A Study to Investigate CEA-PRIT 2.0 in Participants With Metastatic Colorectal Cancer (mCRC)

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