Dostarlimab with carboplatin–paclitaxel for advanced or recurrent endometrial cancer in Chinese patients with dMMR/MSI-H

A Phase 2, Multicenter, Open-label, Single Arm Study of Dostarlimab Plus Carboplatin-paclitaxel Followed by Dostarlimab Monotherapy in Participants With dMMR/MSI-H Primary Advanced or Recurrent Endometrial Cancer in China (China RUBY)

This Phase 2 trial will test whether adding dostarlimab to carboplatin and paclitaxel helps Chinese patients with advanced or recurrent dMMR/MSI‑H endometrial cancer respond to treatment and tolerate the combination.

Quick facts

• Phase: Phase 2
• Study type: Interventional
• Enrollment: 30 (estimated)
• Ages: 18 Years and up
• Sex: Female
• Sponsor: GlaxoSmithKline (Industry-sponsored)
• Drugs / interventions: chemotherapy, immunotherapy, radiation, dostarlimab
• Locations: 1 site (Jinan, Shandong)
• Trial ID: NCT07108270 on ClinicalTrials.gov

What this trial studies

In this Phase 2 interventional study, Chinese participants with recurrent or primary advanced endometrial cancer and confirmed dMMR/MSI‑H tumors receive dostarlimab together with carboplatin and paclitaxel to measure tumor response, safety, pharmacokinetics, and immunogenicity. Eligibility requires histologic or cytologic confirmation, at least one measurable lesion per RECIST 1.1, and either being systemic-therapy naive or having a first recurrence at least six months after prior adjuvant/neoadjuvant therapy. dMMR/MSI‑H status is confirmed by a central reference laboratory and adequate archived tumor tissue must be available. Regular imaging and laboratory assessments will be used to track response and adverse events during treatment and follow-up.

Who should consider this trial

Good fit: Ideal candidates are Chinese adults with histologically or cytologically confirmed primary advanced (Stage III–IV) or first recurrent endometrial cancer that is dMMR/MSI‑H, has at least one measurable lesion per RECIST 1.1, and are either systemic-therapy naive or have recurrence ≥6 months after prior adjuvant therapy.

Not a fit: Patients without dMMR/MSI‑H tumors, those with early-stage disease likely curable by surgery or radiation alone, or those with recent progression during adjuvant therapy are unlikely to be eligible or to benefit from this protocol.

Why it matters

Potential benefit: If successful, the combination could increase tumor response rates and extend progression-free time for Chinese patients with dMMR/MSI‑H advanced or recurrent endometrial cancer.

How similar studies have performed: Other studies of PD‑1 inhibitors, including dostarlimab, have shown meaningful activity in dMMR/MSI‑H endometrial cancer and have supported regulatory approvals, although combining PD‑1 therapy with chemotherapy in this population is still being explored.

Eligibility criteria

Inclusion Criteria:

1. Participant has histologically or cytologically proven EC with recurrent or advanced disease.
2. Participant has molecular subtype of defective mismatch repair (dMMR) or microsatellite instability high (MSI-H) determined by the central reference laboratory before study intervention.
3. Participant must have primary Stage III or Stage IV disease or first recurrent EC with a low potential for cure by radiation therapy or surgery alone or in combination, and presence of at least one target lesion per RECIST 1.1 based on Investigator's assessment and meet at least 1 of the following criteria:

   1. Has primary Stage III to IV disease and is naive to systemic anticancer therapy for EC;
   2. Has first recurrent disease and is naïve to systemic anticancer therapy for EC;
   3. Had received prior neo-adjuvant/adjuvant anticancer therapy and had a recurrence or PD ≥6 months after completing treatment (first recurrence only).
4. Participant has adequate archive tumor tissue sample for MMR/MSI status testing. If no archival tissue is available, tissue sample must be obtained before study intervention.
5. Participant is not pregnant or breastfeeding and agrees to use a highly effective contraceptive method during the study period if a woman of childbearing potential (WOCBP).
6. Participant has an Eastern Cooperative Oncology Group Performance status (ECOG PS) of 0 or 1.
7. Participant has adequate organ function, as assessed by hematologic, renal, hepatic and coagulation parameters.

Exclusion Criteria:

1. Participant has a concomitant malignancy, or participant has a prior non-endometrial invasive malignancy who has been disease-free for \<3 years or who received any active treatment in the last 3 years for that malignancy. Non-melanoma skin cancer is allowed.
2. Participant has any medical history of interstitial lung disease or pneumonitis.
3. Participant has cirrhosis or current unstable liver or biliary disease.
4. Participant has known uncontrolled central nervous system metastases, carcinomatosis meningitis, or both.
5. Participant has a diagnosis of immunodeficiency.
6. Participant has received prior therapy with an anti- Programmed death protein 1 (PD-1), anti- Programmed death ligand 1 (PD-L1), anti- Programmed death ligand 2 (PD-L2), or anti- Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) agent.
7. Participant has not recovered adequately from AEs.
8. Participant has received prior anticancer therapy (chemotherapy, targeted therapies, hormonal therapy, radiotherapy, or immunotherapy) within 21 days prior to the first dose of study intervention.
9. Participant has received any live vaccine within 30 days of the first dose of study intervention. Vaccination against coronavirus disease 2019 (COVID-19) using vaccines that are authorized via the appropriate regulatory mechanisms are not exclusionary.
10. Participant has Hepatitis B surface antigen (HBsAg) positive, or Hepatitis C virus (HCV) Ribonucleic acid (RNA) positive at screening or within 3 months prior to the first dose of study intervention.
11. Participant is known human immunodeficiency virus (HIV) infection.
12. Participant is currently participating and receiving study intervention or has participated in a study of an investigational agent and received study intervention or used an investigational device within 4 weeks of the first dose of treatment.
13. Participant with contraindication to carboplatin and paclitaxel.

Where this trial is running

Jinan, Shandong

• GSK Investigational Site — Jinan, Shandong, China (Recruiting)

Study contacts

• Study coordinator: US GSK Clinical Trials Call Center

Conditions Neoplasms, Endometrial; Endometrial cancer; Dostarlimab; Carboplatin; Paclitaxel