Pet cancer treatment: R&D dead end or the next blockbuster goldmine?

From the online publication Animal Pharm, the leading online business intelligence service for the animal health sector, providing animal health professionals worldwide with news, analysis and insight.

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Treatment of pet cancer is an emotional topic amongst drug developers and owners of companion animals alike. However, drugs specifically approved to treat canine and feline cancers have yet to form a valuable market in the animal health sector. Animal Pharm Editor Joseph Harvey consulted Merial, Aratana Therapeutics and VetDC to find out why this is and what is being done in the R&D stakes.

Why, in 2015, is there not a blockbuster treatment available for cancer in pets?

The statistics paint a clear picture – cancer is a major pet disease.

According to the Morris Animal Foundation, cancer is the leading cause of death in dogs over the age of two in the US. Around 50% of dogs will be diagnosed with cancer at some point in their lives, while one in four dogs will die of cancer.

The current market for treating pet lymphoma – one of the most common pet cancers – is disjointed as it contains chemotherapeutic generic therapies developed for use in humans but not approved for use in companion animals.

Steven Roy, chief executive of Colorado-based VetDC, explained: “There are a wide variety of off-label, multi-drug regimens that are currently being employed across veterinary clinics. Several standards of care have emerged but these can vary based on owner finances, travel ability, frequency of visits, etc.

“Like humans, not all cancers are treated the same in pets, so there are multiple types of drugs being used and different regimens employed, depending on whether a pet is naive to previous treatment (first line) or has relapsed and needs a different approach (second and third lines). As more novel therapies become available, we anticipate that new standards will emerge.”

Additionally, the few cancer drugs approved specifically for use in companion animals have suffered as animal health companies have left the products with veterinary oncologists and not invested in a specialty sales force that understands pet oncology.

While previous research into pet cancer treatments by the majority of leading animal health firms has been limited, both Zoetis and Merial have been active in this space.

As has Aratana Therapeutics, which has been able to source the capital and lead molecules that others have failed to previously gain. The firm is beginning commercialization of canine-specific monoclonal antibody therapies as aids in the treatment of T and B cell lymphoma in dogs – an approach, which to date, have been unfamiliar to animal health companies and the sector’s regulators.

Steven St. Peter, chief executive of Aratana, told Animal Pharm: “Developing our canine analogue to the human monoclonal antibody, Rituxan, has the potential to transform the treatment of canine B cell lymphoma, as Rituxan did on the human health side.”

If previous treatments failed to set the market alight, why do companies still think there is a viable opportunity for pet cancer therapies?

Certain firms have products currently on the market – Merial sells a vaccine for canine oral melanoma, Zoetis markets a canine mast cell tumor drug called Palladia and AB Science sells the conditionally-approved Kinavet-CA1.

Aratana’s monoclonal antibody used as an aid in the treatment of B-cell lymphoma in dogs received full US licensure from the USDA in January 2015, and its monoclonal antibody used as an aid in the treatment of T-cell lymphoma in dogs has conditional USDA approval, with full approval expected something this year.

Prior to its acquisition by Zoetis, Abbott Animal Health licensed the US rights to the Oasmia Pharmaceutical drug conditionally-approved by the FDA, Paccal Vet-CA1.

Merial told Animal Pharm: “We are a leader in oncology, having brought the first vaccine treatment to market with Oncept Canine Melanoma Vaccine for Dogs, built with our recombinant expertise.

In March, the Merial’s Feline Interleukin-2 Immunomodulator (IL2) – an adjunct therapy that is designed to upregulate the post-surgical immune response to feline fibrosarcoma – was granted US conditional licensure.

“Both treatments are changing the way veterinary oncologists approach the management of cancer,” Merial explained. “Each therapy has its strengths and challenges and we closely monitor current treatment options while looking for novel ways to develop new ones that can be linked to existing therapies.”

“Merial recognizes that there is an ongoing need in the market for cancer treatments. We are dedicated to cancer research and treatment, and are making great strides in this area to provide real benefits to pets.”

Meanwhile, Aratana is gaining ground with two products in the market in the US for canine B and T cell lymphoma, the European rights to the cancer molecule for treatment of canine lymphoma that VetDC is developing for North America, and most recently, a licensing deal with Advaxis, for a novel cancer immunotherapeutic for the treatment of canine osteosarcoma, as well as other potential companion animal cancers.

Dr St. Peter said: “Aratana is pleased to be bringing the novel monoclonal antibody therapy for canine lymphoma to pet owners. We are running clinical studies to gather data to help veterinary oncologists understand the benefit of these new therapeutic tools.

“Our two large multi-site, placebo controlled studies in canine lymphoma patients are ongoing. This demonstrates our commitment to high quality, evidence based treatments. In addition, we are working with leading oncologists such as Dr Mason at PennVet, to study our cancer immunotherapeutic.”

However, many types of animal cancers are still without treatment, and there are currently no drugs or vaccinations approved for the treatment of cancer in cats.

