Zhou X, Garbinsky D, Ouyang J, Davenport E, Agarwal I, Oberdhan D. Longitudinal data on treatment duration and compliance from autosomal dominant polycystic kidney disease clinical trials with tolvaptan. Nephrol Dial Transplant. 2020 Jun;35(Supplement_3):gfaa139.S. doi: 10.1093/ndt/gfaa139.SO093.

BACKGROUND AND AIMS: Observation of impactful clinical outcomes in a clinical trial setting for ADPKD is challenging due to the life-long progressive nature of ADPKD and longer-term associated outcomes of interest in this population (e.g., renal function decline, cardiovascular events, and mortality). Since 2004, the tolvaptan (TOL) clinical trial program enrolled subjects in multiple clinical studies with the opportunity to enroll in subsequent clinical trials for treatment and outcomes evaluation.

METHODS: Data from 6 ADPKD studies (protocols 156-04-250, 156-04-251, 156-06-260, 156-09-284, 156-09-290, 156-08-271) were pooled and evaluated over time for overall treatment duration, treatment time, and treatment gaps. Treatment duration for the individual clinical trials ranged from 1 week to up to 3 years.

RESULTS: Overall, 1,437 subjects received TOL in these ADPKD clinical trials. For these subjects, the mean overall treatment duration was 4.1 years (3.8 years on treatment) with a maximum of 9.7 years (9.0 years on treatment). In this cohort, 513 subjects (35.7%) received TOL treatment for more than 5 years. Mean treatment compliance was 94.1%. Overall, 723 subjects (50.3%) received TOL treatment in ≥2 trials, with a median treatment gap duration between trials of 0.1 years (maximum, 5.6 years). At least 7 years of follow-up data are available for estimated glomerular filtration rate in 241 subjects (mean at baseline, 78.6 mL/min/1.73m2) and for total kidney volume in 130 subjects (mean at baseline, 1,816.9 mL).

CONCLUSION: This analysis provides longitudinal follow-up over an extended timeframe in a large number of subjects treated with TOL, with the greatest number of subjects being enrolled in clinical trials enriched for rapidly progressing ADPKD. Treatment compliance over years was reasonably good despite treatment gaps.

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