Celgene's $2.9 billion acquisition of Pharmion would add products that fit snugly into its therapeutic focus on cancer and blood disorders, analysts said on Monday.
Celgene shares fell 90 cents, or 1.4 percent, to $64 in early premarket trading, possibly reflecting the deal price that some analysts called steep.
But the purchase, announced on Sunday, generally received praise from analysts for making strong strategic sense.
Celgene will acquire Vidaza, approved in the United States for myelodysplastic syndromes, a group of blood disorders that can lead to leukemia. Celgene had also licensed European rights to Pharmion to its thalidomide drug, which is under review there as a therapy for multiple myeloma.