signs of hyperproliferation, tumorigenicity, ectopic tissue formation, or apparent rejection after 4 months. Neither patient showed loss of vision, and there were signs of improvement of vision. As a result of this very preliminary study, the researchers decided in the design of future clinical studies to treat patients earlier in the disease processes, potentially increasing the likelihood of improvement of vision.

The other RPE-based retinal repair program is a collaborative effort between Neusentis (A Cambridge U.K. and Durham NC-based Pfizer research unit) and “The London Project” which was formed by Professor Pete Coffey [Institute of Ophthalmology, University College London (UCL)] and his collaborator Lyndon da Cruz (Moorfields Eye Hospital) to develop cellular therapies for all types of AMD. The London Project began collaborating with Pfizer in 2008; this collaboration was brought under the aegis of Neusentis when it was formed in 2011. Research is based on RPE cells derived from hES cells.

The Neusentis/London Project group claims to have developed a deep understanding of the biology of hEC cell-derived RPE cells, and to have worked out methods of producing enough RPE cells under GMP conditions to support clinical studies. They also claim to have developed a clear approach to establishing the safety of the therapy via preclinical studies. The collaborative group is now moving towards clinical studies of their therapies, which they “hope to achieve in the not too distant future”.

As we discussed in our February 15, 2011 article on this blog, Pfizer–as of February 1, 2011–closed its Memorial Drive laboratory in Cambridge, MA. This laboratory housed most of Pfizer’s regenerative medicine research, as well as the company’s RNAi therapeutics research group. However, as we said in this article, Pfizer was folding its Cambridge, UK regenerative medicine group–“which had been focusing on development of preclinical embryonic stem (ES) cell-based ophthalmology therapies, in collaboration with the University of London”–into a “new pain and sensory disorder research unit”. According to its website, Neusentis, which was formed in 2011, has “a particular focus on pain and sensory disorders”.

Japanese government backing for iPS cell research and commercialization

Japan has been a hotbed of iPS cell research, since these cells were first produced by Shinya Yamanaka, M.D. Ph.D. (Kyoto University) in 2006. He received The Nobel Prize in Physiology or Medicine in 2012 for his work on iPS cells. The co-recipient of the Prize, Sir John B. Gurdon, successfully cloned a frog using intact nuclei from the somatic cells of a Xenopus tadpole back in 1958. The two scientists received the 2012 Prize “for the discovery that mature cells can be reprogrammed to become pluripotent”. Since their discovery, iPS cells have been employed in such areas as basic research, disease modeling, and drug screening. (Follow this link for a recently-published example of the potential use of iPS cells in designing personalized treatments for Alzheimer’s disease.)

In 2013, as part of its stimulus package, the Japanese government has been providing generous funding for iPS research. This funding includes ¥700 million for a cell-processing centre at the Foundation for Biomedical Research and Innovation in Kobe, mainly to support Dr. Takahashi’s regenerative medicine research. In general, the iPS funding under the stimulus is aimed at moving university research on iPS cells into commercial and medical applications.

Moreover, according to Mr. Cyranoski’s 27 February 2013 Nature News article, the Japanese parliament is expected to rule by late June 2013 on a provision of a revised drug law, which would fast-track iPS-based therapies that appear to be effective in phase 2 or phase 3 trials. However, the success of the Japanese government’s efforts to accelerate commercialization of iPS-based therapies may depend in part on the success of Dr. Takahashi’s clinical research.

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As the producers of this blog, and as consultants to the biotechnology and pharmaceutical industry, Haberman Associates would like to hear from you. If you are in a biotech or pharmaceutical company, and would like a 15-20-minute, no-obligation telephone discussion of issues raised by this or other blog articles, or an initial one-to-one consultation on an issue that is key to your company’s success, please contact us by phone or e-mail. We also welcome your comments on this or any other article on this blog.

Is gene therapy emerging from technological prematurity?

 

[For updated information on gene therapy, please see our articles on this blog dated November 16, 2015 and November 23, 2015.]

The idea of gene therapy has been around since at least the early 1970s. In 1972, an article by Theodore Friedmann and Richard Roblin advanced the concept of treating genetic diseases by replacing defective endogenous DNA with exogenous “good” DNA. However, these authors concluded that it was premature to begin gene therapy studies in humans because of lack of basic knowledge of genetic regulation and of genetic diseases, and for ethical reasons. They did, however, propose that studies in cell cultures and in animal models aimed at development of gene therapies be undertaken. Such studies–as well as abortive gene therapy studies in humans–had already begun as of 1972.

In the 1970s and 1980s, researchers applied such technologies as recombinant DNA and development of viral vectors for transfer of genes to cells and animals to the study and development of gene therapies. In the 1990s, several research groups conducted FDA-approved human studies of gene therapies, based on this technological development and increased knowledge of genetic diseases. However, several notable failures put a damper on development of gene therapies.

The most notorious case was the 1999 death of 18-year-old Jesse Gelsinger, who had ornithine transcarbamylase deficiency. In a clinical trial at the University of Pennsylvania, he was injected with an adenoviral vector carrying a corrected gene to test the safety of use of this procedure. He suffered a massive immune response triggered by the use of the viral vector, and died four days later. As a result of this incident, the FDA suspended several gene therapy clinical trials pending review of ethical and scientific/medical practices.

This incident, as well as the failure of other clinical studies put a severe damper on the gene therapy field, especially attempts at commercialization of gene therapies and of building biotech companies specializing in this field. Nevertheless, between 2003 and 2012, researchers have been quietly developing more advanced gene therapy technologies and conducting clinical studies, with some success. Entrepreneurs have also been building gene therapy specialty companies to commercialize this research.

Now comes the July 20, 2012 ruling by the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) that recommends marketing of a gene therapy known as Glybera (alipogene tiparvovec) as a treatment for the ultra-rare genetic disease lipoprotein lipase deficiency (LPLD) under exceptional circumstances. LPLD affects no more than two people per million in the general population. People with LPLD cannot break down fat, and must manage their disease with a restricted diet. However, dietary management is difficult, and a high proportion of patients suffer life-threatening pancreatitis.

Glybera is being developed by a small Dutch biotech called uniQure biopharma. Glybera consists of an adeno-associated virus (AAV) vector that carries the gene for LPL. Therapy consist of multiple intramuscular injections of the product, resulting in the delivery of functional LPL genes to muscle cells.

The European Commission (EC) generally follows the recommendations of the CHMP. At the time of the CHMP ruling, uniQure expected initial approval from the EC within 3 months of that decision. Articles published in Nature and Nature Biotechnology in the late September/early October 2012 period anticipate EC approval in a mater of days or a week or two.

If it is approved in the European Union (EU) as expected, that approval will require that Glybera be offered through dedicated centers of excellence with expertise in treating LPLD, and by specially trained doctors to ensure ongoing safety of the therapy. uniQure is now preparing to apply for approval in the U.S., Canada, and other markets.

uniQure is also using its AAVvector platform as the basis of a series of gene therapies for other rare diseases, including porphyria and Sanfilippo B, as well as what it calls “disruptive innovation” products for such diseases with established treatments as Parkinson’s disease and Hemophilia B.

