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Active, not recruitingNCT03407144Updated Nov 4, 2026

Safety and Efficacy of Pembrolizumab (MK-3475) in Children and Young Adults With Classical Hodgkin Lymphoma (MK-3475-667/KEYNOTE-667)

A Phase 2 interventional study of pembrolizumab and doxorubicin in Hodgkin Lymphoma, sponsored by Merck Sharp & Dohme LLC. Active, not recruiting at 93 sites in 16 countries. Open to participants aged 3 Years to 25 Years. Per ClinicalTrials.gov, last updated 2026-11-04.

Sponsored by Merck Sharp & Dohme LLC (part of Merck & Co., Inc) · Phase 2, Interventional, and Treatment

Updated Oct 2, 2026Primary completion movedStudy completion movedGo to Updates ↓
Phase
Phase 2
Study type
Interventional
Enrollment
340
Allocation
Non-randomized
Ages
3 Years to 25 Years
Sex
All
01

Study summary

This study will examine the safety and efficacy of pembrolizumab (MK-3475) in combination with chemotherapy in children and young adults with newly diagnosed classical Hodgkin Lymphoma (cHL) who are slow early responders (SERs) to frontline chemotherapy.

Read the detailed description

Group 1 will consist of low-risk participants with cHL Stages IA, IB and IIA without bulky disease. Group 2 will consist of high-risk participants with cHL Stages IIEB, IIIEA, IIIEB, IIIB, IVA and IVB.

02

Conditions studied

  • Hodgkin Lymphoma

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Keywords

  • Programmed Death-1 (PD-1)
  • PD1
  • Programmed Death-Ligand 1 (PD-L1)
  • PDL1
03

In context

Hodgkin Disease

1,383 studies on the registry are indexed under Hodgkin Disease; 163 are open to participants now.

This study's planned enrollment of 340 is above the median of 40 across 1,095 interventional studies indexed under Hodgkin Disease.

Browse Hodgkin Disease studies →

Lead sponsor

Merck Sharp & Dohme LLC is the lead sponsor of 2,166 studies on the registry; 132 are open to participants now.

Of its 501 completed or terminated interventional studies of FDA-regulated products, 370 (74%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
3 Years to 25 Years
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

  • Group 1: Must have newly diagnosed, confirmed classical Hodgkin Lymphoma (cHL) at Stages IA, IB and IIA without bulky disease. Group 2: Must have newly diagnosed, pathologically confirmed cHL at Stages IIEB, IIIEA,IIIEB, IIIB, IVA and IVB
  • Has per investigator assessment.
  • Male participants are eligible to participate if they agree to the following during the intervention period: refrain from donating sperm plus either be abstinent from heterosexual intercourse as their preferred and usual lifestyle and agree to remain abstinent or must agree to use per protocol unless confirmed to be azoospermic.
  • Female participants who are not pregnant or breastfeeding, and who are either not a woman of (WOCBP), or are a WOCBP who agrees to use approved contraception during the intervention period and for at least 120 days after the last dose of study intervention and agrees not to donate eggs (ova, oocytes) to others or freeze/store for her own use for the purpose of reproduction during this period.
  • Performance status: Lansky Play-Performance Scale ≥50 for children up to 16 years of age OR score ≥50 for participants ≥ 16 years of age
  • Has adequate organ function

Exclusion criteria

Exclusion Criteria:

