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Pan-tumor Neoadjuvant Basket Study of Immune Check-point Inhibition and Novel Immuno-oncology Combinations (NEOASIS)

Netherlands Cancer Institute (NKI) logo

Netherlands Cancer Institute (NKI)

Status and phase

Enrolling
Phase 3
Phase 2

Conditions

Resectable MMR-deficient Solid Tumors
Resectable MMR-proficient Solid Tumors

Treatments

Drug: balstilimab
Drug: FLOT (Fluorouracil+Leucovorin+Oxaliplatin+Docetaxel)
Drug: botensilimab

Study type

Interventional

Funder types

Other
Industry

Identifiers

Details and patient eligibility

About

In this study, the efficacy of botensilimab and balstilimab in mismatch repair deficient (dMMR) and mismatch repair proficient (pMMR) tumors will be assessed.

Full description

The NEOASIS study is an adaptive, pan-cancer, single-center, open-label, basket study assessing the efficacy of botensilimab and balstilimab in patients with resectable dMMR and pMMR solid tumors of various origins. Patients will be included in baskets according to tumor type and mismatch repair (MMR) status and will receive 2 cycles of immunotherapy followed by surgery.

The trial will commence with two safety run-in cohorts: one for patients with dMMR tumors and one for patients with pMMR tumors that will run in parallel. These safety run-in cohort will be used to assess safety and feasibility of pre-operative botensilimab + balstilimab. Data from the safety run-in cohorts will be used to determine the dosing and scheduling to be used in the MMR-specific cohorts of the main study. Safety will be assessed according to dose limiting toxicities. In the run-in cohorts, the first five patients will receive botensilimab 25mg intravenously (IV) on Day1 plus balstilimab 450mg IV on Day1 and Day22. Patients 6-10 will receive botensilimab 50mg IV on Day1 plus balstilimab 450mg IV on Day1 and Day22 followed by surgery 8 weeks after registration.

After full accrual of the run-in cohorts, MMR-specific baskets including a "other cancers" basket will start accrual with the optimal dose and schedule as determined in the safety run-in followed by surgery 8 weeks after registration. The MMR-specific baskets are designed with a Simon's 2 stage design in which first 8 patients will be included, if in the first 8 patients >2 Major pathological responses are reported (defined as ≤10% residual viable tumor) accrual of 10 more patients will continue for a total of 18 patients per basket.

This study was amended (approved in December 2025) to add cohort 10 and cohort 11. In cohort 10, patients with pMMR GEA tumors will receive Botensilimab and Balstilimab in combination with FLOT. In cohort 11, patients with dMMR rectum tumors will receive Botensilimab and Balstilimab. We aim for organ preservation in this cohort. See "Arms and Interventions" for more.

Enrollment

133 estimated patients

Sex

All

Ages

18+ years old

Volunteers

No Healthy Volunteers

Inclusion criteria

  1. Signed written informed consent

  2. Patients at least 18 years of age

  3. Non-metastatic, newly diagnosed dMMR and pMMR cancers either fitting within a specific basket or in the "other" cohort (e.g. sarcoma, head and neck cancers, anal cancer, esophageal SCC)

  4. In case of pMMR tumors: no indication for neoadjuvant therapy according to standard of care, unless adjuvant treatment is considered a standard of care alternative;

  5. Eligible for study biopsy

  6. World health organization (WHO) performance status of 0 or 1

  7. Screening laboratory tests must meet the following criteria and should be obtained within 7 days prior to randomization/registration: White blood cell count (WBC > 2.0 x 10^9/L, Absolute neutrophil count (ANC) > 1.5x10^9/L, platelets > 100 x 10^9/L, Hemoglobin > 5.0mmol/L. Transfusion is allowed to obtain an adequate hemoglobin level. Liver function tests: total bilirubin < 1.5 upper limit of normal (ULN) (except for subjects with Gilbert syndrome, who can have total bilirubin <3.0 mg/dL); alkaline phosphatase <1.5 ULN; transaminases (ASAT/ALAT) <3 x ULN; Lactate dehydrogenase (LDH) < 1.5x ULN; Creatinine clearance (Cockcroft-Gault) of >45 ml/min, Albumin > 3.0 g/dL

  8. Women of childbearing potential (WOCBP)* must use appropriate method(s) of contraception. WOCBP should use an adequate method to avoid pregnancy for 20 weeks after the last dose of investigational drug, Non-childbearing potential is defined as:

    1. Postmenopausal: ≥ 50 years of age and has not had menses for greater than 1 year.
    2. 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.
    3. Status is post-hysterectomy, bilateral oophorectomy, or tubal ligation.
  9. Women of childbearing potential must have a negative serum or urine pregnancy test (minimum sensitivity 25 IU/L or equivalent units of HCG) within 24 hours prior to the start of cycle 1 day 1

  10. Men who are sexually active with WOCBP must use any contraceptive method with a failure rate of less than 1% per year. Men receiving the study treatment and who are sexually active with WOCBP (excluding azoospermic men) will be instructed to adhere to contraception for a period of 28 weeks after the last dose of investigational drug and are not allowed to donate sperm during that timeframe.

