Challenges in conducting a feasibility randomized controlled trial of medicinal cannabis for endometriosis pain in Australia.

Chesterman et al. ·Complementary therapies in clinical practice Impact 2.8

Unclear GRADE Moderate 0 citations

Samplen = 12 Pat.

Durationunclear

ControlTaste- and colour-matched placebo oil

EndpointFeasibility/recruitment and…

Blindingdoppelblind

DesignRCT

Cannabinoidkombination

Key finding

Feasibility study with recruitment failure (12 of 63 planned participants randomised, 7 dropouts); primary efficacy outcomes not reported.

Summary

Feasibility RCT on cannabis for endometriosis pain (n=12 randomised, planned n=63); 3-arm: inhaled THC (16%) + oral CBD (100mg/mL) vs. CBD alone vs. placebo. Study terminated early due to low recruitment/retention (7 of 12 participants dropped out early, only 4 completed). 10 adverse events (8 possibly cannabis-related), 2 serious adverse events (both not intervention-related). Feasibility and acceptability rated low — primarily due to driving ban requirement and high dropout rate.

PopulationPersons with endometriosis, planned n=63, actually randomised n=12

InterventionInhaled cannabis (16% THC, vaporised) + oral CBD oil (100 mg/mL) combined, or oral CBD oil alone

ControlTaste- and colour-matched placebo oil

OutcomeFeasibility and recruitment insufficient: only 12 of 63 planned participants randomised, 7 dropouts, 10 adverse events (8 possibly cannabis-related), 2 serious adverse events (not intervention-related)

Confidence in the evidence

Moderate

The third of four GRADE levels, the effect estimate is probably reliable.

Downgraded for

Imprecision

Quality profile

Sample size ★★★★★

Blinding Double-blind

Effect size —

Citations / year ★★★★★

Authors

Chesterman S, Mikocka-Walus A, Sinclair J, Druitt M, Furyk J, Evans S, Abbott J, Eathorne A, Martin A, Ng C

DOI 10.1016/j.ctcp.2025.102023↗

Design: RCT

Abstract

Background And Purpose: People with endometriosis report consuming cannabis to manage their endometriosis symptoms, however, its efficacy has not been established in clinical studies. This study aimed to determine the feasibility, acceptability, and safety of two different medicinal cannabis interventions against placebo in people with endometriosis. Materials And Methods: A three-armed randomised controlled trial was conducted, comparing the effects of using both inhaled medicinal cannabis using dried flower containing 16 % delta-9-tetrahydrocannabinol (THC) via vaporisation and an oral oil containing 100mg cannabidiol (CBD) per mL together, versus an oral CBD oil alone, versus a taste- and colour-matched placebo oil. The trial aimed to recruit 63 participants (21 per intervention group). Outcome measures included safety and the occurrence of adverse events, and the acceptability and feasibility of recruitment and retention. Results: Overall, 12 participants were randomised to one of three groups, of whom seven withdrew from the study; four completed the study and one was lost to follow-up. Therefore, acceptability and feasibility of recruitment and retention was considered low. There were 10 adverse events reported (two unrelated to cannabis and eight possibly related to cannabis) and two serious adverse events reported (both unrelated to the intervention). Conclusion: Despite an urgent need for an evidence-based approach to using cannabis for endometriosis-related pain, our feasibility trial failed to recruit and retain the small intended sample. Failure of the trial was largely driven by two factors: the requirement to abstain from driving, and a high level of participant withdrawal.

The impediment to action advances action. — Marcus Aurelius