Drug Development and Delivery published an article based on our 2017 report on Cancer Immunotherapy 2.0 in its November/December 2017 issue.

To see the article, please go to http://www.drug-dev.com/Main/Back-Issues/CANCER-IMMUNOTHERAPY-Building-on-Initial-Successes-1402.aspx

To order our report, Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes, please see the CHI Insight Pharma Reports website.

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.

CTLs attacking cancer cells.

On September 15, 2017, Bavarian Nordic’s Phase 3 trial of its cancer vaccine Prostvac ended in failure. Prostvac failed to improve overall survival in patients with metastatic castration-resistant prostate cancer, as determined by the clinical trial.

We had listed Prostvac in Chapter 5 and in Table 5-2 of our 2017 report, Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes, as a cancer vaccine that was in Phase 3 clinical trials. However, as we stated in that chapter, “It is possible that one or more of the experimental agents listed in Table 5-2 may [also] experience late-stage failure.” That is because the cancer vaccine field has been subject to a high rate of clinical failure, including several late-stage failures in 2016.

Despite the high rate of failure in the cancer vaccine field, there are now two FDA approved cancer vaccines— sipuleucel-T (Dendreon/Valeant’s Provenge) and talimogene laherparepvec (Amgen’s Imlygic/T-Vec), the latter of which is an oncolytic virus, rather than a true cancer vaccine. However, both of these agents are rather marginal therapies. Sipuleucel-T has an apparently minimal effect and is very expensive and difficult to manufacture. T-Vec must be injected directly into a tumor, and as a monotherapy, there is no evidence for improvement of overall survival or effects on distant metastases. However, researchers have hypothesized that as a directly-injected agent, T-Vec might produce an inflammatory tumor microenvironment that will provide an ideal target for checkpoint inhibitors. Thus, researchers have had expectations that combination therapies of T-Vec with checkpoint inhibitors which are now in progress may yield much better results.

Indeed, on October 6, 2017, a peer-reviewed Phase 2 published study indicates that a combination of Imlygic and Bristol-Myers Squibb’s (BMS’) CTLA4 checkpoint inhibitor Ipilimumab (Yervoy) doubles response rates in advanced melanoma as compared to Yervoy alone. The published trial results show that the objective response rate for the combination was 39%, compared to 18% for Yervoy alone. With respect to complete responses, the combination gave13% as compared to 7% for Yervoy alone. Responses occurred in patients with and without visceral disease and in uninjected lesions after combination treatment, according to the study.

Amgen’s head of R&D, Sean E. Harper MD says that the trial provides an important proof-of-concept for combining the complementary mechanisms of an oncolytic viral immunotherapy and a checkpoint inhibitor to enhance antitumor effects, adding that the company intends to test Imlygic in combination other checkpoint inhibitors in “a variety of tumor types”.

Imlygic—in combination with another checkpoint inhibitor, pembrolizumab (Merck’s PD-1 inhibitor Keytruda)—is in a Phase 3 trial (KEYNOTE-034, clinical trial number NCT02263508) in advanced melanoma. This trial is expected to yield preliminary results in 2018. In 2014, the Phase 1b/2 MASTERKEY-256 trial of the Imlygic/Keytruda combination in advanced melanoma showed an overall response rate (ORR) of around 56%.

These data indicate that the immunotherapy 2.0 strategy of using Imlygic to generate an inflammatory tumor microenvironment may produce a synergistic clinical effect and enhanced anti-tumor immune response in patients with metastatic melanoma who are also treated with a checkpoint inhibitor.

As we discuss in Chapter 5 of our 2017 Cancer Immunotherapy report, several cancer vaccine developers are pursuing a similar strategy—use cancer vaccines to render tumors inflamed [i.e. especially with cytotoxic tumor-infiltrating lymphocytes (TILs)], and use checkpoint inhibitors to induce regression of the inflamed tumors. In some cases, cancer vaccines are being tested in combination with checkpoint inhibitors in Phase 1 or Phase 2 clinical trials, rather than the “traditional” approach of first getting a vaccine approved and then conducting trials of the vaccine in combination with other agents. The hope is that testing a vaccine in combination with a checkpoint inhibitor in early stage clinical trials might prevent clinical failure of a potentially useful cancer vaccine. However, whether this strategy will work for any particular vaccine remains to be seen.

