Synta halts study of lung cancer treatment, stock plummets

(Reuters) - Synta Pharmaceuticals Corp has decided to end a late-stage trial of its lung cancer treatment after an independent review said it proved ineffective, nearly halving its stock in extended trading on Tuesday. Lexington, Massachusetts-based Synta's shares were down 46.6 percent at $1.09 after the bell. The late stage study aimed to see if a combination of its drug ganetespib with chemotherapy drug docetaxel would work better than docetaxel alone for advanced non-small cell lung adenocarcinoma. The company said it stopped the trials on the recommendation of an independent data-monitoring committee, which said the combination of the two drugs was unlikely to show significant improvement in overall survival compared to docetaxel alone. About 85 percent to 90 percent of lung cancers are non-small cell lung cancer and about 40 percent of lung cancers are adenocarcinomas, according to the American Cancer Society. Adenocarcinomas start in early versions of the cells that would normally secrete substances such as mucus and occurs mainly in current or former smokers, but it is also the most common type of lung cancer seen in non-smokers. Docetaxel is used in the treatment of a variety of cancers including breast, lung, prostate, gastric, head and neck, and ovarian cancer. Synta's shares closed at $2.04 on the Nasdaq. Up to Tuesday's close, the stock had fallen nearly 28 percent this year. (Reporting by Ramkumar Iyer in Bengaluru; Editing by Lisa Shumaker)