By Carl O'Donnell and Greg Roumeliotis

May 8 (Reuters) - Italian specialty pharmaceutical company Chiesi Farmaceutici SpA is close to an agreement to acquire some of Medicines Co's cardiovascular assets for several hundred millions of dollars, according to people familiar with the matter.

The transaction would allow Chiesi to expand its global footprint, while freeing up capital for Medicines Co to invest in its drug development pipeline. Based in Parsippany, New Jersey, Medicines Co has a market capitalization of $2.5 billion.

Medicines Co is in the final stages of negotiating the sale of its main cardiovascular drugs, with the exception of Angiomax, to Chiesi, the people said on Sunday.

Angiomax is an anticoagulant that saw its sales drop by more than 40 percent after losing patent protection in 2015. Medicines Co has challenged the loss of patent protection in court.

The deal with Chiesi, which calls for initial upfront payments followed by subsequent milestone payouts tied to specific performance targets, could come as early as this week, but has not yet been finalized, the people added.

It is still possible that talks fall apart at the last minute, the people cautioned.

The sources asked not to be identified because the negotiations are confidential. Medicines Co declined to comment, while Chiesi did not immediately respond to a request for comment.

Medicine Co's stated strategy has been to sell off its commercialized assets to raise money for the development of its promising suite of pipeline drugs, including two next-generation treatments for heart disease.

In December, Medicines Co agreed to sell its portfolio of hemostasis treatments to Mallinckrodt Plc for $410 million.

In January, Medicines Co announced it has begun phase II clinical trials on its PSCK9 inhibitor, a heart disease drug that is largely seen as its most promising asset.

Founded in 1935, privately held Chiesi focuses in the respiratory, neonatology and special care therapeutic areas. It generates more than 1.4 billion euros ($1.6 billion) in annual sales, according to its website.

(Editing by Mary Milliken)