Acura shares slide on stinging FDA staff review of Acurox

Shares of Acura Pharmaceuticals (NASDAQ: ACUR) tumbled 21 percent after staffers at the FDA questioned whether its pain drug, Acurox, was actually designed to deter abuse or simply negatively affected the adverse event profile of the therapy.

In a stinging review, regulators questioned Acura's combination of oxycodone and niacin, a B vitamin that can trigger discomforting flushing in patients at high doses. "Niacin offers little in the way of deterrence to oral abuse," wrote staffers, raising serious issues ahead of tomorrow's FDA expert panel review and vote. Combining niacin with food can eliminate flushing, offering potential abusers a simple strategy to circumvent that obstacle. And with patients in clinical trials complaining of flushing, staffers noted that niacin "appears to negatively affect the adverse event profile of this drug."

"These are clearly difficult questions for which there are no easy answers," wrote Dr. Bob Rappaport, a director of the FDA.

The review arrived just ahead of Thursday's panel review of Acurox, which could pose a serious hurdle on Acura's application to the FDA for a final marketing ruling. Acura is partnered with King Pharmaceuticals on the pain therapy.

- here's the story from Reuters