ClinicalTrials.gg
RecruitingNCT04966481Updated Nov 12, 2026

Palbociclib and Cetuximab Versus Cetuximab Monotherapy for Patients With CDKN2A-altered, HPV-unrelated Head and Neck Squamous Cell Carcinoma Who Experienced Disease Progression on a PD-1/L1 Inhibitor

A Phase 3 interventional study of Palbociclib and Cetuximab in HPV-unrelated Head and Neck Squamous Cell Carcinoma, sponsored by Washington University School of Medicine. Recruiting at 5 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-12.

Sponsored by Washington University School of Medicine · Phase 3, Interventional, and Treatment

From the registry’s dates

  • Started Apr 2022; still recruiting 4 years 7 months later.
Updated Nov 12, 2026Site recruiting status changedGo to Updates ↓
Phase
Phase 3
Study type
Interventional
Enrollment
81
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Where this study stands

Counted across the records on this site · 2026-11-12

Among 24 studies in Squamous Cell Carcinoma of Head and Neck by Washington University School of Medicine — 6 open to participants now, 12 under way, 1 of them phase 3. Squamous Cell Carcinoma of Head and Neck · Washington University School of Medicine.

Planned enrollment
4th of 23
81 · median 43
Started
2022
the only one that year
Phase 3
Only one
of the 24
Primary completion
2029-02
later than 9 of 11 live
Registered
18th of 24
by date

Among the 24 studies in Squamous Cell Carcinoma of Head and Neck by Washington University School of Medicine, this one is the 4th largest by planned enrollment of the 23 interventional ones that give a count, is the only one that started in 2022, is the only one in phase 3, reaches primary completion later than 9 of the 11 other live ones, and was the 18th registered.

Squamous Cell Carcinoma of Head and Neck

2,019 studies on the registry are indexed under Squamous Cell Carcinoma of Head and Neck; 573 are open to participants now.

Browse Squamous Cell Carcinoma of Head and Neck studies →

Open to participants now

6 of the 24 studies in Squamous Cell Carcinoma of Head and Neck by Washington University School of Medicine are open now, in 1 country. Recruiting first, the newest first:

By country, each count listing its studies:

All 6 open studies →

Where they have run

Who these studies take

Of the 433 Squamous Cell Carcinoma of Head and Neck studies recruiting now, 309 (71%) set no upper age limit and 87 (20%) stop at 75 or younger; 5 take children under 18; 13 take healthy volunteers.

This study: 18 Years and older · all sexes · no healthy volunteers.

The full table on the hub →

This tab as a report to print or save as PDF → With an account.

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Watch this landscapeDownload CSVNarrow it in search →With an account: a weekly mail of what changed among 24 studies in Squamous Cell Carcinoma of Head and Neck by Washington University School of Medicine, or all of them as a file.
02

Study summary

This multicenter, open-label, randomized phase 3 trial will determine if palbociclib and cetuximab (Arm 1) improves overall survival (OS) in comparison to cetuximab monotherapy (Arm 2) in patients with CDKN2A-altered, HPV-unrelated recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) who experienced disease progression on a PD-1/L1 inhibitor (given as monotherapy or in combination with other therapy).

03

Conditions studied

  • HPV-unrelated Head and Neck Squamous Cell Carcinoma
04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

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.

Inclusion criteria

  • or cytologically confirmed RM-HNSCC that is HPV-unrelated disease; defined as SCC of the oral cavity, larynx, or hypopharynx and p16 negative SCC of the oropharynx or p16 negative non-cutaneous SCC unknown primary of the neck.
  • CDKN2A loss-of-function (LOF) alteration: mutation or homozygous deletion described on genomic sequencing report.
  • defined as lesions that can be accurately measured in at least one dimension (longest diameter to be recorded) as ≥ 10 mm with CT scan, as ≥ 20 mm by chest x-ray, or ≥ 10 mm with calipers by clinical exam, per 1.1.
  • Disease progression on a /L1 inhibitor-containing regimen (given as monotherapy or in combination with other therapy).
  • Received no more than three for RM-HNSCC.
  • At least 18 years of age.
  • performance status ≤ 1.
  • Normal bone marrow and organ function as defined below:

    • ≥ 8 g/L
    • ≥ 1,000/mcl
    • ≥ 100,000/mcl
    • Total ≤ 3 x institutional (IULN)
    • (SGOT)/ALT(SGPT) ≤ 5 x IULN (for cases involving liver , AST/ALT ≤ 10 x IULN)
    • Serum creatinine \< 3 x IULN or > 30 mL/min by Cockcroft-Gault
  • The effects of palbociclib and cetuximab on the developing human fetus are unknown. For this reason and because CDK 4/6 inhibitors are known to be teratogenic, women of and men must agree to use adequate (hormonal or barrier method of birth control, abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she must inform her treating physician immediately. Men treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of the study, and 3 months days after completion of the study
  • Ability to understand and willingness to sign an IRB approved written document (or that of legally authorized representative, if applicable).

