THERAPEUTIC SUBSTANCES

BACKGROUND: QR-333, a topical compound that contains quercetin, a flavonoid with aldose reductase inhibitor effects, ascorbyl palmitate, and vitamin D(3), was formulated to decrease the oxidative stress that contributes to peripheral diabetic neuropathy and thus alleviate its symptoms. This proof-of-principle study assessed the efficacy and safety of QR-333 against placebo in a small cohort of patients with diabetic neuropathy. METHODS: This randomized, placebo-controlled, double-blind trial included 34 men and women (21-71 years of age) with Type 1 or 2 diabetes and diabetic neuropathy who applied QR-333 or placebo (2:1 ratio), three times daily for 4 weeks, to each foot where symptoms were experienced. Five-point scales were used to determine changes from baseline to endpoint in symptoms and quality of life (efficacy). Safety was assessed through concomitant medications, adverse events, laboratory evaluations, and physical examinations. RESULTS: QR-333 reduced the severity of numbness, jolting pain, and irritation from baseline values. Improvements were also seen in overall and specific quality-of-life measures. QR-333 was well tolerated. Eleven patients in the QR-333 group reported 23 adverse events (all mild or moderate); 4 in the placebo group reported 5 events (all moderate). One patient who applied QR-333 noted a pricking sensation twice, the only adverse event considered possibly related to study treatment. CONCLUSIONS: From this preliminary safety study, it appears that QR-333 may safely offer relief of symptoms of diabetic neuropathy and improve quality of life. These findings warrant further investigation of this topical compound.