Watch-and-Wait Approach With Dostarlimab in Localized dMMR/MSI-H Gastric Cancer: GERCOR 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
    After inclusion: dostarlimab 500mg IV 30min q3w (± 2-3 days) for 4 cycles (C1-C4) Then: At wk12 • If cCR: dostarlimab 1000mg q6w for 2 cycles (C5-C6) • If downstaging at UGI endoscopy, and no disease progression (PD)/or mets on TAP-CT, \<3 biopsies with tumor cells: dostarlimab 500mg q3w for 4 cycles (C5-C8) • If loco/loco-regional PD on TAP-CT, macroscopic tumor on UGI endoscopy, no distant mets, and \>2 positive biopsies at wk12 followed by surgery and if Becker-TRG 1a, 1b, or 2 after surgery: dostarlimab 1000mg q6w for 6 cycles (C5-C10) At 24wk • If cCR at 12 and 24 wks: dostarlimab 1000mg q6w for 4 cycles (C7-C10) • If downstaging at UGI endoscopy without PD on CT at wk 12 with \<3 biopsies with tumor cells at wk12 and cCR: dostarlimab 1000mg q6w for 4 cycles (C9-C12) • If downstaging at UGI endoscopy without PD on CT at wk 12 with and no cCR, surgery will be proposed and if Becker-TRG 1a, 1b, or 2 after surgery: dostarlimab 1000mg q6w for 4 cycles (C9-C12)

Study Details

This phase II study will evaluate dostarlimab with a watch-and-wait approach for patients with localized mismatch repair deficiency (dMMR)/microsatellite instability (MSI) gastric or oeso-gastric junction adenocarcinoma. The goal of the study is to determine whether the surgery could be avoided in patients with localized dMMR/MSI-H gastric/OGJ adenocarcinoma with complete response at endoscopy and biopsies free of tumoral cells after treatment with dostarlimab, with a watch-and-wait approaches.

Key Dates

Start date
Dec 18, 2023
Status verified
Jan 2024
Primary completion
Sep 1, 2028
Completion
Sep 1, 2028

Study Design

Enrollment
59 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: From the start of therapy with dostarlimab to 1 year; assessed at 1 year. ]

Central Contacts

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