Dose escalation part:  Inclusion Criteria:  Histologically or cytologically confirmed unresectable, locally advanced or metastatic solid tumor malignancies Patients with a malignancy not amenable to surgical intervention Patients with measurable disease and progression radiologically assessed Patients with disease progression after treatment with available standard of care therapies that are known to confer clinical benefit or who are intolerant to treatment. Patients with available archived tumor biopsy specimens or agree to mandatory biopsy Estimated life expectancy ≥ 12 weeks Adequate haematological function Adequate renal function Adequate hepatic function  Exclusion Criteria:  Pregnant and lactating women Patients with any other unresolved Grade > 1 toxicity associated with prior anti-neoplastic therapy Major surgery within 4 weeks prior to the first IMP administration or not recovered from the surgery Patients with serious/active/uncontrolled infection or infection requiring parenteral antibiotics, within 2 weeks prior to first IMP administration Active Hepatitis B Virus infection Carriers of HIV antibodies Patients with active thrombosis, or a history of deep vein thrombosis or pulmonary embolism, within 4 weeks prior to first IMP administration History of organ transplantation History of gastrointestinal perforation, or intra-abdominal abscess within 28 days of inclusion History of cirrhosis History of pulmonary fibrosis or relevant uncontrolled chronic pulmonary condition Treatment with systemic immunosuppressive therapy Active autoimmune disease Administration of a live vaccine within 28 days prior to inclusion  Cohort expansion part 2a:  Inclusion Criteria:  Histologically proven unresectable locally advanced or metastatic HER2+ cancer Have received treatment with first line of standard therapy and eligible for second line  Exclusion Criteria:  Same criteria as for Part 1 with the addition of:  - Left ventricle ejection fraction < 50%  Cohort expansion part 2b:  Inclusion Criteria:  Patients with confirmed adenocarcinoma of metastatic colorectal cancer Patients must have a wild-type gene status for KRAS (exons 2, 3, 4), NRAS (exons 2, 3, 4) and BRAF (absence of V600E mutation) in a tumor biopsy collected at time of screening.  Exclusion Criteria:  Same criteria as for dose escalation part with the addition of:  Patients with a significant gastrointestinal abnormality Patients with skin rash of Grade > 1 from prior anti-EGFR