NCT07740720Not yet recruitingPhase 3
A Study of the Duration of Dostarlimab in Untreated Mismatch Repair Deficient (dMMR)/ Microsatellite Instability-high (MSI-H) Locally Advanced Rectal Cancer
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
Source: ClinicalTrials.gov · Last updated 3 Aug 2026
Brief summary (registry, in English)
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.
- Status (registry)
- Not yet recruiting
- Phase (registry)
- Phase 3
- Study type
- Interventional
- Enrollment
- 90 (estimated)
- First submitted
- 24 Jul 2026
- Start date
- Sept 2026
- Primary completion date
- Dec 2029
- Lead sponsor
- GlaxoSmithKline
- Diseases
- Colorectal cancer
- NCT number
- NCT07740720
- EudraCT number
- 2026-526683-21
What you commit to
- Study type: Interventional · Phase 3
- Planned participants: 90
- From Sept 2026 to the primary completion date, Dec 2029
- No sites listed in no country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- 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 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.
Other illness
- 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.
Who the study is looking for
- 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.
Age in the registry: 18 years to - · Sex: All · Does not accept healthy volunteers
This page is information, not medical advice. Discuss any trial with your doctor.