An Open-label, Phase I Study to Assess the Safety of Multiple Doses of CYAD-101, Administered After Standard FOLFOX or FOLFIRI Chemotherapy in Patients With Unresectable Metastatic Colorectal Cancer

Inclusion Criteria: 1. Histologically proven metastatic adenocarcinoma of the colon or rectum. 1. Confirmed metastatic unresectable adenocarcinoma of the colon or the rectum. 2. Recurrent/progressing disease after at least one line of systemic therapy for metastatic disease. 3. Unequivocal and measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST version 1.1). 4. FOLFOX segment: Neurotoxicity less than or equal to Common Terminology Criteria for Adverse Events (CTCAE) Grade 1 from previous chemotherapy. 5. FOLFIRI segment: Documented progressive disease (PD) under FOLFIRI treatment, with or without targeted therapy, given within 3 months prior to study registration. Anti-cancer therapy post FOLFIRI-documented PD prior to study registration is authorized if discontinued at least 7 days before the planned study registration. Radiotherapy is not authorized. 2. The patient must have an Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. 3. The patient must have adequate bone marrow reserve, hepatic, renal, pulmonary and cardiac functions. Exclusion Criteria: 1. The patient has a confirmed or history of tumor involvement in the central nervous system (CNS). 2. Any non-cancer-directed investigational agent within 3 weeks before the planned day for the first CYAD-101 administration. 3. Filgrastim (Granulocyte-Colony-Stimulating Factor \[G-CSF\]) or similar growth factors within 7 days before the planned day for the first CYAD-101 administration. 4. Prior allogeneic stem cell transplantation, chimeric antigen receptor therapy or other genetically modified T-cell therapy.