FDA Approves Companion Diagnostic for Hemophilia B Gene Therapy Beqvez

The Food and Drug Administration (FDA) has approved Labcorp’s nAbCyte^™ Anti-AAVRh74var HB-FE Assay as a companion diagnostic to determine patient eligibility for treatment with Beqvez^™ (fidanacogene elaparvovec-dzkt), a one-time gene therapy for hemophilia B.

Beqvez is indicated for the treatment of adults with moderate to severe hemophilia B who currently use factor IX prophylaxis therapy, or have current or historical life-threatening hemorrhage, or have repeated, serious spontaneous bleeding episodes and, do not have neutralizing antibodies to adeno-associated virus serotype Rh74var (AAVRh74var) capsid as detected by an FDA-approved test.

The nAbCyte cell-based neutralizing antibody assay detects AAVRh74var pre-existing neutralizing antibodies, which could impact the efficacy of Beqvez. Patients should be tested for pre-existing antibodies prior to treatment. Test results are reported as being negative (not detected) or positive (detected). If a patient tests positive for antibodies to AAVRh74var, Beqvez should not be administered.

“The approval of the nAbCyte companion diagnostic represents a first for a gene therapy that treats eligible patients with hemophilia B, helping to bring clarity to physicians and patients who are considering Beqvez as a treatment option,” said Dr Sonal Bhatia, MD, Head of US Specialty Care Medical Affairs, Pfizer. “We believe this companion diagnostic is an important tool for evaluating patients who may be suitable for gene therapy as the treatment paradigm advances with the introduction of gene therapies like Beqvez.”