Chemotherapy-induced immunosuppression is restored by a fermented soybean extract: a proof of concept clinical trial

Depressed activity of natural killer (NK) cells is often associated with a higher incidence of infection and tumor recurrence. Despite evidence that NK cell activity is depressed after chemotherapy, there have been no clinical trials reporting the amelioration of this side effect. ChemoYoung, a fermented soybean extract, has been shown to activate NK cells in vivo. We conducted a randomized clinical trial to examine the effect of ChemoYoung on the restoration of NK cell activity during chemotherapy. Thirty-two patients were recruited for a self-controlled, randomized, crossover chemotherapy program with 2 consecutive, identical dose intensity chemotherapy cycles, with or without the oral intake of ChemoYoung during each cycle of chemotherapy. Patients were administered ChemoYoung (MicroBio Biotech Comp, Taipei, Taiwan) for 21 days during chemotherapy. The NK cell activity, T4/T8 ratio, NK cell number, and serum interleukin (IL) 2 level on day 21 of each cycle were compared. The mean white blood cell nadir, T4/T8 (%), NK number (%), and IL-2 serum level (ng/mL) of the combined group vs the chemotherapy-alone group were 3096/μL vs 2404/μL, 35.3/15.2 vs 29.2/13.7, 19% vs 17%, and 3.2 vs 2.0, respectively (all P > .1). However, the NK activity was 13.4 ± 10.3 for the combined treatment group and 4.5 ± 3.2 for the chemotherapy-alone group (P = .001). Natural killer cell activities were significantly reduced in patients who received chemotherapy without the adjuvant use of ChemoYoung. A trend to a better quality of life was also noted as assessed using the instrument of the European Organization for Research and Treatment of Cancer core questionnaire.