BioMarin Pharmaceutical has dosed the first patient in a Phase I/II trial investigating valoctocogene roxaparvovec gene therapy to treat severe haemophilia A patients with pre-existing AAV5 antibodies.
The open-label, single-arm, titer-escalation trial (BMN 270-203) is designed to examine the safety and efficacy of valoctocogene roxaparvovec in AAV5+ haemophilia A patients.
The trial seeks to sequentially enrol patients with pre-existing AAV5 antibodies in two titer cohorts, which will comprise the AAV5 antibody titer levels generally found in the haemophilia population and patients treated with the 6e13vg/kg dose.
The trial's primary endpoint is to examine the safety of valoctocogene roxaparvovec in this population.
Secondary endpoints include evaluation of factor VIII (FVIII) activity level, frequency of required FVIII replacement therapy, and the number of bleeding episodes requiring treatment after therapy.
BioMarin Pharmaceutical Worldwide Research and Development president Hank Fuchs said: “Administration of valoctocogene roxaparvovec to this first patient seropositive for the AAV5 capsid is an important next step in our plan to expand the number and types of severe haemophilia A patients who may benefit from gene therapy and have antibodies to the vector.
“The goal with this study is to determine if patients that already have antibodies to AAV5 can be effectively treated with valoctocogene roxaparvovec.
“Our objective is to develop a therapy with the potential to eliminate the need for chronic treatment in severe haemophilia A across all patient sub-groups.”
Haemophilia A, which is also known as FVIII deficiency or classic haemophilia, is a genetic disorder caused by missing or defective FVIII, a clotting protein.
People suffering from the disease cannot form blood clots efficiently and are at risk for excessive bleeding from the mildest injuries.