Exclusion criteria

  1. Signs of distant metastases on imaging and physical examination

  2. Clinical obstruction

  3. Clinical symptoms or radiological suspicion of perforation

  4. Previous treatment with immune checkpoint inhibitors including but not limited to anti-CTLA4 or anti-PD1

  5. Prior chemotherapy for any cancer

  6. Radiotherapy prior to or planned post-surgery radiotherapy for disease under study

  7. Active malignancies other than disease under study within 3 years prior to inclusion, except for malignancies with a negligible recurrence rate (e.g. <10% in 5 years)

  8. Allergies and Adverse Drug Reaction:

    1. History of allergy to study drug components
    2. History of severe hypersensitivity reaction to any monoclonal antibody
  9. Intercurrent illnesses, including but not limited to infections, unstable angina pectoris

  10. Underlying medical conditions that, in the investigator's opinion, will make the administration of the study drug hazardous or obscure the interpretation of toxicity determination of adverse events

  11. Positive test for hepatitis B virus surface antigen (HBsAg) or hepatitis C virus ribonucleic acid (HCV antibody) indicating acute or chronic infection

  12. History of testing positive for human immunodeficiency virus (HIV) or known acquired immunodeficiency syndrome (AIDS)

  13. Active autoimmune disease or a documented history of autoimmune disease, or other medical conditions requiring systemic steroid or immunosuppressive medications, except for subjects with vitiligo, diabetes mellitus type 1, hypothyroidism due to autoimmune condition only requiring hormone replacement, psoriasis or resolved childhood asthma/atopy not requiring systemic treatment

  14. Conditions requiring systemic treatment with either corticosteroids (> 10 mg daily prednisone equivalents) or other immunosuppressive medications within 14 days of study drug administration. Inhaled or topical steroids and adrenal replacement doses > 10 mg daily prednisone equivalents are permitted in the absence of active autoimmune disease

  15. Live vaccines in the 4 weeks prior to inclusion

  16. Psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule

  17. Current pregnancy or breastfeeding

Specific for pMMR GEA cohort:

Known DPD deficiency; refer local clinical guidance, for DPD status recommendation prior to starting treatment.

Trial design

Primary purpose

Treatment

Allocation

Non-Randomized

Interventional model

Parallel Assignment

Masking

None (Open label)

