Efficacy of mistletoe extract as a complement to standard treatment in advanced pancreatic cancer: study protocol for a multicentre, parallel group, double-blind, randomised, placebo-controlled clinical trial (MISTRAL)

BACKGROUND: Most pancreatic cancer patients present with advanced stage at diagnosis with extremely short expected survival and few treatment options. A multimodal palliative approach is necessary for symptom relief and optimisation of health-related quality of life. In a recent open-label trial of mistletoe extract for advanced pancreatic cancer patients not eligible for chemotherapy, promising results on improved overall survival and better health-related quality of life were reported. The objective of the present study is to assess the value of mistletoe extract as a complement to standard treatment (palliative chemotherapy or best supportive care) in advanced pancreatic cancer patients with regard to overall survival and health-related quality of life. METHODS: The trial is prospective, randomised, double-blind, multicentre, parallel group and placebo-controlled. In total, 290 participants are randomly assigned to placebo or mistletoe extract given subcutaneously in increasing dosage from 0.01 to 20 mg three times per week for 9 months. Stratification is performed for site and palliative chemotherapy. Main inclusion criteria are advanced pancreatic cancer and Eastern Cooperative Oncology Group performance status 0 to 2; main exclusion criteria are life expectancy less than 4 weeks and neuroendocrine tumour of the pancreas. Two ancillary studies on sub-sets of participants are nested in the trial: a biomarker study collecting blood samples and a cross-sectional qualitative study with semi-structured face-to-face interviews. DISCUSSION: To our knowledge, this is the first placebo-controlled randomised trial assessing the impact of mistletoe extract as a complement to standard treatment on overall survival and health-related quality of life in patients with advanced pancreatic cancer. The presented trial with its two nested ancillary studies exploring biomarkers and patient experiences is expected to give new insights into the treatment of advanced pancreatic cancer. TRIAL REGISTRATION: EU Clinical Trial Register, EudraCT Number 2014-004552-64. Registered on 19 January 2016. ClinicalTrials.gov NCT02948309. Registered on 28 October 2016.