Botensilimab + Balstilimab for Rectal Cancer
(RECTIFY-1 Trial)
What You Need to Know Before You Apply
What is the purpose of this trial?
This trial tests a combination of two treatments, botensilimab and balstilimab, for individuals with early-stage rectal cancer that hasn't spread to lymph nodes. The goal is to determine if these treatments can shrink tumors before surgery. It targets those with microsatellite stable (MSS) cancer, where cells properly repair DNA errors. Individuals with early rectal cancer confirmed by MRI and who are surgical candidates might be suitable participants. As a Phase 2 trial, the research focuses on measuring the treatment's effectiveness in an initial, smaller group.
Is there any evidence suggesting that this trial's treatments are likely to be safe?
A previous study found that the combination of botensilimab and balstilimab was well tolerated. Importantly, participants experienced no severe grade 4 events or unresolved immune-related problems. Furthermore, researchers observed no new side effects and no treatment-related deaths. This treatment differs from other similar drugs, potentially resulting in fewer side effects. Overall, the safety profile is considered manageable, indicating it should be safe for most patients.12345
Why are researchers excited about this trial's treatments for rectal cancer?
Unlike the standard treatments for rectal cancer, which typically involve chemotherapy and radiation, Botensilimab and Balstilimab are unique because they harness the body's immune system to fight cancer. Botensilimab is an innovative agent that enhances immune response by targeting specific immune checkpoints, while Balstilimab blocks the PD-1 pathway, helping the immune system detect and attack cancer cells more effectively. Researchers are excited about these treatments because they offer a new way to potentially improve outcomes for patients by using the body's natural defenses, which could lead to more targeted and less toxic cancer therapy options.
What evidence suggests that botensilimab and balstilimab might be effective treatments for rectal cancer?
Research has shown that the combination of botensilimab and balstilimab holds promise for patients with microsatellite-stable (MSS) colorectal cancer. In earlier studies, approximately 71% of these patients experienced significant tumor shrinkage. Additionally, this treatment combination resulted in a 42% survival rate over two years and an average survival time of nearly 21 months. It has proven effective for both early and advanced stages of the disease. This trial will specifically evaluate the effectiveness of botensilimab and balstilimab in treating early rectal cancer.12356
Who Is on the Research Team?
Benjamin Schlecher, MD
Principal Investigator
Dana-Farber Cancer Institute
Are You a Good Fit for This Trial?
This trial is for adults with early-stage rectal cancer (T1-T2 N0) that is microsatellite stable and mismatch repair proficient. Participants must be eligible for surgery and not need standard pre-surgery treatments like chemo or radiation.Inclusion Criteria
Exclusion Criteria
Timeline for a Trial Participant
Screening
Participants are screened for eligibility to participate in the trial
Treatment
Participants receive a single IV dose of botensilimab on Day 1 followed by balstilimab IV every 2 weeks for up to 6 months
Follow-up
Participants are monitored for safety and effectiveness after treatment, including 30-day and 90-day safety follow-up, and survival follow-up by phone every 12 weeks
Efficacy Follow-up
Tumor response assessments during treatment and follow-up afterward, with potential non-operative management for complete responders
What Are the Treatments Tested in This Trial?
Interventions
- Balstilimab
- Botensilimab
Trial Overview
The study tests two immunotherapy drugs, botensilimab (one dose) followed by balstilimab (every 2 weeks up to 6 months), before surgery in people with early rectal cancer. The goal is to see how well the tumor responds before removal.
How Is the Trial Designed?
1
Treatment groups
Experimental Treatment
Participants receive: * Botensilimab: one IV infusion on Cycle 1 Day 1, over about 30 minutes * Balstilimab: IV infusion every 2 weeks on Day 1 of each treatment cycle, over about 30 minutes, for up to 6 months The protocol specifies: * Botensilimab dose: 75 mg IV once * Balstilimab dose: 240 mg IV every 2 weeks for up to 6 months
Find a Clinic Near You
Who Is Running the Clinical Trial?
Dana-Farber Cancer Institute
Lead Sponsor
Agenus Inc.
Industry Sponsor
Gateway for Cancer Research
Collaborator
Citations
Botensilimab plus balstilimab in relapsed/refractory ...
The combination of BOT plus BAL demonstrated a manageable safety profile with no metastatic colorectal cancer. The median OS was 20.9 months
2.
investor.agenusbio.com
investor.agenusbio.com/news/news-details/2025/Agenus-Presents-Data-at-ASCO-GI-Demonstrating-Impact-of-BOTBAL-in-Colorectal-Cancer-Across-Neoadjuvant-and-Advanced-Disease/default.aspxAgenus Presents Data at ASCO GI Demonstrating Impact ...
Approximately 1,100 patients have been treated with botensilimab and/or balstilimab in phase 1 and phase 2 clinical trials. Botensilimab alone, ...
3.
cancernetwork.com
cancernetwork.com/view/botensilimab-balstilimab-elicits-sustained-efficacy-in-mss-metastatic-crcBotensilimab/Balstilimab Elicits Sustained Efficacy in MSS ...
The combination attained a 42% 2-year survival rate as well as a median overall survival of 20.9 months among 123 patients with MSS metastatic ...
NCT05608044 | A Study of Botensilimab and Balstilimab ...
This is an open-label, Phase 2, multicenter study to evaluate the efficacy, safety, tolerability, and pharmacokinetic profiles of botensilimab as monotherapy
a comparison between botensilimab + balstilimab and ...
The combination of botensilimab + balstilimab demonstrated promising clinical activity in heavily pre-treated patients with microsatellite-stable metastatic ...
New data, new hope. Agenus has announced landmark three ...
The Phase 1b data showed: • 33% three-year overall survival • 21.2-month median overall survival • 17% of patients alive
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