Chiron’s Stock Falls on News of Drug Study

Chiron Corp. shares tumbled 11% as the biotechnology company said its Regranex treatment didn’t prove as effective as the firm had hoped in testing for a new use in treating bedsores. Johnson & Johnson, which markets Regranex for diabetic foot ulcers, stopped enrolling patients in a study of the drug because the medication didn’t appear to be as effective as it did in an earlier trial, Chiron said. The decision is a setback for Chiron, which is 44%-owned by Swiss drug maker Novartis, because analysts had hoped sales would grow if Regranex won approval as a bedsore treatment. Shares in Emeryville, Calif.-based Chiron fell $3.56 to close at $28.31 on Nasdaq. It was the stock’s biggest one-day percentage decline since 1996. J&J;, based in New Brunswick, N.J., fell 50 cents to $91.50 on the NYSE. Chiron makes Regranex’s active ingredient, a compound known as platelet-derived growth factor, or PDGF.