Does the expected approval of Glybera herald the beginning of a new era of gene therapy?

Jörn Aldag, the CEO of uniQure, believes that “just like antibodies, gene therapy will one day be a mainstay in clinical practice.” Although uniQure is concentrating its development efforts in the area of rare diseases, Mr Aldag believes that “the potential of gene therapy stretches far beyond rare diseases.” He cites a December 2011 publication in the New England Journal of Medicine, which describes a study in which 6 patients with hemophilia B were treated (via peripheral-vein infusion) with an AAV vector carrying a proprietary (codon-optimized) human factor IX (FIX) transgene. This treatment resulted in FIX transgene expression at levels sufficient to improve the bleeding phenotype, with few side effects, all of which were easily treatable. Hemophilia B, the second most common form of hemophilia, is nowhere as rare as the ultra-rare disease LPLD. Some of the patients treated with this gene therapy were able to discontinue prophylactic treatment with FIX. uniQure’s program in gene therapy for Parkinson’s disease exemplifies the companies efforts to move beyond the rare disease area.

However, others are not so sure that the approval of Glybera will usher in a new era of gene therapy, at least not in the near future. In particular, Fulvio Mavilio, Ph.D., Scientific Director of Genethon (Evry, France) (a non-profit center for development of gene therapies), does not believe that a large number of patients will be treated with gene therapies in the near future.

Dr. Mavilio cites the “relatively rich pipeline of gene therapy candidates already in human trials,” which  “suggests there may be a surge in the number of gene therapies approved over the next few years.” However, most of the gene therapy clinical candidates are for ultra-rare single Mendelian genetic deficiencies, with similar frequencies in the population to LPLD. The hemophilias (hemophilia A, 1 in every 5,000 male babies diagnosed per year in the US; hemophilia B, 1 in every 30,000 male babies per year) are the most common diseases to be addressed by gene therapies now in clinical development, according to Dr. Mavilio’s article. Moreover, Dr. Mavilio–as well as others–expects safety issues to thwart or slow the development of at least some gene therapies, which will also face competition from existing enzyme replacement therapies similar to those developed by Genzyme.

No gene therapy has yet been approved in the U.S. However, the FDA has established a system that facilitates faster reporting of adverse events in human gene transfer trials and that tracks such trials that are taking place. And uniQure has been planning to work with the FDA to seek U.S. approval of Glybera.

Gene therapy as a “premature technology”

Gene therapy fits the model of a “premature technology”. A field of biomedical science is said to be scientifically or technologically premature when despite the great science and exciting potential of the field, any practicable therapeutic applications are in the distant future, due to difficult hurdles in applying the technology. Moving a premature technology up the development curve requires the development of enabling technologies that can allow researchers and product developers to overcome the hurdles.

The classic case of a premature technology that has moved up the development curve and become successful is the field of therapeutic monoclonal antibodies (MAbs). We discussed the history of MAbs in detail in our September 28, 2009 blog article. The first ever MAb to enter the market, Johnson & Johnson’s Orthoclone OKT3 was approved in 1986 for use in transplant rejection. However, this drug can only be used once in a patient due to its immunogenicity. There were not any further approvals of MAb drugs until 1994. The numerous MAbs that have entered the market since then were made possible by the development of enabling technologies that overcame the immunogenicity problem. Several of these products are highly successful, and there is a rich pipeline of MAb therapeutics now in development.

Commentators on recent developments in gene therapies, including the ones we cited earlier, compare Glybera to Orthoclone OKT3. Given the limited number of patients for whom Glybera is appropriate, and especially given the exceptional circumstances under which Glybera may be prescribed and used, they are likely to be right.

bluebird bio

Among the many companies that are developing gene therapies, one has been singled our for special attention lately. That is bluebird bio (Cambridge, MA). On September 19, 2012, bluebird bio was named to FierceBiotech’s 2012 “Fierce 15”. By naming bluebird bio to the Fierce 15, FierceBiotech is designating the company as “one of the most promising private biotechnology companies in the industry”. “The Fierce 15 celebrates the spirit of being ‘fierce’ – championing innovation and creativity, even in the face of intense competition.” bluebird bio was formerly known as Genetix Pharmaceuticals.

bluebird bio has developed a novel gene therapy platform, in which a wild-type version of a patient’s disease-causing gene, carried in a lentiviral vector, is inserted into autologous CD34+ bone marrow-derived stem cells. These transformed autologous stem cells are then transfused into the patient. This eliminates potential complications associated with donor cell transplantation, or with systemic administration of gene therapy vectors.

bluebird bio’s platform thus represents both a gene therapy technology and an adoptive cellular transfer (ACT) technology. We have discussed ACT technologies (in this case, for immunotherapy for cancer) in a previous article on this blog. Since some of these technologies involve genetically-engineered autologous T cells, they may also be thought of as representing both ACT and a kind of gene therapy. (However, the “gene therapy” in these cases is not directed toward repairing a genetic disease, as  in classic gene therapy.)

For a list of links to bluebird bio publications using this and other gene therapy technologies, see the publications page of the company’s website.

bluebird bio is preparing a pivotal Phase 2/Phase 3 study of its lead treatment, for childhood cerebral adrenoleukodystrophy (ALD). The company is also in Phase 1/2 trials for its beta-thalassemia therapy, and in Phase 1 for its sickle cell disease program.

ALD is a rare, inherited neurological disorder that affects one in every 21,000 boys worldwide. It can cause damage to neural myelin sheaths in the brain, and progressive dysfunction of the adrenal glands. ALD is the disease that was featured in the 1992 movie Lorenzo’s Oil. Beta-thalassemias affect one in every 100,000 people throughout the world, with the greatest prevalence in the Mediterranean basin and in South Asia. Sickle cell disease mainly affects sub-Saharan Africans and their decedents, as well as residents of other areas with a high prevalence of malaria. Its prevalence in the U.S. is around 1 in 5,000, in France one in 2,415, and in the U.K. 1 in 2,000.

Thus the diseases that constitute the current focus of bluebird bio are much more common than is LPLD, the target of Glybera. The prevalence of the diseases that are the current targets of bluebird bio resemble the prevalence of “rare diseases” targeted by current Genzyme therapies–Gaucher’s disease (1 in 40,000 in the U.S.), and lysosomal storage disorders (individual diseases, an incidence of less than 1:100,000; total lysosomal storage diseases, an incidence of about 1 in 5,000 to 1 in 10,000).

bluebird bio’s business thus lies in the intersection between gene therapy and the “rare diseases” that are the main targets of an increasing number of biotechs and Big Pharmas.

bluebird bio is backed by several venture capital firms, notably TVM Capital, Third Rock Ventures, and Forbion Capital Partners, as well as by Genzyme (which is now part of Sanofi) and Shire. According to the Fierce 15 press release, bluebird bio is also “exploring a potential set of partnerships”.

