TheStreet's Martin Baccardax reported on the deal, which was made public before the market opened Thursday.
According to Bristol-Myers, Celgene investors will receive a Bristol-Myers share and $50 for each Celgene holding that they have. Investors would also get a special rights issue that will pay off if the merged group meets certain business targets.
The deal values Celgene at $102.43 each, the companies said, a 53.7% premium to Wednesday's closing price. The combined group -- which will be 69% owned by Bristol-Myers -- would have a portfolio with nine drugs that generate more than $1 billion in sales, the companies said.
Cramer said that he was worried about the deal.
"Celgene has made so many bad acquisitions," Cramer said. "Bristol-Myers has made so many bad acquisitions. I mean, maybe this is the one [good one]."