Exclusion criteria

Exclusion Criteria:

  • Prior treatment with cetuximab for recurrent or disease (however, prior cetuximab given as a component of multimodality therapy for newly diagnosed, locally advanced, non-metastatic HNSCC is allowable).
  • Prior treatment with a CDK4/6 inhibitor for RM-HNSCC.
  • Rb (retinoblastoma) loss: mutation or homozygous deletion described on genomic sequencing report.
  • Currently receiving any other agents.
  • A history of other with the exception of malignancies for which all treatment was completed at least 1 year before registration and the patient has no evidence of recurrent/persistent disease.
  • Patients with treated are eligible if there is no evidence of progression for at least 4 weeks after CNS-directed treatment, as ascertained by clinical examination and brain imaging (MRI or CT scan) during the screening period
  • A history of allergic reactions attributed to compounds of similar chemical or biologic composition to palbociclib or other agents used in the study (excluding cetuximab).
  • Prior grade 3 or 4 (per 5.0) reaction to cetuximab.
  • Uncontrolled intercurrent illness including, but not limited to, ongoing or active serious infection, symptomatic congestive heart failure, unstable angina pectoris, or cardiac arrhythmia.
  • >500 msec (using Bazette formula).
  • Patients with are eligible unless their are \< 350 cells/mcL or they have a history of AIDS-defining opportunistic infection within the 12 months prior to registration. Concurrent treatment with effective ART according to DHHS treatment guidelines is recommended. Recommend exclusion of specific ART agents based on predicted drug-drug interactions (i.e. for sensitive substrates, concurrent strong CYP3A4 inhibitors (ritonavir and cobicistat) or inducers (efavirenz) should be ).
Terms in these criteria, in plain language(27)

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.

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.

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.

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.

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.

Line of therapy

A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.

“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.

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.

0
Fully active, no restrictions.
1
Limited in strenuous activity, but walking and able to do light work, such as housework or office work.
2
Walking and able to look after yourself, but unable to work; up and about more than half of waking hours.
3
Able to look after yourself only in part; in bed or a chair more than half of waking hours.
4
Unable to look after yourself at all; in bed or a chair all day.

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.

Hemoglobin (Hb)

The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).

Absolute neutrophil count (ANC)

The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.

It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

Bilirubin

A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.

Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.

ULN (upper limit of normal)

The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.

“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.

ALT and AST (liver enzymes)

Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.

Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.

Metastases

Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.

Creatinine clearance (CrCl)

How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.

Childbearing potential

Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).

Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

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.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

Cancer (malignancy)

Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.

Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.

Brain metastases

Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).

Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.

CTCAE grade

The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.

1
Mild.
2
Moderate.
3
Severe.
4
Life-threatening.
5
Death due to the event.

“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.

Hypersensitivity

An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.

QT and QTc

On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.

The study may name a correction formula and a limit in milliseconds, often around 450–480.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

CD4 count

The number of CD4 cells, a type of white blood cell, in a given amount of blood. It is used to follow how well the immune system is doing in HIV.

CYP3A (CYP3A4) inhibitors and inducers

CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.

Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.

Contraindication

A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.

05

Study design

Phase
Phase 3
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
81 participants (estimated)

Study arms

  • Experimental
    Arm 1: Palbociclib + Cetuximab

    * Palbociclib by mouth 125 mg/daily on Days 1-21 of each 28 day cycle * Cetuximab: Initial dose 400mg/m\^2 intravenous (IV); Subsequent doses 250 mg/m\^2 IV, weekly

    Drug: Palbociclib · Drug: Cetuximab

  • Active comparator
    Arm 2: Cetuximab

    -Cetuximab: Initial dose 400mg/m\^2 intravenous (IV); Subsequent doses 250 mg/m\^2 IV, weekly

    Drug: Cetuximab

Interventions

  • Administered on an outpatient basis

    Also known as: Ibrance

  • Given intravenously over approximately 60 minutes

    Also known as: Erbitux

06

What researchers measure

Primary outcomes

  1. Overall survival (OS)

    -Defined as the time from the date of treatment to the date of death, censored at the last follow-up otherwise.

