Immune checkpoint inhibitors and mistletoe

Few studies are available on the simultaneous or sequential combination of immune checkpoint inhibitors (ICI) and mistletoe preparations. As toxicities occurred in advanced and metastatic tumour diseases despite improved response rates under ICI, sequential as well as simultaneous combination of mistletoe extracts together with ICI (mainly nivolumab) have been investigated.

Additional mistletoe therapy may reduce the adverse autoimmune effects of the specific immunotherapy. First clinical experiences with ICI and add-on mistletoe are available for patients with bronchial carcinoma and melanoma. In a health services research study one patient group (advanced and metastatic bronchial carcinoma or melanoma) received only ICI while the other received additional mistletoe therapy in order to determine the rate of side effects in both groups [68]. The results suggest that additional mistletoe therapy does not alter the rate of ICI side effects.

A positive indication of synergies is provided by a health services research study in which add-on mistletoe therapy  significantly reduced the number of discontinued treatments in the context of targeted therapy by half, including immune checkpoint inhibitors [67]. 

Further systematic prospective investigations are currently being carried out in a prospective, randomized, controlled "Phoenix III study", in which patients with bronchial carcinoma are treated with PD-1 inhibitors and mistletoe therapy [70].

Last update: April 30th, 2020/AB