Quest Diagnostics has secured breakthrough device designation for its adeno-associated virus (AAV) test, AAVrh74 ELISA assay, from the US Food and Drug Administration (FDA).

The test is an enzyme-linked immunosorbent in vitro diagnostic assay intended for the semi-quantitative detection of antibodies (IgG) to AAVrh74 capsid in the serum of humans.

It is designed to be used in combination with other clinical data as a tool to help determine patients for treatment with Sarepta Therapeutics's ELEVIDYS (delandistrogene moxeparvovec-rokl), a gene therapy for certain Duchenne muscular dystrophy (DMD) individuals.

Furthermore, Quest has expanded its collaboration with Sarepta to develop companion or complementary diagnostics in connection with the latter’s portfolio of investigational and on-market gene therapies.

The collaboration could include screening assays for antibodies to AAV-vector-based gene therapies of Sarepta for muscular dystrophies, including DMD and limb-girdle muscular dystrophies (LGMD).

Sarepta Therapeutics chief scientific officer and executive vice-president Louise Rodino-Klapac said: “Sarepta is pleased to expand its collaboration with Quest beyond our investigational therapies and to partner to develop essential diagnostic tools for our approved gene therapies that help streamline/match gene therapy treatment to eligible patients.

“Quest's diagnostic R&D capabilities and laboratory capacity play a critical role in identifying the patients who may benefit from these treatments.”

The initial companion diagnostic is intended for Sarepta's first gene therapy, ELEVIDYS.

This will treat the underlying genetic cause of DMD.

Additionally, Quest will provide clinical lab testing for Sarepta.

Quest Diagnostics Pharma Services general manager Bill Finger said: “Achieving breakthrough designation for our AAVrh74 ELISA, and collaboration with AAV-gene therapy pioneer Sarepta, positions Quest at the forefront of companion diagnostics innovation in the growing field of gene therapies.”