Adeno-associated virus. Source: https://commons.wikimedia.org/wiki/File:Adeno-associated_virus_serotype_AAV2.jpg

In recent weeks, buyouts of gene therapy companies by Big Pharmas or Big Biotechs—as well as other major gene therapy deals—have been making the news. Specifically, on February 25, 2019, leading gene therapy company Spark Therapeutics (Philadelphia, PA) announced that it had entered into a merger agreement with Roche. Under this agreement, Roche will fully acquire Spark for $4.3 billion.

Roche will keep Spark as a independent entity, similar to Roche’s Genentech. This should enable the type of innovation that has been demonstrated by Spark since its founding in 2013.

Meanwhile, Biogen is buying gene therapy company Nightstar Therapeutics (London, UK) for $800 million in order to gain access to its suite of gene therapies for rare retinal diseases. According to “Endpoints News”, the Biogen/Nightstar deal is the result of a bidding war for Nighrstar by Biogen and three other (unnamed) companies.

And Johnson & Johnson has signed a deal with MeiraGTX (London and New York) for rights to its experimental gene therapies for rare retinal diseases. The two companies also will collaborate on improving gene therapy manufacturing. J&J paid Meira $100 million in cash upfront, and Meira could get up to $340 million in additional downstream payments plus royalties on sales if its products reach the market. J&J will be paying for clinical development of the therapies.

Our previous discussions of Spark and Nightstar

We discussed Spark and Nightstar and their gene therapy programs in our 2015 book-length report, Gene Therapy: Moving Toward Commercialization. We also updated our discussion of Spark’s lead ophthalmological gene therapy product Luxturna (voretigene neparvovec-rzyl) (formerly known as SPK-RPE65), in our December 21, 2017 article on this blog.

As we discussed in these publications, Spark’s Luxturna is a one-time gene therapy designed to treat patients with an inherited retinal disease (IRD) caused by mutations in both copies of the RPE65 (retinal pigment epithelium-specific 65 kDa protein) gene. It consists of a version of the human RPE65 gene delivered via an adeno-associated virus 2 (AAV2) viral vector, and is administered via subretinal injection. Luxturna is the first FDA-approved gene therapy for a genetic disease, the first FDA-approved pharmacologic treatment for an IRD, and the first AAV-vector gene therapy approved in the USA.

Nightstar is clinical stage company whose initial focus is treatment of the IRD choroideremia (CHM). CHM is an X-linked genetic disease caused by mutations in the X-CHM gene. These mutations interfere with the production of Rab escort protein-1 (REP1). REP1 is involved in intracellular protein trafficking, and the elimination of waste products from retinal cells.

Nightstar’s lead product is NSR-REP1 (formerly known as AAV2-REP1). This gene therapy consists of an AAV2 vector containing recombinant human complementary DNA, (cDNA), that is designed to produce REP1 inside the eye. NSR-REP1 is currently in a Phase 3 registrational clinical trial, known as the STAR trial. It is thus the most clinically advanced candidate for choroideremia in the world.

In addition to discussing gene therapies under development (including the above-mentioned Spark and Nightstar programs, as well as many others), our 2015 gene therapy report also discusses development and use of gene therapy vectors, especially AAV. It thus continues to be a valuable reference for understanding the gene therapy field.

MeiraGTX

MeiraGTX focuses on AAV-based gene therapies. Its five programs in clinical development include three ophthalmological therapies, as well as gene therapies for a salivary gland condition, and for Parkinson’s disease. The company’s most advanced programs are in Phase 1/2 clinical development, and include treatments for achromatopsia and X-linked retinitis pigmentosa.

Spark is also developing gene therapies for hemophilia

As discussed in a February 23, 2019 “Endpoints News” article on the Roche/Spark merger, Roche’s interest in Spark is not only because of its leadership position in ophthalmological gene therapies, but also because of its broad product portfolio. Notably, among Spark’s product candidates is SPK-8011, one of the leading clinical-stage gene therapies for hemophilia A. SPK-8011 is a novel AAV vector containing a codon-optimized human factor VIII gene under the control of a liver-specific promoter. As the result of promising Phase 2 data, SPK-8011 is now in a lead-in study (NCT03876301) for phase 3 clinical trials. Also in a lead-in study for Phase 3 trials (sponsored by Spark’s partner for this therapy, Pfizer) is Spark’s hemophilia B candidate, fidanacogene elaparvovec (SPK-9001).

The hemophilia gene therapy field is highly competitive. Other companies with clinical-stage hemophilia gene therapies include BioMarin, uniQure, and Sangamo/Pfizer.

