A Phase 3 Study of Pelabresib (DAK539) and Ruxolitinib in Myelofibrosis (MF)
MANIFEST-3
A Phase 3, Randomized, Double-blind, Active-control Study of Pelabresib (DAK539) and Ruxolitinib vs. Placebo and Ruxolitinib in Adult Patients With Myelofibrosis Who Are JAK Inhibitor Naive
3 other identifiers
interventional
460
18 countries
109
Brief Summary
The purpose of this trial is to evaluate whether treatment with pelabresib in combination with ruxolitinib leads to improved clinical outcomes compared to ruxolitinib alone in patients with primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (PPV-MF), or post-essential thrombocythemia myelofibrosis (PET-MF) who have not previously received Janus kinase (JAK) inhibitor therapy.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P50-P75 for phase_3
Started May 2026
Longer than P75 for phase_3
109 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
January 15, 2026
CompletedFirst Posted
Study publicly available on registry
January 22, 2026
CompletedStudy Start
First participant enrolled
May 27, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
May 17, 2028
ExpectedStudy Completion
Last participant's last visit for all outcomes
December 27, 2030
October 2, 2026
September 1, 2026
2 years
January 15, 2026
October 1, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (4)
Number of Participants with Splenic Response (SVR35) by Central Radiology Reads at Week 24 in participants with baseline total symptom score (TSS) ≥ 25
Spleen Response (SVR35) is defined as achieving a reduction of at least 35 percent in spleen volume from baseline to Week 24, as measured by magnetic resonance imaging (MRI) or computed tomography (CT) scan, and assessed by a centralized radiology review in participants with baseline TSS ≥ 25.
Week 24
Absolute change from baseline in total symptom score (TSS) at Week 24 in participants with baseline TSS ≥ 25
Symptom improvement at Week 24 is defined as the absolute change from baseline in the total symptom score (TSS) at Week 24, as measured by the Myelofibrosis Symptom Assessment Form version 4.0 (MFSAF v4.0) in participants with baseline TSS ≥ 25.
Baseline, Week 24
Number of Participants with Splenic Response (SVR35) by Central Radiology Reads at Week 24 in participants with baseline TSS ≥ 15
Spleen Response (SVR35) is defined as achieving a reduction of at least 35 percent in spleen volume from baseline to Week 24, as measured by magnetic resonance imaging (MRI) or computed tomography (CT) scan, and assessed by a centralized radiology review in participants with baseline TSS ≥ 15.
Week 24
Absolute change from baseline in total symptom score (TSS) at Week 24 in participants with baseline TSS ≥ 15
Symptom improvement at Week 24 is defined as the absolute change from baseline in the total symptom score (TSS) at Week 24, as measured by the Myelofibrosis Symptom Assessment Form version 4.0 (MFSAF v4.0) in participants with baseline TSS ≥ 15.
Baseline, Week 24
Secondary Outcomes (24)
Number of Participants with Splenic Response (SVR35) by Central Radiology Reads over time
Week 12, Week 36, Week 48 and every 12 weeks thereafter till End of Study (an average of 3 years)
Absolute change from baseline and percentage change from baseline in spleen volume over time
Baseline, Week 12, Week 24, Week 36, Week 48, and every 12 weeks thereafter till End of Study (an average of 3 years)
Time to first SVR35 response
From date of randomization to the date of first SVR35 response, assessed up to approximately 3 years
Duration of first SVR35 response
From first SVR35 response to loss of response, assessed up to approximately 3 years
Number of Participants with TSS50 response at Week 24
Week 24
- +19 more secondary outcomes
Study Arms (2)
Arm 1: Pelabresib + Ruxolitinib
EXPERIMENTALParticipants in this arm receive pelabresib (DAK539) orally once daily for 14 days of each 21-day cycle, in combination with ruxolitinib, which is taken orally twice daily throughout each cycle. Participants may continue receiving study treatment until they experience unacceptable toxicity, disease progression, or until either the investigator or the participant decides to discontinue treatment.
Arm 2: Placebo + Ruxolitinib
PLACEBO COMPARATORParticipants in this arm receive a matching placebo orally once daily for 14 days of each 21-day cycle, together with ruxolitinib, which is also taken orally twice daily throughout each cycle. Participants may continue receiving study treatment until they experience unacceptable toxicity, disease progression, or until either the investigator or the participant decides to discontinue treatment.
