A Study of Dostarlimab vs Placebo After Chemoradiation in Adult Participants With Locally Advanced Unresected Head and Neck Squamous Cell Carcinoma

Phase 3

Recruiting

• Conditions: Neoplasms, Head and Neck
• Interventions: Drug: Dostarlimab; Drug: Placebo

• Registration Number: NCT06256588
• Lead Sponsor: GlaxoSmithKline

Brief Summary

The goal of this study is to assess the safety and effectiveness of Dostarlimab compared to Placebo in adult participants with Head and Neck Squamous Cell Carcinoma (HNSCC)

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2024-02-05
• Study First Submitted QC: 2024-02-05
• Study First Posted: 2024-02-13
• Study Start: 2024-03-21
• Status Verified: 2025-09
• Last Update Submitted: 2025-09-22
• Last Update Posted: 2025-09-25
• Primary Completion: 2028-06-30
• Study Completion: 2029-10-26

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 864

Inclusion Criteria

Participants are eligible to be included in the study only if all of the following criteria apply:

• Has newly diagnosed unresected Locally Advanced (LA) histologically confirmed HNSCC of the oral cavity, oropharynx, hypopharynx or larynx and completed cisplatin plus radiotherapy (termed "CRT" in this protocol) with curative intent and has no evidence of distant metastatic disease.

• Has provided acceptable core or excisional biopsy obtained prior to CRT:

  • PD-L1 positive tumor status
  • If the primary tumor site is oropharyngeal carcinoma, the participant must have p16 immunohistochemistry (IHC) testing.

• Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

• Has adequate organ function.

Exclusion Criteria

Participants are excluded from the study if any of the following criteria apply:

• Has received prior radiation therapy (RT), systemic therapy, targeted therapy, or surgery for management of head and neck cancer not considered part of CRT. Participants receiving induction chemotherapy are excluded. CRT combinations with components other than cisplatin and RT (e.g., experimental agents, including radiosensitizers/radioprotectants, cetuximab) are not eligible.
• Has cancer outside of the oropharynx, larynx, hypopharynx or oral cavity, such as nasopharyngeal, sinus, other para-nasal, or other unknown primary head and neck cancer. Has more than one primary HNSCC tumor.
• Has experienced any of the following with prior immunotherapy: any immune-related adverse event (irAE) of Grade ≥3, immune-related severe neurologic events of any grade (e.g., myasthenic syndrome/myasthenia gravis, encephalitis, Guillain-Barré Syndrome, or transverse myelitis), exfoliative dermatitis of any grade (Stevens-Johnson Syndrome, toxic epidermal necrolysis, or Drug Rash with Eosinophilia and Systemic Symptoms [DRESS] syndrome), or myocarditis of any grade. Non-clinically significant laboratory abnormalities are not exclusionary.
• Has undergone any major surgical procedure or experienced significant traumatic injury that has not resolved by the time of randomization.
• Has any history of interstitial lung disease or pneumonitis (past or current).
• Has cirrhosis of any stage or current unstable liver biliary disease per investigator assessment defined by the presence of ascites, encephalopathy, coagulopathy, hypoalbuminemia, esophageal/gastric varices, or persistent jaundice.
• Has a history or current evidence of any medical condition, therapy, or laboratory abnormality that might confound the study results, interfere with their participation for the full duration of the study intervention, or indicate it is not in the best interest of the participant to participate, in the opinion of the investigator.
• Is receiving any other anticancer or experimental therapy. No other experimental therapies (including but not limited to chemotherapy, radiation, hormonal treatment, antibody therapy, immunotherapy, gene therapy, vaccine therapy, or other experimental drugs) of any kind are permitted while the participant is receiving study intervention.
• Previous treatment with anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or an agent directed to another stimulatory or coinhibitory T-cell receptor [e.g., Cytotoxic T-lymphocyte associated protein 4 (CTLA4), OX-40, CD137]
• Is pregnant, breastfeeding, or expecting to conceive children within the projected duration of the study, starting with the Screening Visit through 120 days after the last dose of study intervention.
• Has a history of severe allergic and/or anaphylactic reactions to chimeric, human or humanized antibodies, fusion proteins, or known allergies to dostarlimab or its excipients.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Arm A: Dostarlimab	Dostarlimab	-
Arm B: Placebo	Placebo	-

Primary Outcome Measures

Name	Time	Method
Event-free Survival (EFS) Assessed by Blinded Independent Central Review (BICR)	Up to approximately 5 years	Event Free Survival (EFS) is defined as the time from the date of randomization to the date of an event, where an event is defined as locoregional progression or recurrence, or distant metastasis per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 as per BICR; Salvage surgery at the primary tumor site; Neck dissection or surgery performed \>20 weeks after completion of Concomitant Chemoradiotherapy (CRT) when invasive cancer is present or Death from any cause.

Secondary Outcome Measures

Name	Time	Method
Number of Participants with treatment emergent adverse events (TEAEs), Immune-mediated TEAEs, and serious adverse events (SAEs) by severity	Up to approximately 5 years
Number of Participants with Anti-Drug Antibodies against Dostarlimab	Up to approximately 15 months
Overall Survival (OS)	Up to approximately 5 years	OS is defined as the time from date of randomization to the date of death by any cause.
Event-free Survival (EFS) assessed by investigator	Up to approximately 5 years	Event Free Survival (EFS) is defined as the time from the date of randomization to the date of an event as per primary endpoint, however with investigator assessment per RECIST 1.1
Number of participants with clinically significant changes in laboratory, vital signs, and safety assessment parameters	Up to approximately 5 years
Serum Concentration of Dostarlimab	Up to approximately 15 months
Serum Concentration of Dostarlimab at End of Infusion (C-EoI)	Up to approximately 15 months
Number of Participants with TEAEs and SAEs leading to dose delays, withdrawals or death	Up to approximately 5 years
Serum Predose trough concentration (Ctrough) of Dostarlimab	Up to approximately 15 months

Trial Locations

Locations (1)

GSK Investigational Site; 🇬🇧 Wolverhampton, United Kingdom