Effects of a Probiotic Intervention on the Gut and Vaginal Microbiome in Patients With Advanced or Recurrent Ovarian Cancer Undergoing Treatment With Platinum Chemotherapy

PRIMARY OBJECTIVE: I. To evaluate changes to the gut microbiome composition in ovarian cancer patients randomized to a probiotic intervention versus placebo during platinum chemotherapy. SECONDARY OBJECTIVES: I. Compliance with probiotic intervention in ovarian cancer patients during chemotherapy. II. Compliance with gut microbiome collection in ovarian cancer patients during chemotherapy. III. Compliance with vaginal microbiome collection in ovarian cancer patients during chemotherapy. IV. Recurrence free survival (RFS). V. Overall survival (OS). EXPLORATORY OBJECTIVES: I. To evaluate changes in the vaginal microbiome composition of ovarian cancer patients randomized to a probiotic intervention versus placebo during platinum chemotherapy. II. Assess pre-chemotherapy diet according to the Food Frequency Questionnaire (FFQ, Diet History Questionnaire \[DHQ3\]) questionnaire and how this influences the patient's baseline gut and vaginal microbiome. III. Assess whether a probiotic intervention influences chemotherapy toxicity and morbidity. IV. Assess whether a probiotic intervention influences stool consistency or need for additional medications during chemotherapy. V. Assess impact of gut and vaginal microbiome on patient quality of life. VI. Assess changes in serum metabolomic and immune markers as a result of the probiotic intervention. VII. Assess whether probiotic intervention is associated with chemotherapy-induced neutropenia, neutropenic fever and dose-delays. VIII. In patients who undergo standard-of-care surgery during chemotherapy, assessment of post-operative infectious outcomes, including surgical site infection in ovarian cancer patients randomized to a probiotic intervention versus placebo during platinum chemotherapy. IX. In patients who undergo standard-of-care surgery during chemotherapy, assessment of the tumor microbiome as a result of probiotic intervention versus placebo. X. In patients who are treated with antibiotics as standard of care for infectious causes during chemotherapy, assess changes in the vaginal and gut microbiome related to antibiotic therapy. OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients receive probiotic orally (PO) twice daily (BID) beginning within seven days of standard of care (SOC) platinum chemotherapy cycle 1 until seven days after their cycle 6. Cycles repeat every 21 days for up to 6 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo blood and vaginal sample collection throughout the study. ARM II: Patients receive placebo PO BID beginning within seven days of SOC platinum chemotherapy cycle 1 until seven days after their cycle 6. Cycles repeat every 21 days for up to 6 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo blood and vaginal sample collection throughout the study.