Evaluation of Co-formulated Pembrolizumab/Quavonlimab (MK-1308A) Versus Other Treatments in Participants With Microsatellite Instability-High (MSI-H) or Mismatch Repair Deficient (dMMR) Stage IV Colorectal Cancer (CRC) (MK-1308A-008/KEYSTEP-008)
NCT ID: NCT04895722
Last Updated: 2026-01-22
Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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ACTIVE_NOT_RECRUITING
PHASE2
302 participants
INTERVENTIONAL
2021-06-25
2026-06-25
Brief Summary
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Detailed Description
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Conditions
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Study Design
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RANDOMIZED
PARALLEL
TREATMENT
NONE
Study Groups
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Pembrolizumab
Participants receive pembrolizumab 400 mg intravenously (IV) every 6 weeks (Q6W) for up to approximately 2 years.
Pembrolizumab
400 mg or 200 mg pembrolizumab administered via IV infusion.
Pembrolizumab/Quavonlimab
Participants receive co-formulated pembrolizumab/quavonlimab (400 mg/25 mg) Q6W for up to approximately 2 years.
Pembrolizumab/Quavonlimab
Co-formulated pembrolizumab/quavonlimab (400 mg/25 mg) fixed-dose combination (FDC) administered via IV infusion.
Pembrolizumab/Favezelimab
Participants receive co-formulated pembrolizumab/favezelimab (200 mg/800 mg) every 3 weeks (Q3W) for up to approximately 2 years.
Pembrolizumab/Favezelimab
Co-formulated pembrolizumab/favezelimab (200 mg/800 mg) FDC administered via IV infusion
Pembrolizumab/Vibostolimab
Participants receive co-formulated pembrolizumab/vibostolimab (200 mg/200 mg) Q3W for up to approximately 2 years.
Pembrolizumab/Vibostolimab
Co-formulated pembrolizumab/vibostolimab (200 mg/200 mg) FDC administered via IV infusion
Pembrolizumab Plus MK-4830
Participants receive pembrolizumab 200 mg plus MK-4830 800 mg Q3W for up to approximately 2 years.
Pembrolizumab
400 mg or 200 mg pembrolizumab administered via IV infusion.
MK-4830
800 mg MK-4830 administered via IV infusion
Interventions
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Pembrolizumab
400 mg or 200 mg pembrolizumab administered via IV infusion.
Pembrolizumab/Quavonlimab
Co-formulated pembrolizumab/quavonlimab (400 mg/25 mg) fixed-dose combination (FDC) administered via IV infusion.
Pembrolizumab/Favezelimab
Co-formulated pembrolizumab/favezelimab (200 mg/800 mg) FDC administered via IV infusion
Pembrolizumab/Vibostolimab
Co-formulated pembrolizumab/vibostolimab (200 mg/200 mg) FDC administered via IV infusion
MK-4830
800 mg MK-4830 administered via IV infusion
Other Intervention Names
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Eligibility Criteria
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Inclusion Criteria
* Has locally confirmed dMMR/MSI-H
* Has a life expectancy of at least 3 months
* Female participants are eligible to participate if not pregnant or breastfeeding, and not a woman of childbearing potential (WOCBP), or if a WOCBP then uses a contraceptive method that is highly effective or is abstinent on a long-term and persistent basis, during the intervention period and for at least 120 days after the last dose of study intervention
* Has measurable disease per RECIST 1.1 as assessed by the site and verified by BICR
* Submit an archival (within 5 years of Screening) or newly obtained tumor tissue sample that has not been previously irradiated; formalin-fixed, paraffin embedded (FFPE) blocks are preferred to slides.
* Has adequate organ function
Cohort A:
\- Has been previously treated for their Stage IV dMMR/MSI-H CRC and radiographically progressed on or after or could not tolerate standard treatment, which must include all of the following agents if approved and locally available in the country where the participant is randomized:
* Fluoropyrimidine, irinotecan and oxaliplatin (capecitabine is acceptable as equivalent to fluorouracil in prior therapy)
* With or without an anti-vascular endothelial growth factor (VEGF) monoclonal antibody (e.g., bevacizumab)
* At least one of the anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (cetuximab or panitumumab) for rat sarcoma viral oncogene homolog (RAS) wild-type participants with left-sided tumors. Prior EGFR therapy is optional for patients with right sided RAS Wild-type (WT) tumors.
