Cystic Fibrosis in the Kidney: Monitoring the Effectiveness of Elexacaftor/tezacaftor/ivacaftor in Urine After a Short Pause of Therapy

University of Aarhus30 enrolled

Overview

In cystic fibrosis (CF) renal base excretion is impaired, due to mutations in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene, since CFTR function is crucial in regulation of the kidney's HCO3- excretion. The investigators suggest that challenged urine HCO3- excretion is a biomarker of CFTR function, which can be used to evaluate the extent of CFTR dysfunction and the possible correcting effects of CFTR modulating therapy. This study aims to evaluate changes in challenged urine HCO3- excretion in CF patients, who are currently in treatment with the triple CFTR modulator combination therapy, Elexacaftor/tezacaftor/ivacaftor (ETI), before, during, and after a short treatment pause.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Enrollment

Conditions

Cystic Fibrosis (CF)CFTR Gene Mutation

Interventions

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Adult (age \>17 years) CF patients. * Normal kidney function estimated by eGFR\>90. * Adults capable of understanding and voluntarily consenting. Exclusion Criteria: * Critical acute illness. * Severe lung disease (ppFEV1\<40%). * Adults not capable of understanding and voluntarily consenting.

Outcomes

Primary Outcomes

Difference in cumulative urine bicarbonate excretion before, during, and after ETI pause.

Challenged urine HCO3- test: Quantification of urine bicarbonate excretion after an acute oral NaHCO3 challenge before, under, and after ETI pause.