Thryv Therapeutics Announces FDA IND Clearance of THRV-1268 for Long QT Syndrome

• Phase 2/3 Wave II Clinical Study to Begin in 2026
• Completion of Financing to Support Registration Program 

MONTREAL, Sept. 17, 2025 /PRNewswire/ - Thryv Therapeutics Inc., a clinical-stage biotechnology company pioneering novel serum glucocorticoid inducible kinase 1 (SGK1) inhibitors for cardiovascular diseases, today announced that the U.S. Food and Drug Administration (FDA) has cleared its Investigational New Drug (IND) application for its lead compound, THRV-1268. This clearance enables Thryv to initiate the Phase 2/3 WAVE II clinical study in Long QT Syndrome (LQTS) Type 2.

Details of the Phase 2/3 WAVE II Clinical Study
The Phase 2/3 Wave II study will evaluate the safety and efficacy of THRV-1268 in patients with LQTS Type 2. The primary endpoint is the mean change from baseline in area under the curve corrected QT interval (QTc AUC _(0-6)/6) over six weeks of treatment in adult patients with a baseline QTc >480 milliseconds, regardless of background beta-blocker therapy.

In parallel with this regulatory milestone, Thryv secured new financing to initiate the Wave II clinical study, marking a significant advancement for THRV-1268 and reflecting strong confidence in Thryv's differentiated science and leadership in SGK1 inhibition. Thryv's investors bring deep expertise in cardiovascular development, digital health integration, and global commercialization—providing the capital strength to accelerate THRV-1268 through registrational studies. The financing was supported by Amplitude Ventures, Fonds de solidarité FTQ, Lumira Ventures, Investissement Québec, adMare BioInnovations, and CTI Life Sciences Fund.

Building on Recent Regulatory Momentum
This is the second IND clearance for Thryv in recent months, following FDA acceptance of an IND for THRV-1268 in heart failure and atrial fibrillation. Together, these regulatory achievements highlight the broad therapeutic potential of SGK1 inhibition across multiple serious cardiovascular diseases.

Thryv's extensive work with its first compound, LQT-1213, provided foundational non-clinical and clinical evidence supporting SGK1 inhibition in LQTS. Building on that success, THRV-1268 is being advanced as a best-in-class, optimized SGK1 inhibitor for LQTS, designed for long-term therapy in this chronic, life-threatening disease.

"This FDA clearance and the launch of the Wave II Phase 2/3 study early next year represent major milestones in the development of what could become the first approved therapy for Long QT Syndrome," said Paul Truex, Chairman and CEO of Thryv Therapeutics. "With strong investor support, Thryv is positioned to move rapidly into registration studies. Adults and children with LQTS deserve therapies that not only protect their lives but also allow them to live more fully—we are determined to deliver on that promise."

About Long QT Syndrome
Long QT Syndrome (LQTS) is a rare inherited cardiac arrhythmia condition characterized by delayed ventricular repolarization, reflected on the electrocardiogram (ECG) as a prolonged QT interval. Prolongation of the QT interval increases the risk of torsades de pointes, a potentially life-threatening ventricular tachyarrhythmia. Individuals with LQTS are at greatest risk of arrhythmic events in response to physiological stressors such as exercise or emotional stress.

The three most common subtypes of congenital LQTS are Type 1, Type 2, and Type 3, each caused by distinct ion channel gene mutations that influence the specific triggers for arrhythmic events. In addition to the congenital forms, LQTS may also be acquired, most often due to exposure to medications that prolong the QT interval and similarly increase the risk of sudden cardiac death.

About Thryv Therapeutics
Thryv Therapeutics Inc. is a privately owned company based in Montreal, Quebec, Canada. Thryv is pioneering a precision medicine approach to treat Long QT Syndrome, heart failure and atrial fibrillation with potent and highly selective inhibitors of serum glucocorticoid inducible kinase 1 (SGK1).  For more information, please visit www.thryvtrx.com.   

SOURCE Thryv Therapeutics Inc.