Shares of Rigel Pharmaceuticals, Inc. (RIGL 10.00%), a clinical-stage biotech, are on the rise today after the company announced results of a recent meeting with the Food and Drug Administration. It looks like the agency isn't too concerned with mixed data from pivotal trials supporting the company's first new drug application for Tavalisse, formerly fostamatinib. In response, the stock has risen 33.9% as of 10:58 a.m. EDT during Monday's session
Between 60,000 and 125,000 Americans suffer from an incurable blood-based disease called immune thrombocytopenic purpura (ITP). Tavalisse could generate perhaps $350 million in peak annual sales if approved to treat this underserved group, but mixed results during pivotal trials underpinning the candidate's new drug application have kept the stock depressed. The stock is surging today because the FDA won't require an independent advisory committee meeting to discuss the application, which strongly suggests the mixed results aren't going to be an issue after all.
Although Tavalisse sailed through the first of two studies to see if it can improve the rate of stable platelet responses for patients with ITP, Rigel stock tanked last October after the candidate technically failed a second, nearly identical trial. As in the first trial, 18% of the fostamatinib-receiving patients achieved a stable platelet response. Unfortunately, one respondent in the placebo arm hit the mark as well. This rendered the difference between the treatment arm and the placebo arm statistically insignificant for the second pivotal trial, but taken together, the data strongly suggests the drug is effective.
Of course, the FDA might not be planning to convene a panel of independent physicians to discuss Rigel's application because the agency already knows it will require more efficacy data. I'd say the odds of this are slim. The FDA generally spends a couple months mulling over new drug applications before it agrees to begin a formal review, and Rigel crossed this hurdle in June.
Instead of preparing for an advisory committee meeting, the company will probably ready itself for its first commercial launch instead. The FDA is expected to deliver an approval decision during or before next April. If approved, today's gains will probably seem minor in comparison.