CVS Caremark has entered into an agreement to buy Apria Healthcare Group’s Coram infusion therapy business for approximately $2.1 billion in cash, the two companies announced Wednesday. Sullivan & Cromwell is advising first-time M&A client CVS, while Simpson Thacher & Bartlett is serving as outside counsel to Apria, which is owned by private equity giant and longtime Simpson Thacher client The Blackstone Group.

Once completed, the purchase will give CVS—which owns 7,600 pharmacies, as well as a mail-order prescription operation—a business that provides more than 20,000 patients each month with intravenous and tube-feeding treatments for conditions including immune and nutritional deficiencies, rheumatoid arthritis and multiple sclerosis, according to a CVS press release. Apria will continue to own a respiratory therapy business after the deal closes.

Denver-based Coram is estimated to generate about $1.4 billion in revenue in its first 12 months under CVS ownership. The deal, which is subject to regulatory approval, is expected to close in the first quarter of next year. CVS said in its release that it does not anticipate any material impact on its 2014 finances as a result of the acquisition, which the company expects will add between 3 and 5 cents to its adjusted earnings per share in 2015.

S&C landed the lead outside counsel role for Woonsocket, R.I.–based CVS, which often turns to Davis Polk & Wardwell on M&A deals. Several past transactions on which Davis Polk has advised CVS include its $25 billion merger with Caremark in 2006; its $2.7 billion acquisition of Longs Drug Stores in 2008; and its purchase earlier this year of Brazilian retailer Drogaria Onofre for an undisclosed sum in the company’s first-ever international deal.

Reached Wednesday, S&C partner Matthew Hurd, who served as the lead M&A lawyer for CVS on the Apria matter, said his firm grabbed the assignment through its relationship with CVS general counsel Thomas Moriarty, who joined the company last year. Hurd and an S&C team had previously been hired by Moriarty when he was general counsel of Medco, which S&C advised on its $29.1 billion sale to Express Scripts in 2011.

Hurd, who specializes in health care–related transactions, said he “would certainly hope” that Moriarty will continue to send deal work S&C’s way and that it has been “thrilling” to work with CVS for the first time.