Elexacaftor-tezacaftor-ivacaftor use after solid organ transplant.

Purpose of review: In 2019, the United States Food and Drug Administration approved a breakthrough therapeutic for cystic fibrosis, elexacaftor-tezacaftor-ivacaftor (ETI), because of its profound effect on lung function in large phase III clinical trials. ETI acts directly on the dysfunctional protein that causes the systemic manifestations of cystic fibrosis and also leads to improvement in nonpulmonary symptoms of cystic fibrosis. Transplant recipients were excluded from the pivotal clinical trials of ETI but may stand to benefit from correction of the underlying protein defect. Drug interactions between the three drugs in ETI and immunosuppression medications are one of the primary concerns about using ETI after transplant. No rigorous studies exist to assess the safety of ETI in transplant recipients.

Recent findings: Multiple recent publications describe the use of ETI after solid organ transplantation, including lung and nonlung transplants, and the real-world evidence for drug interactions between ETI and immunosuppression medications. In nonlung transplant recipients, the pulmonary benefits of ETI have been confirmed, but adverse events occur and may have implications for their transplanted organ (e.g. liver biopsy in the setting of elevated transaminases). Lung transplant recipients may have higher rates of ETI discontinuation than nontransplant recipients given a lack of direct pulmonary benefit and frequency of side effects. Drug interactions have not been difficult to manage, with most studies reporting variable rates of mild to moderate increased tacrolimus levels after initiation of ETI.

Summary: Limited data exist to support the use of ETI after solid organ transplantation and further research is warranted. Given the unknown risks and benefits, case by case consideration of ETI use is indicated when extra-pulmonary manifestations are present in lung transplant recipients with cystic fibrosis. Given the proven benefit in cystic fibrosis lung disease, benefits likely outweigh the risks of ETI for nonlung solid organ transplant recipients.