a two-part study of sativex® oromucosal spray for relieving uncontrolled persistent pain in patients with advanced cancer

Conditions: Pain; Advanced Cancer

Summary: the primary objective of this study was to evaluate the efficacy of nabiximols (sativex®), compared with placebo, when used as an adjunctive measure in relieving uncontrolled persistent chronic pain (not breakthrough pain) in participants with advanced cancer, who had inadequate analgesia even with optimized chronic opioid therapy. this multi-center study was conducted in two parts. all participants enrolled into the trial received nabiximols during one of two parts of the study, but they did not know which part. eligible participants were not required to stop any of their current treatments or medications.

this 11-week, multi-center, placebo-controlled study aimed to determine the efficacy, safety and tolerability of nabiximols administered as an adjunctive treatment for 5 weeks, versus placebo, assessed by a 2-part, randomized withdrawal design. the first part of the study (part a) was single-blind (participants) and the second part of the study (part b) was randomized, double-blind. eligible participants had advanced cancer, with a clinical diagnosis of cancer related pain which was not wholly alleviated by their current optimized opioid treatment. qualifying participants entered the study at screening and commenced a 5- to 14-day eligibility period. during this period, eligible participants had 3 consecutive days where pain severity remained within defined parameters, break-through opioid usage had not exceeded an average of 4 episodes per day, and maintenance opioid medication and dose had not changed. eligible participants underwent nabiximols titration during a single-blind treatment period lasting 10 days, followed by 4 days of therapy at the titrated dose. participants who demonstrated an improvement of 15% or more on the score of the pain numerical rating scale were advanced to part b, where they were randomized 1:1 to nabiximols or placebo in a double-blind fashion. participants then received study treatments at their self-titrated doses for 5 weeks. after the end of the 5-week treatment period, participants were offered the option of entering an open-label extension (ole) study; participants who entered the ole up to 7 days after study completion had their follow-up assessments performed on the same day as their first ole study visit. participants that did not enter the ole study had a safety follow up visit 14 days after treatment completion, which could be via telephone.

Eligibility criteria:
inclusion criteria (abbreviated): * the participant had advanced cancer for which there is no known curative therapy * the participant had a clinical diagnosis of cancer related pain, which was not alleviated with their current optimized opioid treatment * the participant received an optimized maintenance dose of step 3 opioid therapy, preferably with a sustained release preparation, but also allowing a regular maintenance dose of around the clock use of immediate release preparations * the participant received a daily maintenance dose step 3 opioid therapy of less than or equal to a total daily opioid dose of 500 mg/day of morphine equivalence (including maintenance and break-through opioids) * the participant was using no more than one type of break-through opioid analgesia exclusion criteria (abbreviated): * had any planned clinical interventions that would have affected their pain (for example, chemotherapy or radiation therapy where, in the clinical judgment of the investigator, these would be expected to affect pain) * the participant was currently using or had used cannabis or cannabinoid-based medications within 30 days of study entry and was unwilling to abstain for the duration of the study * had experienced myocardial infarction or clinically significant cardiac dysfunction within the last 12 months or had a cardiac disorder that, in the opinion of the investigator would have put the participant at risk of a clinically significant arrhythmia or myocardial infarction * had significantly impaired renal function * had significantly impaired hepatic function * female participants of child-bearing potential and male participants whose partner was of child-bearing potential, unless willing to ensure that they or their partner used effective contraception, for example, oral contraception, double barrier, intra-uterine device, during the study and for three months thereafter (however, a male condom was not to be used in conjunction with a female condom as this may not have proven effective)

Keywords: cancer pain opioid therapy inadequate analgesia optimized chronic opioid therapy