GlaxoSmithKline and Ligand Pharmaceuticals won a key endorsement for Promacta for the short-term treatment of people with chronic immune thrombocytopenic purpura, or ITP. An FDA expert committee voted unanimously to back the drug and a formal decision is expected June 19. The news on Friday provided a big boost to Ligand shares, which shot up almost 50 percent. The rise came after a big loss last week after FDA staffers raised doubts about the drug's ability to significantly lower bleeding.
The decision in favor of the drug came despite concerns that the developers have yet to produce a significant amount of data on the effects of the drug over a long period of use. That's likely to be a key concern for regulators, as ITP is a chronic condition. Glaxo, though, said it has more studies in the works and plans to file additional data later this year.