An FDA-authorized AAVrh74 antibody companion diagnostic is now available through the Sarepta AAVrh74 antibody sponsored testing program to help identify patients with Duchenne muscular dystrophy who may be eligible for the company’s gene therapy
Quest Diagnostics has launched its FDA-authorized AAVrh74 antibody ELISA companion diagnostic (CDx) through Sarepta’s U.S. sponsored testing program for Duchenne muscular dystrophy. The CDx test is intended to aid healthcare providers in identifying patients with Duchenne who may be eligible for Sarepta’s gene therapy. Developed through a multiyear collaboration between Quest and Sarepta, the CDx launch reflects several years of scientific innovation, clinical development, regulatory expertise, and operational preparation.
“We're excited to make our companion diagnostic accessible to physicians and patients as part of the Sarepta AAVrh74 antibody sponsored testing program,” said Trevor Page, Vice President and General Manager, Pharma Services, Quest Diagnostics. “Our AAV testing and companion diagnostics expertise positions us to support life science collaborators seeking to advance innovative gene therapies.”
The development of the FDA-authorized CDx occurred in several stages. Quest initially developed an AAVrh74 antibody clinical trial assay (CTA) to support Sarepta’s clinical development program. The assay evolved into a laboratory-developed test (LDT) offered through Sarepta’s sponsored testing program, which was later retired when the FDA-authorized CDx launched.
In July 2025, the FDA granted premarket approval to the CDx for the semi-quantitative detection of antibodies (IgG) to AAVrh74 capsid in human serum. The approval helped fulfill Sarepta’s post-marketing commitment to establish an FDA-authorized in vitro companion diagnostic for Sarepta’s gene therapy.
Quest and Sarepta collaborated throughout the diagnostic’s development, clinical use and regulatory review. The collaboration included ongoing engagement with the FDA, securing Breakthrough Device Designation for the CDx, completing the pre-market approval process, and preparing the test for broader availability through a CLIA-certified laboratory.
Quest Diagnostics BioPharma Services’ mission is to make testing more accessible to more patients through our collaborations and sponsored testing programs. We collaborate with biopharma companies to offer sponsored, no-cost testing and, in some cases, genetic counseling for patients who meet eligibility criteria.
Benefits of Using Quest for Company-Sponsored Testing Programs
About the Quest Diagnostics AAVrh74 Antibody ELISA CDx
The Quest Diagnostics AAVrh74 Antibody ELISA CDx is an enzyme-linked immunosorbent in vitro diagnostic assay intended for the semi-quantitative detection of antibodies (IgG) to AAVrh74 capsid in human serum. The test reports an antibody titer, and a semi-quantitative interpretation of the test results derived from the antibody titer. Patients with an AAVrh74 antibody titer <1:400 are reported as not elevated for AAVrh74 antibody titers and may be eligible for treatment with the gene therapy. Patients with an AAVrh74 antibody titer ≥1:400 are reported as elevated for AAVrh74 antibody titers and are ineligible for treatment with the gene therapy. The test is for prescription use only. The test is intended to be used in conjunction with other available clinical information as an aid to identify patients eligible for treatment with indicated gene therapies.
About the Sarepta AAVrh74 Antibody Sponsored Testing Program
If you are a neuromuscular provider and interested in learning more about the Sarepta AAVrh74 Antibody Sponsored Testing Program, please reach out via the Contact Us form at https://www.elevidyshcp.com/contact-us or email sarepta@questdiagnostics.com. If you are a patient, please inquire with your neuromuscular provider about the program.