Neoantigen cancer vaccines

Another novel immunotherapy 2.0 strategy for cancer vaccine discovery and development discussed in our report involves neoantigen science. Recent studies exploring mechanisms by which TILs and other components of the immune system recognize tumor cells and differentiate them from noncancer cells have focused on “neoantigens”—i.e. antigens that are specific for cancer cells as opposed to normal, noncancer cells. These neoantigens are associated with somatic mutations that arise in the evolution of tumor cells. Neoantigen-specific TILs appear to mediate tumor regression, and this antitumor activity may be enhanced by checkpoint inhibitor therapy. Such studies have led researchers to hypothesize that personalized neoantigen-based vaccines may be more effective than earlier types of cancer vaccines. Some researchers have therefore been attempting to develop technology platforms for vaccine design based on determination of neoantigens in tumors.

In particular, neoantigen researchers at the Dana-Farber Cancer Institute, the Broad Institute, Massachusetts General Hospital, and Brigham and Women’s Hospital recently founded a company, Neon Therapeutics (Cambridge, MA). Neon focuses on neoantigen science and technology for the development of neoantigen-based therapeutic vaccines and T-cell therapies to treat cancer.

These researchers published a report in the 13 July issue of Nature describing their Phase 1 study in patients with previously untreated high-risk melanoma of a personalized neoantigen vaccine designated NEO-PV-01 by Neon Therapeutics and in Chapter 5 of our report.

As discussed in our report, Neon’s lead clinical program, NEO-PV-01, builds upon initial clinical trials developed collaboratively by the Broad Institute and the Dana-Farber. NEO-PV-01 is a personalized vaccine that is custom-designed and manufactured to include targets for the immune system [i.e. naturally-processed, major histocompatibility complex (MHC)-binding, neoantigen peptide epitopes] that are unique to an individual’s cancer. The 13 July Nature report focuses on results of the ongoing Phase 1 clinical trial designated NCT01970358 of the combination of poly-ICLC [poly-inosinic acid/poly-cytidylic acid/poly-lysine, an adjuvant] and multiple neoantigen peptide epitopes in melanoma.

As discussed in that Nature paper, neoantigens were long envisioned as optimal targets for anti-tumor immune responses. However, the systematic identification of neoantigens in a particular patient’s tumors only became feasible with the availability of massively parallel sequencing for detection of coding mutations, and of machine learning technology to reliably predict those naturally-processed mutated peptides that bind with high affinity to autologous major histocompatibility (MHC) molecules. (The term “naturally-processed” refers to antigenic peptide epitopes that are processed intracellularly and which bind with high affinity to autologous class I or class II MHC molecules. The MHC/peptide complexes are then recognized by T cells.)

In the study described in the 13 July Nature paper, the researchers demonstrated the feasibility, safety, and immunogenicity of a vaccine (designated NEO-PV-01 as discussed earlier), which targets up to 20 predicted personal tumor neoantigens. Vaccine-induced polyfunctional CD4+ and CD8+ T cells targeted 58 (60%) and 15 (16%) of 97 unique neoantigens across patients, respectively. These T cells discriminated mutated from wild-type antigens, and in some cases directly recognized autologous tumor. Of six vaccinated patients, four had no recurrence as of 25 months post-vaccination. Two other patients who had recurrent disease were subsequently treated with the anti-PD-1 antibody pembrolizumab (Merck’s Keytruda). These two patients experienced complete tumor regression, with expansion of the repertoire of neoantigen-specific T cells.

These results strongly support further development of the researchers’ neoantigen vaccine approach, both alone and in combination with checkpoint inhibitors or other immunotherapies. Neon Therapeutics is currently sponsoring an open-label Phase 1b clinical study of NEO-PV-01 plus adjuvant in combination with nivolumab (BMS’ Opdivo) in patients with melanoma, smoking-associated non-small cell lung carcinoma (NSCLC) or transitional cell bladder carcinoma (clinical trial number NCT02897765). Neon entered into a collaboration with BMS to perform this clinical trial in late 2015.

Neon is also developing NEO-PTC-01, a personal neoantigen autologous T cell therapy, which is now in the research and process development stage. As discussed in Chapter 6 of our 2017 cancer immunotherapy report, neoantigen science is also a factor in adoptive cellular immunotherapy for cancer, especially in Steven A. Rosenberg MD, PhD’s recent studies of TIL therapy.

