Background
The 3849+10 kb C->T mutation is categorized as a Class V mutation (leading to reduced amounts of CFTR proteins at the cell surface). The 3849+10 kb C->T mutation leads to a specific splicing defect in the CFTR, resulting in the inclusion of 84 intronic nucleotides as a cryptic exon in the CFTR RNA. This cryptic exon contains a premature stop codon, leading to the degradation of a significant fraction of the RNA by the Nonsense mediated mRNA decay )NMD( mechanism, as well as to the production of truncated non-functional CFTR protein.
Challenge
Although CFTR modulators are approved for patients carrying the 3849 mutation in some countries, their effect is very minimal. Therefore, a treatment with higher efficacy is needed for patients carrying the 3849 mutation.
SpliSense Solution
Our ASO SPL84, delivered via inhalation, effectively penetrates the target cells in the lungs, and specifically binds to the target region, thereby preventing the inclusion of 84 intronic nucleotides as a cryptic exon, and generating a fully functioning CFTR protein.
Phase 1 was successfully completed; Global Phase 2 for people with CF carrying the 3849 mutation is ongoing.