Tenaya Therapeutics, Inc. announced the acceptance of multiple abstracts for presentation at the American Society of Gene and Cell Therapy Annual Meeting, taking place May 11-15, 2026, in Boston, Massachusetts. Of note, new clinical data from both dose cohorts of the RIDGE-1 Phase 1b/2 trial of TN-401 will be featured as a late-breaking oral presentation. TN-401 is being developed for the potential treatment of adults with arrhythmogenic right ventricular cardiomyopathy (ARVC), a form of arrhythmogenic cardiomyopathy (ACM) that primarily impacts the right ventricle, caused by mutations in the plakophilin-2 (PKP2) gene.

PKP2 gene mutations result in insufficient levels of critical proteins needed to maintain the structural integrity and cell-to-cell electrical signaling of heart muscle cells. TN-401 gene replacement therapy is designed to address the underlying cause of disease by delivering a functional PKP2 gene into heart muscle cells using an adeno associated virus serotype 9 (AAV9) capsid. The ASGCT presentation will include new safety, biopsy and efficacy data from patients treated at both the 3E13 vg/kg and 6E13 vg/kg dose levels.

Details of the TN-401 clinical data presentation are as follows: Presentation Date & Time: Friday, May 15, 2026, from 8:00 am ? 9:00 am EDT. Abstract Title: Interim Data from RIDGE-1: A Phase 1b/2 Interventional Study to Evaluate Safety and Efficacy of TN-401, an AAV9 Investigational Gene Replacement Therapy, in Adults with PKP2-Associated Arrhythmogenic Right Ventricular Cardiomyopathy.

Location: Westin Seaport Commonwealth Ballroom ABC (Concourse Level). Two other Tenaya abstracts have been accepted for poster presentations during ASGCT 2026. The first poster will detail results of a survey exploring parental perceptions of gene therapy treatment for children with cardiomyopathies conducted in partnership with DDC Clinic and the patient advocacy group, Children?s Cardiomyopathy Foundation.

Presentation Session Date & Time: Tuesday, May 12, 2026, from 5:00 pm ? 6:30 pm EDT. Abstract Title: Perceptions and attitudes towards gene replacement therapy in parents of children with cardiomyopathy (#1372).

Location: MCEC Exhibit and Poster Hall. The second poster accepted for presentation builds on research previously presented for TN-501, a gene editing therapeutic candidate intended for the treatment of PLN-R14del-associated dilated cardiomyopathy (DCM). TN-501 is uniquely designed to specifically inactivate the pathogenic phosolamban (PLN) R14del allele while preserving healthy function.

Presentation Session Date & Time: Thursday, May 14, 2026, from 5:00 pm ? 6:30 pm EDT. Abstract Title: Development of TN-501, an AAV-Delivered Gene Editing Therapy for PLN-R14del Cardiomyopathy (#3432).

Location: MCEC Exhibit and Poster Hall. The posters presented at ASGCT will be available in the ?Our Science? section of the company?s website at the time of the live presentation.

Tenaya management plans to host a webcast conference call to discuss the TN-401 data being presented at the upcoming ASGCT Annual Meeting 2026. Details will be posted to the ?Events & Presentations? page in the investor section of the Tenaya website.

Plakophilin-2 (PKP2) mutations are the most common genetic cause of arrhythmogenic right ventricular cardiomyopathy (ARVC, also known as arrhythmogenic cardiomyopathy or ACM), occurring in approximately 40% of the overall ARVC population. The prevalence of PKP2-associated ARVC is estimated at more than 70,000 people in the U.S. alone. In PKP2-associated ARVC, mutations of the PKP2 gene results in insufficient expression of a protein needed for the proper functioning of the desmosomal complex that maintains physical connections and electrical signaling between heart muscle cells.

As the desmosome structure degrades, cardiac muscle cells are replaced by fibrofatty tissue and electrical impulses in the heart become unstable, resulting in irregular heart rhythms that can be fatal. ARVC symptoms include arrhythmias, palpitations, lightheadedness, dizziness and fainting. It is typically diagnosed before age 40, and sudden cardiac arrest due to life-threatening ventricular arrhythmias is frequently the first manifestation of disease.

Current treatments include anti-arrhythmic medications, implantable cardioverter-defibrillators (ICDs) and ablation procedures, which do not address the underlying genetic cause of disease. TN-401 is an investigational AAV9-based gene therapy being developed for the treatment of ARVC due to mutations in the PKP2 gene. AAV9 was selected as the vector for delivery of Tenaya?s PKP2 gene therapy based on its extensive clinical and commercial safety record and demonstrated ability to target heart muscle cells.

TN-401 has received Orphan Drug and Fast Track Designations from the U.S. Food and Drug Administration. Tenaya?s development of TN-401 is supported in part by a grant from the California Institute for Regenerative Medicines. The RIDGE-1 Phase 1b/2 clinical trial of TN-401 in patients with PKP2-associated ARVC is a multi-center, open-label, dose escalation study being conducted in the U.S. and UK.

RIDGE-1 is intended to assess the safety, tolerability and preliminary clinical efficacy of a one-time intravenous infusion of TN-401. RIDGE-1 will seek to enroll up to fifteen adults who have been diagnosed with PKP2-associated ARVC, have an ICD and have high counts of premature ventricular contractions (PVCs) during screening, indicating electrical instability and increased risk of fatal arrhythmias.