The first revenue outlook for asundexian, designed to prevent thrombosis and strokes, shows Bayer's confidence that it can replace revenue from one of its pharmaceutical best-sellers, Xarelto, which is set to lose protection from key European patents in 2026.

Despite recent courtroom victories for the German group, its shares have been weighed down by litigation over weedkiller Roundup and over environmental pollution with chemicals known as PCBs. Both are legacy issues from Monsanto, which Bayer acquired for more than $60 billion in 2018.

The underperformance this month attracted activist investment fund Inclusive Capital Partners, run by hedge fund veteran Jeffrey Ubben. Another activist, Elliott, took a 1.1 billion euro stake in Bayer in 2019 but has kept a low profile.

The next-generation blood thinner is one of four new drug hopefuls that Bayer said on Tuesday had combined peak sales potential of more than 12 billion euros.

That included an improved outlook for kidney drug Kerendia, with potential annual sales now seen at more than 3 billion euros.

Bayer had previously seen Kerendia making more than 1 billion euros in its best year, but a strong uptake in the United States and growth prospects in China made for a brighter picture, Bayer's pharmaceuticals head Stefan Oelrich told Reuters.

For asundexian, positive safety results on bleeding from mid-stage trials underpinned hopes that cardiologists will switch to the new drug. The company is following up with much larger late-stage trials for evidence on efficacy.

Asundexian belongs to a novel class of drugs known as factor XI inhibitors, which has also attracted Novartis and its partner, private equity firm Blackstone. They have set up Anthos Therapeutics to develop biotech drug abelacimab.

Another close contestant in the factor XI race is Bristol-Myers Squibb, which is working with Johnson & Johnson on drug candidate milvexian.

Oelrich said Bayer's trial programme was further advanced than those of rivals and a request for regulatory approval was on the cards in early 2026.

"We are making outstanding progress in recruiting Phase III trial participants ... We are ahead and therefore expect that we'll have a good chance of staying ahead," said Oelrich, referring to the last stage of clinical testing.

He added the new revenue goal was realistic because the global market for stroke prevention in atrial fibrillation, a common form of irregular heartbeat that poses the largest opportunity for the drug class, will be up to $30 billion.

($1 = 0.9313 euros)

(Reporting by Ludwig Burger and Patricia Weiss; Editing by Mark Potter)

By Ludwig Burger and Patricia Weiss