Long-term safety profile of tolvaptan in autosomal dominant polycystic kidney disease patients: TEMPO Extension Japan Trial

AIM: The aim of this trial (ClinicalTrials.gov identifier: NCT01280721) was to investigate the long-term safety profile of tolvaptan in Japanese patients with autosomal dominant polycystic kidney disease (ADPKD). METHODS: This open-label multicenter trial was conducted to examine adverse drug reactions (ADRs) related to tolvaptan up to an additional 3 years in 135 Japanese patients who participated in the Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and its Outcomes (TEMPO) 3:4 trial at doses of 60–120 mg/d. Blood samples were collected at baseline; at weeks 1, 2, and 3; at month 3; and every 3 months thereafter. RESULTS: In total, 134/135 (>99%) patients experienced ADRs. The most frequent ADRs were thirst (77.0%), pollakiuria (57.0%), polyuria (37.8%), and hyperuricemia (14.8%). Any unexpected ADRs were not reported in this trial. Most ADRs occurred early during treatment. Fourteen patients (10.4%) experienced hepatic events, and 8 (5.9%) experienced >3-fold increases above the upper limits of normal in serum alanine aminotransferase or aspartate aminotransferase levels between 3 and 9 months following tolvaptan initiation, which recovered after drug interruption. Of the 8 patients, 7 (5.2%) were previously allocated to the placebo arm in the TEMPO 3:4 trial and 4 (3.0%) discontinued due to the hepatic events. One patient (0.7%) was previously allocated to tolvaptan and experienced similar events in the TEMPO 3:4 trial. None of the hepatic ADRs met Hy’s Law laboratory criteria. CONCLUSION: ADRs observed in this extension trial were similar to those identified in the TEMPO 3:4 trial and hepatic events were not progressive.