By Ludwig Burger and Ariane Luthi (Reuters) -Swiss pharmaceutical giant Novartis has agreed to acquire Anthos Therapeutics, a biopharma firm majority-owned by Blackstone's drug development unit, for up to $3.

The pharmaceutical giant said it has agreed to acquire the U.S. privately held, clinical-stage biopharmaceutical company to boost its cardiovascular pipeline.

Under the terms of the agreement, Novartis will pay $925 million upfront and up to $2.15 billion, contingent upon achievement of regulatory and sales milestones. The transaction, which could reach $3.1 billion in total value, is expected to close in the early part of 2025.

Novartis has agreed to buy Anthos Therapeutics from private equity firm Blackstone for $3.1 billion, adding a drug in late-stage clinical testing to prevent complications in patients with atrial fibrillation (AF).

Anthos Therapeutics, based in Cambridge, has a drug in late-stage clinical trials aimed at preventing strokes and blood clots.