Dostarlimab for Stage II and III dMMR Colon Cancer
This study is testing dostarlimab, an immunotherapy drug, in people with Stage II and III colon cancer that has a specific biomarker called dMMR (deficient mismatch repair). The goal is to see if dostarlimab can shrink tumors enough so that patients might not need surgery. You would receive dostarlimab intravenously (through a vein) every three weeks for six cycles, then every six weeks for eight cycles, up to 1.5 years. The main way we'll know if the treatment is working is by looking at your tumor's response after 18 weeks. This study is currently recruiting about 25 participants who are 18 years or older.
- Study design
- This is a Phase II study, meaning it's an early-stage study looking at how well the treatment works. It's a single-arm study, so everyone receives the same treatment.
- What's involved
- You would receive dostarlimab intravenously every 3 weeks for 6 cycles, then every 6 weeks for 8 cycles, until 1.5 years.
- Compensation
- Not stated in the trial record.
- Follow-up
- The main measure of success is taken from when dostarlimab starts until 18 weeks.
AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.
NCT05239546
Single Arm Study of Neoadjuvant Dostarlimab in Stage II and III Deficient Mismatch Repair Colon Cancers
Recruiting
PHASE2Ages 18+InterventionalTreatmentUniversity of IowaInvestigator-initiated
~25 participants
Updated 2026-06-12 on ClinicalTrials.gov
What's tested:Dostarlimab
At a glance
Recruiting sites
2 of 2 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Major Clinical Response (MCR) Rate
Measured over From Dostarlimab initiation to 18 weeks.
Conditions
Where it's being run
2 sites across 2 statesIowa1
Wisconsin1
Study leadership
- Saima M Sharif, MD, MS · PRINCIPAL_INVESTIGATOR · University of Iowa Holden Comprehensive Cancer Center
Who to contact
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Do you actually qualify for this trial?
Add a private profile and we'll compare every criterion below against your situation — and tell you which ones are met, uncertain, or excluding.
Eligibility criteria
Inclusion
Capable of understanding and complying with the protocol requirements and have signed the informed consent document. Patients with mild cognitive impairment may be considered for enrollment in the study if their legally authorized representative provides written informed consent for the patient.
18 years or older in age
Biopsy proven dMMR (by IHC), Stage II or III colon cancer per CT imaging correlation with AJCC 8th edition, 2017, amendable to en block surgical resection as determined by colorectal surgeon.
Biopsy specimen for diagnosis of dMMR Colon cancer should have enough tissue for minimum 4 and max 6 adjacent unstained FFPE slides (4µm each) as determined by Protocol Pathologist Dr. Anthony Snow for CD3+ and CD8+ analysis. If there is not enough tissue present in original sample, a repeat colonoscopy and biopsy may be performed; otherwise patient is not eligible.
Exclusion
ECOG performance status less than or equal to 1
Absence of metastatic disease on CT CAP with Contrast within 28 days from treatment start
Absolute neutrophil count greater than or equal to 1,500/µL
Platelets greater than or equal to 100,000/µL
Hemoglobin greater than or equal to 9 g/dL
Serum creatinine less than or equal to 1.5 x upper limit of normal (ULN) or calculated creatinine clearance 60mL/min using the Cockcroft-Gault equation
Total bilirubin less than or equal to 1.5 x ULN (less than or equal to 2.0 in patients with known Gilberts syndrome) OR direct bilirubin less than or equal to 1 x ULN
Aspartate aminotransferase and alanine aminotransferase less than or equal to 3.0 x ULN
International normalized ratio (INR) or prothrombin time (PT) less than or equal to 1.5× ULN unless patient is receiving anticoagulant therapy if PT or partial thromboplastin (PTT) is within therapeutic range of intended use of anticoagulants. Activated partial thromboplastin time (aPTT) less than or equal to 1.5× ULN unless patient is receiving anticoagulant therapy if PT or PTT is within therapeutic range of intended use of anticoagulants
Participants of childbearing potential must have a negative serum pregnancy test within 72 hours prior to taking study treatment and agree to use an adequate method of contraception from screening through 180 days after the last dose of study treatment. Information must be captured appropriately within the site's source documents. Note: Abstinence is acceptable if this is the established and preferred contraception for the patient.
For males of reproductive potential: use of condoms or other methods to ensure effective contraception with partner starting with first dose of study treatment through 180 days after the last dose of study treatment. Note: Abstinence is acceptable if this is the established and preferred contraception for the patient.
Synchronous primary tumor (i.e. more than 1)
Obstruction or perforation requiring diverting ostomy or immediate resection, or bright red blood per rectum requiring urgent blood transfusion, from their primary tumor.
Clinical T4b tumors
Known hypersensitivity to dostarlimab components or excipients.
Major surgery less than or equal to 3 weeks prior to initiating protocol therapy
Received investigational therapy less than or equal to 3 months, or within a time interval less than at least 5 half- lives of the investigational agent, whichever is shorter, prior initiating protocol therapy.
Heavy bleeding from the colon cancer tumors requiring PRBC transfusions that would require palliative surgical resection
Concurrent, clinically significant, active malignancies within two years of study enrollment.
Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
Active autoimmune disease that has required systemic treatment in the past 2 years (i.e., with use of disease-modifying agents, glucocorticoids, or immunosuppressive drugs). Other than Replacement hormone therapy with thyroxine for hypothyroidism , insulin for T1 diabetes mellitus , or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc.)
Diagnosis of immunodeficiency or has received any systemic glucocorticoid therapy or any other form of immunosuppressive therapy within 7 days prior to initiating protocol therapy.
History of greater than or equal to Grade 3 immune-related AE with prior immunotherapy, except for non-clinically significant lab abnormalities.
Patients with known HIV (Human Immunodeficiency Virus) infection on effective retroviral therapy regardless of CD4 count who have had an opportunistic infection within the past 12 months.
Organ transplant recipients on immunosuppressive medications
Patients with chronic HBV infection with active disease who meet the criteria for anti HBV therapy but not on suppressive antiviral therapy prior to initiation of treatment of this protocol are excluded. Also, patients with history of HCV infection that have not completed curative antiviral treatment and the HCV viral load is not below the limit of quantification areexcluded.(e.g. a patient who is HCV Ab positive but HCV RNA negative due to prior treatment or natural resolution is eligible.)
Prior history of interstitial lung disease.
Received a live vaccine within 30 days of initiating protocol therapy.
Not enough tissue for confirming dMMR status and CD3+ /CD8+ testing
19\. Patients with severe cognitive impairment.
What this trial measures
- Major Clinical Response (MCR) RateFrom Dostarlimab initiation to 18 weeks.
MCR rate is defined as the proportion of patients meeting the following criteria at 18 weeks: 1) ctDNA is stable or declining, 2) a clinically asymptomatic primary tumor, and 3) no metastatic disease.