Other neoantigen cancer vaccine companies

In addition to Neon, other young companies that specialize in development of neoantigen-based cancer vaccines include BioNTech AG (Mainz, Germany), Gritstone Oncology (Emeryville, CA and Cambridge, MA), ISA Pharmaceuticals (Leiden, The Netherlands), Agenus (Lexington, MA), and Caperna (Cambridge, MA). Of these companies, BioNTech and Caperna [which is a Moderna (Cambridge, MA) venture company] are developing RNA-based personalized neoantigen vaccines. The other companies are developing peptide neoantigen vaccines based on their proprietary technologies.

Conclusions

As discussed in this article, and in our 2017 report, Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes, researchers and developers are applying several immunotherapy 2.0 approaches to attempt to reverse the high rate of failure in the cancer vaccine field.

Moreover, neoantigen science has a potentially wide field of application, ranging from improving clinical outcomes of treatments with checkpoint inhibitors to development of more effective cancer vaccines and of novel cellular immunotherapies.

Our report contains materials designed to enable readers to understand complex issues in neoantigen science, and especially to understand applications of neoantigen science in research reports, clinical trials, corporate news, and product development.

For more information on our report, Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes, or to order it, see the CHI Insight Pharma Reports website.

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.

PD-1 extracellular domain

As noted in our 2017 Insight Pharma Report, “Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes” the most successful class of immunotherapeutics continues to be that of the checkpoint inhibitors (discussed in Chapter 2 of our report).

Immune checkpoints refer to a large number of inhibitory pathways in the immune system, especially those that block the response of T cells to antigens. Marketed checkpoint inhibitors are all monoclonal antibodies (mAbs). The two leading checkpoint inhibitors, both of which target PD-1, are pembrolizumab (Merck’s Keytruda), and nivolumab, (Bristol-Myers Squibb’s Opdivo), both approved by the FDA in 2014. Of these two, Keytruda has become the market leader during 2016/2017, after a long process of competition with BMS’ Opdivo..

On July 26, 2017, Forbes published a long article by David Shaywitz MD, PhD, entitled “The Startling History Behind Merck’s New Cancer Blockbuster”. This article is a complete history of Keytruda, from discovery through commercialization. As discussed in this article, Roger Perlmutter MD PhD (who became head of Merck Research Labs during the process of development of Keytruda) redirected virtually all work at Merck towards the Keytruda program. He determined that Keytruda was more valuable than the entire rest of Merck’s portfolio put together. Dr. Perlmutter essentially bet both his own career and Merck’s enterprise on the Keytruda program.

Merck has been engaging in an aggressive R&D and commercialization program for Keytruda. In the second quarter of 2017, Keytruda achieved three accelerated approvals and one full approval in the U.S., a recommendation in the EU, and a 180% increase in sales. As of September 2017, Merck has over 550 clinical trials evaluating Keytruda in more than 30 tumor types.

As expected for such an aggressive program, not all of Merck’s efforts have been successful. Three of the company’s combination trials of Keytruda, with Celgene’s Revlimid (lenalidomide) or Pomalyst (pomalidomide) plus dexamethasone in multiple myeloma, have been on hold because of an excess number of deaths in the treatment arm. Merck also had a missed endpoint in recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) in the KEYNOTE-040 trial. Despite this, Keytruda has held onto its accelerated approval for this indication, and other HNSCC trials are ongoing.

Merck’s acquisition of Rigontec

Keytuda has become as much a platform as a product for Merck. This is illustrated by the recent acquisition by Merck of the German company Rigontec for $150 million in cash and another $453 million in milestones payments. According to John Carroll’s Endpoints News, this is an example of how Merck’s Perlmutter likes to augment the work being done around Keytruda with the occasional add-on.

Mr. Carroll refers to the Rigontec deal as a “bolt-on” acquisition. In a “bolt-on” acquisition, a platform company (such as Merck) with the management capabilities, infrastructure and systems that allows for organic or acquisition growth will look for acquisition of smaller companies “that provide complementary services, technology or geographic footprint diversification and can be quickly integrated into the existing management infrastructure.”

Rigontec’s technology platform is based on developing agents that mimic viral infections. Specifically, double-stranded viral RNA is recognized by pattern recognition receptors called RIG-I-like helicases (RLH) that are present in the cytoplasm. Synthetic RLH ligands (such as those being developed by Rigontec) working via RLH initiate a signaling cascade that leads to an antiviral response program, characterized by the production of type I interferon (IFN) and other innate immune response genes. RLH signaling also induces apoptosis in tumor cells. Finally, exposure of CD8alpha+ dendritic cells (DCs) to RLH-activated apoptotic tumor cells induces DC maturation, efficient antigen uptake and cross-presentation of tumor-associated antigens to naive CD8+ T cells.

