Cannabinoid use alongside dual immunotherapy was not associated with worse cancer treatment outcomes
In a pooled analysis of 684 cancer patients treated with dual immune checkpoint inhibitors, cannabinoid use was not associated with worse survival or increased adverse events, and was linked to improved progression-free survival by one measure.
Quick Facts
What This Study Found
Of 684 patients, 9.5% used cannabinoids during treatment. By multivariate analysis, baseline cannabinoid use was significantly associated with improved iPFS (p=0.05) but not with iBOR, PFS, OS, or incidence of immune-related adverse events. Results were similar when analyzed by cannabinoid use at any time during trial.
Key Numbers
N = 684 patients. 65 (9.5%) used cannabinoids at any time on trial. 32 (4.7%) at baseline. Baseline cannabinoid use associated with improved iPFS (p=0.05). No significant differences in OS (p=0.35), PFS (p=0.12), grade 1-4 irAEs (p=0.65-0.96).
How They Did This
Pooled individual patient data from 4 Canadian Cancer Trials Group (CCTG) trials of patients receiving dual immune checkpoint inhibitors (durvalumab plus tremelimumab) with or without chemotherapy. Cochran-Mantel-Haenszel and log-rank tests stratified by trial/treatment arm.
Why This Research Matters
There is concern that cannabinoids could impair immune checkpoint inhibitor effectiveness by inhibiting T-cell activation. This pooled analysis provides reassurance that cannabinoid use did not worsen outcomes in patients receiving dual immunotherapy.
The Bigger Picture
As more cancer patients use cannabis alongside immunotherapy, evidence on safety becomes increasingly important. This study adds to a growing body of data suggesting cannabinoids do not undermine immunotherapy effectiveness.
What This Study Doesn't Tell Us
Observational analysis within clinical trials. Small number of cannabinoid users (n=65) limits power. Self-reported cannabinoid use without standardized dosing or product information. iPFS improvement did not translate to OS benefit.
Questions This Raises
- ?Could cannabinoids have a biological benefit for immunotherapy response, or is the iPFS finding a statistical artifact?
- ?Would higher cannabinoid doses or specific cannabinoid types affect outcomes differently?
Trust & Context
- Key Stat:
- No harm to immunotherapy outcomes
- Evidence Grade:
- Pooled analysis of clinical trial data provides stronger evidence than single observational studies, but small number of cannabinoid users and self-report limitations reduce certainty.
- Study Age:
- 2025 publication
- Original Title:
- Effects of cannabinoids on immune checkpoint inhibitor response: CCTG pooled analysis of individual patient data.
- Published In:
- Immunotherapy, 17(4), 257-268 (2025)
- Authors:
- Coschi, Courtney H, Ding, Keyue, Tong, Justin, Tu, Dongsheng, O'Callaghan, Christopher, Leighl, Natasha B, Vera-Badillo, Francisco, Juergens, Rosalyn A, Hao, Desiree, Seymour, Lesley, Renouf, Daniel J, Chen, Eric, Gaudreau, Pierre-Olivier, Fung, Andrea S
- Database ID:
- RTHC-06261
Evidence Hierarchy
Looks back at existing records to find patterns.
What do these levels mean? →Frequently Asked Questions
Can cancer patients safely use cannabis during immunotherapy?
This pooled analysis of 684 patients found no negative impact of cannabinoid use on survival, treatment response, or adverse event rates during dual immune checkpoint inhibitor therapy. One measure even showed improved progression-free survival.
Why is there concern about cannabis and immunotherapy?
Immune checkpoint inhibitors work by activating T cells against cancer, while some cannabinoids can suppress T-cell activation. Theoretically, this could reduce immunotherapy effectiveness, but this study did not find evidence of that.
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Cite This Study
https://rethinkthc.com/research/RTHC-06261APA
Coschi, Courtney H; Ding, Keyue; Tong, Justin; Tu, Dongsheng; O'Callaghan, Christopher; Leighl, Natasha B; Vera-Badillo, Francisco; Juergens, Rosalyn A; Hao, Desiree; Seymour, Lesley; Renouf, Daniel J; Chen, Eric; Gaudreau, Pierre-Olivier; Fung, Andrea S. (2025). Effects of cannabinoids on immune checkpoint inhibitor response: CCTG pooled analysis of individual patient data.. Immunotherapy, 17(4), 257-268. https://doi.org/10.1080/1750743X.2025.2485012
MLA
Coschi, Courtney H, et al. "Effects of cannabinoids on immune checkpoint inhibitor response: CCTG pooled analysis of individual patient data.." Immunotherapy, 2025. https://doi.org/10.1080/1750743X.2025.2485012
RethinkTHC
RethinkTHC Research Database. "Effects of cannabinoids on immune checkpoint inhibitor respo..." RTHC-06261. Retrieved from https://rethinkthc.com/research/coschi-2025-effects-of-cannabinoids-on
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.