The FDA is flexing its muscles

Biotechnology companies often have both devoted fans and detractors. But there's one constituency they'd be wise not to anger: U.S. regulators.

In the past few weeks, the Food and Drug Administration has dropped the hammer on pharmaceutical giants and biotech upstarts alike. The agency slammed Novartis for manipulating data and rejected what would've been Sarepta Therapeutics's second drug for a rare form of muscular dystrophy. A company that makes a fish-oil pill caught investors by surprise when it said the agency wanted a closer look at its data. Another had a jet-lag drug rejected after the FDA said its clinical merits weren't clear.