Lexeo Therapeutics Reports Promising Phase I/II Data for Gene Therapy LX2020 in Rare Heart Disease
核心洞察
Lexeo Therapeutics announced positive interim Phase I/II data for LX2020, an AAV-based gene therapy for PKP2-associated arrhythmogenic cardiomyopathy (搜索) affecting approximately 60,000 Americans.
The therapy demonstrated dose-dependent increases in PKP2 (搜索) protein expression, with 93% increase in low-dose cohort and 162% increase in high-dose cohorts, alongside improved arrhythmia burden in majority of participants.
LX2020 was generally well tolerated across ten participants with no clinically significant complement activation, though five participants experienced manageable liver function test elevations at high doses.
Lexeo Therapeutics announced positive interim results from its HEROIC-PKP2 (搜索) Phase I/II clinical trial of LX2020, an adeno-associated virus (AAV)-based gene therapy for PKP2-associated arrhythmogenic cardiomyopathy (搜索) (PKP2-ACM). The data from ten participants demonstrate promising safety, robust protein expression, and clinical improvements in arrhythmia burden.
"These interim data from ten participants reinforce the favorable safety profile of LX2020 and demonstrate promising trends in transduction, protein expression, and reduction in arrhythmia burden at the high dose," said R. Nolan Townsend, Chief Executive Officer of Lexeo Therapeutics.
Trial Design and Participants
The HEROIC-PKP2 (搜索) study enrolled ten participants across three cohorts, with three participants receiving the low dose (2x10¹³ vg/kg) in Cohort 1 and seven participants receiving the high dose (6x10¹³ vg/kg) in Cohorts 2 and 3. Safety data encompass all ten participants, while efficacy analyses include eight participants with at least six months of follow-up as of the January 7, 2026 data cutoff.
Safety Profile
LX2020 demonstrated a generally favorable safety profile across all dose levels. No clinically significant complement activation was observed, and no participants discontinued from the study. Five participants at the high dose experienced elevations in liver function tests, which were successfully managed through protocol-defined interventions including re-introduction of low-dose prednisone in three participants and increased prednisone plus sirolimus in two participants. All elevations resolved without complications or hospitalization.
One Grade 3 serious adverse event of sustained ventricular tachycardia (搜索) occurred three months post-dosing in a single high-dose participant and was assessed as possibly treatment-related. The event, consistent with the natural progression of PKP2 (搜索)-ACM, was successfully treated with anti-arrhythmic medication without requiring additional intervention.
Protein Expression and Transduction
Cardiac biopsy data from seven participants revealed dose-dependent increases in PKP2 (搜索) protein expression. The low-dose cohort (n=2) showed a mean 93% increase in PKP2 protein expression, while high-dose cohorts (n=5) demonstrated a 162% mean increase, as measured by western blot analysis.
Molecular markers confirmed successful gene delivery and expression. Mean exogenous mRNA levels reached 7.9E+04 copies per microgram of nucleic acid in the low-dose cohort and 2.7E+05 copies per microgram in high-dose cohorts. Vector copy numbers averaged 1.5 in the low-dose cohort and 3.3 in high-dose cohorts. Immunofluorescence staining confirmed appropriate PKP2 (搜索) colocalization at cardiac intercalated discs.
Clinical Efficacy Outcomes
Among eight participants with more than six months of follow-up, the majority experienced stabilization or improvement in arrhythmia burden. High-dose cohorts (n=5) showed a 22% mean improvement in non-sustained ventricular tachycardia (搜索) (NSVT) and a 14% mean improvement in premature ventricular contractions (PVCs) at their latest visit.
Patient-reported outcomes supported the clinical findings, with four of five participants in high-dose cohorts reporting improvement relative to baseline on the Patient Global Impression of Change (PGIC) scale. Participants remained stable across other clinical measures including QRS duration, T-wave inversion, right ventricular ejection fraction, and New York Heart Association Class.
Disease Context and Therapeutic Approach
PKP2 (搜索) mutations represent the most common genetic cause of arrhythmogenic cardiomyopathy (搜索), accounting for approximately 50% of cases and affecting an estimated 60,000 people in the United States. PKP2 deficiency can lead to myocardial cell death, fibrosis, heart dysfunction, rhythm abnormalities, and sudden cardiac death.
LX2020 is designed to systemically deliver a functional, full-length PKP2 (搜索) gene within an AAVrh10 capsid to cardiomyocytes, aiming to restore the desmosomal complex and cell-to-cell adhesion. The therapy has received Orphan Drug and Fast Track designations from the FDA.
Development Timeline
HEROIC-PKP2 (搜索) enrollment was completed in Q4 2025, with biopsy results pending for the final two participants. The company expects 12-month data for all high-dose participants by Q4 2026 and plans regulatory engagement throughout 2026.