The 2 Surprising Reasons Exelixis, Inc. Lost 17% in September

Shares of Exelixis (NASDAQ: EXEL), a biotech company focused on the development of therapies to treat cancer, plunged 17% during the month of September, according to data from S&P Global Market Intelligence. Two factors, including new clinical data from a rival and analyst chatter, were the prime catalysts behind its poor showing.

The glaring issue for Exelixis came from rival Bristol-Myers Squibb (NYSE: BMY), which reported surprisingly positive data for its combination of cancer immunotherapies Opdivo and Yervoy in the CheckMate-214 trial in treatment-naive renal cell carcinoma (RCC) patients. The data showed a 37% reduction in the risk of death for intermediate- and poor-risk RCC patients compared to the current standard of care, Sutent, which is developed by Pfizer (NYSE: PFE). The combination therapy also achieved a greater than 15-percentage-point improvement in overall response rate over Pfizer's Sutent.

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Source: Fool.com