Neuropathy is one of the most common long-term complications of diabetes mellitus (DM) and painful neuropathy can be challenging to treat. There is no consensus on optimal treatment and many current therapies are limited by their tolerability, the need for titration, drug-drug interactions, administration of multiple daily doses, or the invasive nature of surgical procedures (Spruce et al., 2003; Baron & Wasner 2006). QutenzaTM, an 8% capsaicin dermal patch, has demonstrated analgesic efficacy in post-herpetic neuralgia and painful HIV-associated neuropathy. This study assessed its efficacy and safety in patients with Painful Diabetic Peripheral Neuropathy (PDPN) in a phase III trial.
Previous clinical studies of Qutenza in other painful aetiologies (post-herpetic neuralgia and HIV-associated neuropathy) have shown a significant effect of Qutenza at 2 weeks and for this reason pain status was assessed over the period 2-8 weeks and 2-12 weeks. While both assessments showed statistically significant effects for Qutenza, there was a slightly longer lag period before the analgesic effect of Qutenza became evident in PDPN (around 3-4 weeks) than in the other aetiologies (1-2 weeks) and thus the data for the latter period showed a higher level of statistical significance.
Qutenza treatment resulted in statistically significant improvements over placebo in reducing the daily pain score from baseline to weeks 2-8 in PDPN and extend the range of neuropathic pain aetiologies (PHN and HIV-AN) for which the efficacy of Qutenza has been demonstrated. Consistent with the results of previous controlled clinical trials of Qutenza, adverse reactions were predominantly limited to application site reactions.
Source: Authors: Stoker, M.,1 Jacobs, H.,1 Lloyd, A.,1 Long, S.K.,1 Simpson, D.M2 – 1. Astellas Pharma Global Development-Europe, Sylviusweg 62, PO Box 344, 2300 AH Leiden, The Netherlands. 2. Professor of Neurology, Director, Clinical Neurophysiology Laboratories, Director, Neuromuscular Division, Director, Neuro-AIDS Program, Mount Sinai Medical Center, Icahn School of Medicine at Mount Sinai.