• Be 18 years or older.

• Be male or non-pregnant females who agree to comply with applicable contraceptive requirements of the protocol (see Table 12. Acceptable Contraceptive Methods.)

• Histologically and/or cytologically confirmed gastrointestinal tumours that are metastatic or unresectable, and are subject to receive FOLFOX as SOC per investigator's judgement. Participants will have received at least one line of chemotherapy in the metastatic setting. Colorectal cancer: Patients must have received at least 1 prior line of therapy prior to enrollment in this study. Pancreatic cancer: Patients must have received at least 1 prior line of therapy. Gastric cancer: Patients who have not received prior treatment may be included in this study. GEJ (gastroesophageal junction) cancer patients are considered eligible to enter this trial. Cholangiocarcinoma: locally advanced or metastatic biliary tract cancer (intra or extrahepatic cholangiocarcinoma or gallbladder cancer) are eligible to enter this trial. Patients must have received at least 1 prior line of therapy (with gemcitabine-based chemotherapy). Colorectal cancer (ARM VI): Patients must have received at least 2 prior lines of therapy prior to enrollment in this study, one of which was a 5-FU based regimen. Colorectal cancer (ARM VII): Patients must have received only 1 prior line of therapy in the metastatic setting but remain naïve to oxaliplatin prior to enrollment in this study.

• Have measurable disease according to RECIST v1.1 (at least one measurable lesion).

• Have an anticipated survival of at least 16 weeks.

• Be ambulatory, with an Eastern Cooperative Oncology Group (ECOG) performance score of 0 or 1.

• Have adequate organ function, defined as:

∙ Hematologic: ANC ≥ 1.5 x 109/L, Hgb ≥ 9.0 g/dL and platelet count ≥ 100 x 109/L

‣ Hepatic: total bilirubin ≤ 1.5 x ULN (or ≤ 3 x ULN for subjects with Gilbert's Syndrome); transaminases ≤ 2.5 x ULN (may be up to ≤ 5x ULN if clearly due to liver metastases) and ALP ≤ 2.5 x ULN (or ≤ 3 x ULN if liver metastases).

‣ Renal: serum creatinine ≤ 1.5 x ULN or creatinine clearance ≥ 50 mL/min.

• c. Urine protein is 0, trace, or +1 on dipstick urinalysis, or \< 1.0 gram on 24-hour urine protein analysis

• Be on stable doses of any drugs that may affect hepatic drug metabolism or renal drug excretion (e.g., non-steroidal anti-inflammatory drugs, corticosteroids, barbiturates, diphenylhydantoin, narcotic analgesics, probenecid). Such drugs should not be initiated while the subject is participating in this study or have been initiated within 30 days beforehand before the start of treatment. Whenever possible, narcotic analgesic doses should be stable within 30 days prior to study entry and during the first cycle of therapy.

• Resolved acute effects of any prior therapy before the start of treatment to baseline severity or grade ≤1 CTCAE 5.0 except for adverse events not constituting a safety risk by investigator judgment (such as alopecia)

⁃ Able to take oral medications (for pre-medications and supportive management)

⁃ Understand and be able, willing, and likely to fully comply with study procedures and restrictions.

⁃ Be fully informed about their illness and the investigational nature of the study protocol, and sign a REB-approved Informed Consent Form (ICF).

⁃ (ARM VII): BRAF wild-type tumour status