NGN-401

The FDA has allowed Neurogene to keep studying the low dose of its Rett syndrome gene therapy candidate in both trial cohorts.\n A patient has died after receiving the high dose of Neurogene’s Rett syndrome gene therapy candidate. The biotech had disclosed the adverse event Nov. 11, and explained the patient was in critical condition Nov. 18. Thursday, Neurogene provided an update on the individual in a financial regulatory filing. The company said the person died “following complications from a rare and life-threatening hyperinflammatory syndrome associated with systemic exposure to high doses of adeno-associated virus (AAV).”The earlier updates established that the patient had received the gene therapy, dubbed NGN-401, Nov. 5 and subsequently showed signs of systemic hyperinflammatory syndrome.Some people develop the syndrome after receiving high doses of AAV, the vector used to deliver many gene therapies. The Rett patient was the third person to receive the high dose of NGN-401. Neurogene\'s chief financial officer Christine Mikail had discussed the impact of dosing Nov. 11, telling analysts the adverse event was “not somewhat surprising as a result of the 3x difference in the dose.”   In yesterday\'s filing, Neurogene explained that the FDA has allowed the biotech to continue studying the low dose in both cohorts, one of which is enrolling children. The other cohort is enrolling adolescents and adults. Neurogene will incorporate the low dose into the planning for the design of its registrational trial, according to the Nov. 21 filing. Mikail had expressed confidence in the low-dose data earlier this month.“We\'re pretty excited about what we\'re seeing in the low dose, both from an efficacy and safety perspective and have collected a significant amount of information to help inform what the pivotal design could look like,” the CFO said. “The low dose data is strong enough to go to the agency with and that\'s really where we collected the most data to date.”