Poor Tolerability of Cystic Fibrosis Transmembrane Conductance Regulator Modulator Therapy in Lung Transplant Recipients

Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) is a highly effective therapy for patients with cystic fibrosis (CF) with potential benefits in lung transplant recipients (LTRs) for extrapulmonary CF manifestations; however, tolerability and efficacy in this population are largely unknown. We report our experience with ELX/TEZ/IVA in LTRs for extrapulmonary complications of CF including tolerability, drug-drug interactions, and therapeutic benefit. All LTRs at a single center initiated on ELX/TEZ/IVA were reviewed. Adverse events and patient-reported outcomes attributed to ELX/TEZ/IVA were documented. Pulmonary function, tacrolimus requirements in mg/kg/dl, body mass index (BMI), and reason for initiation were assessed at the initiation of ELX/TEZ/IVA, and at 12 months post-initiation or at the time of discontinuation for those in whom therapy was discontinued. Thirteen LTRs were initiated on ELX/TEZ/IVA at a mean of 115 ± 92 months post-transplant. All were initiated on ELX/TEZ/IVA for sinus or sinus and gastrointestinal CF manifestations. Five (38.4%) patients discontinued therapy due to declining pulmonary function (2/5, 40%), mood disturbances (2/5, 40%), or lack of benefit (1/5, 20%). Of the eight patients who remain on ELX/TEZ/IVA, four reported adverse effects and three LTRs temporarily held therapy. Six (46.2%) LTRs reported improvement in sinus symptoms, while four (30.7%) reported improved gastrointestinal symptoms. Weight declined in the cohort overall. Tacrolimus dose requirements decreased following initiation of ELX/TEZ/IVA therapy, with a 50% decline in dose requirements observed. In our experience, ELX/TEZ/IVA in LTRs is poorly tolerated with modest perceived extrapulmonary benefit and a significant effect on tacrolimus dose requirements. More data are needed to determine the benefits of ELX/TEZ/IVA therapy in LTRs.