Evaluation of ranirestat for the treatment of diabetic neuropathy

Introduction: Pharmacologic maintenance of normoglycemia in diabetes cannot prevent the eventual complications mainly due to protein glycation-induced cell death, dysregulated antioxidant defense and signal transduction in affected tissues. The rate-limiting enzyme of this process, aldose reductase, is therefore a pharmacologic target. To date, nine inhibitors of this enzyme have been developed. Ranirestat has completed two Phase III clinical trials. The objective of this evaluation is to summarize and provide expert opinion on the status of ranirestat with an emphasis on its pharmacokinetics in the context of its potential effects to prevent/treat diabetic complications. Areas covered: A qualitative systematic literature search of PubMed through November 2013 using MeSH terms-aldose reductase inhibitors, diabetic neuropathy, AS-3201, ranirestat, diabetic complications and pharmacokinetics/ pharmacodynamics-identified relevant publications limited to human and rodent (mouse and rat) and English-language studies. Expert opinion: Ranirestat is a well-tolerated front-line inhibitor. It reproducibly exhibits some degree of measurable objective beneficial outcomes in diabetic neuropathy. It is the furthest advanced in clinical trials with some depth of supporting preclinical data. Trials in subjects with newly diagnosed neuropathy along with the identification of objective biomarkers/measurements of efficacy will be critical in identifying the real value and effect of ranirestat.