A Phase 2/3 interventional study of INBRX-106 and Pembrolizumab in Head and Neck Squamous Cell Carcinoma (HNSCC) and HPV Oropharyngeal Squamous Cell Carcinoma (HPV+ OPSCC), sponsored by Inhibrx Biosciences, Inc. Recruiting at 89 sites in 13 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-28.
Sponsored by Inhibrx Biosciences, Inc · Phase 2/3, Interventional, and Treatment
This seamless phase 2/3 randomized controlled study will evaluate the efficacy and safety of the hexavalent OX40 agonist antibody ordastobart (INBRX-106) combined with the anti-PD-1 antibody pembrolizumab versus pembrolizumab (+ placebo in phase 3) as first-line treatment for patients with recurrent or metastatic (R/M) HPV-positive Oropharyngeal Squamous Cell Carcinoma (HPV+ OPSCC) expressing PD-L1.
2,018 studies on the registry are indexed under Squamous Cell Carcinoma of Head and Neck; 573 are open to participants now.
This study's planned enrollment of 450 is above the median of 48 across 1,653 interventional studies indexed under Squamous Cell Carcinoma of Head and Neck.
Browse Squamous Cell Carcinoma of Head and Neck studies →Inhibrx Biosciences, Inc is the lead sponsor of 6 studies on the registry; 3 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The criteria were revised on the registry on Oct 27, 2026. See what changed
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Has received prior systemic therapy (eg, prior chemo-, immune-, or biologic therapy) for R/M HNSCC.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.
PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.
“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
PD-1, PD-L1 and checkpoint inhibitors
PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.
PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Measurable disease
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
RECIST
The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.
“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive INBRX-106 plus pembrolizumab, both given by intravenous (IV) infusion every 3 weeks (QW3)
Drug: INBRX-106 · Drug: Pembrolizumab
Participants will receive pembrolizumab (plus placebo in Phase 3), given by intravenous (IV) infusion every 3 weeks (QW3)
Drug: Pembrolizumab
INBRX-106 0.1 mg/kg by intravenous (IV) infusion, given every 3 weeks (QW3)
Also known as: Hexavalent OX40 agonist antibody, Ordastobart
Pembrolizumab 200 mg by intravenous (IV) infusion, given every 3 weeks (QW3)
Also known as: Keytruda
Phase 2: Objective Response Rate by investigator (ORRinv)
defined as the proportion of patients with complete response (CR) or partial response (PR) on 2 consecutive occasions ≥4 weeks apart, as determined by the Investigator according to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1).
Time frame: From randomization to progressive disease (PD) or death (up to 1 year)
Phase 3: Progression-Free Survival by Investigator (PFSinv)
defined as the time from randomization to first occurrence of PD, as determined by the Investigator according to RECIST 1.1, or death from any cause (whichever occurs first).
Time frame: From randomization to PD or death (up to 4 years)
Phase 3: Overall Survival (OS)
defined as the time from randomization to death from any cause.
Time frame: From randomization until death from any cause (up to 4 years)
Phase 2 and 3: Objective Response Rate by Blinded Independent Review Committee (ORRbirc)
defined as the proportion of patients with a CR or PR on 2 consecutive occasions ≥4 weeks apart, per RECIST 1.1
Time frame: From randomization to PD or death (up to 1 year)
Phase 2 and 3: Duration of Response by Investigator and by BIRC (DORinv, DORbirc)
defined as the time from the first occurrence of a documented objective response (CR/PR) until PD, both as determined by the Investigator or BIRC, respectively, according to RECIST 1.1, or death from any cause (whichever occurs first)
Time frame: From the first occurrence of a documented objective response to PD or death (up to 4 years)
Phase 2 and 3: Clinical Benefit Rate (CBR) by Investigator and by BIRC
defined as the proportion of patients with stable disease (SD) for ≥12 weeks or a CR or PR, as determined by the Investigator or BIRC respectively, according to RECIST 1.1.
