Novartis builds in cardiovascular with $3.1bn Anthos buy

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).

The centrepiece of the deal – which includes an upfront payment of $925 million and up to $2.15 billion in development and sales milestones – is abelacimab a potential first-in-class antibody targeting the Factor XI (FXI).

Anthos was launched by Novartis and Blackstone in 2019 as a risk-sharing project to advance abelacimab under license, so the takeover is effectively providing a payoff to the private equity partner and returning abelacimab in-house.

The decision to bolster its cardiovascular pipeline comes as Novartis is facing the threat of losing patent protection for Entresto (sacubitril and valsartan), which is the company's top-selling drug with sales last year rising 31% to $7.8 billion – nearly 16% of total group revenues.

The company has said it expects generics of Entresto to reach the US market sometime in the middle of this year – around the time that it hopes to close the Anthos acquisition.

Abelacimab has already generated encouraging phase 2 data in the AZALEA-TIMI 71 trial, which compared two monthly doses of the antibody to open-label treated with Johnson & Johnson and Bayer's daily oral anticoagulant Xarelto (rivaroxaban) in AF patients.

Anthos' drug was more effective at reducing bleeding events among patients with AF and a moderate to high risk of stroke. The company has now taken it into three phase 3 trials, one to see how well it can prevent stroke and systemic embolism in patients with AF (LILAC-TIMI 76) and two in cancer-associated thrombosis (ASTER and MAGNOLIA). The FDA has awarded fast-track status to abelacimab for both indications.

The drug's monthly injectable dosing makes it an intriguing alternative to other drugs in the FXI inhibitor category, which tend to be delivered orally. Bayer and J&J have been leading the field in the oral category, seeking a successor to Xarelto.

Bayer's FXIa inhibitor asundexian was discontinued for AF in 2023 after disappointing results in the phase 3 OCEANIC study, but remains in development for secondary ischaemic stroke prevention in the OCEANIC-Stroke trial.

J&J meanwhile is developing Bristol Myers Squibb-partnered oral FXIa inhibitor milvexian that was advanced into phase 3 testing after a mid-stage trial miss and is being tested in AF, acute coronary syndrome and secondary ischaemic stroke prevention.

Meanwhile, MSD – known as Merck & Co in the US and Canada – is also developing an anti-FXI antibody called MK-2060 which is partnered with Adimab and in a phase 2 trial for preventing blood clots in patients with kidney disease who need dialysis.