Conclusions

In the long history of gene therapy, the expected approval in Europe of Glybera represents a key milestone–if indeed the EC approves the therapy as expected. However, given the very limited number of patients for whom Glybera is appropriate, and the exceptional circumstances under which Glybera may be prescribed and used, this milestone may be analogous to the approval of Orthoclone OKT3. Thus there may be a lag between the approval of the first gene therapy and the beginning of a more steady stream of gene therapy approvals.

However, bluebird bio’s cellular approach may enable it to circumvent many of the pitfalls of gene therapy. Other gene therapy companies may also possess enabling technologies that can help drive the gene therapy field up the technology development curve.

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As the producers of this blog, and as consultants to the biotechnology and pharmaceutical industry, Haberman Associates would like to hear from you. If you are in a biotech or pharmaceutical company, and would like a 15-20-minute, no-obligation telephone discussion of issues raised by this or other blog articles, or an initial one-to-one consultation on an issue that is key to your company’s success, please contact us by phone or e-mail. We also welcome your comments on this or any other article on this blog.

Obesity therapeutics revisited

 

Brown fat in humans

The CNS-targeting “Class of 2010” drugs

We have not had an article on obesity therapeutics on this blog since February 1, 2011. At that time, we had an article entitled “That’s all, folks!”, complete with the old Warner Brothers Porky Pig graphic. As of that date, all three of the obesity drug candidates that came up for FDA review in 2010-–Vivus’ Qnexa, Arena’s lorcaserin, and Orexigen’s Contrave–were rejected for approval by the FDA, and sent back for further studies. Also in 2010, the then-marketed antiobesity drug sibutramine (Abbott’s Meridia) was withdrawn from the market at the FDA’s request. All of these agents targeted the central nervous system (CNS).

Concern about long-term safety was the major consideration in the rejection of the NDAs for Qnexa, lorcaserin, and Contrave, and safety issues were also the reason for the withdrawal of sibutramine. That left only one anti-obesity drug approved by the FDA for long term use– orlistat (Roche’s Xenical), with no new drugs In sight. The outlook for obesity drugs was gloomy indeed.

However, as of May 2012, after the further studies prescribed by the FDA in 2010, two of the obesity drug Class of 2010–Qnexa and lorcaserin have received positive votes by the FDA’s Endocrinologic and Metabolic Drugs Advisory Committee, and are awaiting final FDA action later this year. Contrave, after a February 6, 2012 agreement with the FDA, appears to be on track for possible NDA resubmission in 2014.

We shall continue to follow progress with the consideration of the resubmitted NDAs for Qnexa and lorcaserin in 2012.

Novel approaches based on the physiology of brown fat

Meanwhile, there is renewed interest in earlier-stage, alternative obesity therapies based on the physiology of brown fat, also known as brown adipose tissue (BAT). The May 1, 2012 issue of The Scientist has an article by the publication’s associate editor Edyta Zielinska entitled “Treating Fat with Fat: Is brown fat ready for therapeutic prime time?”  This article focuses on new discoveries in brown fat physiology, and on entrepreneurial companies that are attempting to develop these discoveries into therapeutics.

On the Biopharmconsortium Blog, we also have an article on brown fat physiology and companies attempting to develop therapeutics based on these findings. The article is dated November 17, 2010. As we state in that article, brown fat researchers and companies are seeking to develop therapeutics that work by increasing energy expenditure, rather than the usual approaches of decreasing appetite (as with the Class of 2010 CNS-targeting antiobesity drugs) or blocking absorption of fat in the gut (as with orlistat).

More specifically, these researchers and companies intend to discover and develop drugs that increase the amount and/or activity of BAT, which is a type of mitochondria-rich adipose tissue that oxidizes fat and dissipates the resulting energy as heat rather than storing it. The mitochondrial protein UCP1 (uncoupling protein 1) is the key biomolecule that makes this process possible. BAT has long been known to be central to non-shivering thermogenesis in rodents, for example to maintain body temperature when they are exposed to cold.

Until recently, researchers believed that in humans, significant populations of BAT cells were found only in infants. However, in recent years researchers found that adult humans possess reservoirs of brown fat in the neck region and other areas of the upper body as well as in skeletal muscle. Adult human BAT can be stimulated by acute exposure to cold and via the sympathetic nervous system, and by various pharmacological agents.

Energesis’ autologous brown adipose tissue transplantation program

Our November 17, 2010 article in particular focused on the Boston-based early-stage company Energesis Pharmaceuticals. Energesis was confounded by Olivier Boss, PhD (formerly of Sirtris Pharmaceuticals), Brian Freeman, MD (former Venture Partner at GreatPoint Ventures), and Jean-Paul Giacobino, MD (Professor Emeritus, University of Geneva Medical School, Switzerland). Dr. Boss serves as Energesis’ Chief Scientific Officer, and Dr. Freeman as its Chief Operating Officer.

Energesis is also mentioned in the new article in The Scientist. According to that article, Energesis is using brown fat “stem cells” (which are precursor cells found in skeletal muscle that can differentiate into either muscle or brown fat) to identify novel targets that activate brown fat. Energesis researchers then work to discover new drugs that address these targets. They are also investigating transplantation of brown fat “stem cells” as an obesity therapy.  According to the article, Energesis is planning to initiate clinical trials of their therapies within 2 to 3 years.

In October 2011, Energesis was awarded a U.S. Department of Defense Small Business Technology Transfer (STTR) grant to develop therapeutics based on autologous BAT transplantation. The project is a feasibility study to define a source and culture system for the generation of human BAT for autologous transplantation therapy. It will involve isolating and characterizing the best brown adipocyte progenitor sub-population from human muscle biopsies, expanding these cells, and establishing the optimal culture conditions for in vitro differentiation to generate approximately 50 grams of BAT cells for transplantation. This project is being conducted in collaboration with Dr. Stephen R. Farmer of the Boston University School of Medicine; Boston University is Energesis’ academic partner on the STTR grant.

According to a January 31, 2012 article in Wired magazine, the U.S. Army’s interest in Energesis’ technology is the result of the growing incidence of overweight and obesity in the Army’s recruit pool, as in young Americans in general. The Army is funding the Energesis/Boston University researchers in the hopes of using autologous BAT transplantation to boost weight loss in military personnel.

According to Brian Freeman, an autologous cell transplantation therapy might also be commercialized for treatment of severely obese individuals in lieu of bariatric surgery. Such an autologous cellular therapy would be analogous to the FDA-approved Genzyme cell transplantation therapy products Carticel and Epicel. It may be easier and faster for Energesis to gain FDA approval for an autologous BAT transplantation product than to develop and gain approval for a drug based on the company’s BAT research. Energesis will therefore pursue both drug discovery and autologous cell transplantation programs, with the strategy to gain early approval and revenues for a transplantation product while it continues to pursue drug discovery and development. Success in development of an autologous transplantation product should also boost the company’s prospects for funding, which would enable its wider R&D programs.

