Immunogenic adverse events to CFTR modulators - An international survey

CFTR modulator therapy has unprecedented positive effects on people with CF (pwCF). However, immunogenic reactions to CFTR modulator therapy may lead to drug discontinuation. We aimed to identify pwCF, intolerant to CFTR modulator therapy due to suspected immunogenic adverse events (iAE).

This survey assessed the types of reaction (e.g. rash, liver injury, drug fever) including reactions after re-exposure and was completed by ECFS CTN Centers.

Response rate to the survey was 74 %. 89 CF centers treating approximately 12000 to 17500 pwCF in 28 countries participated and 75 (84 %) CF centers reported discontinuation of CFTR modulator therapy. 37 (41.1 %) of CF centers reported iAE affecting 200 (1.1 - 1.7 %) pwCF. Detailed information about iAEs was provided for 41 of 200 (20.5 % of affected) pwCF. Of the iAEs reported in detail 33/41 (80.5 %) were associated with elexacaftor/tezacaftor/ivacaftor modulator therapy, 6 (14.6 %) with lumacaftor/ivacaftor and 2 (4.9 %) with tezacaftor/ivacaftor. 72 % of pwCF with iAE were re-exposed to CFTR modulator therapy. 32 % of re-exposed pwCF reported a second iAE. Rash and elevated liver enzymes were most frequently reported iAEs.

iAE were mostly transient. Drug allergy to CFTR modulator therapy was rare, but highly relevant for individual pwCF.