Selecta Biosciences to present AAV-based gene therapy vectors data at ASGCT
Selecta Biosciences announced that five presentations of new preclinical data demonstrating the potential for the re-dosing of adeno-associated virus, or AAV-based, gene therapy vectors when administered in combination with its ImmTOR platform will be presented by Selecta scientists and collaborators from the National Institutes of Health and the International Centre for Genetic Engineering and Biotechnology, or ICGEB, at the upcoming American Society of Gene and Cell Therapy, or ASGCT. In naive mice models, co-administration of ImmTOR and AAV-based vectors enhanced transgene expression after the first dose of AAV vector, with rapid and enhanced transgene expression, which may enable therapeutic benefit at lower doses, potentially avoiding toxicities associated with larger doses. In a mouse model of Ornithine TransCarbamylase deficiency, a monogenic urea cycle disease that results in the accumulation of ammonia in the blood, ssAAV8-OTC in combination with ImmTOR was shown to effectively restore the physiological levels of urinary orotic acid and serum ammonia, correcting disease. These data demonstrate a new opportunity to treat pediatric patients with the possibility to re-dose to maintain therapeutic levels. Using a murine passive antibody transfer mouse model, the addition ImmTOR to Anc80-Mut enabled transgene expression even in the presence of moderately neutralizing antibodies against the Anc80 AAV vector. In a mouse model of the severe childhood form of isolated MMA, ImmTOR treatment was well tolerated and enabled repeat dosing of Anc80-Mut vector. A survey of sera from Mut-deficient MMA patients showed only 2/27 patients were seropositive for neutralizing antibodies, or NAb, against the Anc80 vector. The low seroprevalence of pre-existing Anc80 NAbs in the MMA patient population, and the ability to mitigate formation of new NAbs with ImmTOR, has the potential to make this combination therapy versatile and amenable for repeat dosing.