Survival Data Still Key for Medarex

Medarex (MEDX Quote) finished Friday's session up nearly 5% after the public release of the biotech company's research abstracts on its melanoma candidate ipilimumab. But analysts said there were few surprises in the data -- good or bad.

"Our conclusion is that we see little new information in the abstracts to be very excited about; however, we find Abstract No: 20004: 'Prolonged survival in objective responders to ipilimumab therapy,' to continue to suggest that durable responses that translate into an overall survival benefit remains the key to 010's approvability," wrote Susquehanna analyst Jason Kolbert, who has a neutral rating on the stock.

Overall survival data has been the topic of discussion for this drug as the company, which recently -- after discussion with the Food and Drug Administration -- changed the primary endpoint of a late-stage trial to overall survival from measurements of tumor progression. It also delayed filing for approval.

How a Study's Endpoints Changed

To review: Last December, Medarex said that a key ipilimumab phase II study failed to meet its primary endpoint, "which was to rule out a best objective response rate of less than 10 percent."

That trial and two concurrent late-stage studies, on ipiluminab as a second-line treatment, involved melanoma patients previously treated with chemotherapy. Discussing the results, the company pointed investors toward the "totality of the data" as what the FDA will use to review ipilimumab with plans to still file for approval by mid-2008.