Bayer’s New Phase 4 ATTR-CM Study Tests Switching From Tafamidis to Acoramidis

Bayer AG (BAYRY) announced an update on their ongoing clinical study.

Bayer Explores Switch to New ATTR-CM Therapy in Phase 4 Study

The study, officially titled “A Prospective, Single-arm, Phase 4 Study to Evaluate the Course of Serum Transthyretin (TTR) Level With Acoramidis in Adult Patients With Variant or Wild-type Transthyretin Amyloidosis With Cardiomyopathy (ATTR-CM) Previously Treated With Tafamidis,” aims to measure how blood levels of the protein transthyretin change when patients with transthyretin amyloid cardiomyopathy (ATTR-CM) move from tafamidis to acoramidis. The goal is to see if acoramidis can raise and stabilize transthyretin levels more than tafamidis, which could signal better disease control and heart function in this rare but serious heart condition.

The intervention is acoramidis, an oral drug already approved in Europe and the United States for both wild-type and variant ATTR-CM. It works by stabilizing the transthyretin protein so it is less likely to form harmful deposits in the heart. In this study, patients who have been on tafamidis will stop that drug and take acoramidis tablets instead, twice a day, to see whether the switch offers a meaningful biological benefit.

This is a Phase 4, interventional study with a single treatment group. All enrolled patients will receive acoramidis, and there is no randomization or placebo arm. The study is open-label, meaning both doctors and patients know the treatment being given. The primary purpose is treatment-focused: to understand how switching therapy affects blood markers linked to disease activity and, by extension, potential long-term outcomes.

The trial is listed as not yet recruiting, with initial submission on 11 December 2025. The latest update was filed on 8 January 2026, indicating the protocol and operational plans are still being refined ahead of first patient enrollment. As a Phase 4 study, primary completion and final completion dates will matter for investors once disclosed, as they will signal when top-line biomarker and safety data could emerge, but these dates are not yet specified in the current public record.

For investors, this update underscores Bayer’s push to deepen its presence in the ATTR-CM market, a space where tafamidis, marketed by Pfizer, has been the long-standing standard of care. Positive results showing superior biomarker effects after switching from tafamidis to acoramidis could support stronger positioning for acoramidis in both new and existing patients, helping Bayer capture share in a growing rare-cardiology segment. This could improve sentiment around Bayer’s late-stage and post-approval cardiovascular pipeline, particularly if payers and guidelines eventually favor acoramidis over tafamidis in certain patient groups. Conversely, if differences in transthyretin levels are modest, competitive pressure on incumbents like Pfizer may remain limited, and acoramidis uptake could depend more on pricing and access negotiations than clear clinical differentiation.

The study is currently in the setup phase and remains active in planning, with ongoing updates and further details available on the ClinicalTrials.gov portal under NCT07298044.

To learn more about BAYRY’s potential, visit the Bayer AG drug pipeline page.