A Phase 2 interventional study of Metformin Hydrochloride in Cystic Fibrosis-related Diabetes and Cystic Fibrosis, sponsored by University of Kansas Medical Center. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-04-15.
Sponsored by University of Kansas Medical Center · Phase 2, Interventional, and Treatment
The purpose of this study is to assess the efficacy of metformin to improve airway ion channel function in those with CF-related diabetes (CFRD)
Up to 30 patients with CFRD on highly effective CFTR modulator therapy who meet criteria and agree to participation in the study will be placed on metformin. There will be a dose-escalation starting with 500mg twice daily for a week, followed by 500mg in the AM and 1000mg in the PM for another week and finally followed by 1000mg twice daily for 14 weeks. To minimize risk of B12 deficiency, a known side effect of long-term metformin use, we will also provide a supplement of 1000 μg oral cyanocobalamin daily for the duration of the trial
1,581 studies on the registry are indexed under Cystic Fibrosis; 190 are open to participants now.
This study's planned enrollment of 30 is below the median of 36 across 1,034 interventional studies indexed under Cystic Fibrosis.
Browse Cystic Fibrosis studies →University of Kansas Medical Center is the lead sponsor of 483 studies on the registry; 113 are open to participants now.
Of its 38 completed or terminated interventional studies of FDA-regulated products, 24 (63%) have results posted.
Counted across the registry records on this site, refreshed daily.
Diagnosis of CFRD with evidence of continued glucose intolerance at least 6 months after starting qualifying modulator therapy will be based upon one of the following:
Exclusion criteria:
patients with CFRD on highly effective CFTR modulator therapy who meet criteria and agree to participation in the study will be placed on metformin. There will be a dose-escalation starting with 500mg twice daily for a week, followed by 500mg in the AM and 1000mg in the PM for another week and finally followed by 1000mg twice daily for 14 weeks.
Drug: Metformin Hydrochloride
1000 mg twice daily
Also known as: Glucophage
Change in BK channel gene expression
Levels of LRRC26 (big potassium channel regulatory subunit) mRNA will be measured by polymerase chain reaction from nasal cells acquired via brushing
Time frame: Baseline through week 14 of metformin treatment
Change in BK function, as measured by nasal potential difference testing
Nasal potential difference testing measures direct BK current in the nasal epithelium, with greater current indicating greater BK function
Time frame: Baseline through week 14 of metformin treatment
Change in receptor for receptor for advanced glycation end products (RAGE) gene expression
Levels of RAGE mRNA will be measured by polymerase chain reaction from nasal cells acquired via brushing
Time frame: Baseline through week 14 of metformin treatment
Change in advanced glycation end products (AGE)
Plasma levels of AGE, receptor for AGE (RAGE), soluble RAGE and S100A12 will be quantified by ELISA
Time frame: Baseline through week 14 of metformin treatment
Change in sweat chloride
Measured as a secondary marker of CFTR function, with lower levels indicating greater CFTR function
Time frame: Baseline through week 14 of metformin treatment
Change in lung function
Measured by percent predicted forced expiatory volume in one second captured on spirometry (FEV1)
Time frame: Baseline through week 14 of metformin treatment
Change in Quality of Life (CFQ-R)
Measured by Patient Reported Outcome measurement tool called CFQ-R (validated)
Time frame: Baseline through week 14 of metformin treatment
Change in airway inflammatory markers
Inflammatory markers (interleukin-1beta, interleukin-6, interleukin-8, transforming growth factor beta1, tissue necrosis factor-alpha, matrix metalloproteinase-9 and cyclooxygenase-2) collected from nasal fluid will be measured by enzyme linked immunosorbent assay (ELISA)
Time frame: Baseline through week 14 of metformin treatment
Safety of metformin
Number of adverse events during study period
Time frame: Baseline through week 14 of metformin treatment
Pharmacokinetics of metformin
Plasma levels of metformin will be quantified by liquid chromatography-mass spectrometry
Time frame: Week 14 of metformin treatment
Plan to share: No
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University of Kansas Medical Center