The exploitation of the RLH system thus constitutes a potential means to activate tumor-specific CD8+ T cells. As discussed in our 2017 Insight Pharma report, checkpoint inhibitors work by reactivating intratumoral T-cells, especially CD8+ cytotoxic T cells. Rigontec’s agents may work to render “cold” tumors inflamed (specifically, with DCs and CD8+ T cells), thus making them more susceptible to the antitumor action of checkpoint inhibitors such as Keytruda. This type of strategy, as discussed in our report, is a major theme of “second wave” immuno-oncology, or “immuno-oncology 2.0.”

However, so far the potential use of Rigontec’s RLH ligands in cancer therapy is based on studies in preclinical tumor models for melanoma, ovarian cancer and pancreatic cancer. Currently, Rigontec has been sponsoring a first-in-humans Phase 1/2 trial of its lead RIG-1 agonist, RGT100, in solid tumors and lymphoma (clinical trial number NCT03065023). This study is designed to assess “safety, tolerability and pharmacokinetics of RGT100 in patients with injectable solid tumor lesions”. In the absence of evidence for clinical efficacy in human cancer patients, the Merck acquisition of Rigontec is a speculative deal. However, upfront Merck’s investment in Rigontec is small, and it gives Merck access to a new mechanism of action, which is complementary to the larger company’s strategy and current pipeline.

Other immunotherapy 2.0 approaches designed to enhance the effectiveness of checkpoint inhibitors

As noted in our 2017 Insight Pharma Report, although checkpoint inhibitors such as Keytruda have achieved spectacular success in treating some patients, they do not work for the majority of patients. Even in the case of melanoma, where checkpoint inhibitors have shown the greatest degree of efficacy, these agents only cure 20% of patients. Therefore, numerous researchers and companies are working to discover and develop complementary “immunotherapy 2.0” treatments to enhance the efficacy of checkpoint inhibitors in various classes of cancer patients. Rigontec’s technology represents only one such approach.

In a recent article published (Sep 7, 2017) in FierceBiotech, writer Arlene Weintraub discussed two companion treatments that might potentially enhance the effectiveness of checkpoint inhibitors. One of these treatments, discovered by scientists at Columbia University Medical Center, is a drug that’s already on the market: pentoxifylline, which is used to increase blood flow in patients with poor circulation. Pentoxifylline’s activity in cancer immunology is based on its inhibition of NF-kB c-Rel.  This results in the inhibition of regulatory T cells (Tregs) in the tumor mcroenvironment. In mouse models, inhibition of c-Rel function by pentoxifylline delayed melanoma growth by impairing Treg-mediated immunosuppression, and thus and potentiated the effects of anti-PD-1 immunotherapy. Adverse effects, such as the induction of autoimmunity that would be expected if the treatment caused global inhibition of Tregs, were not seen. Once again, these studies in mice await confirmation via human clinical trials; such human trials are currently planned.

The other experimental immunotherapy 2.0 approach discussed in Ms. Weintraub’s article involves combining an oncoloytic virus [the modified vaccinia virus Ankara (MVA)] with a checkpoint inhibitor. Once again, the example discussed in this article was in mouse models. As in other immunotherapy 2.0 approaches, the goal is to enable the immune system to recognize the tumor as foreign by injecting the oncolytic virus into it, thus prompting a CD8+ T-cell response. Checkpoint inhibitors might then reactivate the intratumoral T cells, inducing an antitumor response. These studies were also carried out in mouse models, and human trials are planned.

Our report, “Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes”, also includes discussions of the use of oncolytic viruses to boost the anticancer efficacy of checkpoint inhibitors. Some of these approaches (such as studies of combinations of Amgen’s Imlygic (talimogene laherparepvec), an FDA-approved modified oncolytic virus therapy, with checkpoint inhibitors), are already in human studies.

