Auxillium’s "Positive" Data For Xiaflex Not So Positive Given Severe Side Effects
Auxilium Pharmaceuticals (NASDAQ:AUXL) announced top-line data from a Phase IIIb trial evaluating treatment with Xiaflex for multiple Dupuytren’s Contracture cords at one time. The company called the data “positive”, as the 60-patient trial demonstrated response rates of 76% at the knuckle joint in the hand (MCP joint — 60% of all joints requiring treatment), but just 33% at the finger joint above (the PIP joint – next most common joint). The company plans to begin a larger trial for the treatment of multiple cords in the third quarter. Importantly, adverse events, including bruising, pain, itching, and lymphadenopathy were higher than observed in previous trials, which could make the FDA more cautious in approving the treatment for multiple cords at one time. Also adding to the safety concern there was one pulley rupture/ligament injury of a middle finger and a 24 hour hospitalization for pain control after 2 injections into a little finger. While AUXL states in its press release that the incidence of tendon/ligament injury with 2 concurrent injections is not different from the overall experience with Xiaflex to date (0.1%), the incidence in this trial calculates to 1.67%. These data could give physicians further pause in using Xiaflex, especially when considering for multiple cords. Stock could sell off on this news.