A Study of the Duration of Dostarlimab in Untreated Mismatch Repair Deficient (dMMR)/ Microsatellite Instability-high (MSI-H) Locally Advanced Rectal Cancer
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Dostarlimab.
- Who it may be relevant to
- Registry conditions: Neoplasms, Rectal. Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Official title
A Phase 3b, Open-label Study Investigating the Duration of Neoadjuvant Dostarlimab Monotherapy in Participants With Untreated Stage II/III dMMR/MSI-H Locally Advanced Rectal Cancer
Overview
This study is conducted in adults with rectal cancer that has a certain genetic type. The main goal is to find out whether a longer treatment period with dostarlimab can help more participants have a complete response to treatment and avoid standard treatments like chemotherapy, radiation treatment, or surgery. Scans and endoscopy tests will be conducted to see if the tumor disappears and how long the cancer stays under control. The study will also collect information on side effects and health outcomes after dostarlimab.
Interventions
- Biological Dostarlimab
Dostarlimab will be administered.
Primary outcome measures
- Percentage of participants who achieve clinical complete response (cCR) amongst participants who receive > 9 cycles (> 6 months) of dostarlimab monotherapy by investigator assessment [Time frame: Up to 168 weeks]
Secondary outcome measures (6)
- Overall cCR rate by investigator assessment [Time frame: Up to 171 weeks]
- Number of participants with sustained clinical complete response at 12 months (cCR12) as assessed by investigator [Time frame: Up to 171 weeks]
- Objective response rate (ORR) as assessed by investigator [Time frame: Up to 171 weeks]
- Number of participants with composite cCR12 and pathologic complete response (pCR) as assessed by investigator [Time frame: Up to 171 weeks]
- Time to cCR [Time frame: Up to 171 weeks]
- Number of participants with treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), immune-mediated adverse event (imAEs), and AEs leading to death or discontinuation of study intervention by severity [Time frame: Up to 171 weeks]
Eligibility criteria
Inclusion criteria
- Has histologically confirmed Stage II to III (T3-T4, N0, or T any, N+) locally advanced rectal adenocarcinoma.
- Has radiologically and endoscopically evaluable disease.
- Has a tumor demonstrating the presence of either:
- dMMR status; MMR status must be assessed by immunohistochemistry for MMR protein expression (MLH1, MSH2, MSH6, PMS2) where loss of 1 or more proteins indicates dMMR; MMR status will be determined locally; or
- MSI-H phenotype as determined by polymerase chain reaction or by tissue next generation sequencing; MSI-H will be determined locally.
- Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
- Has adequate organ function.
Exclusion criteria
- Has received prior radiation therapy, systemic therapy, or surgery for management of rectal cancer.
- Has a tumor that, in the investigator's judgment, is causing symptomatic bowel obstruction or otherwise requires urgent/emergent local intervention. Participants with a history of bowel obstruction are eligible after obstruction is relieved by a diverting stoma (defunctioning colostomy). Patients with a history of bowel obstruction in the context of current rectal cancer diagnosis and treated with stenting are not eligible.
- Has an active autoimmune disease that has required systemic treatment in the past 2 years (i.e., with use of disease-modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment.
- Has undergone any major surgical procedure, open biopsy, or experienced significant traumatic injury within 28 days prior to enrollment.
- Is receiving any other anticancer or experimental therapy.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- N/A
- Model
- Single group
- Masking
- Open label
- Primary purpose
- Treatment
Study locations
Center list to be confirmed — check the primary protocol.
Identifiers
NCT: NCT07740720 · 308360 · 2026-526683-21