In a landmark decision that could reshape the treatment landscape for inherited retinal diseases, the FDA's Cellular, Tissue and Gene Therapies Advisory Committee has voted 9-3 to recommend approval for a revolutionary gene therapy targeting Leber congenital amaurosis (LCA).

Key Highlights from the Advisory Committee Meeting

The advisory committee meeting, held on July 25, 2025, reviewed comprehensive clinical data spanning over 5 years of development. The therapy, designed to restore vision in patients with RPE65-mediated LCA, demonstrated significant improvements in functional vision across multiple endpoints.

Primary Efficacy Results:

• 73% of treated patients showed meaningful improvement in light sensitivity
• Significant gains in visual field measurements at 12 months
• Sustained therapeutic benefit observed through 24 months of follow-up
• Improved quality of life scores across all patient-reported outcome measures

Safety Profile and Committee Concerns

While the efficacy data was compelling, the committee extensively discussed the safety profile. Most treatment-related adverse events were mild to moderate and related to the surgical delivery procedure rather than the gene therapy itself.

The three dissenting votes primarily focused on:

• Long-term safety data limitations beyond 2 years
• Questions about optimal patient selection criteria
• Need for more robust post-marketing surveillance plans

Implications for the Gene Therapy Landscape

This positive recommendation represents a significant milestone for the gene therapy field, particularly for rare genetic diseases affecting vision. The therapy utilizes an adeno-associated virus (AAV) vector to deliver a functional copy of the RPE65 gene directly to retinal pigment epithelial cells.

Regulatory Pathway Insights:

• Orphan Drug Designation granted in 2019
• Breakthrough Therapy Designation received in 2022
• Priority Review granted with PDUFA date of September 15, 2025
• Pediatric Review Committee evaluation completed

Next Steps in the Approval Process

Following this positive advisory committee vote, the FDA will now conduct its final review of the Biologics License Application (BLA). The agency is not bound by the advisory committee's recommendation but typically follows these expert opinions in the majority of cases.

Key remaining milestones include:

• Final FDA review and decision by September 15, 2025
• Development of Risk Evaluation and Mitigation Strategy (REMS)
• Establishment of post-marketing study requirements
• Preparation for potential commercial launch

Impact on Future Gene Therapy Development

This recommendation could accelerate development timelines for other ocular gene therapies currently in clinical trials. Several companies are closely watching this approval pathway as it may establish important precedents for:

• Clinical trial design for rare genetic diseases
• Acceptable risk-benefit profiles for life-changing therapies
• Post-marketing surveillance expectations
• Patient selection and eligibility criteria