(659) Inflammation Augments Trikafta-Induced CFTR Rescue in Primary Airway Epithelia Carrying F508del and Rare CFTR Mutations

Background: Due to defective CFTR, CF patients suffer from airway infection and inflammation. Highly effective modulator treatments (HEMT), such as Trikafta, are now available to rescue mutant CFTR proteins. However, in vitro pre-clinical studies evaluating HEMT have been mostly performed under non-inflamed conditions. Notably, we have shown that rescue of F508del by HEMT is drastically enhanced by the CF airway inflammatory milieu [1,2,3]. The present study investigated the impact of CF airways’ supernatant from mucopurulent material (SMM)-triggered airway epithelial inflammation on functional rescue of rare CFTR mutations that do not respond to HEMT.

Methods: To rescue CFTR, well-differentiated F508del/F508del and N1303K/345delTT primary human bronchial epithelial cultures were treated basolaterally with correctors VX-445 (3 µM) and VX-661 (10 µM), and potentiator VX-770 (5 µM) or potentiator QBW251 (5 µM). 30 µl PBS or SMM (diluted with PBS 1:4) were added apically. Treatments lasted for 24 h and CFTR function was subsequently analyzed in Ussing chambers.

Results: Inflamed F508del/F508del cultures exhibited a 2-fold augmentation of CFTR responses following triple therapy with VX-660+VX-445+VX-770 (Trikafta) or, alternatively, with VX-660+VX-445+QBW251. Remarkably, the cultures carrying the N1303K/394delTT genotype, which is not approved for Trikafta, exhibited functional CFTR rescue by both triple treatments when inflamed, which was similar in magnitude to HEMT-induced rescue of F508del/F508del in non-inflamed cultures. These data demonstrate for the first time that a) Trikafta-promoted F508del CFTR rescue is also enhanced by airway inflammation, adding to the repertoire of CFTR modulators whose efficacies are enhanced by inflammation [2] and b) CFTR rescue of rare mutations that lack a significant response to Trikafta in the absence of inflammation can be achieved in the presence of inflammatory conditions.

Conclusions: The CF airway inflammatory milieu improves the efficacy of F508del rescue by Trikafta or a triple combination containing the potentiator QBW251. Importantly, rescue of rare CFTR mutations that do not significantly respond to HEMT can be attained in inflamed airway epithelia. Thus, evaluation of HEMT efficacy must be performed under conditions mimicking the native inflammatory status of CF airways. Additional studies are necessary to address the mechanisms of inflammation-enhanced HEMT efficacy for F508del CFTR as well as rare mutations that do not respond to HEMT in the absence of inflammation. These studies may lead to improvements of the efficacy of CFTR modulators currently used in the CF clinic and benefit CF patients for whom no HEMT is available.

Acknowledgements: Supported by CFF (Cores from BOUCHE19R0) and NIH (P30DK065988).

References: [1] Gentzsch, M, Cholon, DM, Quinney, NL, Boyles, SE, Martino, MEB, and Ribeiro, CMP. Eur Respir J. 2018;52(6). pii: 1801133. doi: 10.1183/13993003.01133-2018.

[2] Gentzsch, M, Cholon, DM, Quinney, NL, Martino, MEB, Minges, JT, Boyles, SE, Lee, TNG, Esther, CR, and Ribeiro, CMP. Front. Pharmacol. 2021;12:628722. doi: 10.3389/fphar.2021.628722. eCollection 2021.

[3] Ribeiro, CMP; Gentzsch, M. Cells. 2021;10, 3260. https://doi.org/10.3390/cells10113260.