Also in our report is a discussion of treatments being developed by NewLink Genetics designed to modulate the IDO (indoleamine-pyrrole 2,3-dioxygenase) pathway. Such compounds are designed to reverse IDO-mediated immune suppression. IDO pathway inhibitors may complement the use of anti- PD-1and/or anti-PD-L1 checkpoint inhibitors. The same Endpoints News article that discusses the Merck/Rigontec acquisition  also mentions an earlier Merck bolt-on deal—the 2016 acquisition of IOmet. IOmet also works on IDO pathway inhibitors.

More generally, our 2017 Insight Pharma Report contains a wealth of potential immunotherapy 2.0 approaches. Importantly, this includes an “immunotherapy 2.0” approach to cancer vaccine development, which emphasizes combinations of cancer vaccines with checkpoint inhibitors. This may both enhance the efficacy of checkpoint inhibitors, and reverse the high rate of failure of cancer vaccines. Other immunotherapy 2.0 strategies discussed in our report may well make the news over the next several years, in terms of corporate deals and product approvals. Our report is thus well worth reading for those who are interested in the further devlelopment of immuno-oncology.

For more information on our report, Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes, or to order it, see the CHI Insight Pharma Reports website.

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.

CAR-T procedures
Source: National Cancer Institite

Late stage cellular immunotherapy products for treatment of hematologic tumors

In the field of commercialization of cellular immunotherapy for cancer, all eyes have been on two chimeric antigen receptor (CAR) T-cell therapies (from Novartis and Kite Pharma), which have been in preregistration with the FDA as of March 2017. We discussed the field of CAR-T cell therapies—as well as other cellular immunotherapies for cancer—in Chapter 6 of our recently published book-length report, Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes

Both the Novartis therapy, CTL019 (tisagenlecleucel-T), and the Kite therapy, KTE-C19 (axicabtagene ciloleucel) target CD19, which is a cell surface protein that is expressed on all malignant and normal B-cells.

On July 13, 2017, Novartis announced  that FDA’s Oncologic Drugs Advisory Committee (ODAC) had unanimously recommended approval of CTL019 for the treatment of relapsed or refractory (r/r) pediatric and young adult patients with B-cell acute lymphoblastic leukemia (ALL). The ODAC recommendation is based on review of Novartis’ CTL019 r/r B-cell ALL development program, including the ELIANA study (NCT02435849). ELIANA is the first pediatric global CAR-T cell therapy registration trial. Findings from other clinical trials in the U.S. also supported the recommendation and the Biologics License Application (BLA) for CTL019.

On August 30, 2017 the FDA approved Novartis’ CTL019—now known as Kymriah (tisagenlecleucel)—for the treatment of patients up to 25 years of age with B-cell precursor acute lymphoblastic leukemia (ALL) that is refractory or in second or later relapse. Novartis’ Kymriah is thus the first-ever commercially approved CAR-T cell therapy to reach the market. However, Kite’s KTE-C19 is close on Novartis’ heels.

On August 28, 2017, Kite and Gilead announced that the two companies have entered into a definitive agreement pursuant to which Gilead will acquire Kite for $11.9 billion. Via this acquisition, Gilead “instantly” becomes a leader in cellular immunotherapy for cancer, going head-to-head with Novartis.

On October 18, 2017, Kite and Gilead announced that the FDA had approved Kite’s Yescarta (axicabtagene ciloleucel, also known as axi-cel), for the treatment of adults with relapsed or refractory large B-cell lymphoma, including aggressive non-Hodgkin lymphoma, who have failed two or more traditional treatments. Yescarta was approved about six weeks earlier than expected.

Other CAR-T based immunotherapies for treatment of hematologic tumors

As discussed in our report, there is also a third company, Juno Therapeutics, that was in the race to develop CD19-targeting CAR-T-based cellular immunotherapies for regulatory approval in 2017. However, Juno’s lead product, JCAR015, suffered a series of toxicity-related setbacks. Juno thus abandoned both JCAR015 and the race for 2017 approval. It is now focusing on development of another CD19-targeting CAR-T product, JCAR017. This therapy is directed towards treatment of relapsed/refractory diffuse large B-cell lymphoma (DLBCL).

JCAR017 demonstrated promising efficacy results in a Phase 1 trial known as TRANSCEND. Adverse results were generally mild, and could be resolved with treatment. [ The company presented the results of the TRANSCEND trial at the 2017 American Society for Clinical Oncology (ASCO) annual meeting in early June.]

Juno expects to begin a pivotal trial of JCAR017 this year in DLBCL. JCAR017 received a breakthrough therapy designation from the FDA for non-Hodgkin lymphoma in December 2016.

