Antibody Test Determines Eligibility for Hemophilia Gene Therapy

The US Food and Drug Administration’s recent approval of the AAV5 DetectCDx test marked the agency’s first-ever approval of a companion diagnostic test for a gene therapy product.

Developed by the University of Utah’s nonprofit ARUP Laboratories, in collaboration with BioMarin Pharmaceutical, the AAV5 DetectCDx test aids in the selection of adults with severe hemophilia A for treatment with Roctavian (valoctocogene roxaparvovec-rvox) gene therapy.

A one-time infusion, Roctavian uses adeno-associated virus serotype 5 (AAV5) as a vector to deliver a functional copy of the gene for coagulation Factor VIII. Roctavian aims to reduce or eliminate the need for chronic prophylaxis treatment in patients with severe hemophilia A without pre-existing anti-AAV5 antibodies.

AAV5 DetectCDx is an immunoassay that tests for pre-existing anti-AAV5 antibodies in patients to determine eligibility for Roctavian therapy. Clinical studies demonstrating the potential benefit of Roctavian in adults with severe hemophilia A used AAV5 DetectCDx.

ARUP Laboratories serves as the sole laboratory testing provider of AAV5 DetectCDx in the United States.

“When someone with severe hemophilia A chooses to embark on Roctavian gene therapy, AAV5 DetectCDx test results give patients and physicians confidence that preexisting AAV5 antibodies are not present,” wrote Jay Patel, MD, MBA, executive director of PharmaDx and Clinical Trials at ARUP Laboratories.

“We are proud,” he added, “to serve patients, physicians, and our industry partners, while advancing gene therapy through diagnostic testing.”

References

Patel J. ARUP laboratories makes history with diagnostic test for hemophilia A. Good Notes. University of Utah Health; November 16, 2023. Accessed December 7, 2023.

FDA approves ARUP Laboratories’ AAV5 DetectCDx, a first-ever companion diagnostic immunoassay for a gene therapy. News release. ARUP Laboratories; June 29, 2023. Accessed December 7, 2023.