Oral medicinal cannabinoids to relieve symptom burden in the palliative care of patients with advanced cancer: a double-blind, placebo controlled, randomised clinical trial of efficacy and safety of cannabidiol (CBD)

BACKGROUND: Despite improvements in medical care, patients with advanced cancer still experience substantial symptom distress. There is increasing interest in the use of medicinal cannabinoids, but there is little high quality evidence to guide clinicians. This study aims to define the role of cannabidiol (CBD) in the management of symptom burden in patients with advanced cancer undergoing standard palliative care. METHODS AND DESIGN: This study is a multicentre, randomised, placebo controlled, two arm, parallel trial of escalating doses of oral CBD. It will compare efficacy and safety outcomes of a titrated dose of CBD (100 mg/mL formulation, dose range 50 mg to 600 mg per day) against placebo. There is a 2-week patient determined titration phase, using escalating doses of CBD or placebo to reach a dose that achieves symptom relief with tolerable side effects. This is then followed by a further 2-week assessment period on the stable dose determined in collaboration with clinicians. DISCUSSION: A major strength of this study is that it will target symptom burden as a whole, rather than just individual symptoms, in an attempt to describe the general improvement in wellbeing previously reported by some patients in open label, non controlled trials of medicinal cannabis. Randomisation with placebo is essential because of the well-documented over reporting of benefit in uncontrolled trials and high placebo response rates in cancer pain trials. This will be the first placebo controlled clinical trial to evaluate rigorously the efficacy, safety and acceptability of CBD for symptom relief in advanced cancer patients. This study will provide the medical community with evidence to present to patients wishing to access medicinal cannabis for their cancer related symptoms. TRIAL REGISTRATION NUMBER: ALCTRN12618001220257 Registered 20/07/2018.