As we also discuss in our report, another CAR-T therapy directed against a hematologic malignancy, bluebird bio’s bb2121, is under development in collaboration with Celgene. bb2121 targets B-cell maturation antigen (BCMA), and is directed toward treatment of multiple myeloma (MM). bluebird and Celgene announced the results of an ongoing first-in-human open-label Phase 1 multicenter clinical study of bb2121 in 18 patients with relapsed/refractory MM at the 2017 ASCO Annual Meeting on June 5, 2017. bb2121 demonstrated promising efficacy results in this study, and no dose-limiting toxicities were observed. No patient in the active dose cohorts has had disease progression. The researchers thus plan on initiating the expansion phase of the study in the coming months of 2017.

Can researchers develop cellular immunotherapy for solid tumors?

As various companies work to move CAR T-cell therapies that target tumor antigens other than CD19 into the clinic, a particularly important question is whether CAR T-cell technology might be used to target solid tumors. Our report  discusses several clinical-stage products designed to target various types of solid tumors. These include products in three categories—tumor-infiltrating lymphocytes (TILs), CAR T-cells, and recombinant T-cell receptor (TCR) cells. Researchers developing such therapies (especially CAR T-cell therapies) recognize the special difficulty in targeting solid tumors, and are including studies attempting to determine the barriers that might prevent effective therapy of solid tumors with their experimental therapies. Some companies have also been producing therapies that are designed to overcome these barriers.

Now comes a “Brief Report” (published in December 2016) in the New England Journal of Medicine that focuses on an experimental treatment for the brain cancer glioblastoma with CAR T-cells. The study was carried out by researchers at the City of Hope (Duarte, CA). In this study, the CAR T-cells used were designed to target the high-affinity interleukin-13 (IL-13) receptor IL13Rα2, which is overexpressed in a majority of glioblastomas. The researchers administered the therapy locally in the brain, by injecting it into the tumor site and/or via infusion in the brain’s ventricular system. This contrasts with the use of CAR T-cells for treatment of hematological malignancies, in which the CAR T-cells are administered systemically.

Treatment with the CAR T-cells induced a transient, complete response in a patient with recurrent multifocal glioblastoma. This included a dramatic improvement in quality of life, including the discontinuation of use of systemic glucocorticoids and a return to normal life activities. The remission was sustained for 7.5 months. Nevertheless, the patient eventually developed new tumors. The authors concluded that their study provides proof-of-principle data that confirm IL13Rα2 as a useful immunotherapeutic target in glioblastoma, and suggest that CAR T cells can mediate profound antitumor activity against a difficult-to-treat solid tumor.

Meanwhile, as discussed in our report, researchers at Kite Pharma and University of Pennsylvania/ Novartis have been studying treatment of glioblastoma with CAR T-cells that target the epidermal growth factor receptor variant III (EGFRvIII). Some 20-30% of glioblastomas express this variant. The two groups are running parallel early-stage clinical trials of two different EGFRvIII CAR agents. The researchers believe that these parallel studies may be informative for future development of CAR therapies for solid tumors. However, no dramatic results such as seen by the City of Hope group have yet been reported for these studies.

TIL therapies for solid tumor cancers

Currently, the most successful cellular immunotherapies for solid tumor cancers have involved treatment with TILs. Steven A. Rosenberg, M.D., Ph.D., of the National Cancer Institute pioneered the study of TIL therapy, and of cellular immunotherapy in general. Our 2017 report  includes extensive discussions of the studies of TIL therapy carried out by Dr. Rosenberg and his collaborators, from the 1980s to today. Unlike CAR T-cell and recombinant TCR-based therapies, TILs are normal T cells that have not been genetically engineered.

Most clinical studies with TIL therapy have been in advanced melanoma. However, more recent studies have included “proof of principle” studies in patients with epithelial cancers of the digestive system. In some cases, these have included studies with TILs that target cancers with the KRAS G12D mutation, a notorious “undruggable” driver mutation that is involved in causation of many human cancers. More recent work in Dr. Rosenberg’s group has included mechanistic studies designed to determine the neoantigens that are targeted by antitumor TILs. Some of these most recent studies are being applied to treatment of non-small cell lung cancer (NSCLC).

