THC/CBD spray helped about 10% of MS patients who failed standard anti-spasticity drugs | Research

The takeaway

A THC/CBD oral spray provided meaningful spasticity relief for roughly 10% of multiple sclerosis patients who were not adequately helped by standard medications.

Read this if you want an honest assessment of how effective cannabinoid spray therapy is for multiple sclerosis spasticity.

About 10% of treatment-resistant MS patients specifically benefit from THC/CBD spray

What the researchers found

This review evaluated clinical trial evidence for a THC/CBD oromucosal spray in MS-related spasticity. Three placebo-controlled trials (about 300 patients total) individually failed to show clear anti-spastic efficacy, but combined analyses showed response rates of approximately 35% with the spray versus 25% with placebo.

In a larger trial of 572 patients, the 241 patients who responded after a 4-week trial period were randomized to continue the spray or switch to placebo. After 12 weeks, 75% of those continuing the spray maintained their response, compared to 51% switched to placebo.

The reviewers estimated that in practice, about 10% of patients whose standard anti-spastic medications are unsatisfactory would specifically benefit from the cannabis extract spray. Key adverse effects included neuropsychiatric symptoms that resolved when treatment stopped, with abuse potential becoming tangible at 16 or more sprays per day.

Why it matters

Conventional anti-spasticity medications have limited effectiveness for many MS patients. This independent review provided a realistic assessment of what cannabinoid spray therapy offers: meaningful benefit for a modest subset of patients, rather than a broadly effective treatment.

The numbers in context

Response rates: approximately 35% with spray vs. 25% with placebo (combined analysis). In the enrichment trial, 75% of initial responders maintained response after 12 weeks vs. 51% on placebo. Estimated real-world benefit: about 10% of patients with inadequate standard treatment. Abuse risk increases from 16+ sprays per day.

How the study worked

Independent review evaluating published double-blind, placebo-controlled trials of THC/CBD oromucosal spray for MS-related spasticity. The review synthesized data from three initial trials (approximately 300 patients) and one larger enrichment trial (572 patients).

What this study cannot tell us

Individual trials failed to show significant efficacy on their own. The enrichment trial design (selecting responders before randomization) tends to exaggerate effect sizes. The estimated 10% real-world benefit rate means 90% of eligible patients would not be meaningfully helped. Drug interactions via P-glycoprotein inhibition add complexity.

How to read the evidence

Independent review of multiple controlled trials, providing a realistic assessment of clinical benefit.

When this study was published

Published in 2014. The THC/CBD spray (Sativex) has since been approved in additional countries.

The bigger picture

This review exemplified honest assessment of a cannabinoid medicine: not a miracle treatment, but a reasonable option for a specific subset of patients. The 10% estimate for meaningful benefit in treatment-resistant patients, while modest, is meaningful for individuals who have exhausted other options.

Questions still open

Can clinicians predict which 10% of patients will respond before starting a trial of the spray? Are there biomarkers or patient characteristics that predict response? How does long-term use affect the benefit-risk balance?

Common questions

How effective is THC/CBD spray for MS spasticity?

This independent review estimated that about 10% of MS patients whose standard medications are inadequate would specifically benefit from the spray. Response rates were about 35% with the spray vs. 25% with placebo in combined analyses.

Is there abuse risk with THC/CBD spray?

The review noted that abuse potential becomes tangible at 16 or more sprays per day. Neuropsychiatric side effects were the main adverse effects but resolved when treatment was stopped.

Read the original research

Delta-9-tetrahydrocannabinol + cannabidiol. A reasonable option for some patients with multiple sclerosis.

Prescrire international, 23(150), 145-8

View on PubMed ↗

Citation

. (2014). Delta-9-tetrahydrocannabinol + cannabidiol. A reasonable option for some patients with multiple sclerosis.. Prescrire international, 23(150), 145-8.