The company advances an investigational GIRK4 inhibitor for atrial fibrillation patients.
Bayer initiated a global Phase II clinical trial on 9 September 2026 to evaluate its experimental drug BAY 3670549. The compound is a selective GIRK4 inhibitor designed to help manage the electrical activity of heart cells in adult patients with atrial fibrillation.
The randomized, double-blind, placebo-controlled study tests the drug's safety, tolerability, efficacy, pharmacokinetics, and pharmacodynamics in patients scheduled for electrical cardioversion. The candidate was developed through a strategic research alliance with the Broad Institute of MIT and Harvard, following positive Phase I safety data in healthy volunteers.
Atrial fibrillation affects more than 60 million people worldwide and raises stroke risks fivefold. Projections cited by the company estimate cases will rise to 15.9 million in America by 2050 and 17.9 million in Europe by 2060. Bayer reported 45.6 billion euros in sales and 5.8 billion euros in research spending for fiscal 2025, while employing around 88,000 workers.
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