Lexeo Therapeutics (NASDAQ:LXEO) shares surge 11.30% pre-market on positive interim Phase I/II data for gene therapy candidate.

Lexeo Therapeutics (NASDAQ:LXEO) surged 11.2988% in pre-market trading on January 12, 2026, following the release of positive interim Phase I/II data for its gene therapy candidate, LX2020, targeting PKP2-associated arrhythmogenic cardiomyopathy (PKP2-ACM).

The HEROIC-PKP2 trial demonstrated that LX2020 was generally well-tolerated across ten participants, with no clinically significant complement activation. Dose-dependent increases in PKP2 protein expression were observed, with a 93% mean rise in the low-dose cohort and 162% in high-dose groups.

Cardiac biopsies confirmed improved protein localization and exogenous mRNA levels. Arrhythmia burden stabilized or improved in most participants, including a 22% reduction in non-sustained ventricular tachycardia and 14% decline in premature ventricular contractions at high doses.

While five high-dose participants experienced transient liver function test elevations, all resolved without complications. A single Grade 3 adverse event of sustained ventricular tachycardia was reported but deemed consistent with the natural disease progression. The company highlighted its favorable safety profile and potential to address the genetic root cause of PKP2-ACM, a condition affecting ~60,000 U.S. patients.

Lexeo plans to release 12-month data for high-dose participants by late 2026 and expects regulatory engagement in 2026. A webcast today provided further insights, underscoring investor confidence in the therapy’s therapeutic potential and pipeline progress.