Regeneron Pharmaceuticals and Intellia Therapeutics are advancing a groundbreaking clinical study evaluating a CRISPR/Cas9-based gene therapy for hemophilia B, a rare bleeding disorder affecting thousands of patients worldwide. The experimental treatment, designated REGV131-LNP1265, represents a potential paradigm shift in hemophilia B management by enabling patients to produce their own clotting factor IX.
Novel Gene Insertion Approach
The therapy combines two investigational components, REGV131 and LNP1265, administered through intravenous infusion. Using CRISPR/Cas9 gene editing technology, the treatment inserts a functional gene into patients' DNA to restore natural factor IX production. This approach could provide a long-term solution for hemophilia B patients who currently require regular factor replacement therapy to prevent bleeding episodes.
The study, titled "A Two-Part Open-Label Study of REGV131-LNP1265, A CRISPR/Cas9 Based Coagulation Factor IX Gene Insertion Therapy in Participants With Hemophilia B," focuses on evaluating both safety and effectiveness of the gene insertion therapy. Primary objectives include determining a safe dosing regimen and assessing the therapy's impact on patients' quality of life, joint health, and their ongoing need for factor replacement treatments.
Study Design and Timeline
The clinical trial follows a non-randomized, sequential interventional design without masking, structured in two distinct phases. The first part involves dose escalation and confirmation studies in adult participants, while the second phase expands enrollment to include adolescents and children. This sequential approach allows researchers to establish safety parameters in adults before treating younger patients.
The study commenced on September 11, 2024, and continues to recruit participants. Recent updates submitted in July and August 2025 indicate ongoing progress in patient enrollment and data collection. The open-label design enables both researchers and participants to know which treatment is being administered, facilitating real-time safety monitoring.
Clinical Significance
For hemophilia B patients, who lack sufficient factor IX protein necessary for blood clotting, current standard care requires regular infusions of clotting factor concentrates. These treatments, while effective, require frequent administration and significant healthcare resources. The CRISPR-based gene therapy approach could potentially provide sustained factor IX production, reducing treatment burden and improving patient outcomes.
The collaboration between Regeneron Pharmaceuticals and Intellia Therapeutics combines Regeneron's expertise in protein therapeutics with Intellia's CRISPR gene editing platform. This partnership positions both companies at the forefront of gene therapy development for rare bleeding disorders, with potential implications for their competitive standing in the broader gene therapy market.