Cohort B:
\- Has untreated Stage IV dMMR/MSI-H CRC with no prior chemotherapy or immunotherapy for this disease
Exclusion Criteria
* Has received prior systemic anticancer therapy including investigational agents within 4 weeks before the first dose of study intervention
* Has not recovered adequately from a surgery procedure, and/or has any complications from a prior surgery before starting study intervention
* Has received prior radiotherapy within 2 weeks of start of study intervention
* Has received a live or live-attenuated vaccine within 30 days before the first dose of study intervention
* Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks before the first dose of study intervention
* Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication
* Has a known additional malignancy that is progressing or has required active treatment within the past 2 years
* Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis
* Has severe hypersensitivity (≥Grade 3) to pembrolizumab, quavonlimab, favezelimab, vibostolimab, MK-4830, and/or any of their excipients
* Has an active autoimmune disease that has required systemic treatment in past 2 years (i.e., with use of disease modifying agents, corticosteroids or immunosuppressive drugs)
* Has a history of (noninfectious) pneumonitis that required steroids or has current pneumonitis
* Has a history of acute or chronic pancreatitis
* Has neuromuscular disorders associated with an elevated creatine kinase
* Has urine protein ≥1 gram/24 hours
* Has an active infection requiring systemic therapy (e.g., tuberculosis, known viral or bacterial infections, etc.)
* Has a known history of Human Immunodeficiency Virus (HIV) infection
* Concurrent active Hepatitis B (defined as Hepatitis B surface antigen \[HBsAg\] positive and/or detectable Hepatitis B Virus \[HBV\] deoxyribonucleic acid \[DNA\]) and Hepatitis C virus (defined as anti-HCV antibody positive and detectable HCV ribonucleic acid \[RNA\] infection
* Has clinically significant cardiac disease, including unstable angina, acute myocardial infarction within 6 months from Day 1 of study intervention administration, or New York Heart Association Class III or IV congestive heart failure. Medically controlled arrhythmia stable on medication is permitted.
* Has present or progressive accumulation of pleural, ascitic, or pericardial fluid requiring drainage or diuretic drugs within 2 weeks before randomization/allocation
* 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 a known psychiatric or substance abuse disorder that would interfere with the participant's ability to cooperate with the requirements of the study
* Has had an allogenic tissue/solid organ transplant
18 Years
ALL
No
Sponsors
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Merck Sharp & Dohme LLC
INDUSTRY
Responsible Party
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Principal Investigators
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Medical Director
Role: STUDY_DIRECTOR
Merck Sharp & Dohme LLC
Locations
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Mid Florida Cancer Center ( Site 1519)
Orange City, Florida, United States
University Cancer & Blood Center, LLC ( Site 1521)
Athens, Georgia, United States
University of Chicago Medical Center-Medicine - Section of Hematology/Oncology - Gastrointestinal P
Chicago, Illinois, United States
Icahn School of Medicine at Mount Sinai ( Site 1528)
New York, New York, United States
Hematology Oncology Associates of Rockland ( Site 1525)
Nyack, New York, United States
