NEW YORK, Dec 4 (Reuters) - Private equity firm Blackstone Inc is exploring the sale of Anthos Therapeutics, a developer of a new generation of blood thinners it launched four years ago with backing from Novartis AG , according to people familiar with the matter.

Anthos, which does not generate any revenue because its products have not yet hit the market, could be worth several billion dollars in a potential sale, significantly more than the $250 million that Blackstone invested when it founded Anthos in 2019, the sources said. The company's anticoagulants have made significant progress in late-stage clinical trials, the sources added.

Cambridge, Massachusetts-based Anthos' most advanced product, a monoclonal antibody called abelacimab, is intended for patients with atrial fibrillation who do not respond well to other anticoagulants because of heavy bleeding.

Over 37 million people worldwide are diagnosed with atrial fibrillation, a heart malfunction that can lead to strokes or other deadly events, Anthos said last month, citing research studies.

Blackstone is working with investment bankers to explore a sale of Anthos, the sources said, cautioning that no deal is certain and requesting anonymity because the matter is confidential.

Blackstone declined to comment.

Anthos has licensed from Novartis an antibody used in the development of its blood thinners and granted it a minority stake.

Major players in the blood thinner drug space include Bristol-Myers Squibb and Pfizer's Eliquis and Bayer's Xarelto.

Bayer announced last month it would stop development of a next-generation blood thinner because of clinical setbacks. The German drug maker was counting on the product to generate an estimated $5.5 billion in peak sales and replace Xarelto when its patent expires in 2026. Eliquis' patent protection is also ending in the coming years.

Blackstone, which has over $1 trillion in assets under management, launched a dedicated life sciences investment arm after it acquired Clarus, an investment firm specializing in clinical trial deals, in 2018. Its bets since then have included investing more than $1 billion to back Alnylam Pharmaceuticals, which is developing drugs to tackle cholesterol and other diseases. (Reporting by David Carnevali in New York; Editing by Leslie Adler)