    Time frame: Through completion of follow-up (estimated to be 15 months)

Secondary outcomes

  1. Overall response rate (ORR) - (complete response + partial response)

    * Complete Response (CR): Disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to \<10 mm. Disappearance of all non-target lesions and normalization of tumor marker level. * Partial Response (PR): At least a 30% decrease in the sum of the diameters of target lesions, taking as reference the baseline sum diameters.

    Time frame: Through completion of treatment (estimated to be 12 weeks)

  2. Duration of response (DoR)

    -The duration of response is measured from the time measurement criteria are met for CR or PR (whichever is first recorded) until the first date that recurrent or progressive disease is objectively documented (taking as reference for progressive disease the smallest measurements recorded since the treatment started).

    Time frame: Through completion of treatment (estimated to be 12 weeks)

  3. Progression-free survival (PFS)

    * Defined as the days from the date of treatment start to progression or death. The alive patients without progression are censored at the last follow-up. * Progressive Disease (PD): At least a 20% increase in the sum of the diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that is the smallest on study). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. ): Appearance of one or more new lesions and/or unequivocal progression of existing non-target lesions.

    Time frame: Through completion of follow-up (estimated to be 15 months)

  4. Frequency of adverse events

    -Will be measured by CTCAE v. 5.0

    Time frame: From start of treatment through 30 days after completion of treatment (estimated to be 16 weeks)

  5. Dose delivery as measured by percent of full doses given over time

    Time frame: Through completion of treatment (estimated to be 12 weeks)

  6. Correlate CCND1 and PIK3CA alterations with efficacy endpoints

    Tailored Next Generation Sequencing Report (performed before trial enrollment) will be collected to tabulate additional somatic genomic alterations to be used to correlate with efficacy endpoints.

    Time frame: Through completion of follow-up (estimated to be 15 months)

  7. Changes in genomic alterations of tumor

    Time frame: At baseline and at time of progression (estimated to be 15 months)

07

Study locations

4 of 5 sites recruiting
  • Sanford Worthington Medical Center
    Worthington, Minnesota 56187, United States
    Recruiting
    • Steven Powell, M.D. · Contact507-372-2941
    • Steven Powell, M.D. · Principal investigator
  • Saint Luke's Hospital
    Kansas City, Missouri 64111, United States
    Withdrawn

    Not enrolling at this site.

  • Washington University School of Medicine
    St Louis, Missouri 63110, United States
    Recruiting
    • Douglas Adkins, M.D. · Contactdadkins@wustl.edu · 314-747-8475
    • Douglas Adkins, M.D. · Principal investigator
    • Peter Oppelt, M.D. · Sub investigator
    • Esther Lu, Ph.D. · Sub investigator
  • Sanford Roger Maris Cancer Center
    Fargo, North Dakota 58122, United States
    Recruiting
    • Daniel Almquist, M.D. · Contact701-234-6161
    • Daniel Almquist, M.D. · Principal investigator
  • Sanford Medical Center
    Sioux Falls, South Dakota 57104, United States
    Recruiting
    • Steven Powell, M.D. · Contact605-328-8000
    • Steven Powell, M.D. · Principal investigator
08

References and documents

09

Timeline

1 registry update since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started Apr 2022 (actual). Primary completion is estimated for Feb 2029, 82 months after the start.

Of 51 non-industry phase 3 interventional studies under Squamous Cell Carcinoma of Head and Neck, half reached primary completion within 95 months of starting (the median), counting those still running; a quarter within 67 and three quarters within 121. This study's planned 82 months is below that.

Counting every sponsor, half of 78 studies reached it within 76 months; a quarter within 38 and three quarters within 117.

How these figures are worked out, and which studies are left out of them.

Registered
Jul 7, 2021
First posted
Jul 19, 2021
StartActual
Apr 6, 2022
Primary completionEst.
Feb 28, 2029
CompletionEst.
Feb 28, 2029
Last update
Nov 12, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
Sites
Sanford Worthington Medical Center is now Recruiting
Nov 12, 2026
Show all 1 update
  1. Nov 12, 2026
    Sanford Worthington Medical Center is now Recruiting
    + 1 other change: verification date

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 ↗

10

Registry details

Key details

Study ID
NCT04966481
Collaborators
Pfizer, The Joseph Sanchez Foundation
Responsible party
Sponsor
First posted
Jul 19, 2021
Start date
Apr 6, 2022
Primary completion
Feb 28, 2029 (estimated)
Completion
Feb 28, 2029 (estimated)
Last update
Nov 12, 2026

Study contacts

Douglas Adkins, M.D.
Contact
dadkins@wustl.edu
314-747-8475
Douglas Adkins, M.D.
principal investigator · Washington University School of Medicine

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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Studies of the drug tested here: Palbociclib

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