  • Has undergone solid organ transplant at any time, or prior hematopoietic stem cell transplantation within the last 5 years
  • who has a positive urine pregnancy test within 24 hours before the first dose of study treatment
  • Baseline value \<50% or shortening fraction of \<27%
  • Has received prior therapy with an anti-Programmed Death (PD)-1, anti-Programmed Death-Ligand 1 (), or anti-PD-L2 agent or with an agent directed to another co-inhibitory T-cell receptor or has previously participated in a MSD pembrolizumab (MK-3475) clinical study
  • Has received any prior systemic anti-cancer therapy,including agents for current diagnosis before randomization
  • Has received a or live-attenuated vaccine within 30 days before the first dose of study intervention. Administration of killed vaccines are allowed
  • Has received an investigational agent or has used an investigational device within 4 weeks prior to study intervention administration
  • Has a diagnosis of lymphocyte-predominant Hodgkin Lymphoma (HL)
  • Has a diagnosis of immunodeficiency or is receiving chronic systemic therapy or any other form of therapy within 7 days prior to the first dose of pembrolizumab
  • Has a known additional that is progressing or requires active treatment within the past 3 years
  • Has radiographically detectable central nervous system and/or carcinomatous meningitis as assessed by local site investigator at the time of diagnosis
  • Has severe (≥Grade 3) to any study therapies including any
  • An active disease that has required systemic treatment in past 2 years
  • Has a history of (non-infectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease
  • Has an active infection requiring systemic therapy
  • Has a known history of (HIV) infection
  • Has a known history of or known active virus infection
  • Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the study, interfere with the participant's participation for the full duration of the study, or is not in the best interest of the participant to participate, in the opinion of the treating investigator
  • Has known psychiatric or substance abuse disorders that would interfere with cooperating with the requirements of the study
  • Participants who have not adequately recovered from major surgery or have ongoing surgical complications
Terms in these criteria, in plain language(20)

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.

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.

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.

Karnofsky performance status (KPS)

A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.

Studies often ask for 60 or 70 and above. Your doctor gives the score.

Allogeneic and autologous transplant

Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.

LVEF (left ventricular ejection fraction)

The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.

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.

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.

Live vaccines

Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.

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.

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.

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.

Metastases

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

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.

Excipients

The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.

Autoimmune disease

A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.

Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.

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.

Hepatitis B tests

Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.

Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.

Hepatitis C tests

Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.

After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.

05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Non-randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
340 participants (estimated)

Study arms

  • Experimental
    Pembrolizumab + AVD (Group 1)

    After receiving two 4-week cycles of ABVD (doxorubicin, bleomycin, vinblastine and dacarbazine) induction therapy, SER participants in Group 1 will receive pembrolizumab 2 mg/kg up to a maximum of 200 mg (3 to 17 years of age) or 200 mg (18 to 25 years of age) on Day 1 of each 3-week cycle (Q3W) in combination with two cycles of AVD chemotherapy (doxorubicin 25 mg/m\^2, vinblastine 6 mg/m\^2 and dacarbazine 375 mg/m\^2 on Days 1 and 15; cycle frequency every 4 weeks \[Q4W\]). All SERs in Group 1 will receive radiotherapy (RT) after completing AVD chemotherapy.

    Biological: pembrolizumab · Drug: doxorubicin · Drug: vinblastine · Drug: dacarbazine · Drug: bleomycin · Radiation: Radiotherapy (RT)

  • Experimental
    Pembrolizumab + COPDAC-28 (Group 2)

    After receiving two 4-week cycles of OEPA (vincristine, etoposide/etopophos, prednisone/prednisolone and doxorubicin) induction therapy, SER participants in Group 2 will receive pembrolizumab 2 mg/kg up to a maximum of 200 mg (3 to 17 years of age) or 200 mg (18 to 25 years of age) Q3W, in combination with 4 cycles of COPDAC-28 chemotherapy (cyclophosphamide 500 mg/m\^2 on Days 1 and 8, vincristine 1.5 mg/m\^2 with maximum single dose 2 mg on Days 1 and 8, prednisone/prednisolone 40 mg/m\^2/day divided in 3 doses on Days 1 to 15, dacarbazine 250 mg/m\^2 on Days 1 to 3; cycle frequency Q4W). SERs in Group 2 will receive RT if they have a positive Positron Emission Tomography (PET) response after completing COPDAC-28 chemotherapy.

    Biological: pembrolizumab · Drug: doxorubicin · Drug: dacarbazine · Drug: cyclophosphamide · Drug: vincristine · Drug: prednisone/prednisolone · Drug: etoposide · Radiation: Radiotherapy (RT)

Interventions

  • Biologicalpembrolizumab

    2 mg/kg intravenous (IV) up to a max of 200 mg (3 to 17 years of age) or 200 mg IV (18 to 25 years of age); cycle frequency Q3W

    Also known as: MK-3475

  • 25 mg/m\^2 IV on Days 1 and 15 as part of ABVD induction therapy (cycle frequency: Q4W, Group 1) 40 mg/m\^2 IV on Days 1 and 15 as part of OEPA induction therapy (cycle frequency: Q4W, Group 2) 25 mg/m\^2 IV on Days 1 and 15 as part of AVD chemotherapy (cycle frequency: Q4W, Group 1)

