U.S. FDA rejects filing for Celgene MS drug, shares fall

(Reuters) - U.S. health regulators have rejected Celgene Corp's application seeking approval of a key multiple sclerosis drug due to insufficient data, the company said on Tuesday, a surprise development that will likely delay the entry to market of one of Celgene's most important pipeline assets.Celgene shares fell nearly 8 percent after it revealed that it had received a "refusal to file" letter from the Food and Drug Administration (FDA) for its ozanimod for the treatment of patients with rel