Bayer Launches Global Phase II Trial of GIRK4 Inhibitor BAY 3670549 in Atrial Fibrillation
核心洞察
Bayer (搜索) has initiated a global Phase II trial (NCT07625215) of BAY 3670549 (搜索), an investigational highly selective GIRK4 (搜索) inhibitor, in adults with atrial fibrillation (搜索).
The randomized, double-blind, placebo-controlled, multi-cohort study will assess efficacy, safety, tolerability, pharmacodynamics and pharmacokinetics in patients requiring electrical cardioversion.
The program is being investigated as a novel approach for rapid cardioversion to normal sinus rhythm and a potential alternative to electrical cardioversion, the current gold standard.
Bayer (搜索) announced the initiation of a global Phase II clinical trial (NCT07625215) evaluating BAY 3670549 (搜索), an investigational highly selective G-protein-coupled inwardly rectifying potassium channel 4 (GIRK4 (搜索)) inhibitor, in adult patients with atrial fibrillation (搜索) (AFib). The program is being developed as a potential new approach to control the electrical activity of heart cells in AFib and, if successful, could offer a fast-acting and well-tolerated alternative to electrical cardioversion.
The Phase II single-treatment study uses a randomized, double-blind, placebo-controlled, parallel-group, multi-cohort design. It will investigate efficacy, safety and tolerability, as well as pharmacodynamics and pharmacokinetics, of BAY 3670549 (搜索) in adult participants with AFib. The study will compare BAY 3670549 with placebo in patients with AFib who need electrical cardioversion, a procedure that helps the heart return to a normal rhythm.
"The start of the Phase II marks an important step in our commitment to redefining what may be possible in cardiovascular care, with GIRK4 (搜索) inhibition carrying the potential to meaningfully advance the treatment of atrial fibrillation (搜索), a condition affecting millions of people worldwide," said Dominik Ruettinger, M.D., Ph.D., Head of Research and Early Development at Bayer (搜索)'s Pharmaceuticals Division. "We are advancing this program because patients and physicians need fast-acting and well-tolerated treatment options that can make a real difference."
From Phase I to a Novel Mechanism
BAY 3670549 (搜索) demonstrated a favorable safety and tolerability profile in healthy participants in the completed first-in-human single-ascending-dose Phase I study, supporting its continued clinical advancement and strengthening Bayer (搜索)'s cardiovascular development portfolio. In that Phase I study, the compound was generally well-tolerated in healthy male and female participants.
The molecule emerged from Bayer (搜索)'s strategic research alliance with the Broad Institute of MIT and Harvard (搜索). It is being investigated as a novel approach for rapid cardioversion to normal sinus rhythm.
GIRK4 (搜索) channels are specialized proteins that regulate the electrical activity of heart cells by facilitating the flow of potassium ions (K+) in response to the neurotransmitter acetylcholine (ACh). This mechanism is particularly crucial during the later phases of the heart's electrical signaling, specifically during the atrial effective refractory period (AERP). Increased activity of these channels shortens the AERP in the atria, thereby reducing the recovery time after each heartbeat — an alteration that can contribute to the onset and persistence of AFib.
The Unmet Need in Acute AFib Management
AFib is the most common type of sustained cardiac arrhythmia, affecting more than 60 million people worldwide, and is a significant risk factor for stroke and heart failure. It results from rapid, disorganized electrical signals in the upper chambers of the heart, causing them to quiver and contract quickly and irregularly. As a result, the atria do not empty efficiently, leading to impaired blood flow and an increased risk of blood clot formation; these clots can break loose, travel to the brain and cause a stroke. AFib also disrupts the coordinated function of the upper and lower chambers of the heart, impairing overall cardiac performance and producing symptoms such as palpitations, shortness of breath, fatigue and reduced quality of life.
The prevalence of AFib continues to increase globally. Projection studies cited by Bayer (搜索) show the number of people with AFib will rise to 15.9 million in 2050 in America and 17.9 million in 2060 in Europe. People with AFib are five times more likely to suffer a stroke than people without the condition, and AFib-related strokes are associated with a 50% likelihood of death within one year.
The current gold standard for treating acute AFib episodes is electric cardioversion (ECV). According to Bayer (搜索), this is an effective but resource-intensive and logistically challenging procedure, normally scheduled in advance and typically requiring sedation or even anesthesia to safely deliver an electrical shock to restore normal sinus rhythm. Currently available anti-arrhythmic drugs, commonly used for management of symptomatic AFib, cannot be applied to broad patient populations due to contraindications — such as in patients with structural heart disease — and safety risks including abnormal heart rhythms and sudden death. Bayer notes these agents also show limited, short-term efficacy, require close monitoring and carry the risk of serious side effects.
Bayer (搜索) positions BAY 3670549 (搜索) as a potential option that may help reduce the burden on both patients and healthcare systems by offering an alternative to electrical cardioversion and its associated anesthesia, external defibrillation and prolonged hospital-based care.