Several companies have recognized the value of including pet dogs in trials of cancer therapies being tried in people, and some have even gone on to develop new therapies in parallel for both people and pets. One of the latest examples of this trend is Rhizen Pharmaceuticals, a Swiss company that is working on an emerging class of drugs called PI3K delta inhibitors. On September 22, Rhizen announced that its drug, RV1001, is moving into midstage trials for the treatment of dogs with lymphoma.
PI3K (Phosphoinositide 3-kinase) is an enzyme that's been linked to several functions in cells, including cell growth and proliferation. In blood cancers, studies have shown that inhibiting the enzyme frees up the immune system to target disease-causing abnormal white blood cells and destroy them. Rhizen is also in early-stage testing of PI3K inhibitors to treat people with hematological cancers.
In a Phase I study of RV1001, three out of 21 dogs treated with the drug had a complete response, and 11 dogs had a partial response, according to a press release from Rhizen. The overall objective response rate was 67%. Dogs with both T-cell and B-cell lymphoma were included in the study, which was led by the Ohio State University College of Veterinary Medicine.
RV1001, which Rhizen is developing as a pill, was granted "minor use" designation by the FDA in July, allowing Rhizen 7 years of exclusive marketing rights if the drug is approved to treat dogs. The Phase II study will be conducted at several veterinary clinics throughout the U.S., according to Rhizen.
Canine lymphoma is similar to non-Hodgkin lymphoma in people, so dogs that develop the disease naturally are seen as ideal animal partners for researching new treatments. But a growing group of companies now see the veterinary market as an attractive market opportunity, as well.
That said, canine lymphoma is proving to be a difficult disease to crack. Aratana Therapeutics ($PETX), for example, has been running clinical trials of two drugs to treat the disease: AT-004, which was fully approved by the USDA in January to treat canine B-cell lymphoma, and AT-005, which is conditionally approved to treat T-cell lymphoma. Aratana is expanding its manufacturing capacity, and in July it told investors to expect a full launch of both drugs in late 2016. But after the market closed on September 24, the company announced that clinical trial results have been mixed and it expects revenue and profit opportunities to be modest.
- here's Rhizen's press release
Editor's note: This story has been updated to include the Aratana news on its two canine lymphoma treatments.