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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)

A Randomized, Multicenter, Double-blind, Phase 3 Study to Investigate the Safety and Efficacy of Belrestotug in Combination With Dostarlimab Compared With Placebo in Combination With Pembrolizumab in Participants With Previously Untreated, Unresectable, Locally Advanced or Metastatic PD-L1 Selected Non-small Cell Lung Cancer (GALAXIES Lung-301)

Status
Active, not recruiting
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06472076
Enrollment
88
Registered
2024-06-24
Start date
2024-06-10
Completion date
2027-02-02
Last updated
2025-09-10

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Lung Cancer, Non-Small Cell

Keywords

Belrestotug, GSK4428859A, EOS-448, Dostarlimab, Pembrolizumab, PD-L1 selected NSCLC

Brief 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.

Interventions

BIOLOGICALDostarlimab

Dostarlimab will be administered.

BIOLOGICALBelrestotug

Belrestotug will be administered.

BIOLOGICALPembrolizumab

Pembrolizumab will be administered.

DRUGPlacebo

Placebo will be administered.

Sponsors

iTeos Therapeutics
CollaboratorINDUSTRY
GlaxoSmithKline
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion 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

Exclusion 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.

Design outcomes

Primary

MeasureTime frame
Number of Participants with Treatment Emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs)Up to approximately 138 weeks
Number of Participants with TEAEs or SAEs leading to dose withdrawals or treatment discontinuationUp to approximately 138 weeks

Countries

Argentina, Belgium, Brazil, Bulgaria, Canada, China, Finland, France, Germany, Hong Kong, India, Japan, Mexico, Netherlands, Panama, South Korea, Spain, Sweden, Taiwan, Turkey (Türkiye), United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026