Conditions: Polycystic Kidney, Autosomal Dominant
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 46
Healthy volunteers: no

Brief summary:
This study's purpose is to evaluate the long-term safety of open-label tolvaptan regimens to determine the maximally-tolerated dose and acquire pilot efficacy data in patients with autosomal dominant polycystic kidney disease (ADPKD).

Detailed description:
Autosomal Dominant Polycystic Kidney Disease is a genetic disease classified by the formation of fluid-filled cysts in the kidneys. The accumulation of these cysts causes the kidneys to enlarge several times the normal size and leads to the eventual loss of renal function and ultimately results in renal failure in end-stage patients. This is a disease with life-threatening implications to those who have it, and their family members who may also be affected. Aside from early anti-hypertensive control and dietary protein restriction, which are presumed to offer a modest degree of protection, most surviving patients require renal replacement therapy (dialysis and transplant) and suffer from high morbidity and mortality.

A rationale for use of tolvaptan in these genetic disorders has been proven, in principle, through use of a variety of animal models. In these models, tolvaptan is effective in halting or reversing the progression of this renal disease.

The current study is being undertaken in order to evaluate whether tolvaptan, an oral vasopressin V2 receptor inhibitor, will maintain an adequate safety profile and show a potential clinical benefit by reducing total renal volume in the hopes of making an impact upon disease progression.

Arms:
arm 1: Participants received tolvaptan 45 mg orally in the morning and 15 mg orally 8 hours later for up to 4 years. arm 2: Participants received tolvaptan 60 mg orally in the morning and 30 mg orally 8 hours later for up to 4 years.

Interventions: intervention 1: Tolvaptan
Intervention descriptions: intervention 1: Participants were titrated to either the tolvaptan 45/15 or 60/30 mg split-dose over a 2-month Titration Period. They received the titrated dose for 34 months during the Fixed-dose Period. Following a planned off-treatment period, participants had the option to enter an Extension Period for an additional 12 months. Tolvaptan was supplied as tablets.

Protocol document: