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Cannabis Drug Flops in Cancer Pain Study
Disappointing results have been reported from the first of three phase III trials of the investigational cannabinoid product Sativex (GW Pharmaceuticals/Otsuka) in the treatment of pain in patients with advanced cancer who have experienced inadequate analgesia during optimized chronic opioid therapy.
In the study, Sativex (as adjunctive treatment to optimized chronic opioid therapy) did not meet the primary endpoint of demonstrating a statistically significant difference from placebo. Secondary endpoints followed the same pattern.
Overall, Sativex was well tolerated. The only adverse events (AEs) reported at greater than 10% for the Sativex population were neoplasm progression (16% for Sativex vs. 18% for placebo) and somnolence (12% vs. 4%). The other most frequently reported AE for Sativex was dizziness (8% vs. 5% for placebo). Thirty-eight patients (19%) withdrew from the Sativex group because of AEs compared with 29 withdrawals (15%) from the placebo group.
The randomized, double-blind, placebo-controlled, parallel-group study recruited 399 patients in the U.S., Mexico, and Europe. Sativex was evaluated at a dose range of three to 10 sprays per day over a 5-week treatment period, with an additional 5- to 14-day stabilization period at the beginning of the trial and a 1-week follow-up period at the end of the trial. The subjects received Sativex or placebo as an add-on treatment to optimized opioid therapy and remained on stable doses of their background opioid treatment during the study.
Results from a second phase III pivotal trial of Sativex in patients with cancer pain are expected to be reported in the second quarter of 2015.
Sativex is approved for the treatment of spasticity due to multiple sclerosis in 27 countries outside the U.S. A request for a special protocol assessment has been submitted to the FDA for a proposed phase III study in this indication.
Source: GW Pharmaceuticals; January 8, 2015.