Roche’s acquisition of Spark’s SPK-8001 may enable Roche/Genentech to strengthen its leading competitive position in the hemophilia A market. Roche received FDA approval for its blockbuster prophylactic Hemlibra for hemophilia A without factor VIII inhibitors in October 2018.

Pfizer enters the gene-therapy buyout arena

In late-breaking (March 20, 2019) news, Pfizer has taken an exclusive option to acquire Vivet Therapeutics (Paris, France).

Vivet focuses on the development of gene therapies for inherited liver diseases with high unmet medical need. Under the new agreement, Pfizer has acquired 15% of Vivet’s equity, and an exclusive option to acquire all outstanding shares. Initially, the two companies will collaborate on the development of Vivet’s VTX-801, a preclinical-stage gene therapy for Wilson disease.

Wilson disease is a rare and potentially life-threatening liver disorder involving impaired copper transport, resulting in severe copper poisoning. The Wilson’s disease mutation disables the excretion pathway for copper via the bile. This results in excess copper accumulation in the liver and other organs, including the central nervous system. Untreated, Wilson disease results in severe copper toxicity, which can be fatal. It can only be cured by liver transplantation. Existing therapies for Wilson disease are of low efficacy and/or result in significant side effects.

VTX-801, like other therapies discussed in this article, is an AAV-based gene therapy. It is Vivet’s first gene therapy, and the most advanced in development.

Under the terms of the agreement, Pfizer paid approximately €45 million (US$51 million) upon signing and may pay up to €560 million (US$635.8 million) in milestone payments. Pfizer also has an option to acquire 100% of Vivet, based on the results of a Phase 1/2 clinical trial for VTX-801. Pfizer senior executive Monika Vnuk, M.D., Vice President, Worldwide Business Development, is also joining Vivet’s Board of Directors.

Vivet’s earlier-stage preclinical liver-directed gene therapies include a program for progressive familial intrahepatic cholestasis (PFIC) for bile excretion defects and in citrullinemia for defects in the urea cycle.

The Pfizer/Vivet agreement is yet another example of the recent Large Pharma/Biotech enthusiasm for buying up small gene-therapy companies.

Concerns about cost and patient selection for “one and done” gene therapies

As we discussed in our December 21, 2017 article on this blog, Luxturna, as the first FDA-approved gene therapy for an inherited disease, is expected to be a one-time (“one and done”) therapy for its targeted condition. It is expensive, priced at $850,000 ($425,000 per eye affected by an RPE65 gene mutation). This made Luxturna the highest priced therapy in the U.S. to date. Other “one and done” gene therapies are also expected to be expensive. Pricing and related issues with “one and done” gene therapies thus affect the prospects for gene therapy companies and for larger companies that are planning to acquire or partner with them.

In our December 21, 2017 article, we discussed payer programs designed to enable patient access to treatment with Luxturna. These include an outcomes-based rebate plan with a long-term durability measure, and a proposal under which payments for Luxturna would be made over time. Such programs are designed to reduce risk and financial burden for payers and treatment centers. As we discussed, pricing and payer programs that become established for Luxturna may have a wide impact on the entire gene therapy field.

A March 5, 2019 article on gene therapy by Jeremy Schafer, PharmD, MBA of Precision for Value was published in Clinical Leader. This article focused on designing gene therapy clinical trials to meet the concerns of payers and health systems.

At the recent annual meeting of the Academy of Managed Care Pharmacy, the results of a survey that included the perceptions of gene therapy among health plans and health system stakeholders were presented. Among these respondents, 35% stated that their primary concern with gene therapy was “selecting appropriate patients.” Another 30% named “the potential need for retreatment” as their main concern. The major concern of 5% of respondents was that patients treated with gene therapy would still need conventional treatment for their condition. A total of 88 percent of respondents felt that information on appropriate patient selection as well as durability of response would be extremely valuable. Another 60 percent would like to have an economic model on the long-term value of the gene therapy.

Dr. Schafer’s article discussed how clinical trial design might help address these concerns. For example, gene therapy clinical trials might include a long-term follow-up plan to capture data on an ongoing basis. This might help address the question as to whether a gene therapy is truly “one and done”. Ongoing data from these trials might be shared in peer-reviewed publications. The long-term data might be used in economic models by health plans.

In terms of identifying appropriate patients for gene therapies, clinical trial design might include clearly-defined inclusion and exclusion criteria, based on good scientific rationales. Preplanned subgroup analyses might show which groups respond well or not so well to a gene therapy. Clinical trials could also be designed to determine whether and to what extent gene-therapy patients will still need ongoing therapy with conventional drugs.

All these issues in structuring payer programs and in clinical trials designed to meet the concerns of payers and health plans (and of partner and acquiring companies) may enable the development and acceptance of gene therapies as this field moves beyond the release of the first few products.

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

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.