A Study of Belrestotug Plus Dostarlimab Compared With Placebo Plus Pembrolizumab in Previously Untreated Participants With Programmed Death Ligand 1 (PD-L1) High Non-small-cell Lung Cancer (NSCLC)

Study summary

The goal of this clinical trial is to evaluate the safety and tolerability profile of dostarlimab in combination with belrestotug when compared with pembrolizumab and placebo in participants with previously untreated, unresectable, locally advanced or metastatic PD-L1 high NSCLC.

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Key things to know

Main goalTreatment

This describes the study’s primary purpose.

What is being studiedDostarlimab and Belrestotug

Plus 2 other study approaches.

Who it may be forNon-small cell lung cancer (NSCLC) · PD-L1 · Early-stage or resectable

These are broad labels—not an eligibility decision.

Checked against the public recordLast updated Jul 21, 2026 · Source: ClinicalTrials.gov

Is enrollment open?Active Not Recruiting

The study is underway but is not accepting new participants.

What kind of study?Phase 3

Interventional

Where is it offered?108 U.S. locations

Locations may change over time.

Who runs it?GlaxoSmithKline

Study sponsor

Study overview

What this study is about

Purpose: Treatment
Study type: Interventional
Phase: Phase 3
Sponsor: GlaxoSmithKline
Interventions being studied: Biological: Dostarlimab; Biological: Belrestotug; Biological: Pembrolizumab; Drug: Placebo

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How this study is categorized

These labels come from structured fields and exact terms in the public record.

Cancer type

Non-small cell lung cancer (NSCLC)→

Disease setting

Early-stage or resectable→Locally advanced→Metastatic or stage IV→

Biomarkers

PD-L1→

Treatment approach

Immunotherapy→

Public criteria

Who may be able to participate

The sponsor separates these requirements into two groups. You do not need to interpret them alone—use them to guide a conversation with the study team.

Requirements people may need to meetInclusion criteria

Has a histologically or cytologically confirmed diagnosis of locally advanced, unresectable NSCLC (not eligible for curative surgery and/or definitive radiotherapy with or without chemotherapy), or Metastatic NSCLC
Has not received prior systemic therapy for their locally advanced or metastatic NSCLC.
Provides a fresh tumor tissue sample obtained at the time of or after the initial diagnosis of locally advanced or metastatic NSCLC.
Has a PD-L1-high (Tumor cells \[TC\] ≥50%) tumor
Has measurable disease (at least 1 target lesion) based on RECIST 1.1
Has an Eastern Cooperative Oncology Group (ECOG) Performance status (PS) score of 0 or 1.
Has adequate organ function

Reasons someone may not be able to joinExclusion criteria

Has NSCLC with a tumor that harbors any of the following molecular alterations: 1. Epidermal growth factor receptor (EGFR) mutations that are sensitive to available targeted inhibitor therapy 2. Anaplastic lymphoma kinase (ALK) translocations that are sensitive to available targeted inhibitor therapy 3. Any other known genomic aberrations or oncogenic driver mutations for which a locally approved targeted therapy is available for first line treatment of locally advanced or metastatic NSCLC.
Has had surgery within 4 weeks of the first dose of study intervention and has not recovered from AEs (i.e., has any ongoing surgery-related events ≥ Grade 1)/complications related to surgery or has received lung radiation therapy of \>30 gray (Gy) within 6 months
Has received prior therapy with any immune checkpoint inhibitors, including antibodies or drugs targeting PD-(L)1, Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T cell immunoglobulin and ITIM domain (TIGIT), or other checkpoint pathways.
Has never smoked, defined as smoking \<100 tobacco cigarettes in a lifetime.
Has an invasive malignancy or history of invasive malignancy other than the disease under study within the last 5 years, with the exception of those with a negligible risk of metastasis or death and/or treated with expected curative outcome.
Has symptomatic, untreated, or actively progressin g brain metastases or leptomeningeal disease
Has autoimmune disease or syndrome (current or history thereof) that required systemic treatment within the past 2 years.
Has received any live vaccine within 30 days prior to first dose of study intervention.
Has any history of idiopathic pulmonary fibrosis, organizing pneumonia, drug induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis.
Has symptomatic ascites, pleural effusion, or pericardial effusion.
Has active inflammatory bowel disease
Has a history of significant acute or chronic cardiac diagnosis requiring intervention/treatment in the last 6 months.
Has severe infection or complication thereof 4 weeks prior to randomisation including active tuberculosis.
Has a history of allogeneic tissue/stem cell transplant or solid organ transplant.

Important: This is the sponsor’s public criteria, not a determination of eligibility. The study team must review your individual situation.

Study sites

U.S. locations

GSK Investigational SiteOcala, Florida
GSK Investigational SiteHonolulu, Hawaii
GSK Investigational SiteLexington, Kentucky
GSK Investigational SiteLexington, Kentucky
GSK Investigational SiteOmaha, Nebraska
GSK Investigational SiteNashville, Tennessee
GSK Investigational SiteFort Worth, Texas
GSK Investigational SiteOlympia, Washington
GSK Investigational SiteBuenos Aires
GSK Investigational SiteCipoletti Rio Negro
GSK Investigational SiteCiudad Autonoma de Buenos Aire
GSK Investigational SiteCiudad Autonoma de Bueno

Source and freshness
Processed from ClinicalTrials.gov. Last public update: Jul 21, 2026. Always confirm current availability with the study team.

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