GENE REPLACEMENT THERAPY PROGRAM
URBAGEN is being developed to be a single-dose intracerebroventricular injection of non-replicating, single-stranded AAV9 vector for loss-of-function variants in the CTNNB1 syndrome.
It contains the human CTNNB1 gene, which encodes for the beta-catenin protein, under the control of the cytomegalovirus-enhanced chicken-beta-actin hybrid (CBh) promoter.
The size of the packaged single-stranded vector genome is ~4.7 kb, which is ideal for the ctnnb1 gene encoding β-catenin, as it ensures effective transport without degradation, enhancing gene therapy efficacy.
Within our project, more than a dozen therapeutic CTNNB1 gene therapy variants with the CBh promoter have been designed, and some of them have passed early in silico evaluation and were cloned for in vitro and in vivo evaluation.
Initial testings were performed in iNPCs in order to triage the best ones for in vivo assessment. Within each candidate researchers have systematically evaluate regulatory elements in both the coding and non-coding components to ensure both therapeutic efficacy and safety profiles of any therapeutic lead.
These constructs were individually packaged into AAV vectors, and the vectors were used to transduce patient-derived neuro-progenitor cells and cortical brain organoids. We found that only 1 of our AAV-CTNNB1 constructs was able to restore β-catenin expression levels and function in both preclinical models.
The AAV-CTNNB1 construct was tested for efficacy in a disease mouse model from Jackson Laboratory. Three doses of AAV9-Construct4 were given via ICV route to a 28 days old mice (corresponds to 6-12 years old human) , and behavioral tests showed phenotype improvements. High doses enhanced anxiety, in male activity and motor skills and mid doses improved gait in both sexes. Brain analysis showed increased hCTNNB1 expression correlating with dosage. Further studies in wild type mice monitored behavior, physical health, and organ collection. (Information regarding the safety of AAV gene therapy)
In November 2023, we have initiated manufacturing process with our European partner Viralgen VC. Our construct has passed 2l development and the comparability with the research-grade vector was acceptable. At this moment, we are developing 50l toxicology batch and will start with toxicology testings in October/November 2024. We expect to start with the 250l clinical batch manufacturing early 2025.
The proprietary technology underlying Urbagen is protected by licensed patent rights (application number 2023903490), filed by Children’s Medical Research Institute (CMRI) on 31st of October 2023, based on the work of Dr Leszek Lisowski. The CTNNB1 Foundation has obtained from CMRI an exclusive, worldwide license for the development and commercialization of Urbagen.
This license agreement underscores the commitment to address the unmet need within the CTNNB1 syndrome community and creates a clear pathway for bringing this breakthrough therapy to patients worldwide.