  • 6 mg/m\^2 IV on Days 1 and 15 as part of ABVD induction therapy (cycle frequency: Q4W, Group 1) 6 mg/m\^2 IV on Days 1 and 15 as part of AVD chemotherapy (cycle frequency: Q4W, Group 1)

  • 375 mg/m\^2 IV on Days 1 and 15 as part of ABVD induction therapy (cycle frequency: Q4W, Group 1) 375 mg/m\^2 IV on Days 1 and 15 as part of AVD chemotherapy (cycle frequency: Q4W, Group 1) 250 mg/m\^2 IV on Days 1 to 3 as part of COPDAC-28 chemotherapy (cycle frequency: Q4W, Group 2)

  • 500 mg/m\^2 IV on days 1 and 8 as part of COPDAC-28 chemotherapy (cycle frequency: Q4W, Group 2)

  • 1.5 mg/m\^2 IV with maximum single dose 2 mg on Days 1, 8, and 15 as part of OEPA induction therapy (cycle frequency: Q4W, Group 2) 1.5 mg/m\^2 IV with maximum single dose 2 mg on Days 1 and 8 as part of COPDAC-28 chemotherapy (cycle frequency: Q4W, Group 2)

  • Drugprednisone/prednisolone

    Drug pages: Prednisone · Prednisolone

    60 mg/m\^2/day orally divided in 3 doses on Days 1 to 15 as part of OEPA induction therapy (cycle frequency: Q4W, Group 2) 40 mg/m\^2/day orally divided in 3 doses on Days 1 to 15 as part of COPDAC-28 chemotherapy (cycle frequency: Q4W, Group 2)

  • 10 units/m\^2 IV on Days 1 and 15 as part of ABVD induction therapy (cycle frequency: Q4W, Group 1)

  • 125 mg/m\^2 IV on Days 1 to 5 as part of OEPA induction therapy (cycle frequency: Q4W, Group 2)

    Also known as: Etoposide Phosphate

  • RadiationRadiotherapy (RT)

    RT administered daily, dose dependent on randomization group and disease response.

06

What researchers measure

Primary outcomes

  1. Objective Response Rate (ORR) in SER Participants By Risk Group (Low, High) as Assessed by Blinded Independent Central Review (BICR)

    ORR is defined as the percentage of SER participants who have a Complete Response (\[CR\], disappearance of all evidence of disease) or Partial Response (\[PR\], regression of measurable disease and no new sites) using IWG revised response criteria and determined by BICR. The ORR will be estimated by risk group in SER participants.

    Time frame: Up to approximately 8 years

Secondary outcomes

  1. Rate of Positron Emission Tomography (PET) Scan Negativity in SER Participants By Risk Group (Low, High) After AVD or COPDAC-28 Chemotherapy

    The rate of PET negativity for SER participants is the percentage of participants with PET negativity (defined as Deauville score 1, 2 or 3) after two cycles of AVD (Group 1) or four cycles of COPDAC-28 (Group 2), in combination with pembrolizumab. The Deauville 5-point scoring system is an internationally accepted and utilized five-point scoring system for the Fluorodeoxyglucose (FDG) avidity of a Hodgkin's lymphoma or Non-Hodgkin's lymphoma tumor mass as seen on FDG PET scan: Score 1= No uptake above the background, Score 2= Uptake ≤ mediastinum, Score 3= Uptake \> mediastinum but ≤ liver, Score 4= Uptake moderately increased compared to the liver at any site, Score 5= Uptake markedly increased compared to the liver at any site or new lesions, Score X= New areas of uptake unlikely to be related to lymphoma. In the present study, scores of 1, 2 and 3 are considered to be negative and scores of 4 and 5 are considered to be positive.

    Time frame: Up to approximately 8 years

  2. Event-Free Survival (EFS) in SER Participants By Risk Group (Low, High) as Assessed by BICR

    EFS is defined as the time from first dose to the first documented disease progression or recurrence, or death due to any cause, whichever occurs first. Progression/disease recurrence will be determined by BICR using IWG criteria.