Other approaches to brown adipose tissue-based therapies

The May 1 2012 Edyta Zielinska article begins with a discussion of metabolic diseases start-up Ember Therapeutics. As stated in the article, Ember was founded by Third Rock Ventures partner Lou Tartaglia, a scientist by background who was formerly the Vice President of Metabolic Diseases at Millennium Pharmaceuticals. Ember was launched with $34 million in financing from Third Rock. The company plans to work both on therapeutics based on BAT biology, and on developing a new generation of safer insulin sensitizers for treatment of type 2 diabetes. The latter area of focus is based on studies by Ember scientific founders Dr. Bruce Spiegelman (Dana-Farber Cancer Institute and Harvard Medical School, Boston MA) and Patrick R. Griffin (Scripps Research Institute, Scripps FL) We discussed that work on our blog in an August 29, 2010 article, which was followed by two additional articles on September 16, 2010 and September 21, 2011.

In the January 11 2012 issue of Nature, Dr. Spiegelman’s group reported the discovery of a myokine hormone (i.e., a cytokine produced by muscle cells), which the researchers named irisin. Irisin is named after the Greek goddess Iris, the messenger of the gods. It acts on white adipose cells in culture and in vivo to stimulate what appears to be development into brown fat-like cells. Specifically, irisin stimulates expression of UCP1 and an array of other brown fat genes. Mildly increased blood levels of irisin results in an increase in energy expenditure in mice with no changes in movement or food intake, as would be expected with an increase in brown fat levels. This results in improvements in obesity and glucose homeostasis. Exercise increases levels of blood irisin in mice and humans, leading to the hypothesis that irisin is an “exercise hormone” that mediates at least some of the beneficial metabolic effects of exercise. Irisin is therefore a potential therapeutic for metabolic diseases such as type 2 diabetes and obesity. Ember entered into an exclusive license agreement with Dana-Farber Cancer Institute for the irisin technology, and is optimizing and developing a proprietary molecule based on this technology. This molecule is designed to augment and activate the body’s brown fat. This research constitutes the company’s lead BAT biology program.

On March 28, 2012, Ember also exclusively licensed technology from the Joslin Diabetes Center (Boston, MA) covering bone morphogenetic protein 7 (BMP7), and its role in BAT development. The role of BMP7 in BAT biology was discovered by Ember scientific co-founder C Ronald Kahn, M.D. and his colleagues, who published their findings in Nature in 2008.

In addition to its lead irisin program, Ember is developing a pipeline of biologics (including those based on BMP7) and small molecules designed to increase BAT levels and to activate BAT-specific pathways. According to the article in The Scientist, among the pathways being investigated by Ember are those involving the PRDM-16 transcription factor and FoxC2.

Zafgen’s beloranib (ZGN-433)

Meanwhile, the other obesity start-up founded by Brian Freeman, Zafgen (Cambridge, MA) has been making progress in developing its lead drug candidate, beloranib (ZGN-433). Beloranib, a methionine aminopeptidase 2 (MetAP2) inhibitor, was originally discovered by the Korean company CKD Pharmaceuticals, and was being developed as an angiogenesis inhibitor for treatment of solid tumors. However, the drug was poorly efficacious for this indication in animal models. At much lower concentrations, however, beloranib exerts an antlobesity effect. Zafgen therefore licensed the compound from CKD, and has been developing it as an agent to induce weight loss in severely obese patients.

Beloranib targeting of MetAP2 in vivo results in downregulation of signal transduction pathways within the liver that are involved in the biosynthesis of fat. Animals or humans treated with the drug oxidize fat to form ketone bodies, which can be used as energy or are excreted from the body. The result is breakdown of fat cells and weight loss. Obese individuals do not usually have the ability to form ketone bodies.

In January 2011, Zafgen reported top-line data from a Phase Ib multiple-ascending dose study in which 24 obese women were given 0.9 milligrams/meter(2) of beloranib twice-weekly intravenous. The subjects had a median reduction in body weight of 1 kg/week or 3.1% over 26 days. Treatment with beloranib also reduced triglycerides by 38% and LDL cholesterol (“bad cholesterol”) by 23% from baseline. These results were statistically significant  (p<0.05).

Patients (who were given no instructions regarding diet or exercise) also showed a decline in hunger, and showed no treatment-related serious adverse effects. If sustained (e.g., over a 6-9 month course of treatment in individuals requiring a 20-40 percent reduction in weight) the degree of weight loss seen in this study would be comparable to bariatric surgery.

On July 7, 2011, Zafgen secured a $33 million Series C financing, which was led by the company’s original investor syndicate, including Atlas Venture and Third Rock Ventures. Proceeds from the financing were to be used to support development of Zafgen’s pipeline and especially to advance its lead compound beloranib for the treatment of severe obesity into Phase 2 clinical studies. Zafgen, like Energesis, is operated as a lean virtual company, with only 5 employees. Thus Zafgen should have sufficient cash to advance its beloranib program to the next stage.

Inducing brown fat via modulation of TGFβ signaling

In our November 17, 2010 article, we also mentioned Acceleron Pharma (Cambridge, MA), and its R&D program aimed at brown fat induction via inhibition of signaling by members of the TGFβ (transforming growth factor beta) superfamily. Acceleron is continuing to investigate this approach, and has published a report on this research in the online version of the journal Endocrinology in May 2012. Novartis researchers also published a report on their studies in this area in the online version of the journal Molecular and Cellular Biology.

Conclusions

Despite the doom-and-gloom atmosphere of the obesity drug field in late 2010 and early 2011, with investment bank and business press analysts declaring the field to be “dead”, obesity drug R&D has shown definite signs of life in recent months. NDAs for two of the “Class of 2010” CNS-targeting antiobesity drugs, Qnexa and lorcaserin, have been resubmitted and are up for reconsideration by the FDA later this year. Meanwhile, R&D efforts aimed at producing therapeutics to increase energy expenditure via brown fat induction are progressing, mainly in small entrepreneurial biotech companies. The latter approach, if confirmed by future clinical trials, appears to have a greater likelihood of inducing the degree of weight loss needed to reverse even severe obesity.

Regulatory hurdles–especially safety concerns–were the most significant factor in the failure of the initial NDA submissions of the “Class of 2010” CNS-targeting drugs. The developers of these drugs are working to overcome these hurdles via performing the additional studies mandated by the FDA followed by NDA resubmission. We shall see how well this approach is working when the FDA rules on marketing approval of Qnexa and lorcaserin later this year. Meanwhile, developers of brown-fat targeting therapies are attempting to target severe obesity rather than the general obese population. They are positioning their therapeutics as alternatives to bariatric surgery. They expect that the regulatory hurdles to treating this population will be lower than for the general obese population.

As discussed in several articles on the Biopharmconsortium Blog, the need for antiobesity agents is great, and with the fast accelerating incidence of obesity and its complications, the need is also accelerating. Moreover, our understanding of the pathogenesis of obesity is limited. Thus both continuing basic research and development of agents with novel mechanisms are sorely needed.

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As the producers of this blog, and as consultants to the biotechnology and pharmaceutical industry, Haberman Associates would like to hear from you. If you are in a biotech or pharmaceutical company, and would like a 15-20-minute, no-obligation telephone discussion of issues raised by this or other blog articles, or of other issues that are important to  your company, please click here. We also welcome your comments on this or any other article on this blog.

