Sponsor: Benjamin Spieler (other)
Phase: 2
Start date: June 18, 2025
Planned enrollment: 20
Balstilimab (AGEN2034; BAL) is an investigational, fully human IgG4 monoclonal antibody targeting PD‑1. It has been evaluated as monotherapy and in combination with the CTLA‑4 antibody zalifrelimab in previously treated recurrent/metastatic cervical cancer, with published phase 2 data. A U.S. BLA for second‑line cervical cancer was submitted in April 2021, accepted for Priority Review in June 2021, and voluntarily withdrawn in October 2021 after full approval of pembrolizumab in the same setting; development has continued in combinations. (pubmed.ncbi.nlm.nih.gov)
Cervical cancer (previously treated, recurrent/metastatic)
Balstilimab monotherapy (open‑label, single‑arm, phase 2; n=140 efficacy‑evaluable): Confirmed ORR 15.0% (95% CI, 10.0–21.8), including 3.6% complete responses; median duration of response (DoR) 15.4 months. ORR 20.0% in PD‑L1–positive tumors and 7.9% in PD‑L1–negative tumors. DCR 49.3%. Dosing: 3 mg/kg IV every 2 weeks (up to 24 months). (pubmed.ncbi.nlm.nih.gov)
Balstilimab + zalifrelimab (open‑label, single‑arm, phase 2; n=125 efficacy‑evaluable): Confirmed ORR 25.6% (95% CI, 18.8–33.9), with 10 complete and 22 partial responses; median DoR not reached at median follow‑up 21 months (response durability 64.2% at 12 months). ORR 32.8% in PD‑L1–positive and 9.1% in PD‑L1–negative tumors. DCR 52%. Dosing: balstilimab 3 mg/kg Q2W + zalifrelimab 1 mg/kg Q6W (up to 24 months). (pubmed.ncbi.nlm.nih.gov)
Other tumor types (early signals)
Note: Additional early‑phase combination studies with botensilimab (next‑generation CTLA‑4) have reported responses in ovarian and other solid tumors, but these are primarily from conference presentations and company communications and remain exploratory. (cancernetwork.com)
Balstilimab monotherapy (phase 2 cervical cancer): Most common grade ≥3 treatment‑related AEs were immune‑mediated enterocolitis (3.1%) and diarrhea (1.9%). Overall safety was consistent with PD‑1 inhibitors. (pubmed.ncbi.nlm.nih.gov)
Balstilimab + zalifrelimab (phase 2 cervical cancer): Grade ≥3 treatment‑related AEs occurred in 20.0%; common immune‑mediated AEs included hypothyroidism (14.2%) and hyperthyroidism (7.1%). Serious TRAEs occurred in 10.3%; three treatment‑related deaths (pneumonitis, immune‑mediated nephritis, diabetes mellitus) were reported. (ascopubs.org)
Doxorubicin + zalifrelimab + balstilimab in soft tissue sarcoma: Grade 3/4 TRAEs in 45%; immune‑mediated AEs requiring immunosuppression in 9%. (pubmed.ncbi.nlm.nih.gov)
Notes: Balstilimab is not FDA‑approved as of October 7, 2025. Efficacy and safety summaries above reflect non‑randomized trials; comparative effectiveness versus approved PD‑1 inhibitors has not been established. (investor.agenusbio.com)
Last updated: Oct 2025
Botensilimab (AGEN1181; BOT) is an Fc‑engineered, next‑generation anti–CTLA‑4 monoclonal antibody being developed primarily in combination with the anti–PD‑1 antibody balstilimab (BAL). Early clinical activity has been reported across “cold” or immunotherapy‑refractory tumors, especially microsatellite‑stable (MSS) metastatic colorectal cancer (mCRC) without active liver metastases and in relapsed/refractory metastatic sarcomas. Fast Track designation has been granted by the FDA for BOT/BAL in non‑MSI‑H mCRC without active liver involvement. (pmc.ncbi.nlm.nih.gov)
Microsatellite‑stable metastatic colorectal cancer (MSS mCRC)
Relapsed/refractory metastatic sarcomas
Neoadjuvant, resectable colorectal cancer
Combination with chemotherapy
Notes: Reported efficacy in MSS mCRC is largely confined to patients without active liver metastases in early‑phase studies; definitive benefit will require results from randomized phase 3 testing. (pmc.ncbi.nlm.nih.gov)
Last updated: Oct 2025
Goal: To evaluate whether stereotactic body radiation therapy (SBRT) followed by dual immune checkpoint inhibition with botensilimab (anti–CTLA-4) and balstilimab (anti–PD-1) provides clinical benefit for patients with metastatic pancreatic ductal adenocarcinoma (PDAC) after progression on prior systemic therapy.
