Last updated: 10/14/2026 11:40:53

Two Part (Phase1b/ Phase3) Trial of Subcutaneous Dostarlimab plus Carboplatin-Paclitaxel in Participants with Primary Advanced or Recurrent Endometrial CancerSAPPHIRE

GSK study ID
300118
Clinicaltrials.gov ID
NCT07860450
EudraCT ID
Not applicable
EU CT Number
2025-525060-15-00
Trial status
Not yet recruiting
Not yet recruiting
Overview
Eligibility
Locations
Study documents
Results summary
Plain language summaries
Additional information

Trial overview

Official title: An Open-label, Multicenter, 2-Part Study: A Phase 1b Dose Selection followed by a Randomized Phase 3 to Evaluate the Pharmacokinetics, Efficacy, and Safety of Subcutaneous Dostarlimab Plus Carboplatin-Paclitaxel Versus Intravenous Dostarlimab Plus Carboplatin-Paclitaxel in Participants with Primary Advanced or Recurrent Endometrial Cancer (SAPPHIRE)
Trial description: This is an open-label study, meaning both the researchers and participants will know which treatment is being given.
The study has two parts. In Part 1, researchers will identify the most suitable SC dose. In Part 2, participants will be randomly assigned by chance to receive dostarlimab as either an SC injection or an IV infusion. All participants will also receive carboplatin and paclitaxel. Treatment may continue for up to 3 years, with participants closely monitored throughout the study.
Primary purpose:
Treatment
Trial design:
Sequential Assignment
Masking:
None (Open Label)
Allocation:
Randomized
Primary outcomes:

Part 1: Serum Trough Concentration (Ctrough) After First Dose of Dostarlimab

Timeframe: Up to 42 days

Part 1: Area Under the Concentration-time Curve (AUC) of Dostarlimab

Timeframe: Up to 42 days

Part 2: Observed Ctrough of Dostarlimab

Timeframe: Up to 168 days

Part 2: Model-predicted (MP) AUC of Dostarlimab

Timeframe: Up to 21 days

Part 2: MP AUC of Dostarlimab

Timeframe: Up to 168 days

Secondary outcomes:

Part 1: Ctrough of Dostarlimab

Timeframe: Up to 42 days

Part 1: AUC of Dostarlimab

Timeframe: Up to 42 days

Part 1: Maximum Observed Concentration (Cmax) of Dostarlimab

Timeframe: Up to 42 days

Part 1: Time to Peak Drug Concentration (Tmax) of Dostarlimab

Timeframe: Up to 42 days

Parts 1 and 2: Number of Participants Experiencing Adverse Events (AEs), Serious AEs (SAEs), Treatment-emergent AEs (TEAEs) and Immune-mediated AEs (imAEs)

Timeframe: Up to 39 months

Parts 1 and 2: Number of Participants with TEAEs Leading to Infusion or Injection Interruption, Dose Modifications, Trial Intervention Discontinuation, or Death

Timeframe: Up to 39 months

Parts 1 and 2: Confirmed Overall Response Rate (ORR)

Timeframe: Up to 3 years

Parts 1 and 2: Duration of Response (DoR)

Timeframe: Up to 3 years

Parts 1 and 2: Progression-free Survival (PFS)

Timeframe: Up to 3 years

Parts 1 and 2: Overall Survival (OS)

Timeframe: Up to 3 years

Part 1: Number of Participants with Antidrug Antibody (ADAs) against Dostarlimab

Timeframe: Up to 39 months

Part 2: Number of Participants with ADAs against Dostarlimab

Timeframe: Up to 3 years

Part 2: MP Ctrough of Dostarlimab

Timeframe: Up to 168 days

Part 2: MP Ctrough at Steady State of Dostarlimab

Timeframe: Up to 168 days

Part 2: MP AUC at Steady State of Dostarlimab

Timeframe: Up to 168 days

Part 2: MP Cmax of Dostarlimab

Timeframe: Up to 168 days

Interventions:
Biological/vaccine: Dostarlimab
Drug: Carboplatin and paclitaxel
Enrollment:
378
Primary completion date:
2030-05-11
Observational study model:
Not applicable
Time perspective:
Not applicable
Clinical publications:
Not applicable
Medical condition
Endometrial Carcinoma, Neoplasms, Endometrial
Product
Dostarlimab
Collaborators
Not applicable
Study date(s)
November 2026 to November 2032
Type
Interventional
Phase
3

Participation criteria

Sex
Female
Age
18+ years
Accepts healthy volunteers
No
  • Participant is at least 18 years of age (or the legal age of consent in the jurisdiction in which the trial is taking place) at the time of signing the Informed Consent Form (ICF).
  • Participant has primary Stage III or Stage IV disease or first recurrent EC.
  • Participant has history of or active autoimmune disease that has required systemic treatments within the 2 years prior to screening.
  • Participant has a history of severe allergic and/or anaphylactic reactions to chimeric, human or humanized antibodies, fusion proteins, or known hypersensitivity to carboplatin, paclitaxel or dostarlimab components or excipients.
Inclusion and exclusion criteria
Inclusion criteria:
  • Participant is at least 18 years of age (or the legal age of consent in the jurisdiction in which the trial is taking place) at the time of signing the Informed Consent Form (ICF).
  • Participant has primary Stage III or Stage IV disease or first recurrent EC.
  • Participant must have a documented Mismatch repair (MMR)/Microsatellite Instability (MSI) status.
  • Participant is capable of giving signed informed consent, including compliance with the requirements and restrictions listed in the ICF and in the protocol.
  • Participant has an Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2 for Part 1 and an ECOG performance status of 0 or 1 for Part 2.
  • Participant has adequate organ function.
Exclusion criteria:
  • Participant has history of or active autoimmune disease that has required systemic treatments within the 2 years prior to screening.
  • Participant has a history of severe allergic and/or anaphylactic reactions to chimeric, human or humanized antibodies, fusion proteins, or known hypersensitivity to carboplatin, paclitaxel or dostarlimab components or excipients.
  • Participant has received prior therapy with anti-programmed death protein 1 (PD-1), anti-programmed cell death ligand 1 (PD-L1), or anti-PD-L2 agent.
  • Participant has known uncontrolled brain or central nervous system (CNS) metastases.

Trial location(s)

No location data available.

Study documents

No study documents available.

Results overview

Study Results yet to be posted

Recruitment status
Not yet recruiting
Actual primary completion date
Not applicable
Actual study completion date
Not applicable

Plain language summaries

Plain language summaries of clinical trial results for Phase 2-4 clinical trials that were initiated on or after January 2022 will be posted by GSK within one year following study completion.

Additional information about the trial

Additional information
Not applicable
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