The Five Dumbest Things on Wall Street This Week

5. Celgene Slip-Up

Celgene (CELG Quote) jumped the gun.

The Summit, N.J., biotech surprised Wall Street last Friday by saying its Revlimid cancer drug won full European marketing approval for treatment of multiple myeloma, a cancer of the plasma cell.

"The EU approval of Revlimid," the company said, "is an especially important and positive milestone for Celgene."

It wasn't an especially durable milestone, though. Less than two hours after Celgene reported its EU victory, the company dispatched a bulletin disavowing the announcement. The reversal delivered an unpleasant surprise to anyone who had bought the stock on the European approval news.

"Journalists and other readers should disregard the news release," Celgene said later Friday. "The drug remains under review ... and has not been approved."

The retraction press release conveyed the company's urgency. The headline started with these words: "Kill Kill Kill Celgene."

Someone must have read investors' minds.

Dumb-o-Meter score: 78. Full European approval for Revlimid was really and truly granted Tuesday.