Infinity Pharma to stop rheumatoid arthritis treatment

(Reuters) - Infinity Pharmaceuticals Inc said it would stop testing its lead drug as a treatment for rheumatoid arthritis after it failed a study, the second failure for the drug in four months. The company's shares fell as much as 11 percent on Thursday. Duvelisib, which aims to stop tumors from growing by blocking certain enzymes involved in the regulation of cell growth, was, in October, also found to be unsuccessful in treating patients with mild allergic asthma. These two trial failures likely spells the end of any hopes of Infinity Pharma expanding duvelisib into any "lucrative indications", Stifel Nicolaus analysts said in a note. Infinity Pharma said duvelisib, being developed with AbbVie Inc in oncology, will still be tested to treat various types of blood cancer. Not enough patients given duvelisib showed a significant enough improvement over those given a placebo in a 12-week mid-stage study involving 322 adults with moderate to severe rheumatoid arthritis, Infinity Pharma said. The patients were also given another commonly-used treatment called methotrexate, used to fight certain cancers as well as psoriasis and arthritis. Rheumatoid arthritis, which affects about 1.5 million people in the United States, occurs when the immune system attacks the body's tissues, causing joint pain, swelling and stiffness. Infinity's shares were down 8 percent at $15 in midday trading on the Nasdaq. Through Wednesday, the stock had risen about 23 percent since the trail failure in October. (Reporting by Rosmi Shaji in Bengaluru; Editing by Savio D'Souza)