An investigational cannabinoid therapy helped provide effective analgesia when used as an adjuvant medication for cancer patients with pain that responded poorly to opioids, according to results of a multicenter trial reported in The Journal of Pain, published by the American Pain Society, a multidisciplinary community that brings together a diverse group of scientists, clinicians and other professionals to increase the knowledge of pain and transform public policy and clinical practice to reduce pain-related suffering.
While opioid therapy is the mainstay treatment for cancer pain in patients with advanced disease, a substantial minority experience pain that cannot be adequately controlled at safe and tolerable doses. The most common treatment approach is co-administration of another analgesic.
Potential adjuvant therapy
Cannabinoids are being analyzed as potential adjuvant analgesics. In a randomized multicenter Phase III study, nabiximols (Sativex?, GW Pharmaceuticals), a cannabinoid oromucosal mouth spray developed for multiple sclerosis (MS) patients, who can use it to alleviate neuropathic pain, spasticity, overactive bladder, and other symptoms, was studied for as a potential treatment to alleviate pain due to cancer. It has also been researched in various models of peripheral and central neuropathic pain. Nabiximols is distinct from all other pharmaceutically produced cannabinoids currently available because it is derived from cannabis plants, rather than a solely synthetic process. The drug is a pharmaceutical product standardized in composition, formulation, and dose, although it is still effectively a tincture of the cannabis plant. Its principal active cannabinoid components are the cannabinoids tetrahydrocannabinol (THC) and cannabidiol (CBD). The drug is formulated as an oral mucosal spray and was studied to obtain information about the dose response for analgesia and safety in a population with pain not adequately controlled with an opioid.
Cancer and Chronic Pain
Patients were eligible to participate in the study if they had active cancer and chronic pain that was moderate to severe despite taking opioids. The study timeline was a 5 to 14 day baseline period, a 5 weeks titration and treatment, and a post-study visit after 2 weeks. Every day, patients responded to questions to rate their pain, gauge their sleep quality, and determine how many sprays of the nabiximols they were taking.
Study Results
Results of the study showed that nabiximols has analgesic efficacy when used as an add-on therapy for cancer patients with pain not controlled by an opioid alone. In the low-dose nabiximols group, there was a 25% improvement in pain compared with baseline. However, the research show that there was no analgesic effect in the high-dose group and the high dose was not well tolerated. Just 66% of subjects in that group finished the study. The authors concluded that nabiximols in a tolerable dose range may offer analgesic benefits to very ill cancer patients with refractory pain.
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