Certain commercially-available treatments have significant side effects that need to be managed considerably, while cost remains a significant barrier for long-term use. The combination of no side effects with a viable cost is a combination many companies are aiming to solve.

Mr Roy of VetDC said: “Some of the newer pet treatments that have been launched are somewhat limited in their scope. Most mast cell cancer is treated successfully with surgery, thus the drug market is currently limited to subjects with recurrent or metastatic tumors.

“In the case of lymphoma, we believe there is a significant opportunity, as drugs are the primary treatment option.  Our data suggest that ~30% of all dogs today being treated for lymphoma are getting some form of chemotherapy (at owner costs ranging from $2,500-$8,000 per course of therapy), so a market already exists in spite of the lack of industry support.”

Other companies vying to succeed in the companion animal cancer drug space include: Regeneus and its autologous canine cancer vaccine Kvax; Functional Nutriments’ cell suicide candidate; CanFel Therapeutics’ crowd-funded solution; BNOAT Oncology’s vitamin B12-based anti-tumor agent; Karyopharms’ Verdinexor; and VetDC’s Tanovea™-CA1 for canine lymphoma, amongst others.

There are a lot of pet cancer products being developed at the moment. Is there room for multiple winners in this space? Or is it likely one treatment will become the ‘gold standard’?

The consensus from companies developing cancer candidates is that a whole toolbox of treatments should be available in the future, to either complement or replace generic chemotherapy. This toolbox will provide targeted options for different species and varying tumors in very much the same way human oncology does. Clinicians may eventually use a combination of treatments, tailored for the individual patient based on genetic markers of response.

This means there is plenty of room for innovation and success in the pet cancer treatment area, whether a product is used alongside another treatment or as a second-line/later-stage therapy.

Merial told Animal Pharm: “It is important to understand that there is not a one-size-fits-all solution with this disease, and there are many opportunities for cancer research and effective treatments.

“Merial’s objective is to expand the veterinary oncology toolbox – each product brought into the marketplace represents an important option that allows for tailored treatment regimens for each patient based on disease occurrence and the overall health of the pet.”

Mr Roy of VetDC said: “One of the keys to managing cancer is to treat it as a chronic disease, attacking cancer cells with multiple therapies over time to increase lifespan. The primary difference in pets is that veterinarians are lacking multiple effective options, so unfortunately, euthanasia or palliative care is still fairly common.

“The reality is that very few breakthrough human cancer drugs will ever be used in pets, given lack of adequate testing and significantly higher price points ranging from $10,000 to $100,000 for a course of therapy.

“However, as more novel, effective, safe and affordable options become available for companion animals, the use of pet cancer therapies is likely to grow dramatically over time. In the same way human cancer treatment has evolved from old generic drugs to novel, highly targeted therapies, we see the pet arena replicating this model.  Our vision is to bring important, novel drugs to market, so that pets with cancer can live longer, fuller lives.”

Aratana’s Dr St. Peter agreed: “Aratana has made a commitment to bring the best of human biomedical science to bear on the problem of cancer in pets. Doing the research to understand the safety profile, and providing evidence of effectiveness in placebo controlled trials is the gold standard for human medicine, and the standard we are happy to set, as we work with veterinary oncologists.

“We have put significant resources into starting our commercialization effort, including hiring two board-certified veterinary oncologists.”

However, there are many areas of the US without local veterinary oncologists. Primary care doctors may not be comfortable with the protocols and the therapeutic choices needed in pet cancer treatment, nor are they staffed and experienced in managing these types of cases.

Aratana clearly feels this is an area ripe for change. The firm told Animal Pharm: “Pet owners are looking for solutions that keep their pets with them as long as possible but with an acceptable the quality of life. Veterinary oncologists and general practitioners want to offer their clients solutions, and we believe they will be eager to explain that new and perhaps better tolerated therapies are available.

“We believe that cancer immunotherapy, and monoclonal antibody therapy in particular, will be game changers in veterinary medicine, like they have been in human medicine.”

Mr Roy said: “Veterinarians are increasingly cognizant of the growth in the number of pet cancer cases in their practices and are looking for new opportunities to assist their clients.

“Obviously, owner out-of-pocket costs limit the potential of pet therapies to achieve billion-dollar projections as in human cancer, but it is not unreasonable to assume novel pet cancer drugs could eventually generate sales in the $50m-$100m range.

“My experience in the human health space suggests that blockbuster markets are created once the industry gets behind them. I truly believe this opportunity is coming for pet cancer, and I anticipate an emergence of veterinary oncology as a force for this change.”

Whether or not industry gets behind cancer treatments, the real key is the development of pet cancer therapies that are effective in prolonging a good quality life for dogs and cats, as well as providing the evidence of their safety and effectiveness that will give the oncologists the confidence to prescribe them. More tools like this in the toolbox, particularly backed by regulatory approval, will be beneficial to both industry and pets alike.

Written by Joseph Harvey

Published: 18 May 2015 10:46 AM