The U UGA C sequence provides a favorable context to ELX-02 induced CFTR readthrough.

•Treatment with CFTR modulators is ineffective for patients carrying nonsense mutations introducing a premature termination codon (PTC). •The best-characterized drugs active against PTCs are aminoglycoside antibiotics, including ELX-02, previously referred to as NB-124. •ELX-02 induced a significant enhancement of mRNA level and protein function of S1196X and S466X CFTR variants. •The S1196X and S466X CFTR variants provide a favorable "U UGA C" genetic context for stabilization of CFTR transcript and their readthrough by ELX-02.