“It’s not junk”–RaNA Therapeutics emerges from stealth mode with $20.7 million in venture funding-Part 2

 

Atlas!

This is Part 2 of the article on RaNA Therapeutics that we began on March 29, 2012.

Jeannie Lee’s research and RaNA’s technology platform

Jeannie Lee’s laboratory focuses on the study of the mechanism of X-chromosome inactivation in mammals. In X-chromosome inactivation, one of the two copies of the X chromosome present in the cells of female mammals is inactivated. The inactive X chromosome is silenced by packaging into transcriptionally inactive heterochromatin.  X-chromosome inactivation results in dosage compensation, the process by which cells of males and females have the same level of expression of X-chromosome genes, even though female cells have two X chromosomes and male cells have only one. In placental mammals such as mice and humans, the choice of which X chromosome will be inactivated is random, but once an X chromosome is inactivated it will remain inactive throughout the lifetime of the cell and its descendants.

The Lee laboratory has focused on genes encoded by the X-chromosome whose actions coordinate X-chromosome inactivation. These genes  are contained in the 100 kilobase long X-inactivation center (Xic). One of these genes, Xist, encodes the lncRNA XIST, which as discussed in Part 1 of this article inactivates an X-chromosome by spreading along the X chromosome and recruiting the silencing factor PRC2. XIST is regulated in cis by TSIX, an antisense version of XIST which works to keep the active X-chromosome active. Tsix is in turn regulated by Xite (X-Inactivation intergenic transcription element), an upstream locus that harbors an enhancer that enables the persistence of TSIX expression on the active X chromosome. The mechanism by which Xite acts (including whether it acts via its RNA transcripts) is not clear. Xite and Tsix appear to regulate pairing between the two X chromosomes in a female cell, and determine which X chromosome will be chosen for inactivation. Several other recently discovered genes in the region of the Xic, which work via lncRNAs, also serve as regulators of XIST function. For example, the Rep A and Jpx genes, work via lncRNA transcripts to induce Xist. Thus Xist is controlled by positive and negative lncRNA-based switches–TSIX for the active X chromosome and JPX and REPA for the inactive X. Of these lncRNAs, REPA, XIST, and TSIX bind to and control PRC2.

In late 2010, the Lee laboratory published an article in Molecular Cell in which the researchers identified a genome-wide pool of over 9000 lncRNA transcripts that interact with PRC2 in mouse ES cells. Many of these transcripts have sequences that correspond to potentially medically-important loci, including dozens of imprinted loci (i.e., loci that are epigenetically modified such that only the paternal or maternal allele is expressed), hundreds of oncogene and tumor suppressor loci, and multiple genes that are important in development and show differential chromatin regulation in stem cells and in differentiated cells. The researchers obtained evidence that at least in one case, an RNAs works to recruit PRC2 to a disease-relevant genes, similar to PRC2 recruitment by XIST and HOTAIR. This case of specific PRC2 recruitment has not been previously known, suggesting that the researchers’ methodology could be used to discover new examples of PRC2 recruitment by lncRNAs.

Some of the PRC2-associated lncRNAs identified in the Molecular Cell report may be potential therapeutic targets and/or biomarkers. Overexpression of PCR2 proteins have been linked to various types of cancer, including metastatic prostate and breast cancer, and cancers  of the colon, breast, and liver. Pharmacological inhibition of PRC2-mediated gene repression was found to induce apoptosis in several cancer cell lines in vitro, but not in various types of normal cells. Induction of apoptosis in this system is dependent on reactivation of genes that had been repressed by PRC2. There is also evidence that PRC2-mediated gene repression may be linked to the maintenance of the stem-cell properties of cancer stem cells. These results suggest that at least in some cases, inhibition of PRC2-mediated gene repression–including via targeting lncRNAs that recruit PRC2 to critical genes–is a potential strategy for treating various types of cancer.

RaNA’s R&D strategy

Not much information is available about RaNA’s strategy.  However, according to the January 2012 Mass High Tech article, RaNA Therapeutics has licensed technology from Mass General Hospital based on Dr. Lee’s research. The company has also filed several patent applications, some of which are described as being very broad. This includes patent applications on the existence and method of use of thousands of lncRNA targets. However, Dr. Lee’s published patent applications currently include only three items involving the X-chromosome inactivation system or TERC. Presumably, the patent applications mentioned in the Mass High Tech article will be published at the end of the 18-month publication period for U.S. patent applications.

According to the Mass High Tech article, RaNA is in the process of narrowing down the diseases it will initially focus on. Likely areas will include genetic diseases, including diseases that result from haploinsufficiency. In haploinsufficiency, one allele of a gene is nonfunctional, so all of the protein coded by the gene is made from the other allele. However, this results in insufficient levels of the protein to produce a normal phenotype. RaNA intends to use its technology to increase expression of the functional gene, resulting in a adequate dosage of the protein for a normal phenotype.

RaNA intends to choose one indication out of a short list of 20 diseases for internal R&D, and to seek collaborations for other indications. Dr. Krieg says that he hopes to have a collaboration by the end of 2012, and also to have Investigational New Drug (IND)-enabling safety studies on its internal drug candidate by the end of the year as well.

As one might expect, RaNA will target the appropriate lncRNAs using oligonucleotides, similar to how RNAi companies target mRNAs. Dr. Krieg, an oligonucleotide therapeutic development veteran, recruited some of his old oligonucleotide team from Pfizer into RaNA, according to a Fierce Biotech article. Thus Dr. Krieg and his team can quickly get up and running in designing and testing oligonucleotide therapeutics, once RaNA selects the targets for its initial focus.

In the Mass High Tech article, Dr. Krieg says that he believes that “oligonucleotides are on the cusp of being recognized as the third leg of drug development,” along with small-molecule and protein therapeutics. However, as we discussed in our August 22, 2011 article on this blog, oligonucleotide drug development, as exemplified by RNAi and microRNA-based therapeutics, has run into several technological hurdles, especially those involving drug delivery. The August 2011 article cites an editorial by Dr. Krieg, in which he voices his optimism despite these hurdles.

Nevertheless, large pharmaceutical companies and investors have been moving away from the oligonucleotide field. This is exemplified by Alnylam’s January 20, 2012 restructuring, which cut one-third of its work force and focused the company on two of its Phase 1 programs. Having exhausted its ability to capture major Big Phama licensing and R&D deals, Alnylam has had to become a normal early-2012 biotech company and focus its strategy. (However, Alnylam did a $86.9 million public offering in February 2012.)

The emergence of RaNA, and its $20.7 million funding, thus swims against the tide of the general pessimism about oligonucleotide therapeutics of Big Pharmas, investors, and stock analysts. However, at least some oligonucleotide therapeutics will eventually emerge onto the market, and lncRNA regulation is likely to be crucial to many disease pathways. RaNA is thus the pioneering company in this field.

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As the producers of this blog, and as consultants to the biotechnology and pharmaceutical industry, Haberman Associates would like to hear from you. If you are in a biotech or pharmaceutical company, and would like a 15-20-minute, no-obligation telephone discussion of issues raised by this or other blog articles, or of other issues that are important to  your company, please click here. We also welcome your comments on this or any other article on this blog.

