Positive new Phase III data on tolvaptan for ADPKD

Positive top-line results from an additional Phase III clinical trial of tolvaptan in adult patients with autosomal dominant polycystic kidney disease (ADPKD) have been released by Japanese drug major Otsuka Pharmaceutical (TYO: 4578).

The primary endpoint of the trial was the change in estimated glomerular filtration rate (eGFR) from pre-treatment baseline levels to post-treatment assessment. In patients treated with tolvaptan the reduction in eGFR was significantly less than in patients treated with placebo (p<0.0001). eGFR is an estimate of the sum of the filtration rates of all single functional nephrons (filtering units) in the kidneys, measured through creatinine-based estimation equations. The difference observed in this study represents a 35% reduction in the loss of kidney function compared to placebo in these patients over the course of one year. The key secondary endpoint was a comparison of the efficacy of tolvaptan treatment versus placebo in reducing the decline of annualized eGFR slope across all measured time points in the study. These data also showed significant benefit from tolvaptan vs. placebo (p<0.0001).

The trial was completed to supply confirmatory data to the previous study to address the Complete Response Letter (CRL) issued by the US Food and Drug Administration in 2013 for a New Drug Application for tolvaptan in the treatment of adults with ADPKD. The drug was approved for ADPKD under the brand name Jinarc in Europe in May 2015 and as Samsca in Japan in March 2014.