Functional Restoration of CFTR Nonsense Mutations in Intestinal Organoids.

Pharmacotherapies for people with cystic fibrosis (pwCF) who have premature termination codons (PTCs) in the cystic fibrosis transmembrane conductance regulator (CFTR) gene are under development. Thus far, clinical studies focused on compounds that induce translational readthrough (RT) at the mRNA PTC location. Recent studies using primary airway cells showed that PTC functional restoration can be achieved through combining compounds with multiple mode-of-actions. Here, we assessed induction of CFTR function in PTC-containing intestinal organoids using compounds targeting RT, nonsense mRNA mediated decay (NMD) and CFTR protein modulation. Rescue of PTC CFTR protein was assessed by forskolin-induced swelling of 12 intestinal organoid cultures carrying distinct PTC mutations. Effects of compounds on mRNA CFTR level was assessed by RT-qPCRs. Whilst response varied between donors, significant rescue of CFTR function was achieved for most donors with the quintuple combination of a commercially available pharmacological equivalent of the RT compound (ELX-02-disulfate or ELX-02ds), NMD inhibitor SMG1i, correctors VX-445 and VX-661 and potentiator VX-770. The quintuple combination of pharmacotherapies reached swelling quantities higher than the mean swelling of three VX-809/VX-770-rescued F508del/F508del organoid cultures, indicating level of rescue is of clinical relevance as VX-770/VX-809-mediated F508del/F508del rescue in organoids correlate with substantial improvement of clinical outcome. Whilst variation in efficacy was observed between genotypes as well as within genotypes, the data suggests that strong pharmacological rescue of PTC requires a combination of drugs that target RT, NMD and protein function.

Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.

Declaration of Competing Interest J.M.B. and C.K.v.d.E. are inventors on patent(s) related to the FIS-assay and received financial royalties from 2017 onward. J.M.B report receiving research grant(s) and consultancy fees from various industries, including Vertex Pharmaceuticals, Proteostasis Therapeutics, Eloxx Pharmaceuticals, Teva Pharmaceutical Industries and Galapagos outside the submitted work. C.K.v.d.E report receiving research grant(s) grant(s) from Vertex Pharmaceuticals (money to institution) outside the submitted work. G.H.K. reports research grants from Vertex Pharmaceuticals, GSK, TEVA, Ubbo Emmius Foundation, European Union, Lung Foundation Netherlands (Money to institution), outside the submitted work. M.A.M. reports research grants and patient recruitment fees for clinical trials from Vertex, for which his institution Charité-Universitätsmedizine Berlin received payment; fees for consulting and advisory board participation from Antabio, Arrowhead, Boehringer Ingelheim, Enterprise Therapeutics, Kither Biotech, Sathera, Sterna Biologicals, and Vertex outside the submitted work. S.Y.G. reports fees for advisory board participation from Chiesi outside the submitted work. All other authors have nothing to disclose.