GB Pharmaceuticals has reported that preliminary trials of Sativex, the Cannabis derived pain relief spray, have narrowly missed 'statistical significance' due to unusually high placebo responses:
The placebo response in the study reported today appears related to dosing design, whereby patients were able to self-administer the oral spray at will. This was intended to reflect as far as possible the “real world” use of Sativex whereby patients initially experiment with dosing of Sativex to find their optimum dose level and which, once established, is usually maintained thereafter. Analysis of the efficacy data at fixed dose levels demonstrates a highly significant difference between Sativex and placebo. However, a consequence of allowing patients to determine their own dose was that patients on placebo took significantly more doses than patients on Sativex, thus confounding the overall comparison. This validates the decision by GW last year to adopt a fixed target dose approach in both the ongoing studies of Sativex in MS Spasticity and Cancer Pain.Further details can be found at the GW Pharma site here.