“It’s not junk”–RaNA Therapeutics emerges from stealth mode with $20.7 million in venture funding-Part 1

 

XIST Source: Alexbateman http://bit.ly/GZNTZg

 

On January 18, 2012, start-up company RaNA Therapeutics (Cambridge, MA) emerged from stealth mode with 20.7 million in cash. The Series A venture funding was co-led by Atlas Venture, SR One, and Monsanto, with participation of Partners Innovation Fund.

RaNA will work on developing a technology platform that involves targeting long noncoding RNA (lncRNA), in order to selectively upregulate gene expression.

Arthur Krieg, M.D. will serve as RaNA’s President and CEO. He is the former Chief Scientific Officer of the now-closed Pfizer Oligonucleotide Therapeutics Unit, who later became an Entrepreneur in Residence at Atlas Venture (Cambridge, MA). Dr. Krieg was mentioned in two of our previous Biopharmconsortium Blog articles, dated February 15, 2011 and August 22, 2011.

Atlas quietly nurtured RaNA while working to complete the Series A venture round. According to a January 18, 2012 article in Mass High Tech, the company plans to move into about 9,000 square feet of space “somewhere in Cambridge” in early 2012.  RaNA has approximately a dozen employees.

According to the Mass High Tech article, RaNA’s platform is based on technology developed by scientific founder Dr. Jeannie Lee (Massachusetts General Hospital/Howard Hughes Medical Institute, Boston MA).  Drs. Lee and Krieg and Atlas Ventures are cofounders of RaNA.

This is Part 1 of our discussion of RaNA Therapeutics.

RaNA and “junk DNA”

RaNA’s focus is related to what has traditionally been called “junk DNA”. As shown by work on the Human Genome Project and other genomics studies, only about 2-3 percent of the human genome consists of protein-encoding genes. Genomics researchers had not been able to identify a function for most of the remaining 97-98% of the human genome. This gave rise to the idea that these sequences consisted of parasitic DNA sequences that had no function whatsoever. Most researchers thus called these sequences “junk DNA”. Some of the leading lights of the genomics field gave presentations in which they dismissed this DNA as “junk”, and they even proposed models for how this “junk DNA” might accumulate during evolution. Then they would go on to discuss the “interesting” 2-3 percent.

However, the “junk DNA” concept was not really established science, but a hypothesis. I–among a few others–would call these sequences “DNA of unknown function”.

In more recent years, many researchers showed that at least the vast majority of DNA of unknown function was transcribed. Then researchers found a function for a relatively small percentage of these sequences–they are precursors of microRNAs and other small regulatory RNAs. These RNAs are related to the phenomenon of RNA interference (RNAi), which has been the subject of much basic research, including the Nobel Prize-winning research of Drs. Andrew Fire and Craig Mello. RNAi is the basis for various therapeutic RNAi drug discovery and development efforts at such companies as Alnylam, Silence Therapeutics, Quark Phamaceuticals, Dicerna, and Santaris, as well as several large pharmaceutical companies.

The majority of DNA sequences of unknown function, however, are transcribed into lncRNA. As exemplified by the first article [“Quantity or quality?”, by Monika S. Kowalczyk and Douglas R. Higgs (University of Oxford)] in a point/counterpoint Forum published in the 16 February 2012 issue of Nature, many researchers postulate that at least most of these transcripts are nonfunctional. Transcription of these sequences might be, for example, at a low level, as the result of experimental artifacts or of exposure of sequences to the transcriptional machinery due to changes in chromatin during such processes as cell division or expression of nearby genes. This point of view moves the “junk DNA” hypothesis to the RNA level–now one might speak of “junk RNA”.

However, in the second article in the Nature Forum [“Patience is a virtue”, by Thomas R. Gingeras (Cold Spring Harbor Laboratory)], the author counsels “patience” in carefully unraveling the function, one by one, of each noncoding RNA (ncRNA) transcript. According to Dr. Gingeras’ article, there are currently some 161,000 human transcripts, 53% of which are ncRNAs. About 2% of these ncRNAs are precursors to microRNAs. Approximately 10% of the transcripts are lncRNAs that map to intergenic and intronic regions, and many of these transcripts have been implicated in regulation — both of locally and at a distance— of developmentally important genes. Another 16% of the ncRNAs are transcripts of pseudogenes — genes that appear to have lost their original functions during evolution. Some of the pseudogene transcripts have been shown to regulate gene expression by acting as decoys for microRNAs. Despite this progress in assigning functions to ncRNAs, no function has yet been found for the majority of these transcripts. However, these are early days in the ncRNA field, so patience and openness to new discoveries is advisable.

The same 16 February 2012 issue of Nature contains a “Nature Insight” supplement on “Regulatory RNA”. Of particular interest with respect to the functions of lncRNAs is the review by Mitchell Guttman (Broad Institute and MIT, Cambridge MA) and John Rinn (Broad Institute and Harvard, Cambridge MA), entitled “Modular regulatory principles of large non-coding RNAs”. Among the lncRNAs discussed in that review are the X-inactive specific transcript (XIST) (see the figure above) and the telomerase RNA component (TERC). Both of these lncRNAs were identified and their functions determined in the 1990s–XIST in 1991  and TERC in 1995. XIST is expressed exclusively from inactive X chromosomes and is required for X inactivation in mammals. TERC is an essential RNA component of telomerase, the enzyme that replicates chromosome ends (telomeres). At the same time as the functions of XIST and TERC were beginning to be unraveled, most researchers were continuing to dismiss ncDNA as “junk”. Should they have known better?

The Guttman and Rinn review discusses several other lncRNAs with known, important functions, all of which were discovered since the pioneering work on XIST and TERC. Among the genes that encode these lncRNAs are HOTAIR and HOTTIP, which affect expression of the HOXD and HOXA gene family, respectively. HOX genes are a superfamily of evolutionarily conserved genes that are involved the determination of the basic structure of an organism. They encode transcription factors that regulate target genes by binding to specific DNA sequences in enhancers. The large intergenic non-coding RNA-RoR (lincRNA-RoR) modulates reprogramming of human induced pluripotent stem cells (iPS cells, which were discussed in earlier articles on this blog). The lncRNA NRON regulates transcription factors of the NFAT (nuclear factor of activated T-cells) family, which are involved in regulating the immune response, as well as in the development of cardiac and skeletal muscle, and of the nervous system. These genes have also been implicated in breast cancer, especially in tumor cell invasion and metastasis.

A common theme in the function of several lncRNAs, as highlighted in the Guttman and Rinn review, is association of the lncRNA with a chromatin-regulatory protein complex. The lncRNA serves to guide the regulatory protein complex to specific regions of chromatin. The protein complex then modifies specific histones in the chromatin regions, resulting in silencing of target genes.

