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Frequently asked Questions
BOT/BAL is a next-generation immuno-oncology combination therapy that brings together two advanced antibodies: Botensilimab (BOT), a next‑generation CTLA‑4 antibody designed to prime the immune system by activating new cancer‑fighting T cells and building long‑term immune memory; and Balstilimab (BAL), a PD‑1 inhibitor that sustains T‑cell engagement and prevents immune shutdown. Together, they are engineered to convert 'immune‑cold' tumors into immune‑active ones that can be recognized and eliminated.
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More than 1,200 patients across more than nine tumor types have been treated with BOT alone or in combination with BAL. Patients have been studied across neoadjuvant, first‑line, and late‑line refractory settings, reflecting one of the most extensive datasets for a next‑generation CTLA‑4 + PD‑1 combination.
France has granted reimbursed compassionate access (AAC) for BOT/BAL in refractory MSS metastatic colorectal cancer, certain types of ovarian cancers and sarcomas enabling eligible patients to receive treatment during the regulatory review process. Patients and physicians can refer to the Access policy under Medical Affairs for details on eligibility, availability, and the scope of the AAC program.
Immunotherapy trains the body's own immune system to identify and destroy cancer cells while sparing healthy tissue. Unlike chemotherapy or radiation, which have broad cytotoxic long‑lasting immune memory that continues to protect patients long after treatment has ended. Research continues to understand what patients may be most likely to derive benefit from these treatments.
Tumors are often described as “hot” or “cold” based on how visible they are to the immune system. Hot tumors have immune cells already present in and around the tumor, making them more responsive to immunotherapy. In contrast, cold tumors hide from the immune system, showing little to no immune activity and typically resisting available immuno-oncology treatments. Most colorectal cancers (approximately 85–95%) are considered “immune-cold,” which is why new strategies—such as BOT/BAL—are being developed to help “heat up” these tumors so the immune system can recognize and eliminate them.
These terms describe how well tumor cells repair DNA damage—a key factor in determining whether a cancer is likely to respond to immunotherapy.
- MSS (microsatellite stable) or pMMR (proficient mismatch repair) tumors have an intact DNA-repair system. These tumors typically lack the mutation burden, inflammation, or antigen visibility required to naturally attract immune cells and are considered immune “cold”— which is why they rarely respond to first-generation immunotherapy.
- MSI-H (microsatellite instability-high) or dMMR (deficient mismatch repair) tumors have faulty DNA-repair mechanisms, resulting in many accumulated mutations. These mutations make the cancer more visible to the immune system, which is why MSI-H/dMMR tumors are often more responsive to immunotherapy.
The vast majority of tumors including colorectal, pancreatic, prostate, and some forms of ovarian and sarcomas commonly considered immune “cold”, representing a major unmet need that next-generation immunotherapy combinations like BOT/BAL aim to address.
Many tumors—including most MSS colorectal cancers—lack the immune visibility needed to respond to standard immunotherapy. BOT/BAL is designed to change this by priming and activating new cancer-fighting T cells, eliminating suppressive immune cells, and sustaining immune engagement long enough to generate meaningful responses. Together, these mechanisms help convert immune-cold tumors into immune-active ones that can be targeted and destroyed, offering a potential new option for patients with limited effective treatments today.
Checkpoint inhibitors remove the immune system's natural brakes—such as CTLA‑4 or PD‑1—that cancer cells exploit to avoid detection. By blocking these pathways, checkpoint inhibitors empower T cells to mount a stronger and more sustained attack against tumors. BOT is a next‑generation CTLA‑4 inhibitor, while BAL is a next‑generation PD‑1 inhibitor. Their combined effect amplifies immune attack while supporting safety.
BOT/BAL (botensilimab + balstilimab) is an investigational therapy and is not approved by the U.S. FDA. Agenus is committed to responsible access for patients with serious unmet medical needs. Access options may include clinical trials, Paid Named Patient Programs (where permitted), or Compassionate Use programs. These pathways are available only under defined regulatory frameworks, and eligibility varies. For specific guidance, patients and healthcare professionals should contact Medical Affairs.
Agenus conducts global clinical trials evaluating BOT/BAL and other immune‑activating agents across multiple tumor types and disease stages. Eligibility varies by study and is based on medical history, prior treatments, and cancer type. You can review active trials on our website or clinicaltrials.gov, including the global Phase 3 BATTMAN study in refractory colorectal cancer.
BOT/BAL has been evaluated across colorectal, sarcoma, breast, ovarian, hepatocellular (liver), lung (NSCLC), melanoma, and other solid tumors. The combination is being studied in both early‑stage and refractory disease settings to understand its potential across diverse tumor biology.