About this trial
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.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Severe Crigler-Najjar syndrome requiring ≥ 6 hours/ day of phototherapy
Molecular confirmation of mutation in the UGT1A1gene by DNA sequencing
Detectable serum neutralizing antibodies against AAV8
Laboratory parameters value not clinically significant
Disqualifiers
Participation in another interventional trial within 6 months prior to start of clinical trial intervention and during the whole clinical trial
Fibrosis score ≥ 3 (METAVIR) or 10 kPa (FibroScan®)
Liver transplantation
Significant underlying liver disease, chronic hepatitis B, C and/or infected with Human immunodeficiency virus
Trial design
Single group
Treatments tested in this trial
Imlifidase
DrugImlifidase: single administration (dose is confidential), Lyophilized powder for concentrate for solution for infusion
GNT0003
DrugGNT0003: single administration 5E+12 VG/kg, Sterile concentrate for solution for infusion
Treatment groups
Trial outcomes
Primary outcomes
Proportion of participants with serum total bilirubin ≤ 300 μmol/L, 48 weeks after GNT0003 infusion and without phototherapy from Week 16
Decrease of serum total bilirubin level after interruption of daily phototherapy; change in serum total bilirubin from baseline to week 48.
Secondary outcomes
Incidence of significant clinical and/or laboratoy abnormalities, of all treatment-emergent adverse events, serious adverse events, adverse events of special interrests, adverse drug reactions, malignancies
Incidence and severity for each body system and laboratory parameter will be presented and summarized overall
Change in Health-related quality of Life form baseline to week 48 post GNT0003 administration
Scale 36-Item Short From Survey (SF-36 Health Survey); from 0 (negative) to 100 (positive)
Sponsors and contacts
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Genethon
Lead sponsor
Hansa Biopharma AB
Collaborator