In a randomized, placebo-controlled trial of 147 cancer patients, oral THC:CBD capsules (2.5mg each, three times daily) improved complete response for chemotherapy-induced nausea and vomiting from 8% to 24% when added to standard antiemetics.
Medical oncologists managing chemotherapy side effects; palliative care teams supporting cancer patients with refractory nausea.
Complete response tripled: 24% vs 8% (p=0.01)
What the researchers found
THC:CBD improved complete response rate (no vomiting, no rescue medication) from 8% to 24% (absolute difference 16%, 95% CI 4-28, p=0.01) during the first chemotherapy cycle. Similar improvements were seen for absence of significant nausea, reduced rescue medication use, and quality of life. Adverse events included sedation (18% vs 7%), dizziness (10% vs 0%), and transient anxiety (4% vs 1%). No serious adverse events attributed to THC:CBD.
Why it matters
Despite modern antiemetics, many cancer patients still experience nausea and vomiting. This trial demonstrates that low-dose THC:CBD can meaningfully improve outcomes when standard treatments are insufficient, using a product that is standardized and tested rather than ad hoc cannabis use.
The numbers in context
147 evaluable participants. Complete response: 24% THC:CBD vs 8% placebo (p=0.01). Absolute difference: 16%. Background antiemetics: corticosteroid+5-HT3 antagonist (97%), NK1 antagonist (80%), olanzapine (10%). Sedation: 18% vs 7%. Dizziness: 10% vs 0%.
How the study worked
Randomized, double-blind, placebo-controlled, two-stage phase II/III trial. 147 evaluable participants (of planned 250) with refractory nausea/vomiting during moderately or highly emetogenic chemotherapy despite guideline-consistent antiemetics. THC 2.5mg + CBD 2.5mg capsules three times daily, days -1 to 5.
What this study cannot tell us
Enrolled 147 of planned 250 participants. Background antiemetic regimens varied. Additional sedation and dizziness may limit use in some patients. Drug availability, legal status, and cultural attitudes may affect implementation. Cost-effectiveness analysis pending.
How to read the evidence
Randomized, double-blind, placebo-controlled trial with clinically meaningful primary endpoint, though under-enrolled.
When this study was published
2024 study
The bigger picture
This is one of the strongest RCT evidence bases for cannabis in cancer care. The standardized dosing (2.5mg THC + 2.5mg CBD, TID) provides a clear protocol that could be implemented in clinical practice, unlike variable cannabis products.
Questions still open
- Would different THC:CBD ratios be more effective or better tolerated? Could this become standard of care for refractory chemotherapy-induced nausea?
Common questions
What dose of cannabis was used?
Why were these patients still nauseated despite standard treatment?
Read the original research
Oral Cannabis Extract for Secondary Prevention of Chemotherapy-Induced Nausea and Vomiting: Final Results of a Randomized, Placebo-Controlled, Phase II/III Trial.
Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 42(34), 4040-4050
Citation
Grimison, Peter; Mersiades, Antony; Kirby, Adrienne; Tognela, Annette; Olver, Ian; Morton, Rachael L; Haber, Paul; Walsh, Anna; Lee, Yvonne; Abdi, Ehtesham; Della-Fiorentina, Stephen; Aghmesheh, Morteza; Fox, Peter; Briscoe, Karen; Sanmugarajah, Jasotha; Marx, Gavin; Kichenadasse, Ganessan; Wheeler, Helen; Chan, Matthew; Shannon, Jenny; Gedye, Craig; Begbie, Stephen; Simes, R John; Stockler, Martin R. (2024). Oral Cannabis Extract for Secondary Prevention of Chemotherapy-Induced Nausea and Vomiting: Final Results of a Randomized, Placebo-Controlled, Phase II/III Trial.. Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 42(34), 4040-4050. https://doi.org/10.1200/JCO.23.01836
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