America's third-largest health insurer, Aetna Inc (AET.N), said it would no longer reimburse Questcor Pharmaceutical's (QCOR.O) sole drug for most diseases, wiping off more than $1 billion of the drugmaker's market value. In a clinical policy bulletin published on its website on Wednesday, Aetna said Questcor's Acthar gel was medically necessary only to treat infantile spasms as the drug was no better than existing therapies in the 18 other diseases that it was approved to treat. Shares of Anaheim, California-based Questcor fell as much as 56 percent, before regaining some losses to trade down 40 percent at $30.37 Wednesday afternoon on the Nasdaq.
