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.

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.

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.

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 article.  Vicriviroc 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.

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.

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.

[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.