The European Medicines Agency (EMA) has granted PRIME (Priority Medicines) status to the gene therapy, GNT-0003, currently in clinical trials for Crigler-Najjar syndrome, a rare liver disease.
This status, granted only to drug candidates with major therapeutic potential, follows the successful completion of the first phases of the clinical trials.
The manufacturer, Genethon, is a non-profit gene therapy R&D organisation founded by the French Muscular Dystrophy Association (AFM-Telethon).
“We’re excited about the EMA’s PRIME recognition of GNT-0003,” said Genethon CEO Frederic Revah. “If successful, GNT-0003 would be the first gene therapy for Crigler-Najjar syndrome.”
PRIME status was granted to GNT-0003 following promising results from early phases of the European trial currently underway in collaboration with the CureCN consortium, and sponsored by Genethon. The trial is taking place in three countries: France, Italy and the Netherlands.
A deficiency of the UGT1A1 enzyme
Crigler-Najjar syndrome is a rare genetic liver disease characterised by abnormally high levels of bilirubin in the blood (hyperbilirubinemia). Accumulation of bilirubin is caused by a deficiency of the UGT1A1 enzyme, responsible for transforming bilirubin into a substance that can be eliminated by the body.
High levels of bilirubin can result in significant neurological damage and death if not treated quickly. Symptoms of the most severe form of the disease become apparent shortly after birth. At present, patients must undergo phototherapy for up to 12 hours a day to keep their bilirubin levels below the toxicity threshold.
GNT-0003 combines normal copies of the UGT1A1 gene coding for the bilirubin metabolising enzyme with an AAV vector.
In the early phases of the GNT-0003 clinical trials, the treatment of five adult patients demonstrated the safety and good tolerance of the gene therapy as well as a dose effect. In three patients treated at the highest dose, the bilirubin level decreased sufficiently to stop phototherapy for at least one year.
The trial has now entered its pivotal phase, with the objective of confirming the efficacy of this dose in additional patients including children.