UPMC Hillman Cancer Center ( Site 1516)
Pittsburgh, Pennsylvania, United States
The West Clinic, PLLC dba West Cancer Center ( Site 1576)
Germantown, Tennessee, United States
Vanderbilt University Medical Center-Vanderbilt-Ingram Cancer Center ( Site 1509)
Nashville, Tennessee, United States
UT Southwestern Medical Center ( Site 1551)
Dallas, Texas, United States
Baylor Scott & White Medical Center - Temple-Division of Hematology/Oncology ( Site 1549)
Temple, Texas, United States
Northwest Medical Specialties, PLLC ( Site 1546)
Tacoma, Washington, United States
UZ Brussel ( Site 0105)
Brussels, Bruxelles-Capitale, Region de, Belgium
Cliniques universitaires Saint-Luc-Medical Oncology ( Site 0104)
Brussels, Bruxelles-Capitale, Region de, Belgium
Université Catholique de Louvain-Namur - Centre Hospitalier -Oncology ( Site 0102)
Yvoir, Namur, Belgium
UZ Leuven ( Site 0101)
Leuven, Vlaams-Brabant, Belgium
AZ Delta vzw ( Site 0106)
Roeselare, West-Vlaanderen, Belgium
The Moncton Hospital-Oncology ( Site 0307)
Moncton, New Brunswick, Canada
Sunnybrook Research Institute - Odette Cancer Centre ( Site 0316)
Toronto, Ontario, Canada
McGill University Health Centre-CIM - Oncology ( Site 0306)
Montreal, Quebec, Canada
Instituto de Cancerología ( Site 1610)
Medellín, Antioquia, Colombia
Fundación Colombiana de Cancerología Clínica Vida ( Site 1606)
Medellín, Antioquia, Colombia
Clinica de la Costa S.A.S. ( Site 1608)
Barranquilla, Atlántico, Colombia
Clinica Colsanitas S.A, Sede Clínica Universitaria Colombia ( Site 1611)
Bogotá, Bogota D.C., Colombia
Sociedad De Oncologia Y Hematologia Del Cesar-Oncology ( Site 1601)
Valledupar, Cesar Department, Colombia
Oncomédica S.A.S ( Site 1602)
Montería, Departamento de Córdoba, Colombia
Mediservis del Tolima IPS S.A.S ( Site 1609)
Ibagué, Tolima Department, Colombia
CIMCA-Hemato-Oncology ( Site 2101)
San José, Provincia de San José, Costa Rica
Hospital Metropolitano - Sede Lindora-Metropolitano Research Institute Sede Lindora ( Site 2102)
Santa Ana, Provincia de San José, Costa Rica
Rigshospitalet ( Site 1904)
Copenhagen, Capital Region, Denmark
Regionshospitalet Gødstrup ( Site 1901)
Herning, Central Jutland, Denmark
Aalborg Universitetshospital, Syd ( Site 1903)
Aalborg, North Denmark, Denmark
Odense Universitetshospital ( Site 1902)
Odense, Region Syddanmark, Denmark
North Estonia Medical Centre Foundation-Chemotherapy ( Site 2301)
Tallinn, Harju, Estonia
Tartu University Hospital ( Site 2302)
Tartu, Tartu, Estonia
Assistance Publique Hôpitaux de Marseille - Hôpital de la Ti-Service d'Hepato-Gastro-Enterologie et
Marseille, Bouches-du-Rhone, France
Centre Georges François Leclerc ( Site 0506)
Dijon, Cote-d Or, France
CHU Rangueil-Digestive oncology department ( Site 0502)
Toulouse, Haute-Garonne, France
Hopital Claude Huriez - CHU de Lille ( Site 0510)
Lille, Nord, France
Centre Hospitalier Universitaire de Poitiers ( Site 0511)
Poitiers, Vienne, France
Hôpital Saint Antoine-Oncologie médicale ( Site 0508)
Paris, , France
Muenchen Klinik Neuperlach, Klinik fuer Haematologie und Onkologie ( Site 0612)
Munich, Bavaria, Germany
Universitätsklinikum Marburg ( Site 0610)
Marburg, Hesse, Germany
Kliniken Essen-Mitte, Evangelische Huyssens-Stiftung ( Site 0611)
Essen, North Rhine-Westphalia, Germany
Universitaetsklinikum Carl Gustav Carus Dresden-Medical Dept I - Medical Oncology ( Site 0601)
Dresden, Saxony, Germany
Otto-von-Guericke-Universität Magdeburg-Klinik für Gastroenterologie, Hepatologie und Infektiologie
Magdeburg, Saxony-Anhalt, Germany
