Thryv Therapeutics has announced significant progress in the development of its investigational therapy THRV-1268, marking a key step forward in the treatment of inherited cardiac arrhythmias. The company confirmed the initiation of patient dosing in its ongoing Phase II/III Wave II clinical trial, alongside receiving Fast Track Designation from the U.S. Food and Drug Administration for the treatment of Long QT Syndrome (LQTS) Types 2 and 3.

The Wave II study is a multicentre trial evaluating THRV-1268 in patients with genetically confirmed LQTS Type 2, a condition associated with abnormal cardiac electrical activity and an increased risk of life-threatening arrhythmias. The study is currently enrolling participants across leading inherited arrhythmia centres in the United States, with initial data expected in the fourth quarter of 2026.

Designed to assess safety, efficacy and tolerability, the trial will evaluate two dose levels of THRV-1268 over a 12-week period. The primary endpoint focuses on changes in QTcF intervals, a key marker of cardiac rhythm, along with measures of overall heart stability. Patients will initially receive the therapy as an oral suspension, with the option to transition to tablet form for extended treatment up to one year.

The first patient in the study has been dosed under the supervision of Vasanth Vedantham at UCSF Health, highlighting the study’s clinical momentum. Experts note that targeting serum glucocorticoid inducible kinase 1 (SGK1) could offer a new therapeutic pathway by addressing the underlying electrophysiological mechanisms of the disease rather than just managing symptoms.

In parallel, the Fast Track Designation granted by the FDA is expected to accelerate the development and regulatory review of THRV-1268. The designation is reserved for therapies addressing serious conditions with unmet medical needs and enables closer regulatory engagement, as well as eligibility for expedited review pathways.

According to company leadership, the dual milestone underscores the potential of THRV-1268 as a first-in-class, disease-modifying therapy for genetically defined LQTS populations. By targeting SGK1, the therapy aims to reduce QT interval prolongation and mitigate arrhythmic risk in affected patients.

Thryv Therapeutics is focused on advancing precision medicine approaches for genetic arrhythmia syndromes and cardiometabolic diseases, leveraging its proprietary platform of selective SGK1 inhibitors to address critical gaps in treatment.