Plain language summary
Grifola frondosa (maitake) is a medicinal mushroom which has been shown to be able to modulate the immune system. Many cancer patients use maitake extracts, however, evidence from clinical trials is lacking. This open label trial set out to determine the optimal dose of maitake extract based on possible toxic effects and blood parameters reflecting the state of the immune system. Eligible patients (post-menopausal women with previously treated breast cancer who were free of disease) were sequentially allocated to one of five groups (six subjects in each group) who received 0.2, 1, 3, 6 and 10 mg/kg of liquid maitake extract, respectively, daily for three weeks. Bloods were taken prior to the study beginning and on days 7, 14 and 21. No adverse effects or toxicities were observed. There were statistically significant dose response relationships for 25 out of the 146 parameters measured, with a stimulatory effect on some parameters, and a suppressing on others. The authors concluded that maitake was well tolerated and was associated with significant effects on immune balance, however, the effects were complex and depended on the different cell types and cytokines (specific signalling molecules of the immune system) evaluated, suggesting that maitake should be seen as an immune “modulator” rather than “enhancer”. The study was not designed to evaluate clinical efficacy of maitake.
Abstract
BACKGROUND Cancer patients commonly use dietary supplements to "boost immune function". A polysaccharide extract from Grifola frondosa (Maitake extract) showed immunomodulatory effects in preclinical studies and therefore the potential for clinical use. Whether oral administration in human produces measurable immunologic effects, however, is unknown. METHODS In a phase I/II dose escalation trial, 34 postmenopausal breast cancer patients, free of disease after initial treatment, were enrolled sequentially in five cohorts. Maitake liquid extract was taken orally at 0.1, 0.5, 1.5, 3, or 5 mg/kg twice daily for 3 weeks. Peripheral blood was collected at days -7, 0 (prior to the first dosing), 7, 14, and 21 for ex vivo analyses. The primary endpoints were safety and tolerability. RESULTS No dose-limiting toxicity was encountered. Two patients withdrew prior to completion of the study due to grade I possibly related side effects: nausea and joint swelling in one patient; rash and pruritus in the second. There was a statistically significant association between Maitake and immunologic function (p < 0.0005). Increasing doses of Maitake increased some immunologic parameters and depressed others; the dose-response curves for many endpoints were non-monotonic with intermediate doses having either immune enhancing or immune suppressant effects compared with both high and low doses. CONCLUSIONS Oral administration of a polysaccharide extract from Maitake mushroom is associated with both immunologically stimulatory and inhibitory measurable effects in peripheral blood. Cancer patients should be made aware of the fact that botanical agents produce more complex effects than assumed, and may depress as well as enhance immune function.
Methodological quality
Jadad score
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3
Allocation concealment
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Not applicable
