Study withdrawn prior to enrollment due to changing standard of care landscape.

Columbia 2 is a Phase 2 platform study to evaluate the safety and efficacy of standard of care (FOLFOX) alone and in combination with novel oncology therapies in adjuvant high-risk microsatellite-stable colorectal cancer

Columbia 2 is a Phase 2, open-label, randomized, multicenter, platform study of novel oncology therapies in combination with adjuvant chemotherapy in patients with high-risk microsatellite-stable colorectal cancer.

Inclusion Criteria

1. Written informed consent and any locally required authorization obtained from the subject/legal representative prior to performing any protocol-related procedures, including screening evaluations.

2. Age ≥ 18 years at the time of screening

3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

4. Histologically proven Stage II or Stage III CRC

   Subjects must also meet the following criteria:

   1. Eligible for 6 months of mFOLFOX6 adjuvant chemotherapy within 8 weeks after surgery
   2. Must NOT have received prior systemic chemotherapy, immunotherapy, or radiotherapy for treatment of CRC.
   3. Must NOT have defective DNA mismatch repair (MSI) as documented by testing

5. Margin-negative (R0; defined as >1 mm clearance) surgical resection

6. Postoperative ctDNA-positive status defined by the presence of ctDNA derived from plasma; determined using a validated assay per protocol

7. Subjects must have adequate organ function

8. Body weight > 35 kg

9. Adequate method of contraception per protocol

Exclusion Criteria:

1. Any condition that, in the opinion of the investigator, would interfere with evaluation of the investigational product or interpretation of subject safety or study results.

2. Evidence of metastatic disease (including presence of tumor cells in ascites or peritoneal carcinomatosis resected "en bloc").

3. History of allogeneic organ transplantation.

4. Active or prior documented autoimmune disorders within the past 5 years as noted in the protocol.

5. Cardiac and vascular criteria:

   1. History of venous thrombosis within the past 3 months prior to the scheduled first dose of study treatment.
   2. Presence of acute coronary syndrome including myocardial infarction or unstable angina pectoris, other arterial thrombotic event including cerebrovascular accident or transient ischemic attack or stroke within the past 6 months prior to the scheduled first dose of study treatment.
   3. New York Heart Association (NYHA) Class II or greater congestive heart failure, serious cardiac arrhythmia requiring medication, or uncontrolled hypertension.
   4. History of hypertensive crisis/hypertensive encephalopathy within the past 6 months prior to the scheduled first dose of study treatment.
   5. Mean QT interval corrected for heart rate using Fridericia's formula (QTcF) ≥ 470 ms

6. Uncontrolled intercurrent illness, see the protocol for details.

7. History of another primary malignancy except for: (a) Malignancy treated with curative intent and with no known active disease ≥ 5 years prior to the scheduled first dose of study treatment and of low potential risk for recurrence

8. History of active primary immunodeficiency.

9. Active infection including tuberculosis, hepatitis B, hepatitis C, or human immunodeficiency virus.

10. Known allergy or hypersensitivity to any of the investigational product or noninvestigational product formulations.

11. Any condition that, in the opinion of the investigator, would prevent the initiation of 6 months adjuvant therapy within 8 weeks of surgery

12. Any concurrent chemotherapy, investigational product, biologic, or hormonal therapy for cancer treatment.

13. Major surgical procedure, open biopsy, or significant traumatic injury within 28 days prior to the scheduled first dose of study treatment, or anticipation of the need for major surgical procedure during the course of the study.

14. Current or prior use of immunosuppressive medication within 14 days prior to the scheduled first dose of study treatment.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal. All request will be evaluated as per the AZ disclosure commitment:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the de-identified individual patient-level data in an approved sponsored tool . Signed Data Sharing Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information. Additionally, all users will need to accept the terms and conditions of the SAS MSE to gain access. For additional details, please review the Disclosure Statements at

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.