However, as discussed in our report and in another article on this blog , TIL therapies have been difficult to commercialize. Nevertheless, in recent years, a San Carlos, CA company called Lion Biotechnologies (which on June 27, 2017 changed its name to Iovance Biotherapeutics has been focusing on doing just that. Iovance has been working with Dr. Rosenberg and his colleagues at the NCI under a Cooperative Research and Development Agreement (CRADA) to develop and commercialize TIL therapies.

On June 5, 2017, Iovance announced a poster presentation  of a study of 16 patients enrolled in the first cohort of its ongoing Phase 2 study of LN-144 for the treatment of metastatic melanoma, at the ASCO Annual Meeting.   LN-144 is the company’s autologous TIL therapy for the treatment of patients with refractory metastatic melanoma. Iovance’s Phase 2 clinical trial of LN-144 (clinical trial number NCT02360579) is designed to assess the safety, efficacy, and feasibility of the autologous TIL therapy, followed by interleukin-2 (IL-2), in the treatment of this class of patients.

The data presented at the ASCO meeting showed that Iovance can manufacture TILs at its central GMP facilities to treat patients at multiple clinical sites. According to the company, the initial data show clinically-meaningful outcomes, as assessed both by objective response rate (ORR) and disease control rate (DCR), in a heavily pre-treated patient group, all of whom had received prior anti-PD-1 (e.g., pembrolizumab or nivolumab) and over 80% with prior anti-CTLA-4 (e.g., ipilimumab) checkpoint inhibitors.

In the ASCO poster presentation, the company’s academic collaborators presented updated data from 16 patients who were infused as of April 24, 2017. These advanced metastatic melanoma patients were a median age of 55 and were highly refractory to multiple prior lines of therapy with significant tumor burden at baseline. Of the evaluable patients, a 29% ORR was reported, including one complete response (CR) continuing beyond 15 months post-administration of a single TIL treatment. 77% percent of patients had reduction in target tumor size. The mean time to first response was 1.6 months, with the CR developing at 6 months.

Responses were observed in patients with wild type tumors and with tumors carrying BRAF  mutations. The protocol for this study was amended to increase the sample size for the study, as well as to further define the patient population to patients with unresectable or metastatic melanoma who have progressed after immune checkpoint inhibition therapy, and if BRAF mutation-positive, after BRAF targeted therapy.

In addition to the melanoma study, Iovance plans to initiate Phase 2 TIL therapy studies in cervical and head-and-neck cancers during 2017. The TIL populations to be used for these studies, LN-145, will be selected for reactivity to human papillomavirus (HPV) proteins E6 and E7. The selection and use of such TIL populations was developed by researchers in Dr. Rosenberg’s group. Iovance is currently enrolling patients in its Phase 2 melanoma and cervical and head-and-neck cancer studies.

Recent review on treating solid tumors with CAR-T cell therapies

Now comes a review by Irene Scarfò, Ph.D. and Marcela V. Maus, MD, Ph.D. published in March 2017 in the Journal for ImmunoTherapy of Cancer. This review focuses on factors that may limit the efficacy of CAR-T cell therapies in solid tumors, and how these factors might be overcome.

Some of the factors discussed in this review include:

• Hypoxia, nutrient starvation, and resulting changes in T-cell metabolism (many human solid tumors contain high percentages of hypoxic tissue)
• Interactions between CAR T-cells and tumor stroma that may inhibit the ability of CAR T-cells to penetrate tumors
• Targeting cytokine networks, for example by inducing the local release of cytokines that promote anti-tumor immune responses. For example, interleukin-12 (IL-12) is a key inflammatory cytokine, which is able to induce several pathways that promote such a response. (We discussed IL-12-based therapeutics for use in immuno-oncology, as well as therapeutics based on such cytokines as IL-2, IL-10 and IL-15, in Chapter 1 of our report.) Starting from these considerations, several groups are investigating so-called “fourth generation” CAR T-cells, which are CAR-T cells that are designed to secrete IL-12.

The immunosuppressive environment of the interior of solid tumors results in the upregulation of surface inhibitory receptors, especially programmed death-1 (PD-1) on CAR T-cells. PD-1 inhibits the antitumor activity of the CAR T-cells. Researchers are therefore developing therapies in which they treat solid tumors with a combination of CAR T-cells directed to an appropriate tumor antigen and an immune checkpoint inhibitor such as pembrolizumab or nivolumab. Alternatively, researchers may use a genetic engineering strategy to block PD-1.

