Efficacy of Gene Therapy Demonstrated in Patients Suffering from Rare Liver Disease (Crigler-Najjar Syndrome); NEJM-Published Results Described As “Exciting, Encouraging, and Even Moving”

Crigler-Najjar syndrome is characterized by hyperbilirubinemia. If it is not treated quickly, the build-up of bilirubin, due to a deficiency in the enzyme UGT1A1 which is responsible for metabolizing bilirubin into a substance that can be eliminated by the body, can cause significant neurological damage and become fatal. At the current time, the only treatment is phototherapy of up to 12 hours per day or a liver transplant. The results of a European gene therapy clinical trial sponsored by Généthon, involving clinicians from France, Italy, and the Netherlands, were published on August 17, 2023 in The New England Journal of Medicine. The study demonstrates the possibility of restoring expression of liver enzyme UGT1A1 by using gene therapy in cases of Crigler-Najjar syndrome. The candidate drug designed by Genethon lowered bilirubin levels below the toxic threshold with a single intravenous injection to such an extent that 3 patients treated with the highest dose have been able to stop using phototherapy for the last 18 months or more. The clinical trial is currently in the pivotal phase.