Clinical and functional efficacy of elexacaftor/tezacaftor/ivacaftor in people with cystic fibrosis carrying the N1303K mutation

Ido Sadras, Eitan Kerem*, Galit Livnat, Ifat Sarouk, Oded Breuer, Joel Reiter, Alex Gileles-Hillel, Ori Inbar, Michael Cohen, Ayelet Gamliel, Noemie Stanleigh, Tarini Gunawardena, Claire Bartlett, Tanja Gonska, Theo Moraes, Paul D.W. Eckford, Christine E. Bear, Felix Ratjen, Batsheva Kerem, Michael WilschanskiMichal Shteinberg, Malena Cohen-Cymberknoh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Background: Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) significantly improves health outcomes in people with cystic fibrosis (pwCF) carrying one or two F508del mutations. According to in vitro assays performed in FRT cells, 178 additional mutations respond to ELX/TEZ/IVA. The N1303K mutation is not included in this list of mutations. Recent in vitro data suggested that ELX/TEZ/IVA increases N1303K-CFTR activity. Based on the in vitro response, eight patients commenced treatment with ELX/TEZ/IVA. Methods: Two homozygotes; and six compound heterozygotes N1303K/nonsense or frameshift mutation pwCF were treated off label with ELX/TEZ/IVA. Clinical data before and 8 weeks after starting treatment were prospectively collected. The response to ELX/TEZ/IVA was assessed in intestinal organoids derived from 5 study patients and an additional patient carrying N1303K that is not receiving treatment. Results: Compared to the values before commencing treatment, mean forced expiratory volume in 1 second increased by 18.4 percentage points and 26.5% relative to baseline, mean BMI increased by 0.79 Kg/m2, and mean lung clearance index decreased by 3.6 points and 22.2%. There was no significant change in sweat chloride. Nasal potential difference normalized in four patients and remained abnormal in three. Results in 3D intestinal organoids and 2D nasal epithelial cultures showed a response in CFTR channel activity. Conclusions: This report supports the previously reported in vitro data, performed in human nasal and bronchial epithelial cells and intestinal organoids, that pwCF who carry the N1303K mutation have a significant clinical benefit by ELX/TEZ/IVA treatment.

Original languageAmerican English
Pages (from-to)1062-1069
JournalJournal of Cystic Fibrosis
StatePublished - Nov 2023

Bibliographical note

Publisher Copyright:
© 2023 European Cystic Fibrosis Society


Dive into the research topics of 'Clinical and functional efficacy of elexacaftor/tezacaftor/ivacaftor in people with cystic fibrosis carrying the N1303K mutation'. Together they form a unique fingerprint.

Cite this