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Comparing Dostarlimab to Placebo after Chemoradiation for Head and Neck Cancer

A Randomized, Double-blind, Placebo-controlled Phase 3 Study to Evaluate Dostarlimab as Sequential Therapy After Chemoradiation in Participants With Locally Advanced Unresected Head and Neck Squamous Cell Carcinoma

PHASE3 · GlaxoSmithKline · NCT06256588

This study is testing if the immunotherapy drug Dostarlimab can help adults with advanced head and neck cancer feel better after they finish their chemoradiation treatment, compared to a placebo.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment864 (estimated)
Ages18 Years and up
SexAll
SponsorGlaxoSmithKline (industry)
Drugs / interventionscetuximab, dostarlimab, chemotherapy, immunotherapy, radiation
Locations240 sites (Jonesboro, Arkansas and 239 other locations)
Trial IDNCT06256588 on ClinicalTrials.gov

What this trial studies

This study evaluates the safety and effectiveness of Dostarlimab, an immunotherapy drug, compared to a placebo in adults with locally advanced unresected head and neck squamous cell carcinoma (HNSCC) who have completed chemoradiation. Participants must have a confirmed diagnosis of HNSCC and meet specific criteria regarding tumor status and performance levels. The study aims to determine if Dostarlimab can improve outcomes for these patients after their initial treatment.

Who should consider this trial

Good fit: Ideal candidates are adults with newly diagnosed, unresected locally advanced HNSCC who have completed chemoradiation and have PD-L1 positive tumors.

Not a fit: Patients who have received prior treatments for head and neck cancer or have distant metastatic disease may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option that enhances recovery and survival rates for patients with advanced head and neck cancer.

How similar studies have performed: Other studies have shown promising results with immunotherapy approaches in similar patient populations, indicating potential for success in this trial.

Eligibility criteria

Show full inclusion / exclusion criteria 
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.

Where this trial is running

Jonesboro, Arkansas and 239 other locations

+190 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Neoplasms, Head and Neck, JEMPERLI, Dostarlimab, Placebo, Chemoradiation, HNSCC

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.