Drug distributor McKesson Corp said on Monday it would buy drugstore operator CVS Health Corp's specialty distribution unit in a deal valued at US$735 million in cash.

McKesson said it would expand its services to biopharma manufacturers by acquiring RxCrossroads, which provides services such as reimbursement and sales operations support and mail order pharmacy services to the medical industry.

CVS acquired RxCrossroads from Omnicare Inc in 2015. The deal with McKesson comes amid media reports that CVS is in talks to buy health insurer Aetna Inc.

Shares of McKesson and CVS were little changed in trading after the bell.

McKesson said the deal will add about 20 cents US to its adjusted earnings per share by the third year after the deal closes, which is expected in the fourth quarter of fiscal 2018.

Earlier on Tuesday, CVS had reported a better-than-expected quarterly profit and said it would start next-day delivery from its stores in 2018, a move analysts said came as a bulwark against online retailer Amazon.com's potential entry into prescription drug sales.