Clinical trials

GNT0004 is a recombinant adeno-associated viral (AAV) vector gene therapy composed of an AAV8 serotype capsid containing a sequence-optimized gene for a human microdystrophin. Duchenne muscular dystrophy (DMD) is a neuromuscular disorder caused by dystrophin gene mutations leading to absence of functional dystrophin, a key protein that prevents muscle cell damage during physiological contractions. To address the underlying cause of the disease, GNT0004 delivers an optimized dystrophin gene that is capable to produce a shortened but functional dystrophin protein in target tissues (heart and skeletal muscles) in DMD subjects. It is expected to significantly delay or slow disease progression. GNT0004 will be given as a one-time intravenous (IV) infusion to help it reach muscles throughout the body.

This study aims to assess the overall seroprevalence of neutralizing antibodies against different AAVs potentially used in gene therapy in patients with genetic neuromuscular diseases.

Baseline Study on Duchenne Muscular Dystrophy (DMD) in view to collect data on the natural disease course in a cohort in young male subjects aged from 4 to 9 Years over a period of 6 to 36 months using disease appropriate evaluations.

Clinical trial rationale: CNS is an ultra-rare (\<1/1 million newborns), autosomal recessive disorder of bilirubin conjugation caused by mutation in the gene coding for uridine 5'-diphosphate glucuronosyltransferase (UGT1A1), that causes the accumulation of neurotoxic unconjugated bilirubin (UCB). Reduction of UCB is managed with phenobarbital in mild CNS, and daily phototherapy in severe CNS. There is no authorized curative medical treatment for CNS. Liver transplantation is currently the only curative treatment for severe CNS. GNT0003 is a genetically modified recombinant (r) viral vector composed of the AAV8 viral capsid carrying the UGT1A1 transgene which aims to correct the dysfunction of the mutated gene by achieving durable expression of a functional copy of the affected gene. Imlifidase (IgG-degrading enzyme) has demonstrated its efficacy in highly sensitized adult kidney transplant patients. To give participants with pre-existing anti-AAV8 antibodies access to gene therapy treatments, this trial aims to demonstrate the safety and efficacy of GNT0003 following imlifidase pre-treatment in adult participants with severe CNS requiring daily phototherapy and presenting with pre-existing anti-AAV8 antibodies. Primary objective: to assess efficacy of a single intravenous administration of GNT0003 following imlifidase pre-treatment in participants with severe CNS requiring phototherapy and pre-existing AAV8 antibodies Secondary objective: to collect data on safety and tolerability of GNT0003 and imlifidase, efficacy of imlifidase, pharmacokinetic and pharmacodynamic profile of GNT0003, and Quality of Life. The trial will include 3 parts: * A baseline period for at least 3 months * A treatment period * A follow-up period: * Initial post-treatment follow-up over 48 weeks * Long-term follow-up for 4 additional years This trial will be conducted in accordance with the International Conference on Harmonization Guideline for Good Clinical Practice and the Declaration of Helsinki. Participants must be consented using the approved Informed Consent Form before any procedures specified in the protocol are performed.

This is a Phase 1/2, multinational, open-label, study to evaluate the safety and efficacy of an intravenous infusion of GNT0003 in patients with Crigler-Najjar aged ≥10 years and requiring phototherapy. Patients will received a single administration of GNT0003 and will be followed for safety and efficacy of approximately 60 months (5 years): * a follow-up of approximately 12 months (48 weeks) * a long term follow-up of approximately 48 months (4 years), in order to be in line with the latest EMEA Guideline on follow-up of patients administered with gene therapy medicinal products, released on 22 Oct.2009 by the Committee for medicinal products for human use.