Reduction of Preexisting AAV9 Antibody Titers Before Onasemnogene Abeparvovec Administration in Twins With Spinal Muscular Atrophy

Therapeutic plasma exchange and rituximab successfully reduced the AAV Ab titers to the range of eligibility, but this regimen combined with corticosteroids was not sufficient to prevent infusion reactions to AAV gene therapy in our patients with preexisting AAV Abs. Further studies are needed to define a protocol that could enable patients to receive AAV-based gene therapy in the presence of preexisting immunity.