Time frame: From randomization to PD or death (up to 1 year)
Phase 2 and 3: Progression-free survival by BIRC (PFSbirc)
defined as the time from randomization to first occurrence of PD, as determined by the BIRC according to RECIST 1.1, or death from any cause (whichever occurs first).
Time frame: From randomization to PD or death (up to 4 years)
Phase 2 and 3: PFSinv and PFSbirc rates at 6, 9, 12 and 24 months
defined as the proportion of patients who are progression-free, as determined by the Investigator or BIRC, respectively, according to RECIST 1.1, and alive 6, 9, 12 and 24 months after randomization.
Time frame: From randomization to PD or death, with landmark-specific timeframes (up to 2 years)
Phase 2 and Phase 3: OS rates at 12 and 24 months
defined as the proportion of patients who are alive 12 and 24 months after randomization.
Time frame: From randomization to death, with landmark-specific timeframes (up to 2 years)
Phase 2: PFS by Investigator (PFSinv)
defined as the time from randomization to first occurrence of PD, as determined by the Investigator according to RECIST 1.1, or death from any cause (whichever occurs first).
Time frame: From randomization to PD or death (up to 4 years)
Phase 2: Overall Survival (OS)
defined as the time from randomization to death from any cause
Time frame: From randomization to death (up to 4 years)
Phase 3: Objective Response Rate by investigator (ORRinv)
defined as the proportion of patients with CR or PR on 2 consecutive occasions ≥4 weeks apart, as determined by the Investigator according to RECIST 1.1.
Time frame: From randomization to progressive disease (PD) or death (up to 1 year)
Phase 3: Time to Chemotherapy (TTCtx)
defined as the time from randomization until the start date of chemotherapy or death from any cause (whichever occurs first).
Time frame: From randomization until the start of chemotherapy or death (up to 4 years)
Phase 2 and Phase 3: Incidence and Severity of treatment-emergent Adverse Events (AEs)
Incidence will be reported as the number of participants with at least one AE, with severity determined according to the National Cancer Institute Common Toxicity Criteria for Adverse Events, version 5 (NCI CTCAE v 5.0)
Time frame: From first study treatment dose until the end of protocol-defined safety follow-up period (up to 2 years)
Phase 2 and Phase 3: Evaluate the safety and tolerability of study treatment
Incidence of dose interruptions and treatment discontinuation.
Time frame: Up to approximately 24 months
Phase 2 and Phase 3: Number of patients who experienced abnormalities in vital signs and clinical laboratory parameters
Vital signs include respiratory rate, pulse rate, systolic and diastolic blood pressure, and temperature. Clinical laboratory parameter include hematology and biochemistry tests over the course of the study.
Time frame: From first study treatment dose until the end of protocol-defined safety follow-up period (up to 2 years)
Phase 3: Time to Confirmed Deterioration (TTCD) in Pain Presence and Interference
TTCD in pain presence and interference is defined as the time from randomization to the first documentation of ≥10-point increase in pain score, as determined using the European Organization for Research and Treatment of Cancer Quality of Life-Core 30 (EORTC QLQ-C30) questionnaire
Time frame: From randomization until treatment discontinuation (up to 2 years)
Phase 3: TTCD in physical functioning (PF)
defined as the time from randomization to the first documentation of a ≥10 point decrease from baseline in the EORTC QLQ-C30 linearly transformed PF scale score.
Time frame: From randomization until treatment discontinuation (up to 2 years)
Phase 3: TTCD in role functioning (RF)
defined as the time from randomization to the first documentation of a ≥10 point decrease from baseline in the EORTC QLQ-C30 linearly transformed RF scale score.
Time frame: From randomization until treatment discontinuation (up to 2 years)
Phase 3: TTCD in Global Health Status/quality of life (GHS/QoL)
defined as the time from randomization to the first documentation of a ≥10 point decrease from baseline in the EORTC QLQ-C30 linearly transformed GHS/QoL scale score.
Time frame: From randomization until treatment discontinuation (up to 2 years)
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Plan to share: No
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
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Studies of the drug tested here: Ordastobart
Squamous Cell Carcinoma of Head and Neck →
Inhibrx Biosciences, Inc