A Phase I, Open-Label, Escalation and Expansion Study to Evaluate Dosimetry, Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Clinical Activity of CEA-Pre-Targeted 212Pb Therapy in Participants With Metastatic Colorectal Cancer

Inclusion Criteria: * Histologically confirmed adenocarcinoma originating from the colon or rectum * Metastatic disease (Stage IV American Joint Committee on Cancer, Version 7) * Confirmed MSS and/or proficient mismatch repair (MMR) status * Experienced disease progression during or within 3 months following the last administration of systemic anti-cancer therapies for metastatic disease * Presence of measurable disease according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. * Life expectancy estimated by the Investigator to be \>=12 weeks * Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 0-1 * Adequate cardiovascular, hematological and renal function and laboratory parameters Exclusion Criteria: * Pregnant or breastfeeding or intending to become pregnant * Participants with active central nervous system (CNS) metastases * History of malignancy other than the one under investigation * Any unresolved toxicities from prior therapy, i.e., radiotherapy, chemotherapy, targeted therapy or surgical procedure * Major surgery or significant traumatic injury \<4 weeks prior to the first CEA-PRIT 2.0 administration (excluding biopsies) or anticipation of the need for major surgery during study treatment * Participants have a known confirmed positive test for HIV * Positive hepatitis B surface antigen (HBsAg) test, and/or positive total hepatitis B core Ab (HBcAb) test at screening. * Positive hepatitis C (HCV) Ab test result at screening * Any anticancer treatment or any investigational agent within 4 weeks (or 5 times the half-life, whichever is shorter) prior to C1D1 * Prior treatment with a CEA-targeted agent or systemic radio therapy