Currently, researchers are testing approaches based on these factors in animal models, and may soon be advancing into human clinical trials. As with other approaches classified as “immuno-oncology 2.0”, these trials will involve the use of combination therapies. The goal of early clinical trials in this area will be to determine the safest and most effective combinations for treatment of patients with solid tumors.

Conclusions

The field of cellular immunotherapy for cancer is an increasingly exciting and fast-moving area. Most of the focus is on breakthrough treatments of CD19+ hematologic tumors, with late-stage CAR T-cell therapies such as Novartis’ CTL019 (tisagenlecleucel-T), and Kite’s KTE-C19 (axicabtagene ciloleucel), which are rapidly approaching the market. However, there are also new indications that researchers and companies might be able to develop cellular immunotherapy-based treatments for certain types of solid tumors in the next several years. All in all, cellular immunotherapy will be an increasing area of focus for researchers, companies, and analysts over the remainder of this decade and beyond.

For more information on our recent report, Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes, or to order it, see the CHI Insight Pharma Reports website. 

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.

CAR T cells attacking a cancer cell. (Source: National Cancer Institute)

On May 3, 2017 Cambridge Healthtech Institute’s (CHI’s) Insight Pharma Reports announced the publication of a new book-length report, Cancer Immunotherapy: Building on Initial Successes to Improve Clinical Outcomes, by Allan B. Haberman, Ph.D.

The new 2017 report includes an updated discussion of approved and clinical stage agents in immuno-oncology. It also addresses the means by which researchers and companies are attempting to build on prior achievements in immuno-oncology to achieve improved outcomes for more patients. This approach is often referred to as “immuno-oncology 2.0.” The American Society of Clinical Oncology (ASCO) named “immunotherapy 2.0” as its “Advance of the Year” for 2017.

As discussed in the report, researchers have found that checkpoint inhibitors such as pembrolizumab (Merck’s Keytruda) and nivolumab (Bristol-Myers Squibb’s Opdivo) produce tumor responses by reactivating TILs (tumor infiltrating lymphocytes). As a result, they have been developing biomarkers that distinguish inflamed (i.e. TIL-containing) tumors—which are susceptible to checkpoint inhibitor therapy—from “cold” tumors, which are not. They have also been working to develop means to render “cold” tumors inflamed, via treatment with various conventional therapies and/or development of novel agents. These studies constitute the major theme of immuno-oncology 2.0.

Meanwhile, cellular immunotherapy has also been advancing, with two chimeric antigen receptor (CAR) T-cell therapies (from Novartis and Kite Pharma) in preregistration with the FDA as of March 2017.

These and other areas of current cancer immunotherapy R&D are discussed in the new report.

The first wave of immuno-oncology 2.0 treatments has begun to achieve regulatory approval:

• On May 12, 2017, Merck gained FDA approval to market a combination of pembrolizumab with chemotherapy (specifically, carboplatin plus pemetrexed) for first-line treatment of non-small cell lung cancer (NSCLC). This is based on a Phase 2 clinical study that showed that the chemo/pembrolizumab combination resulted in a much higher statistically-significant overall response than chemo alone — 55% vs. 29%. As we discuss in our report, certain types of chemotherapy can induce immune responses that convert “cold” tumors into inflamed tumors, thus making them susceptible to checkpoint inhibitor treatment.
• On May 23, 2017, the FDA awarded accelerated approval to Merck’s pembrolizumab for the treatment of adult and pediatric patients with unresectable or metastatic solid tumors that exhibit high microsatellite instability (MSI-H) or are mismatch repair deficient (dMMR). This indication includes patients with solid tumors that have progressed following prior treatment, and who have no satisfactory alternative treatment options. It also includes patients with colorectal cancer that has progressed following treatment with chemotherapy. This is the first approval of an anticancer agent based on a tumor’s biomarker, regardless of where the tumor originated in the body. As we discuss in our report, mismatch-repair deficiency results in a large somatic mutation load. This supports a large and diverse population of TILs, which are specific for mutation-associated neoantigens. Treatment with checkpoint inhibitors may reactivate these TILs, resulting in effective antitumor immune responses.

Our report is designed to enable readers to understand current and future developments in immuno-oncology, especially including new developments in immunotherapy 2.0. It is also designed to inform the decisions of leaders in companies and in academic groups that are working in areas that relate to cancer R&D and treatment.

For more information on the report, or to order it, see the CHI Insight Pharma Reports website.

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.