Mistletoe Extract in Patients With Advanced Pancreatic Cancer: A Double-Blind, Randomized, Placebo-Controlled Tial (MISTRAL).

BACKGROUND:Patients with advanced pancreatic cancer have -limited survival and few treatment options. We studied whether mistletoe extract (ME), in addition to comprehensive oncological treatment and palliative care, prolongs overall survival (OS) and -improves health-related quality of life (HRQoL). METHODS:The double-blind, placebo-controlled MISTRAL trial was conducted in Swedish oncology centers. The main inclusion criteria were advanced exocrine pancreatic cancer and Eastern Cooperative Oncology Group (ECOG) performance status 0-2. The subjects were randomly assigned to ME (n=143) or placebo (n=147) and were stratified by study site and by eligibility (yes/no) for palliative chemotherapy (June 2016-December 2021). ME or placebo was injected subcutaneously three times a week for nine months. The primary endpoint was overall survival (OS); one of the secondary endpoints was the HRQoL dimension global health/QoL (EORTC-QLQ-C30), as assessed at seven time points over nine months. Trial registration: EudraCT 2014-004552-64, NCT02948309. RESULTS:No statistically significant benefit of adding ME to standard treatment was seen with respect to either OS or global health/QoL. The adjusted hazard ratio for OS was 1.13 [0.89; 1.44], with a median survival time of 7.8 and 8.3 months for ME and placebo, respectively. The figures for the HRQoL dimension "global health/QoL" were similar in the two groups (p=0.86). The number, severity, and outcome of the reported adverse events were similar as well, except for more common local skin reactions at ME injection sites (66% vs. 1%). CONCLUSION:ME is unlikely to have a clinically significant effect on OS or the HRQoL dimension global health/QoL when administered in patients with advanced pancreatic cancer in addition to comprehensive cancer care.