By LINDA A. JOHNSON AP Medical Writer
FAIRLESS HILLS, PA (AP) — Investors are driving shares of drug developer BioMarin down by a third after U.S. regulators rejected its potentially game-changing gene therapy for Hemophilia A patients. The Food and Drug Administration’s rejection late Tuesday means BioMarin will have to complete an ongoing late-stage patient study. That will delay possible approval for a couple of years. The therapy could have freed Hemophilia A patients from frequent IV infusions of blood-clotting therapy to prevent internal bleeding from the rare bleeding disorder. Questions about whether it would work for a lifetime or just several years arose recently. The FDA now wants study participants to be followed longer. BioMarin shares were down 34% in midday trading.