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Primary lateral sclerosis: diagnosis and management
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  • Published on:
    Response to Weydt et al
    • Martin Turner, Prof Oxford University
    • Other Contributors:
      • Kevin Talbot, MD

    We thank Dr Weydt and colleagues for their interest in our review. We are aware of the subjective benefit of cannabinoids reported by some living with multiple sclerosis, and a trial of THC:CDB spray is also approved by the UK’s National Institute for Health & Care Excellence (NICE). The CANALS study mentioned, in which PLS patients were well represented (28% of treatment arm and 20% of placebo arm), was a Phase 2 study powered to consider safety and tolerability. Adverse events were reported in 76% of the treatment group versus 27% in the placebo group. A reduction in the clinician’s Modified Ashworth Spasticity scale score was noted, and in the patient’s numeric rating scale score for pain, but not their scores for spasm or spasticity. In the discussion, the authors note that muscle cramping was not alleviated in a prior randomised trial of THC in ALS (1). We agree with their call for further evaluation, through a Phase 3 study of the benefit of cannabinoids over the licensed therapies for spasticity outlined in our review.


    1. Weber M, Goldman B, Truniger S. Tetrahydrocannabinol (THC) for cramps in amyotrophic lateral sclerosis: a randomised, double-blind crossover trial. J Neurol Neurosurg Psychiatry. 2010 Oct;81(10):1135-40. doi: 10.1136/jnnp.2009.200642. PMID: 20498181.

    Conflict of Interest:
    None declared.
  • Published on:
    Cannabinoids for spasticity in primary lateral sclerosis (PLS)
    • Patrick Weydt, MD University Hospital Bonn
    • Other Contributors:
      • Sergio Castro-Gomez, MD
      • Michael Thomas Heneka, MD

    To the editor

    We greatly enjoyed the excellent recent review on the diagnosis and management of primary lateral sclerosis (PLS). Turner and Talbot emphasize the importance of controlling spasticity as the most troublesome symptom, which is often associated with pain, discomfort and physical disability [1].
    As the authors point out, the current standard of care (baclofen, tizanidine, benzodiazepines and botulinum toxin) is frequently complicated by side effects, difficulties in titration and a lack of well controlled clinical studies [2]. We were thus surprised that the authors omitted the option of medicinal cannabis from the discussion of this very important topic.
    A study by Riva and colleagues offers clear evidence on the efficacy of the cannabinoid preparation Nabiximol for the control of spasticity in ALS and PLS patients [3], which is further supported by Meyer and colleagues providing compelling real world evidence of this effect [4].
    The THC:CBD oromucosal spray (nabioximols, brand name Sativex) became approved in European Union countries in 2010. Although only approved for people with moderate to severe spasticity in multiple sclerosis, who have not responded adequately to other anti-spasticity regimes, THC:CBD is increasingly being used off-label for spasticity in patients with motor neuron diseases. In addition, the patients themselves have self-medicated with recreational cannabis for many years [5].
    The multicenter, double-blind,...

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    Conflict of Interest:
    None declared.

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