WOONSOCKET, R.I. — CVS Caremark Corp. is buying Coram LLC from Apria Healthcare Group Inc.

The $2.1 billion transaction — CVS Caremark’s largest deal in five years — was announced earlier this month. It will add specialty infusion services to the company’s offering.

CVS executives say the acquisition won’t have a material impact on 2014 results and will add adjusted earnings of as much as 5 cents a share in 2015. The unit will have about $1.4 billion in revenue in the first 12 months after the transaction closes.

“Bringing together CVS Caremark’s unique range of specialty pharmacy services with Coram’s infusion capabilities will expand our competitive offerings in the specialty arena,” CVS Caremark Pharmacy Services president Jon Roberts says.

“Infusion will be a valuable component of our broad specialty pharmacy offering going forward,” he says. “Our comprehensive services will enable us to streamline care management for patients as well as their physicians, leading to better health outcomes while avoiding unnecessary costs.”

Over the past few years infusion therapy has become a growing area of pharmaceutical care. It is also one of the costliest. Analysts note that the deal will allow CVS to help clients control health costs by offering them at Coram’s more than 85 locations nationwide instead of at costlier hospitals.

“They are moving into home infusion, which is a high-growth area,” Ross Muken, an analyst for ISI Group LLC in New York, told the Bloomberg news service.

In the next five years, he said, several infusion treatments are expected to rank among the 10 best-selling drugs. Currently, no infusion drugs are in that listing.

CVS’ acquisition of Coram is its largest deal since the company bought Longs Drug Stores for about $2.8 billion in 2008.

The acquisition also is the third-largest in the North American drug retail industry in the past five years, trailing Loblaw Cos.’s agreement to buy Shoppers Drug Mart this year and Walgreen’s purchase of a 45% stake in Alliance Boots GmbH last year.