Phytocannabinoids for Reducing Chronic Chemotherapy-Induced Peripheral Neuropathy in Breast and Colon Cancer Survivors

PRIMARY OBJECTIVE: I. Assess the ability of CBD and THC:CBD to reduce chronic chemotherapy-induced peripheral neuropathy (CIPN) symptoms as compared to placebo using the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) among breast and colon cancer survivors. SECONDARY OBJECTIVES: I. Evaluate the impact of CBD and THC:CBD as compared to placebo on quality of life using the Functional Assessment of Cancer Therapy-General (FACT-G) among breast and colon cancer survivors with chronic CIPN. II. Document the utilization of neuropathic and pain medications by cancer patients with chronic CIPN during treatment with CBD and THC:CBD as compared to placebo. III. Describe the side effects of CBD and THC:CBD treatment. EXPLORATORY OBJECTIVES: I. Assess neurological symptoms and function with the Neuropathy Pain Scale (NPS), Total Neuropathy Score - Clinically Based (TNSc), Quantitative Sensory Testing (QST), Grooved Pegboard Test (GPT), Timed Up and Go (TUG) Test, and Unipedal Stance Balance Test (USBT) among patients with chronic CIPN treated with CBD and THC:CBD as compared to placebo. II. Evaluate for predictors of response to CBD and THC:CBD for chronic CIPN. OUTLINE: Patients are randomized to 1 of 3 arms. ARM I: Patients receive CBD orally (PO) once daily (QD) on days 1-3 of cycle 1, twice daily (BID) on days 4-6 of cycle 1, and three times daily (TID) on days 7-28 of cycle 1. Patients receive CBD PO TID on days 1-28 of cycle 2. Cycles repeat every 28 days for up to 2 cycles in the absence of unacceptable toxicity. Patients undergo urine collection during screening. ARM II: Patients receive THC:CBD PO QD on days 1-3 of cycle 1, BID on days 4-6 of cycle 1, and TID on days 7-28 of cycle 1. Patients receive THC:CBD PO TID on days 1-28 of cycle 2. Cycles repeat every 28 days for up to 2 cycles in the absence of unacceptable toxicity. Patients undergo urine collection during screening. ARM III: Patients receive placebo PO QD on days 1-3 of cycle 1, BID on days 4-6 of cycle 1, and TID on days 7-28 of cycle 1. Patients receive placebo PO TID on days 1-28 of cycle 2. Cycles repeat every 28 days for up to 2 cycles in the absence of unacceptable toxicity. Patients undergo urine collection during screening. After completion of study treatment, patients are followed up at 28 days.