Aldose reductase inhibitor ranirestat significantly improves nerve conduction velocity in diabetic polyneuropathy: a randomised double-blind placebo-controlled study in Japan

Diabetic polyneuropathy (DPN) is one of the most frequent diabetic complications, and impairs patients’ quality of life. In the present study, the authors evaluated the efficacy and safety of ranirestat (40 mg/day) in patients with DPN. This was a multicentre placebo-controlled randomised double-blind parallel-group phase III study in which 557 patients were randomly assigned to either the ranirestat or placebo group and assessed for 52 weeks. The co-primary endpoints were the changes in tibial motor nerve conduction velocity (TMNCV) and total modified Toronto clinical neuropathy score (mTCNS) as a measure of clinical symptoms. There was a significant increase in TMNCV in the ranirestat group compared with the placebo group. The difference between groups in the change at last observation was 0.52 m/s (p = 0.021). Increases in nerve conduction velocity (NCV) in the ranirestat group were found not only in the tibial motor nerves but also in the median motor nerves, proximal median sensory nerves, and distal median sensory nerves. No significant differences in mTCNS or safety parameters were found between the two groups. Ranirestat (40 mg/day) was well tolerated and improved NCV. Regarding symptoms and signs, no detectable benefits over placebo were observed in the ranirestat group over 52 weeks of treatment.

Authors: Sekiguchi K, Kohara N, Baba M, Komori T, Naito Y, Imai T, Satoh J, Yamaguchi Y, Hamatani T; Ranirestat Group. ; Full Source: Journal of Diabetes Investigation. 2018 Jul 5. doi: 10.1111/jdi.12890. [Epub ahead of print]