Stepwise Introduction of Elexacaftor-Tezacaftor-Ivacaftor in Patients With Cystic Fibrosis and Liver Cirrhosis Child-Pugh A or B Using Clinical and Therapeutic Drug Monitoring: A Case Series

PURPOSE

Cystic fibrosis (CF) is a monogenetic disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein and affecting multiple organs, including the lungs and liver. Almost 90% of people affected carry at least 1 Phe508del CFTR mutation. Medical treatment with the CFTR-modulating drug elexacaftor-tezacaftor-ivacaftor (ETI) has been proven to be efficacious in carriers of at least 1 Phe508del CFTR mutation. Use of ETI in patients with CF (pwCF) and liver cirrhosis is still controversial. Therefore, stepwise introduction of ETI in pwCF and liver cirrhosis Child-Pugh A or B was evaluated using clinical and therapeutic drug monitoring.

METHODS

Seven consecutive pwCF received ETI. Four dosing steps were defined, at each of which the patients underwent clinical examination, routine blood tests, and therapeutic drug monitoring. Exposure of elexacaftor, tezacaftor, and ivacaftor was assessed by means of determination of AUC.

FINDINGS

ETI was successfully introduced and maintained in all pwCF. In those with Child-Pugh B cirrhosis (n = 2), diminishment of the dose as recommended by the label resulted in AUC values that were lower than the mean AUC values in pwCF without hepatic impairment, as reported previously.

IMPLICATIONS

Despite the limitations of this small case series, stepwise elevation of ETI dose did not induce clinical adverse effects or increases in serum liver test results under strict clinical follow-up and therapeutic drug monitoring, and may allow tolerable introduction of this therapy in pwCF and cirrhosis Child-Pugh A and possibly B.

Real-life efficacy and safety of elexacaftor/tezacaftor/ivacaftor on severe cystic fibrosis lung disease patients

Elexacaftor/tezacaftor/ivacaftor (ETI) is a cystic fibrosis (CF) transmembrane conductance regulator modulator, which has shown efficacy in CF patients (≥6 years) with ≥1 Phe508del mutation and a minimal function mutation. In October 2019, ETI became available on compassionate use basis for Dutch CF patients with severe lung disease. Our objective was to investigate safety and efficacy of ETI in this patient group in a real-life setting. A multicenter longitudinal observational study was conducted to examine changes in FEV1 , BMI, and adverse events at initiation and 1, 3, 6, and 12 months after starting ETI. The number of exacerbations was recorded in the 12 months before and the 12 months after ETI treatment. Patients eligible for compassionate use had a FEV1 <40% predicted. Wilcoxon signed-rank test analyzed changes over time. Twenty subjects were included and followed up for up to 12 months after starting ETI. Treatment was well tolerated with mild side effects reported, namely, rash (15%) and stomach ache (20%) with 80% resolving within 1 month. Mean absolute increase of FEV1 was 11.8/13.7% (p ≤ .001) and BMI was 0.49/1.87 kg/m2 (p < .001-0.02) after 1/12 months, respectively. In comparison to the number of exacerbations pretrial, there was a marked reduction in exacerbations after initiation. Our findings show long-term effects of treatment with ETI in patients with severe CF lung disease in a real-life setting. Treatment with ETI is associated with increased lung function and BMI, less exacerbations, and only mild side effects.

Predictors of response in initial users of metformin and sulphonylurea derivatives: a systematic review

AIM

To provide an overview of factors predicting metformin and sulphonylurea treatment response.

BACKGROUND

A large variability between individuals in treatment response to metformin and sulphonylurea derivatives exists. Understanding which factors determine response to these drugs may pave the way for more individualized therapy.

METHODS

We conducted a systematic search in the MEDLINE, Cochrane and EMBASE databases, between 2003 and 2012 for articles assessing demographic and clinical prediction factors of treatment response in initial users of metformin or sulphonylurea. A literature search of articles referenced within the studies identified was also performed. Treatment response was defined as change in HbA1c level, reaching target HbA1c levels or time to treatment change. Studies were assessed on quality, sample size and type of analysis. Results were summarized by tabulating positive, null and negative associations observed for included predictors.

RESULTS

A total of 10 articles (six trial reports and four cohort studies) were obtained, including three of sufficient quality. For metformin, baseline HbA1c , older age, lower BMI and shorter disease duration were found to be predictors of better treatment response in at least three studies of sufficient quality. For sulphonylurea derivatives, baseline HbA1c and shorter duration were identified as predictors of better treatment response in at least two studies of sufficient quality. Race, smoking status, lipid levels, blood pressure, kidney function and comorbidities were not significantly associated with treatment response.

CONCLUSIONS

Several demographic and clinical factors were identified as possible predictors of response to metformin and sulphonylurea, but the number of studies with sufficient quality was small. Generally, early treatment seems important for achieving better glycaemic outcomes.