Dietary Intervention in ADPKD on Tolvaptan (DIAT)
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|ClinicalTrials.gov Identifier: NCT03858439|
Recruitment Status : Recruiting
First Posted : February 28, 2019
Last Update Posted : March 5, 2020
|Condition or disease||Intervention/treatment||Phase|
|Polyuria Autosomal Dominant Polycystic Kidney||Other: Dietary||Not Applicable|
Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited renal disorder affecting 12.5 million persons worldwide, and impacting approximately 35,000-66,000 Canadians. An estimated 45% to 70% of patients with ADPKD progress to end-stage renal disease by age 65 years.
Tolvaptan has been approved in Canada as a treatment for ADPKD. Tolvaptan was discovered in Japan by Otsuka Pharmaceutical and was first approved there for ADPKD in 2014. The Health Canada approval of Tolvaptan is based on the results of the pivotal Phase 3 randomized, double-blind and placebo-controlled TEMPO 3:4 Trial, the largest study conducted to date in adults with ADPKD.
The treatment of ADPKD had previously been symptomatic with the aim of reducing morbidity and mortality associated with disease manifestations. This changed with the publication of the TEMPO 3:4 trial, which proved the efficacy of the arginine vasopressin (AVP) V2 receptor antagonist tolvaptan in decreasing the progression of CKD. In this trial, 1445 patients with ADPKD eGFR > 60 were randomized to receive either placebo or tolvaptan in a split-dose regimen of 45 mg in the morning and 15 mg in the afternoon, up titrated to 90/30 mg as tolerated. The REPRISE study investigated the value of tolvaptan in 1300 patients with lower levels of eGFR (25-65 mL/min/1.73 m2).
AVP plays a major role in the pathogenesis of cysts in ADPKD via cAMP stimulation. The AVP antagonist blocks V2 receptors in collecting ducts and therefore blocks the concentrating ability of the tubule. This leads to increased urine volume. Recently, it has been demonstrated that this increased urine volume is related to solute excretion. Therefore, it seems possible that dietary modification to decrease solute intake (salt, protein) would decrease the urine volume in patients taking tolvaptan.
The most common side effect of AVP antagonist is increased renal water excretion which presents as polyuria, nocturia, increased thirst, and dry mouth. The daily urine volumes 5 days after starting different split doses of tolvaptan (15/15, 30/0, 30/15, 30/30 mg) in a preliminary phase 2 study were 4 to 6 L. In the treatment of hyponatremia and heart failure (another indication for tolvaptan therapy), a meta-analysis found an average increase in water clearance of only 68 mL/h after tolvaptan treatment. This more modest increase in urine output may be related to the low sodium diet most of these patients should be adhering to.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||15 participants|
|Intervention Model:||Single Group Assignment|
|Intervention Model Description:||Single group before / after dietary intervention.|
|Masking:||None (Open Label)|
|Official Title:||Dietary Intervention in Patients With ADPKD on Tolvaptan: Urine Output and Quality of Life|
|Actual Study Start Date :||June 6, 2019|
|Estimated Primary Completion Date :||September 2020|
|Estimated Study Completion Date :||December 2020|
Single arm study. All participants will receive dietary intervention.
Low sodium, low protein dietary recommendation
- Change in 24-hour urine volume [ Time Frame: Change from baseline to 3 months ]24-hour urine volume in ml.
- Change in ADPKD-IS [ Time Frame: Change from baseline to 3 months ]Autosomal dominant polycystic kidney disease impact score - quality of life. Eighteen items, score from 18 to 90 with higher values reflecting lower quality of life
- Change in Nagasaki Diabetes Insipidus Questionnaire [ Time Frame: Change from baseline to 3 months ]Validated measure of polyuria on quality of life. Subset of questions 1-10 will be used (Questions 11-12 relate to therapy with DDAVP). Score from 10 to 40 with higher scores reflecting worse quality of life.
- Change in urine total solute [ Time Frame: Change from baseline to 3 months ]Urine total solute measured by (urine sodium + urine urea) * urine volume
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03858439
|Contact: Peter Margetts, MD PhD||9055221155 ext email@example.com|