Evaluating REGV131-LNP1265 Gene Therapy for Males Aged 2 and Older with Severe or Moderate Hemophilia B

What this Trial Is About

Researchers are studying males aged 2 years and older with severe or moderately severe hemophilia B caused by a genetic mutation in the coagulation Factor 9 gene. This trial evaluates an experimental gene insertion therapy called REGV131-LNP1265, which aims to help the body produce clotting factor long-term, reducing the need for regular factor replacement therapy. The main goal is to find a safe and well-tolerated dose by monitoring side effects both shortly after treatment and over time. The study has two parts. Part 1 involves dose escalation and confirmation in adult participants aged 18 years and older to determine the recommended dose for expansion RDE. Part 2 includes dose expansion at the RDE for adults, adolescents aged 12 to under 18, and younger children aged 2 to under 12 years, with doses adjusted by weight. Participants receive the study drugs REGV131 and LNP1265 according to the protocol, including different ascending dose levels in Part 1 and weight-adjusted doses in Part 2. Participants will be monitored for side effects, factor IX activity in the blood, antibody responses, bleeding rates, and use of factor replacement therapy. Blood samples and other biological samples will be collected to measure drug concentrations and detect antibodies or vector DNA. Safety will be followed for up to 15 years, with assessments of adverse events and bleeding episodes. The study duration allows long-term observation of treatment effects and safety.

A Study to Investigate the Safety and Effectiveness of a Coagulation Factor IX Gene Insertion Therapy (REGV131-LNP1265) in Pediatric, Adolescent and Adult Participants With Hemophilia B