Regeneron Pharmaceuticals Inc. and Sanofi said a clinical trial showed their drug candidate sarilumab reduced symptoms of moderate to severe rheumatoid arthritis.
The companies said late Tuesday that they are discussing the doses of the drug that will be tested in a late-stage clinical trial. In a mid-stage trial, the companies said patients who were treated with sarilumab and methotrexate improved more than patients who were treated with methotrexate and a placebo.
Sanofi shares rose 50 cents, or 1.3 percent, to $38.59 in morning trading and Regeneron added 23 cents to $57.38.
The study compared five different doses of the drug to placebo. Regeneron and Sanofi said 49 percent of patients who were treated with the lowest dose had their symptoms improve by at least 20 percent, while 72 percent of the patients in the highest-dose group met that benchmark. They said 46.2 percent of the methotrexate and placebo patients had the same improvement. Sarilumab patients were also more likely to have improvements of 50 percent and 70 percent, and also did better on a separate measurement of symptoms.
The most common side effects of sarilumab included infections, low white blood cell count, and liver function test abnormalities. The results are from a 12-week study involving 306 patients who were not helped by previous treatment with methotrexate. The study will continue for 12 more weeks.
The companies said a separate study showed sarilumab did not work better than a placebo as a treatment for ankylosing spondylitis, a painful, progressive form of spinal arthritis.
Citi Investment Research analyst Yaron Werber said it is too soon to tell how well sarilumab compares to Roche's rheumatoid arthritis drug Acemtra, which is already on the market. However he said the data on side effects looks encouraging. Werber said the results show the depth of the Tarrytown, N.Y., company's collaboration with Sanofi. The most advanced drug in that collaboration is the cancer treatment aflibercept, but it also includes treatments for high lipid levels and pain.