Neoadjuvant Pembrolizumab and Porustobart in Resectable pMMR/MSS Colon Cancer

A Phase 2, Open-Label, Multicenter, Randomized Trial Evaluating the Efficacy and Safety of Different Schedules of Neoadjuvant Pembrolizumab and Porustobart in Patients With Resectable pMMR/MSS Colon Cancer

The goal of this clinical trial is to learn if giving two medicines together, porustobart and pembrolizumab, before surgery can treat a common type of colon cancer called microsatellite stable (MSS) colon cancer in adults. This type of cancer can be removed with surgery and has not spread to other parts of the body. Both medicines work by helping the immune system fight cancer.

The main questions this study wants to answer:

How well do the medicines destroy the cancer before surgery? What side effects do participants have when taking the medicines?

Researchers will compare two groups to see which treatment schedule works better and is safer. Both groups get pembrolizumab. One group gets one dose of porustobart (Day 1 only), and the other group gets two doses (Day 1 and Day 22).

Participants will:

Complete certain tests and procedures to make sure they are eligible Get the medicines through a vein on Day 1 and Day 22 then have surgery 6-9 weeks after starting treatment Return for checkups and tests every 6 months for up to 3 years after surgery

Inclusion Criteria:

≥18 years of age at consent

Adenocarcinoma of the colon (rectosigmoid considered non-rectal); pMMR/MSS status

Any T3 or T4, N any, M0; disease amenable to surgical resection

ECOG Performance Status 0-1

Adequate tumor tissue sample with associated pathology report

Adequate hematologic, hepatic, and renal function

Reproductive status/contraception requirements per protocol

Exclusion Criteria:

Investigational agent within 3 weeks of first dose

Imminent or urgent need for surgery

Prior treatment with ICIs targeting CTLA-4, PD-1, or PD-L1

Systemic corticosteroid/immunosuppressive therapy within 1 week of first dose (exceptions apply)

History of severe hypersensitivity to a fully human mAb; interstitial lung disease; pneumonitis requiring corticosteroids

Active or history of autoimmune disease requiring systemic treatment within 2 years

Major surgery within 4 weeks of first dose; active infection requiring treatment