DEWI: Watch-and-Wait With Dostarlimab in Localized dMMR/MSI-H Gastric/GEJ Adenocarcinoma Phase II Study

Sponsor
GERCOR - Multidisciplinary Oncology Cooperative Group
Study ID
NCT06059495
Phase
PHASE2
Status
Recruiting
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Conditions

  • Adenocarcinoma - GEJ
  • Gastric Adenocarcinoma

Eligibility Criteria

Sex
ALL
Age
18 Years - 75 Years
Healthy Volunteers
Not accepted

Interventions

  • Dostarlimab — DRUG
    Post-Inclusion: Dostarlimab 500mg IV q3wx4 cycles (Cs). Week 12 (W12) * cCR (both cohorts): Dostarlimab 1,000mg q6w×2 cycles. * Downstaging (Stage 2-3), no PD/mets: Dostarlimab 500mg q3w×4Cs. * Main cohort: SD/PD, Stage 1, positive(+), no cCR→Surgery. Post-surgery: Becker-TRG 1a/1b/2→Dostarlimab 1,000mg q6w×6Cs; Becker-TRG 3→Stop Trt. * Additional unfit cohort: SD/PD, Stage 1, biopsy(+) ± mets→Stop dostarlimab, withdraw from Trt, investigator-directed care, remain in FU. W24 * cCR at W12\&W24: Dostarlimab 1,000mg q6w×4Cs. * cCR at W12 but not W24: * Main cohort: Stop dostarlimab; surgery/adjuvant Trt per investigator. * Additional unfit cohort: Stop dostarlimab; withdraw from Trt; FU only. * Downstaging at W12 + cCR at W24: Dostarlimab 1,000mg q6w×4Cs. * Downstaging at W12 but no cCR at W24: * Main cohort: Surgery; if Becker-TRG 1a/1b/2, dostarlimab 1,000mg q6w×4Cs. * Additional unfit cohort: Stop dostarlimab, withdraw from Trt, investigator-directed care, remain in FU.

Study Details

This phase II study evaluates dostarlimab followed by a watch-and-wait strategy in patients with localized dMMR/MSI-H gastric or gastroesophageal junction (GEJ) adenocarcinoma. The study aims to determine whether surgery can be safely avoided in patients achieving a complete response, defined by negative endoscopy and tumor-free biopsies after treatment.

Key Dates

First listed
Sep 28, 2023
Start date
Jan 22, 2024
Status verified
Aug 2026
Primary completion
Sep 1, 2028
Completion
Sep 1, 2028

Study Design

Enrollment
89 participants (estimated)
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT

Arms

  • Experimental: Dostarlimab-based treatment
    After inclusion patients will receive dostarlimab at 500 mg q3w (± 2-3 days) for 4 cycles (C1-C4). Then, an adaptive treatment strategy will be determined based on clinical assessment of the patient.

Primary Outcome Measure

Clinical complete response (cCR) [ Time Frame: At 1 year from the start of treatment with dostarlimab. ]

Central Contacts

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