    Time frame: Up to approximately 2 years

  3. Overall Survival (OS) in SER Participants By Risk Group (Low, High)

    OS is defined as the time from first dose to death due to any cause. Participants without documented death will be censored at the date of the last follow-up.

    Time frame: Up to approximately 2 years

  4. Exposure to Radiotherapy (RT) in SER Participants By Risk Group (Low, High)

    The frequency of RT received by eligible participants (positive PET response, i.e. Deauville score of 4 or 5) will be reported.

    Time frame: Up to approximately 8 years

  5. Rate of PET Scan Negativity In Group 1 Participants After ABVD Induction Therapy

    The rate of PET negativity for Group 1 participants is the percentage of participants with PET negativity (defined as Deauville score 1, 2 or 3) after two cycles of ABVD induction as per investigator assessment. The Deauville 5-point scoring system is an internationally accepted and utilized five-point scoring system for the FDG avidity of a Hodgkin's lymphoma or Non-Hodgkin's lymphoma tumor mass as seen on FDG PET scan: Score 1= No uptake above the background, Score 2= Uptake ≤ mediastinum, Score 3= Uptake \> mediastinum but ≤ liver, Score 4= Uptake moderately increased compared to the liver at any site, Score 5= Uptake markedly increased compared to the liver at any site or new lesions, Score X= New areas of uptake unlikely to be related to lymphoma. In the present study, scores of 1, 2 and 3 are considered to be negative and scores of 4 and 5 are considered to be positive.

    Time frame: Up to approximately 8 years

  6. EFS in Rapid Early Responder (RER) Participants By Risk Group (Low, High) as Assessed by Investigator

    EFS is defined as the time from first dose to the first documented disease progression or recurrence, or death due to any cause, whichever occurs first. Progression/disease recurrence will be determined by the investigator.

    Time frame: Up to approximately 3 years

  7. OS in RER Participants By Risk Group (Low, High)

    OS is defined as the time from first dose to death due to any cause. Participants without documented death will be censored at the date of the last follow-up.

    Time frame: Up to approximately 3 years

  8. Number of SER Participants Experiencing an Adverse Event (AE) By Risk Group (Low, High)

    An AE is any untoward medical occurrence in a participant that is temporally associated with the use of study treatment, whether or not considered related to the study treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study treatment. The number of SER participants who experience an AE will be reported for each arm.

    Time frame: Up to approximately 8 years

  9. Number of SER Participants Discontinuing Study Treatment Due to AEs By Risk Group (Low, High)

    An AE is any untoward medical occurrence in a participant that is temporally associated with the use of study treatment, whether or not considered related to the study treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study treatment. The number of SER participants who discontinue study treatment due to an AE will be reported for each arm.

    Time frame: Up to approximately 8 years

07

Study locations

93 sites
08

References and documents

Publications

  • Castellino SM, Giulino-Roth L, Harker-Murray P, Kahn JM, Forlenza C, Cho S, Hoppe B, Parsons SK, Kelly KM; COG Hodgkin Lymphoma Committee. Children's Oncology Group's 2023 blueprint for research: Hodgkin lymphoma. Pediatr Blood Cancer. 2023 Sep;70 Suppl 6(Suppl 6):e30580. doi: 10.1002/pbc.30580. Epub 2023 Jul 28. PubMed 37505794 ↗

Individual participant data

Plan to share: Yes — https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Data sharing details ↗ · externaldatasharing-msd.com

09

Updates

2 registry updates since Sep 25, 2026
Primary completion
Nov 6, 2026→Feb 12, 2027
Oct 2, 2026
Study completion
Nov 6, 2026→Feb 12, 2027
Oct 2, 2026
Show all 2 updates
  1. Nov 4, 2026
    Minor edits only
    + 1 other change: verification date
  2. Oct 2, 2026
    Primary completion Nov 6, 2026→Feb 12, 2027
    Study completion Nov 6, 2026→Feb 12, 2027

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
NCT03407144
Responsible party
Sponsor
First posted
Jan 23, 2018
Start date
Apr 9, 2018
Primary completion
Feb 12, 2027 (estimated)
Completion
Feb 12, 2027 (estimated)
Last update
Nov 4, 2026

Study contacts

Medical Director
study director · Merck Sharp & Dohme LLC

Oversight

Data monitoring committee
No
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: Pembrolizumab

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