In particular, HOTAIR serves as a molecular scaffold that binds to two protein complexes. A 5′ domain of HOTAIR binds polycomb repressive complex 2 (PRC2), and a 3′ domain of HOTAIR binds the CoREST–LSD1 complex. This enables the targeting of PRC2 and LSD1 to chromatin for coupled histone H3 lysine 27 methylation by PRC2 and histone H3 lysine 4 demethylation by LSD1. Both are required for proper repression of HOX genes.

XIST has at least two discrete domains, one involved in silencing (RepA) and the other in localization (RepC) of the XIST molecule on the X chromosome. The silencing domain RepA binds to PRC2, and the localization domain RepC binds to the YY1 protein and heterogeneous nuclear ribonucleoprotein U (hnRNP U).

The cases of HOTAIR and XIST are examples of how lncRNAs may function as molecular scaffolds of regulatory protein complexes. This may be general phenomenon, since a recent study by Drs. Guttman and Rinn and their colleagues indicates that about 30% of lincRNAs in mouse embryonic stem (ES) cells are associated with multiple regulatory complexes. In this study, the researchers found that RNAi knockdown of dozens of lincRNAs causes either exit from the pluripotent state or upregulation of specific differentiation programs. Thus lincRNAs appear to have important roles in the circuitry controlling the pluripotent state of ES cells, and in commitment to differentiation into specific lineages.

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As the producers of this blog, and as consultants to the biotechnology and pharmaceutical industry, Haberman Associates would like to hear from you. If you are in a biotech or pharmaceutical company, and would like a 15-20-minute, no-obligation telephone discussion of issues raised by this or other blog articles, or of other issues that are important to  your company, please click here. We also welcome your comments on this or any other article on this blog.

Preclinical-stage biotech Verastem goes public. Really‽

 

Salinomycin

On November 3, 2011, Cambridge MA biotech firm Verastem announced that it was filing a prospectus for an initial public offering (IPO). At that time, the company was 15 months old.

Verastem is led by Christoph Westphal, MD, PhD, a founder and the former CEO of Sirtris and a veteran entrepreneur and venture capitalist. The IPO has been underwritten by UBS, Leerink Swann, Lazard Capital Markets, Oppenheimer & Co., and Rodman & Renshaw.

On January 27, 2012, Fierce Biotech reported that Verastem had announced the previous night that its IPO raised $55 million from the sale of 5.5 million shares at $10 apiece. This price fell exactly in the middle of its expected $9 to $11 price range, and the company had even increased the offering by a million shares over what had originally been planned.

On the same day, Verastem’s stock opened at $11 a share on the NASDAQ, up from its initial public offering price of $10.

Verastem not only has Christoph Westphal as its Chairman and CEO, but is also based on science from eminent MIT researchers Robert Weinberg, Ph.D. and Eric Lander, Ph.D., and has several other well-respected academic researchers (including Nobelist Phillip Sharp, Ph.D.) plus biotech industry drug discoverers Julian Adams, Ph.D. (MIllennium’s Velcade) and Roger Tung, Ph.D. (Vertex’ Lexiva and Agenerase) on its Scientific Advisory Board. The company has had considerable fundraising success prior to its IPO, including raising $32 million in venture capital  in July 2011.

However, Verastem has not one lone drug in human clinical trials, its most advanced compounds are in the preclinical stage, and the company does not plan to file an IND until 2013! Thus Verastem has successfully gone public, in an era in which even most private biotech companies with drugs in late-stage clinical trials are finding it very difficult to do so, despite its lack of any clinical-stage drugs.

As noted in the Fierce Biotech article, Dr. Westphal as well as other venture capital funders of Verastem agreed to buy up to $16.3 million of the IPO. This in part explains the success of the IPO. As also noted by Fierce Biotech, with over 19 million common shares outstanding, the offering valued Verastem at $192 million.

We discussed Verastem in our August 2, 2011 Biopharmonsortium Blog article entitled “Development of personalized therapies for deadly women’s cancers”. Verastem focuses on discovery and development of drugs to target cancer stem cells. Its technology is based on a strategy for screening for compounds that specifically target cancer stem cells, developed by Drs. Weinberg, Lander, Piyush Gupta (MIT and Broad Institute) and their colleagues.

Cancer stem cells are best known in acute myeloid leukemia (AML), but their existence in other cancers (especially solid tumors) is controversial, as discussed in our article. Whether cancer stem cells are involved in the pathobiology of solid tumors (or a particular type of solid tumor) or not, the biology of the putative cancer stem cell phenotype can be important in certain subtypes of cancer. Cancer stem cells are characterized by the epithelial-mesenchymal transition (EMT). In the Cell paper, the researchers screened for compounds that specifically targeted breast cancer cells that had been experimentally induced into an EMT, and which as a result exhibited an increased resistance to standard chemotherapy drugs.   They identified the compound salinomycin (now being marketed as a generic veterinary antibiotic) as a drug that specifically targeted these cells, as well as putative cancer stem cells from patients.

As we discussed in our article, triple-negative (TN) breast cancer cannot be treated with standard receptor-targeting breast cancer therapeutics (e.g., tamoxifen, aromatase inhibitors, trastuzumab) but must be treated with cytotoxic chemotherapy. It is generally more aggressive than other types of breast cancer, and even treatment with aggressive chemotherapy typically results in early relapse and metastasis. However, TN breast cancer includes two experimentally defined subtypes that have gene expression signatures related to the EMT. One or both of these subtypes might therefore be expected to be sensitive to compounds that specifically target putative breast cancer stem cells. This may be true whether the cancer stem cell hypothesis applies to TN breast cancer or not. Verastem is focusing on TN breast cancer as its first therapeutic target.

Verastem’s VS-507, a proprietary formulation of salinomycin, is being developed to treat TN breast cancer. The company is also screening for additional compounds, including New Chemical Entities (NCE) that can achieve stronger intellectual property protection than a salinomycin formulation. Verastem had not chosen a lead compound as of the middle of 2011. The company is now reported to be doing preclinical studies on three of its compounds, and also plans to create diagnostic tests to identify patients that could benefit from its treatments. (As we discussed in our article, biomarker-based tests will be critical in making such therapies work.)

As one can discern from our blog article, we are intrigued by Verastem’s approach to cancer treatment, and especially its approach to TN breast cancer. The science behind Verastem’s drug discovery strategy, developed by 2011 ASCO award-winning oncogene and cancer stem-cell pioneer Bob Weinberg, is very compelling. We would love to see Verastem’s therapeutic strategy succeed.

However, as virtually all pharmaceutical and biotechnology R&D researchers well know, it is difficult to translate even the most compelling science developed by the most brilliant researchers into the clinic. Even therapeutic strategies with an excellent scientific rationale that have achieved proof of principle in the best animal models can result in clinical failure, especially with the first compound tested in proof-of-concept studies in human patients. The cancer stem cell hypothesis remains controversial. Moreover, diseases such as TN breast cancer are complicated, they may have mechanisms of resistance to a new experiential therapy that no one knows about, and our understanding of disease biology is limited.