Charité Universitaetsmedizin Berlin - Campus Mitte ( Site 0604)
Berlin, , Germany
Asklepios Altona-Oncology ( Site 0602)
Hamburg, , Germany
Alexandra General Hospital of Athens-ONCOLOGY DEPT. ( Site 2704)
Athens, Attica, Greece
Evgenidion Hospital ( Site 2702)
Athens, Attica, Greece
University General Hospital of Heraklion-Internal Medicine-Oncology ( Site 2703)
Heraklion, Irakleio, Greece
European Interbalkan Medical Center-Oncology Department ( Site 2701)
Thessaloniki, , Greece
CELAN,S.A ( Site 2202)
Guatemala City, , Guatemala
INTEGRA Cancer Institute-Oncology ( Site 2201)
Guatemala City, , Guatemala
MEDI-K CAYALA ( Site 2205)
Guatemala City, , Guatemala
Centro Regional de Sub Especialidades Médicas SA ( Site 2204)
Quetzaltenango, , Guatemala
Centro Medico Integral De Cancerología (CEMIC) ( Site 2203)
Quetzaltenango, , Guatemala
Pécsi Tudományegyetem Klinikai Központ-Onkoterápiás Intézet ( Site 2009)
Pécs, Baranya, Hungary
Bacs-Kiskun Megyei Korhaz-Onkoradiologiai Kozpont ( Site 2005)
Kecskemét, Bács-Kiskun county, Hungary
Jász-Nagykun-Szolnok Megyei Hetényi Géza Kórház-Onkologiai Kozpont ( Site 2001)
Szolnok, Jász-Nagykun-Szolnok, Hungary
Somogy Megyei Kaposi Mór Oktató Kórház-Oncology center ( Site 2010)
Kaposvár, Somogy County, Hungary
Semmelweis Egyetem-Belgyógyászati és Hematológiai Klinika ( Site 2002)
Budapest, , Hungary
Debreceni Egyetem Klinikai Kozpont-Onkológiai Klinika ( Site 2008)
Debrecen, , Hungary
Fondazione IRCCS Istituto Nazionale dei Tumori-Struttura Complessa Oncologia Medica 1 ( Site 0802)
Milan, Lombardy, Italy
Istituto Nazionale Tumori IRCCS Fondazione Pascale-Department of Abdominal Oncology ( Site 0803)
Napoli, , Italy
Istituto Oncologico Veneto IRCCS ( Site 0804)
Padua, , Italy
Hospital of Lithuanian University of Health Sciences Kauno klinikos ( Site 2402)
Kaunas, Kaunas County, Lithuania
National Cancer Institute ( Site 2401)
Vilnius, Vilniaus Miestas, Lithuania
VILNIUS UNIVERSITY HOSPITAL SANTAROS KLINIKOS ( Site 2403)
Vilnius, , Lithuania
Nederlands Kanker Instituut - Antoni van Leeuwenhoek (NKI-AVL) ( Site 2901)
Amsterdam, North Holland, Netherlands
DOLNOSLASKIE CENTRUM ONKOLOGII PULMONOLOGII I HEMATOLOGII ( Site 0920)
Wroclaw, Lower Silesian Voivodeship, Poland
Luxmed Onkologia sp. z o. o. ( Site 0915)
Warsaw, Masovian Voivodeship, Poland
Narodowy Instytut Onkologii im. Marii Sklodowskiej-Curie - P-Klinika Onkologii i Radioterapii ( Site
Warsaw, Masovian Voivodeship, Poland
Mrukmed-Mrukmed ( Site 0901)
Rzeszów, Podkarpackie Voivodeship, Poland
Szpital Wojewódzki im. Mikoaja Kopernika w Koszalinie-Oddzial Dzienny Chemioterapii ( Site 0903)
Koszalin, West Pomeranian Voivodeship, Poland
Powiatowe Centrum Zdrowia ( Site 0911)
Brzeziny, Łódź Voivodeship, Poland
Spitalul de Oncologie Monza Oncologie Medicala ( Site 2601)
Bucharest, București, Romania
Fundeni Clinical Institute-Medical Oncology ( Site 2603)
Bucharest, București, Romania
Cardiomed SRL Cluj-Napoca ( Site 2602)
Cluj-Napoca, Cluj, Romania
Centrul de Oncologie "Sfântul Nectarie"-Medical Oncology ( Site 2604)
Craiova, Dolj, Romania
Saint-Petersburg City Clinical Oncology Dispensary-Department of chemotherapy ( Site 1001)
Saint Petersburg, Leningradskaya Oblast', Russia
Fed State Budgetary Inst N.N. Blokhin Med Center of Oncology-Clinical Pharmacology and Chemotherapy
Moscow, Moscow, Russia
First Moscow State Medical University I.M. Sechenov-Interhospital Institution Health Management Cl
Moscow, Moscow, Russia
Rostov Cancer Research Institute ( Site 1014)
Rostov-on-Don, Rostov Oblast, Russia