Patients: Adults (≥18 years) with histologically or cytologically confirmed metastatic PDAC that is microsatellite stable, ECOG 0–1, with measurable disease per RECIST 1.1, progression on at least one prior systemic regimen, adequate organ function, life expectancy ≥3 months, at least one previously unirradiated lesion amenable to pre-treatment biopsy, and liver tumor burden ≤25%. Key exclusions include active/untreated CNS metastases, significant autoimmune disease or immunosuppression, prior liver-directed radiation/embolization, significant ascites or hepatic failure, recent bowel obstruction, significant cardiovascular disease, ongoing infections, and prior allogeneic transplant.
Design: Single-arm, phase 2, non-randomized treatment study with planned enrollment of 20 participants. Primary purpose is therapeutic. Responses will be assessed with iRECIST, with follow-up for survival up to 5 years.
Treatments: Participants receive SBRT followed by combination immunotherapy: botensilimab for up to 24 weeks with balstilimab for up to one year. Botensilimab is an investigational, Fc-enhanced anti–CTLA-4 monoclonal antibody engineered to augment T-cell priming, deplete intratumoral Tregs, activate myeloid cells, and reduce complement-mediated toxicity through diminished C1q binding. In early-phase trials, particularly when combined with the PD-1 inhibitor balstilimab, botensilimab has shown activity across multiple solid tumors including MSS colorectal cancer, with objective responses and prolonged overall survival in select cohorts. Balstilimab is a fully human IgG4 anti–PD-1 antibody that blocks PD-1 interaction with PD-L1/PD-L2 to enhance T-cell effector function; it has demonstrated antitumor activity in cervical cancer and is being developed broadly in combination strategies, notably with botensilimab.
Outcomes: Primary outcome is clinical benefit rate (CR, PR, or stable disease) by iRECIST up to 15 months. Secondary outcomes include objective response rate by iRECIST up to 15 months, progression-free survival from start of radiation to progression or death up to 5 years, overall survival from start of radiation up to 5 years, and incidence of grade ≥3 adverse events per CTCAE v5.0 up to 15 months.
Burden on patient: Moderate. Participants will undergo SBRT, pre-treatment biopsy of at least one lesion, and serial imaging for iRECIST assessments, along with regular clinic visits and laboratory monitoring for immune-related adverse events. Dual checkpoint blockade can necessitate prompt evaluation and management of toxicities (e.g., colitis, hepatitis, endocrinopathies), increasing visit and lab frequency compared with standard follow-up. There are no intensive pharmacokinetic blood draws, but the combination therapy period of up to one year and survival follow-up to five years imply recurrent travel for infusions, scans, and safety checks.
Last updated: Oct 2025
Inclusion Criteria:
1. ≥18 years old
2. Histologically or cytologically confirmed diagnosis of pancreatic ductal adenocarcinoma.
3. Microsatellite stable (MSS) disease by pathologic assessment.
4. Patients must have measurable disease as defined by RECIST 1.1.
5. Progression on ≥1 line of systemic therapy.
6. No concomitant therapy with any of the following: interleukin (IL)-2, interferon, non study immunotherapy regimens, cytotoxic chemotherapy, immunosuppressive agents, other investigational therapies, and/or chronic use of systemic corticosteroids.
7. No known infection with human immunodeficiency virus (HIV) or active infection with Hepatitis B.
8. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1.
