Phase I/II Trial of Antagonism of HER in GI Cancer

Inclusion Criteria: 1. Histopathological/cytological diagnosis of non-resectable, recurrent or metastatic colorectal cancer 2. Tumour with wild-type RAS 3. Measurable disease evaluated by RECIST criteria v1.1 4. WHO performance status 0 or 1 5. Age ≥ 16 6. Estimated life expectancy \> 3 months 7. Adequate haematological function: * Haemoglobin ≥100 g/L * Absolute neutrophil count ≥1.5 x 10\^9/L * Platelet count ≥100 x 10\^9/L 8. Adequate liver function: * Total bilirubin ≤1.5 x upper limit of normal (ULN) (except for patients with known documented cases of Gilbert's syndrome) * ALT, AST \& ALP ≤2.5 x ULN in the absence of noted liver metastases * ALT, AST \& ALP ≤5 x ULN in the presence of liver metastases 9. Adequate renal function: * Serum creatinine ≤1.5 x ULN * Calculated creatinine clearance ≥30 mL/min 10. Adequate biliary drainage (patients with stents are eligible) 11. Adequate venous access for collection of exploratory biological samples 12. Women of child-bearing potential must have a negative pregnancy test prior to study entry. Female patients and male patients with partners of child-bearing potential must agree to use an adequate contraception method, which must be continued for 6 months after completion of chemotherapy 13. Must be able to swallow AZD8931 tablets 14. Capable of giving written informed consent 15. The following prior therapy is allowed: * Surgery - patients may have undergone a non-curative operation or palliative bypass surgery only. Patients who have previously undergone curative surgery must have evidence of non-resectable disease relapse * Radiotherapy - for localised disease * Prior adjuvant chemotherapy - provided this was completed at least 6 months before trial entry Exclusion Criteria: 1. Patients undergoing treatment with curative intent 2. Any prior treatment with agents targeting the ERBB pathway 3. Treatment with experimental drugs within 30 days or 5 half-lives of first dose of AZD8931 4. Previous palliative chemotherapy 5. Prior treatment with anthracyclines or mitoxantrone 6. Current disease or condition known to interfere with absorption, distribution, metabolism or excretion of drugs (including refractory nausea and vomiting, chronic gastrointestinal disease (e.g. inflammatory bowel disease), or significant bowel resection) 7. History of prior malignancy that will interfere with the response evaluation (exceptions listed in protocol) 8. Evidence of severe/uncontrolled systemic diseases or laboratory finding that makes it undesirable for the patient to participate in the trial 9. Evidence of active uncontrolled infection 10. Patients with clinically significant ascites and/or effusions 11. Regular use of anti-diarrhoeal 12. Pregnant or lactating women 13. Cardiac conditions (as detailed in the trial protocol) 14. Any psychiatric or other disorder (e.g. brain metastases) likely to impact the ability to give informed consent 15. Eye conditions (as detailed in the trial protocol) 16. Patients with chronic skin conditions e.g. acne rosacea, psoriasis, severe atopic eczema 17. Past medical history of interstitial lung disease, drug-induced interstitial lung disease, radiation pneumonitis which required steroid treatment, or any evidence of clinically active interstitial lung disease 18. History or repeated unexplained episodes of syncope/dizziness 19. Known hypersensitivity to AZD8931, its excipients, or drugs in its class 20. The use of drugs/substances known to inhibit or induce CYP3A4 or CYP2D6, or those known to prolong QT interval, which cannot be discontinued for the duration of trial treatment 21. Patients with hereditary fructose intolerance