Clinical trials confirmed THC/CBD spray works for one-third of treatment-resistant MS spasticity patients

What the researchers found

This review summarized the phase III clinical trial program for THC/CBD oromucosal spray in MS spasticity. A meaningful proportion of patients with treatment-resistant spasticity achieved clinically relevant improvement with active treatment versus placebo.

A 4-week initial trial of therapy proved useful for identifying which patients would respond. After 50 weeks of treatment in a post-approval study, approximately two-thirds of patients, physicians, and caregivers reported improvement in spasticity. Importantly, the post-approval study showed no statistically significant effect on cognition or mood compared to placebo.

The spray was well tolerated, with no evidence of effects typically associated with recreational cannabis use. Responders experienced relief not only from spasticity but also from associated symptoms including spasms, urinary dysfunction, and sleep disturbances.

Why it matters

These trial results established the clinical evidence base for regulatory approval of THC/CBD spray in multiple countries. The finding that cognition and mood were unaffected after nearly a year of use addressed key safety concerns about long-term cannabis-based medicine use.

The numbers in context

Approximately one-third of treatment-resistant patients responded. Two-thirds reported improvement at 50 weeks. No significant effect on cognition or mood. Associated symptom relief included spasms, urinary dysfunction, and sleep.

How the study worked

Review of pivotal phase III clinical trials and a post-approval clinical trial for THC/CBD oromucosal spray in MS spasticity.

What this study cannot tell us

The enriched design, while clinically practical, can overestimate effect sizes. Response rates of one-third mean two-thirds do not benefit. The specific responder characteristics were not well defined.

How to read the evidence

Summary of phase III clinical trials, the gold standard of evidence for medication approval.

When this study was published

Published in 2014.

The bigger picture

The enriched-design trial strategy (identifying responders before randomization) set a precedent for how cannabis-based medicines could be tested and prescribed: start with a trial period, continue only in those who respond. This approach maximizes benefit while minimizing exposure in non-responders.

Questions still open

• Can clinicians predict who will respond before starting the trial period? What happens after multiple years of continuous use? Would higher doses benefit non-responders, or have they simply reached the ceiling of cannabinoid effect?

Common questions

Read the original research

Advances in the management of multiple sclerosis spasticity: recent clinical trials.

European neurology, 72 Suppl 1, 9-11

Citation

Fernández, Oscar. (2014). Advances in the management of multiple sclerosis spasticity: recent clinical trials.. European neurology, 72 Suppl 1, 9-11. https://doi.org/10.1159/000367616

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