9. Life expectancy ≥3 months.
10. Patients must have the following lab values obtained \<4 weeks prior to starting protocol treatment:
1. absolute neutrophil count (ANC) ≥1,000 cells/μL
2. white blood count (WBC) ≥2,000 cells/μL
3. platelets ≥75,000 per μL
4. hemoglobin ≥8.0 g/dL
5. creatinine clearance ≥40 mL/min)
6. serum total bilirubin ≤ 1.5 times the upper limit of normal (ULN)
7. aspartate aminotransferase (AST) and alanine transaminase (ALT) ≤3 × ULN (or ≤5 × ULN in patients with liver metastases)
8. international normalized ratio or prothrombin time ≤1.5 × ULN
9. activated partial thromboplastin time ≤2.5 × ULN
10. absolute lymphocyte count (ALC) ≥1000 cells/μL at baseline
11. At least 1 previously unirradiated lesion amenable to pre-treatment biopsy.
12. No limit on overall numbers of lesions, but liver tumor burden ≤25% of total liver volume.
13. Women of childbearing potential (WOCBP): negative serum pregnancy test (within 7 days prior to Day 1 of protocol therapy)
a. Females of non-childbearing potential are defined as: i. ≥ 50 years of age and has not had menses for greater than 1 year ii. Amenorrheic for ≥ 2 years without a hysterectomy and bilateral oophorectomy and a follicle-stimulating hormone value in the postmenopausal range upon pre-study (screening) evaluation iii. Status is post-hysterectomy, bilateral oophorectomy, or tubal ligation.
14. Male and female patients of reproductive potential must use effective methods of contraception or abstain from sexual activity for the course of the study through at least 6 months after the last dose of balstilimab and/or botensilimab. See Section 4.11, Contraception.
Exclusion Criteria:
1. Liver tumor burden exceeding 25% of total liver volume.
2. Active, untreated central nervous system (CNS) metastases.
3. Active autoimmune disease or history of autoimmune disease that required systemic treatment within 2 years of the start of study treatment (i.e., with use of disease-modifying agents or immunosuppressive drugs).
4. Participants with a condition requiring systemic treatment with either corticosteroids (\> 10 mg daily prednisone equivalent) within 14 days or another immunosuppressive medication within 30 days of randomization. Inhaled or topical steroids, and adrenal replacement steroid doses (≤ 10 mg daily prednisone equivalent) are permitted in the absence of active autoimmune disease.
5. Previous external beam radiation therapy to the liver or radioisotope therapy directed to the liver or any liver embolization.
6. Clinically significant ascites requiring a paracentesis in the last 4 weeks, or clinically significant history of liver failure defined as any prior episode of hepatic encephalopathy and/or any prior history of an elevated serum ammonia level.
7. Partial or complete bowel obstruction within the last 3 months prior to study enrollment, signs/symptoms of bowel obstruction, or known radiologic evidence of impending obstruction.
8. Clinically significant (i.e., active) cardiovascular disease: cerebral vascular accident/stroke or myocardial infarction within 6 months of study enrollment, unstable angina, congestive heart failure (New York Heart Association class ≥ III), or serious uncontrolled cardiac arrhythmia requiring medication.
a. QT interval corrected using Fridericia's formula (QTcF) of \> 480 ms.
9. Prior allogeneic organ transplantation.
10. Treatment with chemotherapy or targeted therapy within 2 weeks prior to initiating EMPIRE treatment.
11. Persistent grade ≥2 adverse events (aEs) from prior therapy (except neuropathy).
12. Known additional malignancy requiring active treatment.
13. History of non-infectious pneumonitis.
14. Active infection requiring antibiotic.
15. Live vaccine within 30 days of protocol treatment.
16. Severe acute respiratory syndrome (SARS) coronavirus 2 (CoV 2) (SARS-CoV-2) vaccine or booster \< 7 days before Cycle 1 Day 1 (C1D1). For vaccines requiring more than 1 dose, the full series should be completed prior to C1D1, when feasible. Booster shot not required but also must be administered \> 7 days from C1D1 or \> 7 days from future cycle on study.
17. History of severe hypersensitivity reaction to monoclonal antibody.
18. Participants with impaired decision-making capacity.
Miami, Florida, 33136, United States
[email protected] / 305-243-4229
Status: Recruiting