Exelixis shares sink after Helsinn halts study

Shares of Exelixis took a hit after the biotech reported that Helsinn Healthcare had shelved a late-stage trial for the anti-cancer therapy becatecarin (XL119). Helsinn had licensed the therapy from Exelixis, which in turn, had licensed it from Bristol-Myers Squibb. Helsinn halted enrollment after concluding that the therapy was proving less effective than chemotherapy. The drug was aimed at tumors of the biliary tract.

- here's the AP report on the trial