Lexeo Therapeutics Gains FDA Breakthrough Therapy Designation for AAV Gene Therapy in Friedreich Ataxia

NEW YORK – July 07, 2025 – Lexeo Therapeutics, Inc. (Nasdaq: LXEO), a clinical-stage genetic medicine company, today announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to LX2006, an AAV-based investigational therapy. This significant designation for their AAV vector therapy in Friedreich ataxia (FA) is based on promising clinical evidence impacting both cardiac and neurologic measures of the disease.

Friedreich ataxia is a devastating, progressive genetic disorder with cardiomyopathy as the leading cause of death. LX2006, an AAV-delivered gene therapy, is designed to restore frataxin expression, the protein deficient in FA patients.

The FDA’s decision stems from interim clinical data from two trials (SUNRISE-FA Phase 1/2 and an investigator-initiated Phase 1A), involving 17 treated participants. This data from the AAV therapy demonstrated:

• Clinically significant improvements in cardiac biomarkers and in cardiac and neurologic functional measures.
• Increased frataxin expression observed in all participants with cardiac biopsies at three months post-treatment, a direct indicator of the AAV vector’s biological activity.

“Receiving Breakthrough Therapy designation is a significant milestone, highlighting the potential of LX2006 and the strength of clinical evidence generated to date,” said Dr. Sandi See Tai, Chief Development Officer. “We are highly encouraged by the impact of this AAV-based treatment on key measures of cardiac health, especially given the lack of treatments for FA cardiomyopathy today.”

In addition to this designation, LX2006 has also been selected for the FDA Chemistry, Manufacturing, and Controls (CMC) Development and Readiness Pilot (CDRP) program, further accelerating its path to patients. This builds on prior FDA designations including Regenerative Medicine Advanced Therapy (RMAT), Orphan Drug, and Fast Track, all granted to this promising AAV gene therapy candidate.

Lexeo expects to initiate a registrational study by early 2026, with a prospective natural history study (CLARITY-FA) serving as a concurrent external control arm. The company is actively working with the FDA to finalize the statistical analysis plan, aiming to bring this potential AAV gene therapy to patients as quickly as possible.