Rechallenge of Elexacaftor/Tezacaftor/Ivacaftor After Skin Rash in Two Pediatric Patients

Trials and tribulations of highly effective modulator therapies in cystic fibrosis

Highly effective modulator therapies (HEMTs) have revolutionised the management approach of most patients living with cystic fibrosis (CF) who have access to these therapies. Clinical trials have reported significant improvements across multiorgan systems, with patients surviving longer. However, there are accumulating case reports and observational data describing various adverse events following initiation of HEMTs including drug-to-drug interactions, drug induced liver injury, Stevens-Johnson syndrome, and neurocognitive symptoms including psychosis and depression, which have required discontinuation of therapy. Current clinical trials are assessing efficacy in younger patients with CF, yet long-term studies are also required to better understand the safety profile in the real-world setting across all ages and the impact of HEMT dose alteration or discontinuation.

Triple Therapy for Cystic Fibrosis (Elexacaftor, Tezacaftor, and Ivacaftor): Desensitization After Skin Rash

Cystic fibrosis (CF) is an autosomal recessive disorder of the CF transmembrane conductance regulator (CFTR) gene. CFTR modulators are novel approved therapies, and triple therapy with elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) is the current gold standard for patients with at least one F508del mutation. CFTR modulators are usually well-tolerated, but some adverse effects may occur, including skin rash. We report a case of a female patient who developed a severe skin rash after initiating treatment with ELX/TEZ/IVA. Modulator therapy and contraception were discontinued, and consequently, there was a drop in lung function and reappearance of respiratory symptoms. After rash resolution, a gradual reintroduction of ELX/TEZ/IVA was started, and this is the protocol the authors have summarized. Triple therapy with CFTR modulators has a significant impact on lung function and the quality of life of CF patients who have at least one F508del mutation, justifying its reintroduction and desensitization even after a severe adverse effect.

Post-approval studies with the CFTR modulators Elexacaftor-Tezacaftor—Ivacaftor

Triple combination therapy with the CFTR modulators elexacaftor (ELX), tezacaftor (TEZ) and ivacaftor (IVA) has been qualified as a game changer in cystic fibrosis (CF). We provide an overview of the body of literature on ELX/TEZ/IVA published between November 2019 and February 2023 after approval by the regulators. Recombinant ELX/TEZ/IVA-bound Phe508del CFTR exhibits a wild type conformationin vitro, but in patient’s tissue a CFTR glyoisoform is synthesized that is distinct from the wild type and Phe508del isoforms. ELX/TEZ/IVA therapy improved the quality of life of people with CF in the real-life setting irrespective of their anthropometry and lung function at baseline. ELX/TEZ/IVA improved sinonasal and abdominal disease, lung function and morphology, airway microbiology and the basic defect of impaired epithelial chloride and bicarbonate transport. Pregnancy rates were increasing in women with CF. Side effects of mental status changes deserve particular attention in the future.

Malassezia Folliculitis following Triple Therapy for Cystic Fibrosis

Triple-combination therapy with elexacaftor, tezacaftor and ivacaftor has been recently approved for cystic fibrosis patients with at least one F508del mutation in the transmembrane conductance regulator of the cystic fibrosis gene. Among the adverse events of elexacaftor, tezacaftor and ivacaftor, the cutaneous ones have been rarely reported, mainly dealing with urticarial-like rashes. On this topic, we report two cases of Malassezia folliculitis following triple therapy administration in two young females. In the first patient, a papulopustular rush appeared before the folliculitis while in the second patient it was not preceded by other skin manifestations. The diagnosis was confirmed both by dermoscopy and histology. The prompt response to systemic antimycotic drugs provided further evidence for the causative role of Malassezia, requiring no discontinuation of cystic fibrosis therapy. We could hypothesize that the triple regimen treatment may induce changes in the skin microbiome, potentially able to favor colonization and proliferation of Malassezia species. Physicians should be aware of such associations to allow prompt diagnosis and early interventions, avoiding useless drug removal.