# Botensilimab

Source: https://onco.cc/drugs/botensilimab/  
OnCo record `botensilimab` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Botensilimab is an experimental monoclonal antibody from Agenus in phase 2 trials for colorectal cancer, aimed at CTLA-4.

## Summary

Botensilimab (AGEN1181) is a monoclonal antibody developed by Agenus. Its target is CTLA-4 (the sponsor names CTLA-4). The sponsor states: Botensilimab is an Fc-enhanced anti-CTLA-4 monoclonal antibody designed to prime a broader anti-tumour immune response, typically studied in combination with balstilimab (anti-PD-1). ClinicalTrials.gov describes the intervention as: An anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) monoclonal antibody. It is the investigational product in 1 recruiting or active industry-led phase 2 and phase 3 interventional cancer trial, in colorectal cancer. The largest, NCT05608044, plans to enrol 234 participants (actual) with primary completion expected 2027-09. Status reflects the highest phase registered on ClinicalTrials.gov; no efficacy results are recorded here.

## Fields

- Kind: Treatment
- Status: phase-2
- Last checked: 2026-09-11
- Tags: pipeline; ctgov-ingest
- Code: AGEN1181
- Modality: monoclonal antibody
- Mechanism: Botensilimab is an Fc-enhanced anti-CTLA-4 monoclonal antibody designed to prime a broader anti-tumour immune response, typically studied in combination with balstilimab (anti-PD-1).

## Notes

- Colorectal cancer biomarkers: this is the one agent aimed at the microsatellite-stable majority rather than the deficient minority. With balstilimab it gave an objective response rate of 17% and disease control of 61% in 101 response-evaluable microsatellite-stable patients out of 148 treated, with no biomarker threshold beyond microsatellite stability and prior treatment (Bullock 2024).

## Sources

- ClinicalTrials.gov: trials of Botensilimab: https://clinicaltrials.gov/search?intr=AGEN1181
- Sponsor pipeline page: https://agenusbio.com/pipeline/

## Connected records

- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/)
- targets: [CTLA-4](https://onco.cc/targets/ctla4/)
- companies: [Agenus](https://onco.cc/companies/agenus/)
- trials: [A Clinical Study Evaluating a New Treatment Strategy for Patients With Advanced Pancreatic Cancer Who Have Not Received Prior Treatment for Advanced Disease.](https://onco.cc/trials/nct07578337/), [A Study of Botensilimab and Balstilimab for Colorectal Cancer With ctDNA+ After Surgery and Chemotherapy](https://onco.cc/trials/nct07227636/), [A Study of Botensilimab and Balstilimab for Rectal Adenocarcinoma](https://onco.cc/trials/nct06843434/), [A Study of Botensilimab and Balstilimab for the Treatment of Colorectal Cancer](https://onco.cc/trials/nct05608044/), [BAL/BOT/agenT-797 in pMMR CRC With Liver Metastases](https://onco.cc/trials/nct07550088/), [FOLFOX, Botensilimab, and Balstilimab for the Treatment of Localized Rectal Cancer Before Surgery](https://onco.cc/trials/nct06780787/), [Neoadjuvant Botensilimab and Balstilimab for the Treatment of Advanced Resectable Colorectal Cancer NEST3](https://onco.cc/trials/nct07595874/), [Phase 2 Study of SR-8541A in Combination With Botensilimab and Balstilimab in Subjects With Refractory Metastatic Microsatellite Stable Colorectal Can](https://onco.cc/trials/nct06589440/), [Phase 2a Immune Modulation With Ultrasound for Newly Diagnosed Glioblastoma](https://onco.cc/trials/nct05864534/), [Platform Study of Immunotherapy Combinations in Colorectal Cancer Liver Metastases](https://onco.cc/trials/nct06300463/), [Pre-operative Targeted Treatments in Molecularly Selected Resectable Colorectal Cancer (UNICORN)](https://onco.cc/trials/nct05845450/), [RECTIFY-1: Neoadjuvant Botensilimab + Balstilimab in MSS/pMMR Early Rectal Cancer](https://onco.cc/trials/nct07735624/), [Testing the Combination of Anti-Cancer Drugs, Botensilimab (AGEN1181) and Balstilimab (AGEN2034), After Standard Treatment for Colorectal Cancer, Combat Trial](https://onco.cc/trials/nct07551596/), [The Miami "EMPIRE" Trial - Eradication of Metastatic Pancreatic Cancer With Immuno-Radiation](https://onco.cc/trials/nct06843551/)
- key papers: [Botensilimab plus balstilimab in relapsed/refractory microsatellite stable metastatic colorectal cancer: a phase 1 trial](https://onco.cc/key-papers/paper-bullock-botensilimab-balstilimab-mss-colorectal-nat-med-2024/)
- roadmaps: [Colorectal cancer roadmap: from the adenoma-carcinoma sequence and the first screening trials to total mesorectal excision, oxaliplatin, RAS testing, immunotherapy for mismatch repair-deficient disease, ctDNA-guided treatment and organ preservation](https://onco.cc/roadmaps/colorectal-roadmap/)
- ideas: [Select microsatellite stable patients for immunotherapy by a measured immune biomarker, not by how many treatments they have already failed](https://onco.cc/ideas/idea-crc-mss-immunotherapy-by-biomarker-not-by-line/)

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