Effect of aldose reductase inhibitor, fidarestat(SNK-860), on subjective symptoms, vibration, perception, and autonomic nerve functions in patients with diabetic neuropathy

To determine the efficacy of fidarestat, subjective nerve symptoms and peripheral nerve function in patients with diabetic neuropathy were studied by administering a novel aldose reductase inhibitor, fidarestat, 1 mg once daily for 28 weeks. Peripheral and autonomic nerve functions were examined with vibration perception threshold and R-R interval variations on electrocardiogram. The improvement of overall nerve function was assessed based on the combined improvement of each nerve function. Subjects were 27 patients with diabetic neuropathy. Of these, 25 completed the study. HbA1c was 7.6% at baseline and 7.7% at posttreatment, indicating no changes during treatment. Improvement (equal or better than moderate) in overall nerve function and subjective symptoms were 45.8% and 48.0%. Vibration perception thresholds of upper and lower extremities improved significantly (upper: p=0.0198, lower: p=0.0093), but no significant changes were observed in any parameters of autonomic nerve function tests. A statistically significant correlation was seen between improvement in the vibration perception threshold and that of autonomic nerve function (r=0.5530). In safety profile, 1 case each of abnormal GPT, γ-GTP, and ALP returned to normal at the end of this trial. No other side effects were observed. These results suggest that fidarestat may be a useful therapeutic drug for patients with diabetic neuropathy.