GBUZ SPb CRPCstmc(o) ( Site 1005)
Saint Petersburg, Sankt-Peterburg, Russia
Republican Clinical Oncology Dispensary-Chemotherapy #3 ( Site 1006)
Kazan', Tatarstan, Respublika, Russia
Kyungpook National University Chilgok Hospital-Hematology/oncology ( Site 1103)
Daegu, Taegu-Kwangyokshi, South Korea
Korea University Anam Hospital ( Site 1107)
Seoul, , South Korea
Seoul National University Hospital-Internal Medicine ( Site 1101)
Seoul, , South Korea
Severance Hospital, Yonsei University Health System-Medical oncology ( Site 1104)
Seoul, , South Korea
Asan Medical Center-Department of Oncology ( Site 1105)
Seoul, , South Korea
Samsung Medical Center-Division of Hematology/Oncology ( Site 1102)
Seoul, , South Korea
The Catholic Univ. of Korea Seoul St. Mary's Hospital-Medical Oncology ( Site 1106)
Seoul, , South Korea
Hospital Universitario Marqués de Valdecilla ( Site 1202)
Santander, Cantabria, Spain
Hospital Universitari Vall d'Hebron ( Site 1201)
Barcelona, Catalonia, Spain
HOSPITAL GENERAL UNIVERSITARIO GREGORIO MARAÑON ( Site 1206)
Madrid, Madrid, Comunidad de, Spain
H.R.U Malaga - Hospital General ( Site 1207)
Málaga, Malaga, Spain
COMPLEJO HOSPITALARIO DE NAVARRA-oncologia médica ( Site 1210)
Pamplona, Navarre, Spain
Hospital Universitario Central de Asturias-Medical Oncology ( Site 1203)
Oviedo, Principality of Asturias, Spain
Fundación Instituto Valenciano de Oncología ( Site 1209)
Valencia, Valenciana, Comunitat, Spain
Hospital Clinico San Carlos-Oncology Department ( Site 1204)
Madrid, , Spain
Baskent University Dr. Turgut Noyan Research and Training Center ( Site 1303)
Adana, , Turkey (Türkiye)
Hacettepe Universitesi-oncology hospital ( Site 1301)
Ankara, , Turkey (Türkiye)
Ankara City Hospital-Medical Oncology ( Site 1306)
Ankara, , Turkey (Türkiye)
Istanbul Universitesi Cerrahpasa-Medical Oncology ( Site 1302)
Istanbul, , Turkey (Türkiye)
TC Saglik Bakanligi Goztepe Prof. Dr. Suleyman Yalcin Sehir Hastanesi-oncology ( Site 1305)
Istanbul, , Turkey (Türkiye)
Beatson West of Scotland Cancer Centre-Clinical Trials Unit ( Site 1401)
Glasgow, Glasgow City, United Kingdom
UCLH-Cancer Clinical Trials Unit ( Site 1402)
London-Camden, London, City of, United Kingdom
Velindre Cancer Centre-Research and Development ( Site 1415)
Cardiff, , United Kingdom
University Hospital Coventry & Warwickshire ( Site 1406)
Coventry, , United Kingdom
Countries
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References
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Andre T, Pietrantonio F, Avallone A, Gumus M, Wyrwicz L, Kim JG, Yalcin S, Kwiatkowski M, Lonardi S, Zolnierek J, Odeleye-Ajakaye A, Leconte P, Fogelman D, Kim TW. KEYSTEP-008: phase II trial of pembrolizumab-based combination in MSI-H/dMMR metastatic colorectal cancer. Future Oncol. 2023 Dec;19(37):2445-2452. doi: 10.2217/fon-2022-1105. Epub 2023 Sep 13.
Related Links
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Merck Clinical Trials Information
Plain Language Summary
Other Identifiers
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MK-1308A-008
Identifier Type: OTHER
Identifier Source: secondary_id
2022-502100-70-00
Identifier Type: OTHER
Identifier Source: secondary_id
KEYSTEP-008
Identifier Type: OTHER
Identifier Source: secondary_id
U1111-1283-2434
Identifier Type: REGISTRY
Identifier Source: secondary_id
2020-005114-18
Identifier Type: EUDRACT_NUMBER
Identifier Source: secondary_id
1308A-008
Identifier Type: -
Identifier Source: org_study_id
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