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, www.ampainsoc.org.
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. Cannabinoids are being analyzed as potential adjuvant analgesics. In this randomized multicenter study, nabiximols, a cannabinoid delivered as an oral mucosal spray, was studied to obtain information about the dose response for analgesia and safety in a population with pain not adequately controlled with an opioid.
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 five to 14 day baseline period, five weeks titration and treatment, and a post-study visit after two 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.
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 percent improvement in pain compared with baseline. However, there was no analgesic effect in the high-dose group and the high dose was not well tolerated. Just 66 percent 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.