Nabiximols: A new prescription cannabinoid on the horizon
Nabiximols (Sativex) is not FDA-approved for any indication in the US. It’s an oral spray approved in roughly 25-30 countries (UK, Canada, most of Europe) for MS spasticity, but the US market has been the holdout since GW Pharmaceuticals first developed it. Jazz Pharmaceuticals, which now owns the drug, has been running a US-based Phase 3 program to try to change that.
That program hit an early setback. The first trial in the series, RELEASE MSS1 (68 patients), missed its primary endpoint: no significant difference from placebo on the Lower Limb Muscle Tone-6 scale at day 21. Jazz said it remained “committed to the nabiximols program” but that’s the kind of statement companies make whether or not they mean it.
Two other Phase 3 trials in the same program were still active as of the most recent public reporting:
RELEASE MSS3 (NCT04203498) — 446 participants, testing effect on muscle spasm frequency over 12 weeks, with sites in the US, Czech Republic, Poland, and UK.
RELEASE MSS5 (NCT04984278) — 190 participants, a crossover design measuring lower-limb muscle tone over 3 weeks.
As an aside, Massachusetts General Hospital got FDA and DEA sign-off for a Phase 2b trial testing nabiximols for spasticity in NMOSD (neuromyelitis optica spectrum disorder, a different condition from MS). That trial will include 44 patients. Enrollment began in early 2025, and is expected to finish in late 2026. So, the MassGen trial is a smaller, indication-expanding trial, not part of the MS approval pathway.
Evidence for Nabiximols to treat MS
A newly published meta-analysis in the journal Medical Sciences investigates the use of nabiximols for other MS symptoms beyond spasticity, since spasticity is rarely the only complaint in that population. This ties into a newer idea in MS care called “spasticity-plus syndrome,” which holds that spasticity tends to travel with other problems like bladder issues, poor sleep, and trouble walking, possibly because they share overlapping nerve pathways that respond to cannabinoids.
Keep reading on my Substack.
