Cabo crashes

The 2012 approval of Cometriq cabozantinib for medullary thyroid cancer has always been no more than a way station for Exelixis Inc. (NASDAQ:EXEL) as it waited for results in bigger indications. Last week's failure in metastatic castration-resistant prostate cancer leaves the biotech's prospects pinned on two tough indications: metastatic renal cell carcinoma, which is an even more crowded space than mCRPC, and hepatocellular carcinoma, where few programs have shown a benefit.

Thus it wasn't surprising that following Tuesday's data the stock plummeted 55% from $4.14 to $1.85, where it would end the week. The tumble reduced Exelixis' market cap by $447 million to $361 million...