133 participants in 11 patient groups

Cohort 2: pMMR Safety run-in 1 - closed (accrual reached)
Experimental group
Description:
5 Patients will be included and will be treated with 2 cycles of neoadjuvant immunotherapy consisting of 450mg balstilimab and 25mg botensilimab in Cycle 1 and 450mg balstilimab in Cycle 2 followed by surgery Accrual was reached in June 2024, cohort is closed.
Treatment:
Drug: botensilimab
Drug: balstilimab
Cohort 4: pMMR Safety run-in 2 - closed (accrual reached)
Experimental group
Description:
5 Patients will be included and will be treated with 2 cycles of neoadjuvant immunotherapy consisting of 450mg balstilimab and 50mg botensilimab in Cycle 1 and 450mg balstilimab in Cycle 2 followed by surgery Accrual was reached in August 2024, cohort is closed.
Treatment:
Drug: botensilimab
Drug: balstilimab
Cohort 1: dMMR Safety run-in 1 - closed (accrual reached)
Experimental group
Description:
5 Patients will be included and will be treated with 2 cycles of neoadjuvant immunotherapy consisting of 450mg balstilimab and 25mg botensilimab in Cycle 1 and 450mg balstilimab in Cycle 2 followed by surgery Accrual was reached in June 2025, cohort is closed.
Treatment:
Drug: botensilimab
Drug: balstilimab
Cohort 3: dMMR Safety run-in 2 - closed (accrual reached)
Experimental group
Description:
5 Patients will be included and will be treated with 2 cycles of neoadjuvant immunotherapy consisting of 450mg balstilimab and 50mg botensilimab in Cycle 1 and 450mg balstilimab in Cycle 2 followed by surgery Acrrual was reached in August 2024, cohort is closed.
Treatment:
Drug: botensilimab
Drug: balstilimab
Cohort 6: dMMR Colorectal basket - closed (accrual reached)
Experimental group
Description:
Patients with resectable colon and rectal cancer will be treated with the regimen assesses as safe and feasible in the dMMR safety run-in. Treatment will be administered at day 1 and day 22 followed by surgery 8 weeks after registration. Accrual will be temporarily halted after accrual of the first 8 patients. If \>2 major pathological responses are observed accrual will continue to a total of 18 patients. Accrual was reached in July 2025, cohort is closed.
Treatment:
Drug: botensilimab
Drug: balstilimab
Cohort 5: dMMR Upper gastro-intestinal cancer basket
Experimental group
Description:
Patients with resectable oesophageal (adenocarcinoma), gastro-oesophageal junction, gastric and small bowel cancer will be treated with the regimen assessed as safe and feasible in the dMMR safety run-in. Treatment will be administered at day 1 and day 22 followed by surgery 8 weeks after registration. Accrual will be temporarily halted after accrual of the first 8 patients. If \>2 major pathological responses are observed accrual will continue to a total of 18 patients.
Treatment:
Drug: botensilimab
Drug: balstilimab
Cohort 7: dMMR "other cancers" basket
Experimental group
Description:
Patients with resectable solid tumors of various origins such as but not limited to breast-, prostate-, bladder cancer, Head\&Neck SCC, oesophageal SCC and sarcoma will be treated with the regimen assessed as safe and feasible in the dMMR safety run-in. Treatment will be administered at day 1 and day 22 followed by surgery 8 weeks after registration. Accrual will be temporarily halted after accrual of the first 8 patients. If \>2 major pathological responses are observed accrual will continue to a total of 18 patients.
Treatment:
Drug: botensilimab
Drug: balstilimab
Cohort 8: pMMR TNBC cohort
Experimental group
Description:
Patients with resectable Triple Negative Breast Cancer will be treated with the regimen assessed as safe and feasible in the pMMR safety run-in. Treatment will be administered at day 1 and day 22 followed by surgery 8 weeks after registration. Accrual will be temporarily halted after accrual of the first 8 patients. If \>2 major pathological responses are observed accrual will continue to a total of 18 patients.
Treatment:
Drug: botensilimab
Drug: balstilimab
Cohort 9: pMMR "other cancers" - cohort closed
Experimental group
Description:
Patients with resectable pMMR tumors of various origins will be treated with the regimen assessed as safe and feasible in the pMMR safety run-in. Treatment will be administered at day 1 and day 22 followed by surgery 8 weeks after registration. Accrual will be temporarily halted after accrual of the first 8 patients. If \>2 major pathological responses are observed accrual will continue to a total of 18 patients. Accrual was halted after 8 patients in July 2025, not more then 2 major pathological responses were observed, cohort remains closed.
Treatment:
Drug: botensilimab
Drug: balstilimab
Cohort 10: pMMR GEA basket
Experimental group
Description:
Patients with pMMR gastro-, esophageal or GE-junction tumors will receive study treatment that consists of cycle 1) botensilimab 50mg plus balstilimab 240mg 2) FLOT + bal 240mg 3) FLOT plus bot 50mg/bal 240mg 4-5) FLOT + bal 240mg. Surgery will take place a maximum of 6 weeks after start last treatment cycle. Patients will receive 8mg dexamethasone as premedication for docetaxel on the first day of infusion, and no additional doses of dexamethasone are allowed in the following days as an anti-emetic. Post-surgery, patients may receive 4 additional cycles of FLOT according to the standard of care. Evaluation will be performed after the first 3 patients are treated; if the proposed treatment is deemed feasible and all patients received the intended chemotherapy regimen, accrual may continue with the next 3 patients. If the first three patients undergo surgery according to plan without delays that are considered immune-related, accrual may continue beyond six patients (max 21).
Treatment:
Drug: botensilimab
Drug: FLOT (Fluorouracil+Leucovorin+Oxaliplatin+Docetaxel)
Drug: balstilimab
Cohort 11: dMMR Rectal Organ Preservation basket
Experimental group
Description:
Patients with stage I-III dMMR rectal adenocarcinoma who prefer organ preservation are eligible. The study treatment will consist of 1 cycle of combination therapy on day 1: botensilimab 50mg plus balstilimab 450mg, followed by 2 cycles of balstilimab 450mg monotherapy on day 22 and day 43. If at the 1st response evaluation at 10 weeks a limited response, no response or progressive disease is observed, treatment according to standard of care, which may consist of direct surgery or additional neoadjuvant therapy may be considered after discussion in the MDT and with the study team.
Treatment:
Drug: botensilimab
Drug: balstilimab

Trial contacts and locations

1

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Central trial contact

Marieke van de Belt, MsC

Data sourced from clinicaltrials.gov

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