In an Australian phase II/III trial reported in the Journal of Clinical Oncology, Grimison et al found that oral cannabis extract improved the antiemetic complete response rate vs placebo in patients with cancer who had refractory chemotherapy-induced nausea and vomiting (CINV) despite use of guideline-consistent antiemetic prophylaxis.
Study Details
In the double-blind multicenter study, 147 patients with refractory CINV on moderately or highly emetogenic intravenous chemotherapy were randomly assigned between 2016 and 2022 to receive 2.5-mg of tetrahydrocannabinol plus 2.5-mg cannabidiol capsules (THC:CBD; n = 73) or placebo (n = 74) taken three times a day from days –1 to 5, in addition to guideline-consistent antiemetic prophylaxis. Background antiemetic prophylaxis included a corticosteroid and a 5-hydroxytryptamine antagonist in 97% of participants, a neurokinin-1 antagonist in 80%, and olanzapine in 10%. The most common cancers in the cohort were breast (37%) and gastrointestinal (31%) malignancies. The primary outcome measure of the study was complete response, defined as no vomiting or retching and no use of rescue medications during hours 0 to 120 after the first cycle of chemotherapy during the study.
Key Findings
Complete response rate was 24% in the THC:CBD group vs 8% in the placebo group (absolute difference = 16%, 95% confidence interval [CI] = 4%–28%, P = .01). Similar effects were observed for absence of significant nausea (20% vs 7%, P = .03), no use of rescue medications (28% vs 9%, P = .01), daily vomiting (mean = 0.2 vs 0.5, P = .01; mean maximum = 0.6 vs 1.3, P = .02), and the nausea scale on the Functional Living Index–Emesis quality-of-life questionnaire (mean = 2.8 vs 4.3, P < .001; mean maximum = 3.8 vs 5.7, P <.001).
The THC:CBD group had an increased risk of bothersome adverse events of special interest compared with the placebo group, including sedation (18% vs 7%), dizziness (10% vs 0%), and transient anxiety (4% vs 1%). No serious adverse events were attributed to THC:CBD.
The investigators concluded: “THC:CBD is an effective adjunct for chemotherapy-induced nausea and vomiting despite standard antiemetic prophylaxis but was associated with additional adverse events. Drug availability, cultural attitudes, legal status, and preferences may affect implementation. Future analyses will evaluate the cost-effectiveness of THC:CBD.”
Peter Grimison, PhD, MPH, MBBS, BSc, of the NHMRC Clinical Trials Centre, University of Sydney, is the corresponding author of the Journal of Clinical Oncology article.
Disclosure: The study was supported by the Department of Health, New South Wales Government, Australia. For full disclosures of the study authors, visit ascopubs.org.
