Ligand says FDA extends blood-clot drug review

Drug developer Ligand Pharmaceuticals Inc. said after the bell Friday the Food and Drug Administration will take an additional three months to review its experimental blood-clotting drug Promacta.

The drug, which Ligand developed with partner GlaxoSmithKline PLC, is designed to treat chronic ITP, an immune system disorder that causes the body to destroy its own platelets, which can cause excessive bleeding.

The FDA was scheduled to make a regulatory decision on the drug by June 19, but has extended the review to Sept. 19. Though outside advisers have unanimously recommended the drug's approval, the FDA previously said Promacta wasn't much better than placebo in studies. The agency also cited several safety concerns.

A key issue for the FDA in prior statements was the absence of long-term safety data and concerns over the potential for liver toxicity. Though the company is only seeking approval for the drug's short-term use, physicians would still be able to prescribe the drug long-term.

Shares of San Diego-based Ligand rose 15 cents, or 5.6 percent, to close earlier at $2.83. Shares of U.K.-based GlaxoSmithKline fell 32 cents to end at $43.32.