Publication extender

The Phase 3 ROBBIN Trial Evaluating Neoadjuvant BOT+BAL in High-Risk Stage II/III MSS Colon Cancer

Agenus

DOI: 10.26303/8beq-n491

Key takeaways

  • ROBBIN will test whether neoadjuvant BOT+BAL can improve event-free survival in high-risk, resectable MSS/pMMR colon cancer.
  • The Phase 3 trial builds on the deep pathological responses, ctDNA clearance and encouraging recurrence-free outcomes observed in NEST and UNICORN.
  • If successful, ROBBIN could establish a new treatment approach intended to reduce recurrence and increase the potential for long-term cure.

What is it about?

ROBBIN is a global, randomized, open-label, registrational Phase 3 study designed to determine whether adding a short course of neoadjuvant BOT+BAL to the current standard of care can improve outcomes for patients with previously untreated, resectable, high-risk Stage II or Stage III MSS/pMMR colon cancer.

Approximately 850 patients are planned to be randomized 1:1 to one of two treatment arms:

  • BOT+BAL arm: One dose of BOT plus three doses of BAL administered every two weeks before surgery. Surgery is planned approximately eight weeks after treatment begins, followed by guideline-directed adjuvant chemotherapy or observation based on pathological stage and clinical guidelines.
  • Control arm: Surgery is planned approximately four weeks after randomization, followed by guideline-directed adjuvant chemotherapy or observation based on pathological stage and clinical guidelines.

The primary endpoint is event-free survival. Key secondary endpoints include overall survival and ctDNA negativity. The study will also assess health-related quality of life, safety, pharmacokinetics, pathological response, use of adjuvant chemotherapy and potential biomarkers. Exploratory analyses will examine whether pathological response is associated with longer-term event-free and overall survival.

First patient dosed is anticipated in Q1 2027 with interim pathological response readout after at least 50 patients have received BOT+BAL in the second half of 2027. These timelines are projections and remain subject to change.

Why is it important?

Patients with high-risk Stage II or Stage III MSS/pMMR colon cancer remain at meaningful risk of recurrence following surgery and standard postoperative care, while conventional immunotherapies have historically shown limited activity in these tumors.

The deep pathological responses, ctDNA clearance and encouraging recurrence-free follow-up observed with neoadjuvant BOT+BAL in NEST and UNICORN provide the rationale for Phase 3 evaluation. ROBBIN will determine whether these early clinical and molecular findings translate into improved event-free survival in a large, randomized study.

If successful, ROBBIN could establish a new neoadjuvant immunotherapy approach with the potential to reduce recurrence, decrease the need for chemotherapy and increase the potential for cure in patients with high-risk MSS/pMMR colon cancer.

Click on the next story below – BOT+BAL is Investigational and May be Accessed Through Clinical Trials and Authorized Pathways – to learn about the current pathways for accessing BOT+BAL.

Page published: 12-Nov-2026

Resources3 total

Who is involved?

Important information

In October 2026, BOT+BAL reached an important milestone with its first marketing authorizations in Armenia, where Botvymo® (botensilimab) and Evamplix® (balstilimab) were approved for use in combination in eligible adults with microsatellite-stable (MSS) metastatic colorectal cancer without active liver metastases who have previously received available standard therapies.

Show more