J&J, AstraZeneca halt studies as safety fears spread

Johnson & Johnson ($JNJ) and AstraZeneca ($AZN) have slammed the brakes on ongoing clinical trials of their next-gen painkillers, the latest victims of serious side effects that have been linked to a drug class that once was believed to hold mega-blockbuster potential.

The FDA told Regeneron ($REGN) to stop its clinical trial last week, around the same time that J&J got the word to stop dosing. And AstraZeneca voluntary halted early-stage work on its anti-nerve growth factor program. Cowen's Ziad Bakri told Bloomberg that the trial embargo immediately cast a pall over the class, adding that any further work in the field would likely face a steep new safety hurdle.

"You'd have to have a lot of safety data to ever get a drug like this approved, so for investors this is not a class that's generating very high hopes," Bakri told the news service. Analysts have pegged potential revenue for the class at $11 billion.

Trouble for the class began to emerge last summer when Pfizer was forced to halt work on tanezumab after patients taking the drug required joint replacement surgery. The drugs have appeared to trigger instances of bone tissue death.

- here's the story from Bloomberg