In a recent paper published in The Lancet Neurology, researchers evaluated the analgesic effect of prolonged-release oxycodone-naloxone (OXN PR) in patients with Parkinson’s disease (PD) suffering from severe and chronic pain in a pioneer Phase II clinical trial. Pain is a very common, non-motory symptom in PD patients (approximately 60% of patients) and is one of the symptoms associated with a depressed mood and reduced quality of life. Pain in PD patients has commonly only been treated by increasing the doses of dopaminergic therapy, and so far there is no full understanding on the different types of pain these patients suffer from either a medical or patient perspective.
The multi-center, double-blind randomized placebo controlled trial, funded by Mundipharma and named PANDA, included 202 patients, 93 assigned to OXN PR and 109 to placebo. The primary endpoint was set to average 24-hour pain scores at 16 weeks in the full analysis population. Although this endpoint (week 16) was not significant, results were encouraging given the statistically significant differences at week 4 (p=0.018), week 8 (p=0.011) and week 12 (p=0.021). Also, secondary endpoints (including frequency of rescue medication intake and percentage of responders) revealed OXN PR treated patients used less rescue medications and had clinically relevant improvements, relative to placebo. Moreover, researchers observed an improvement in severe musculoskeletal (p=0.023) and severe nocturnal pain (p=0.010) compared to placebo. However, secondary adverse effects like nausea and constipation were more frequent in patients taking OXN PR than those administered with placebo.
“This study provides key learnings on the potential use of oxycodone/naloxone for the treatment of severe pain in Parkinson’s disease. The encouraging secondary endpoint data suggest that further studies may help to uncover the potential role of OXN PR in this patient population,” said Claudia Trenkwalder, principal investigator of the study. “This study adds to the very limited knowledge base on the efficacy and safety of opioid-based treatment of patients with Parkinson’s disease suffering from complex pain.”
Prof. Dr. Karen Reimer, Managing Director, Mundipharma Research, added: “To our knowledge, this is the first randomized, double-blind, controlled trial specifically designed to investigate treatment in Parkinson’s disease pain. At Mundipharma, it is our vision to set ourselves apart as pioneers in pain management. We have a proven track record of bringing pain treatment innovations to market and want to build on this heritage, in an effort to continue to provide novel treatment options that really make a difference to people living in pain.”
Oxycodone is an opioid analgesic and naloxone is an opioid receptor antagonist: while oxycodone is responsible for pain-relieving effects, naloxone has shown to be extremely efficient in reducing the risk of opioid-induced constipation.