Thus at least until Verastem’s therapies achieve proof of concept in human studies, purchase of Verastem stock is risky indeed. Moreover, there are other risks involved other than technical and clinical risk–especially competition for developing cancer stem cell-based therapies by other biotech/pharma companies. Venture capitalists (and certain knowledgeable individual investors and funds) are in the business of taking on high-risk investments for the sake of potential large rewards, but ordinary retail investors in the public markets are not. Therefore, it seems too early for Verastem to go public, even if it has founders and investors with enough clout to make an IPO successful.

Expert analysts in the IPO field, as stated in the Fierce Biotech article, are puzzled by the rationale for Verastem going public at this time. The financial news and services website “TheStreet.com” agrees. Our own sense of puzzlement is symbolized by the interobang (‽) in the title of this article.

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As the producers of this blog, and as consultants to the biotechnology and pharmaceutical industry, Haberman Associates would like to hear from you. If you are in a biotech or pharmaceutical company, and would like a 15-20-minute, no-obligation telephone discussion of issues raised by this or other blog articles, or of other issues that are important to  your company, please click here. We also welcome your comments on this or any other article on this blog.

The Big Pharma retreat from RNAi therapeutics continues

 

Source: Narayanese. http://bit.ly/oi10H1

On July 29, 2011, Merck announced that It was shutting down the San Francisco research laboratory that it had acquired as part of its $1.1 billion acquisition of therapeutic RNAi specialist company Sirna Therapeutics. This announcement was covered in a July 29, 2011 article in Xconomy, and in a news brief in the 4 August issue of Nature and a linked Nature news blog article.

According to the Xconomy article, the shutdown will include the loss of around 50 jobs. Around ten people are being offered transfers to other Merck facilities in nearby Palo Alto CA and on the East Coast.

The Merck facility shutdown continues the exit or retrenchment from therapeutic RNAi research at other Big Pharma companies. The Biopharmconsortium Blog has covered these moves at Roche and Pfizer.

As we discussed in the Roche article, Novartis had also decided to end its 5-year partnership with therapeutic RNAi specialty company Alnylam In September 2010. However, Novartis acquired technology and exclusive development rights for RNAi therapeutics against 31 targets for in-house use as the result of its partnership with Alnylam.  Alnylam is entitled to receive milestone payments for any RNAi therapeutic products that Novartis develops based on these targets. Thus Novartis is still involved in RNAi therapeutics, despite the termination of the Alnylam partnership.

Moreover, according to the Nature news blog, Ian McConnell of Merck’s Scientific Affairs, R&D and Licensing and Partnerships said that Merck will continue to have over 100 scientists working on RNA-based therapeutics, and that it continues to invest significantly in the field. Closing the San Francisco lab represents an effort to trim the budget by eliminating the cost of maintaining a separate RNAi facility.

In our previous blog articles on Big Pharma RNAi therapeutics retrenchment, and in our October 2010 book -length report, RNAi Therapeutics: Second-Generation Candidates Build Momentum, we discussed the strategic issues that are involved in undertaking (or in retrenching from) R&D programs in RNAi therapeutics, and in investing in that area. The therapeutic RNAi (and microRNA) field represents an early-stage area of science and technology. The field may be technologically premature, as was the monoclonal antibody (MAb) drug field in the 1980s.

Big Pharma originally got into RNAi therapeutics in order to help fill weak pipelines, and with the hope of staking out a commanding position in the RNAi field once it became successful. However, with the short-term pressure at Big Pharma companies to cut expenses and programs, Big Pharmas have been losing the needed patience to continue with a technologically premature field like RNAi therapeutics.

In the June 2011 issue of Molecular Therapy, there is an editorial by Arthur Krieg, M.D. (former Chief Scientific Officer of the now-closed Pfizer Oligonucleotide Therapeutics Unit, and now Entrepreneur in Residence at Atlas Venture, Cambridge, MA), entitled “Is RNAi dead?” As discussed in the editorial, the move of Big Pharma away from RNAi, according to some observers, signals the death of the therapeutic RNAi platform. Dr. Krieg outlines an alternative view.

According to Dr. Krieg, Big Pharmas got into RNAi therapeutics with the hope of enabling the rapid development of targeted drugs without the long time lags and uncertainties of small molecule drugs and biologics. In theory, if a research team has a good target, it could rationally design a lead RNAi drug specific for the target and ready for human clinical trials within 15 months. And researchers would not have to worry about “undruggability” of targets. However, there have been several unforeseen hurdles to the development of RNAi drugs, the most formidable of which is the issue of drug delivery. Although certain high-profile publications suggested that the challenge of RNAi drug delivery could be easily overcome, this proved not to be the case in practice.

However, Dr. Krieg believes that the progress in RNAi delivery in recent years has been “nothing short of spectacular”. In 2008, the best RNAi delivery systems for a liver target might have an IC50 (i.e., the RNAi dose required for 50% inhibition of target expression) of 1–3 mg/kg, but in 2010/2011, the IC50 has been reduced to about 1% of this value, which is an improvement of two logs. Dr. Krieg also says that there have also been significant advances in reducing off-target and other undesired systemic effects of RNAi therapeutics in animal models in recent years.

Nevertheless, the advances in RNAi delivery and safety are moving too slowly for Big Pharma’s current short-term mindset. According to Dr. Krieg, if companies are not able to take an RNAi drug into clinical development this year, then the next time there is an R&D portfolio review, investments in “high-risk” technology platforms such as RNAi are likely to be cut. As we have discussed in this blog, and as is well-known to most of you, every Big Pharma company has been cutting R&D and shedding poorly productive and high-risk programs. The focus at many Big Pharmas is on fast, sure returns. High-risk or premature technologies that have not yet yielded any marketed drugs, such as RNAi (and for example, stem cells/regenerative medicine) is not likely to offer such returns.

Dr. Krieg also notes that in the case of another once-premature technology, monoclonal antibody (MAb) drugs, it took several waves of technology development to advance from repeated clinical failure to one of the most successful classes of drugs today. In our view, MAb technology is the classic case (in the life sciences, anyway) of how researchers and companies can take such a premature technology up the technology curve by developing enabling technologies. We discussed this case in our September 28, 2009 blog article, and its applicability to RNAi and stem cells in our July 13, 2009 blog article. As discussed in these articles, and as noted by Dr. Krieg, it was not Big Pharmas, but biotech companies “on the cutting edge” (together with academic labs) that advanced the therapeutic MAb field. Big Pharmas later bought into the MAb field, typically by large acquisitions. This is especially exemplified by the acquisition of MAb drug leader Genentech by Roche.

With respect to RNAi, as mentioned above, at least Merck and Novartis among the Big Pharmas are continuing with in-house RNAi therapeutics programs. And such biotechs as Alnylam, Silence Therapeutics, Quark Phamaceuticals, Dicerna, and Santaris have RNAi and/or microRNA-based drug candidates in clinical trials, often partnered with Big Pharma companies (such as Pfizer) that have cut or reduced their own RNAi drug programs. Therefore, there are companies that are working on advancing RNAi therapeutics up the technology curve. As Dr. Krieg says in his editorial, success in such programs will be expected to lead to Big Pharma reinvestment in RNAi/microRNA therapeutics, just as in the case of MAb drugs.