Oral curcumin (complex C3, Sabinsa Corp, Utah) will be given to patients with inoperable colorectal metastases who will be commencing standard care oxaliplatin-based (FOLFOX) chemotherapy for up to 12 cycles(approximately 6 months) of treatment.

Primary measurements focus on safety and tolerability. These will be recorded in real-time and report the number and severity of adverse events.

Secondary measurements will include efficacy, (measured by response rate with RECIST and overall survival in months) supported by biomarker analysis.

Hypothesis Combination of oral curcumin with FOLFOX-based chemotherapy will be a safe and tolerated regimen for long-term administration to patients with colorectal metastases.

Primary objectives

To establish a tolerated dose of daily oral curcumin to be taken long-term with FOLFOX-based chemotherapy in patients with metastatic colorectal cancer will be conducted to assess:

1. Safety, tolerability and feasibility of administering oral curcumin at increasing doses escalating to 4 capsules (≈2 g C3-complex) during FOLFOX-based chemotherapy and continued for the duration of the chemotherapy course.

Secondary objectives

1. To observe any changes to the neuropathic side-effects of chemotherapy.
2. To observe potential for efficacy in terms of disease response and survival.
3. To identify putative biomarkers in plasma.

This is a phase I/IIa study:

Phase I will be a traditional escalation response design study (or 3+3+3) to firstly assess the safety of this combination and identify a maximum tolerated dose up to 4 g per day.

Phase IIa will be a randomised control study comparing curcumin and FOLFOX with FOLFOX alone, recruited at a 2:1 ratio respectively.

Inclusion Criteria:

• Histological or cytological diagnosis of metastatic colorectal cancer
• Measurable disease by Response Evaluation Criteria in Solid Tumours version 1.1 (RECIST 1.1) (Appendix 1)
• Adequate haematological, hepatic and renal function
• Age ≥ 18 years
• Eastern Cooperative Oncology Group (ECOG) Performance status 0 or 1
• Patients must have recovered from effects of any recent major surgery
• Willing to use contraception if applicable
• Informed consent
• Life expectancy estimated to be more than 12 weeks

Exclusion Criteria:

• Main exclusion criteria
• Contraindications to FOLFOX chemotherapy: Peripheral neuropathy NCI CTC >1, Liver failure, uncontrolled coronary heart disease, myocardial infarction within the previous 6 months.
• Unwilling or unable to comply with the study protocol.
• Patients who are pregnant or lactating or contemplating pregnancy. Patients or their partners who become pregnant during the study will be referred to the appropriate experts.
• Undergone chemotherapy (other than adjuvant for CRC) or participating in another drug study.
• Previous cancer <5 years (other than colorectal, basal cell carcinoma, in-situ cervical cancer).
• Major surgery within 4 weeks of starting the study
• Co-existing active infection or serious concurrent medical condition
• Significant cardiovascular disease
• Bone metastases
• Known brain or leptomeningeal metastases
• Surgery or hospital admissions for symptomatic intra-abdominal adhesions
• Active endoscopically proven peptic ulcer disease or colitis