Interventions
Ruxolitinib phosphate tablets
Eligibility Criteria
You may qualify if:
- Participants have diagnosis of primary myelofibrosis (PMF) or post-polycythemia vera myelofibrosis (post-PV MF) or post-essential thrombocythemia myelofibrosis (post-ET MF) according to the International Consensus Classification (ICC) of Myeloid Neoplasms and Acute Leukemias 2022
- DIPSS risk category of intermediate-1, intermediate-2 or high-risk
- Spleen volume ≥ 450 cm3 by CT or MRI scan (local read sufficient if no central read available)
- Have an average TSS of ≥15 within 7 days prior to randomization, using MFSAF v. 4.0 (at least 4 out of 7 TSS assessments required for average calculation)
- Participants with an Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2
- Blasts \<5% in peripheral blood. Assessment of blasts in peripheral blood is mandatory at screening
- Platelet count ≥ 100 x 10\^9/L in the absence of growth factors or transfusions for the previous 4 weeks
You may not qualify if:
- Prior splenectomy at any time or splenic irradiation in the previous 6 months
- Prior hematopoietic cell transplant or participant anticipated to receive a hematopoietic cell transplant within 24 weeks from the date of randomization
- Blasts ≥ 5% in bone marrow if results available at screening or history of accelerated phase (AP) or leukemic transformation
- History of a malignancy (other than MF, PPV-MF or PET-MF) in the past 3 years in need of systemic treatment
- Received any approved or investigational agent other than hydroxyurea or anagrelide for the treatment of MF within 14 days of first dose of study treatment or within 5 half-lives of the approved or investigational agent, whichever is longer
- Prior treatment with any JAK inhibitor or Bromodomain and extraterminal domain (BET) inhibitor
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (111)
Yale University School Of Medicine
New Haven, Connecticut, 06520, United States
Florida Cancer Specialist South Reg
Fort Myers, Florida, 33916, United States
The Anderson Family Cancer Institute
Jupiter, Florida, 33458, United States
Miami NS Ins Baptist Health S FL
Miami, Florida, 33176, United States
Florida Cancer Specialists-North
St. Petersburg, Florida, 33705, United States
Florida Cancer Specialists East
Stuart, Florida, 34994, United States
Winship Cancer Institute of Emory University
Atlanta, Georgia, 30322, United States
Franciscan Health Indianapolis
Indianapolis, Indiana, 42637, United States
American Oncology Partners PA Center for Cancer and Blood Disorders
Bethesda, Maryland, 20817, United States
Summit Medical Group Oncology
Berkeley Heights, New Jersey, 07922, United States
New York Oncology Hematology P C
Albany, New York, 12206, United States
The Ohio State University Comprehensive Cancer Center
Columbus, Ohio, 43221, United States
Texas Oncology PA Dallas Presbyterian Hospital
Dallas, Texas, 75231, United States
MD Anderson Cancer Center
Houston, Texas, 77030, United States
SCRI Texas Oncology Northeast Texas
Tyler, Texas, 75702, United States
Fred Hutch Cancer Research
Seattle, Washington, 98109, United States
Novartis Investigative Site
Buenos Aires, Buenos Aires F.D., 1221, Argentina
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CABA, C1181ACH, Argentina
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Capital Federal, C1114AAN, Argentina
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Córdoba, X5016KEH, Argentina
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Adelaide, South Australia, 5000, Australia
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Clayton, Victoria, 3168, Australia
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Graz, 8036, Austria
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Sankt Pölten, 3100, Austria
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Goiânia, Goiás, 74605-050, Brazil
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Florianópolis, Santa Catarina, 88020-210, Brazil
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Barretos, São Paulo, 14784-400, Brazil
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Hefei, Anhui, 230001, China
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Guangzhou, Guangdong, 510080, China
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Guangzhou, Guangdong, 510515, China
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Wuhan, Hubei, 430022, China
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Wuhan, Hubei, 430030, China
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Nanjing, Jiangsu, 210029, China
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Nantong, Jiangsu, 226000, China
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Nanchang, Jiangxi, 330006, China
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Changchun, Jilin, 130021, China
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Jinan, Shandong, 250012, China
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Yantai, Shandong, 264000, China
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Kunming, Yunnan, 650101, China
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Hangzhou, Zhejiang, 310003, China
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Wenzhou, Zhejiang, 325000, China
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Beijing, 100730, China
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Chongqing, 400016, China
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Fuzhou, 350001, China
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Shanghai, 200025, China
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Shenyang, 110004, China
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Tianjin, 300020, China
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Ostrava, Poruba, 708 52, Czechia
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Brno, 625 00, Czechia
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Hradec Králové, 500 05, Czechia
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Olomouc, 779 00, Czechia
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Brest, 29200, France
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Nîmes, 30029, France
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Poitiers, 86021, France
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Mannheim, Baden-Wurttemberg, 68305, Germany
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Aachen, 52074, Germany
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Aurangabad, Maharashtra, 431005, India
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Pune, Maharashtra, 411006, India
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Rishikesh, Uttarakhand, 249203, India
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Kolkata, West Bengal, 700014, India
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Delhi, 110085, India
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Meldola, FC, 47014, Italy
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Florence, FI, 50134, Italy
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Padova, PD, 35128, Italy
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Roma, RM, 00161, Italy
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Verona, VR, 37134, Italy
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Novara, 28100, Italy
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Kamogawa, Chiba, 2968602, Japan
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Sapporo, Hokkaido, 0030006, Japan
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Kobe, Hyōgo, 6500047, Japan
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Shiwa-Gun, Iwate, 0283695, Japan
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Tsu, Mie-ken, 5148507, Japan
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Bunkyo Ku, Tokyo, 1138431, Japan
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Bunkyo-ku, Tokyo, 1138603, Japan
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Chūō, Yamanashi, 4093898, Japan
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Fukuoka, 8128582, Japan
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Miyazaki, 8891692, Japan
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George Town, Pulau Pinang, 10450, Malaysia
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Kota Kinabalu, Sabah, 88586, Malaysia
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Kuching, Sarawak, 93586, Malaysia
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Johor Bahru, 80100, Malaysia
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Kuala Selangor, 68000, Malaysia
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Katowice, 40-519, Poland
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Lublin, 20-090, Poland
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Skorzewo, 60-185, Poland
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Warsaw, 02-776, Poland
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Wałbrzych, 58-309, Poland
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Suwon, Gyeonggi-do, 16247, South Korea
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Jeonju, Jeollabuk-do, 54907, South Korea
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Seoul, Yangcheon Gu, 07985, South Korea
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Busan, 49241, South Korea
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Seoul, 03080, South Korea
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Seoul, 05505, South Korea
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Seoul, 06351, South Korea
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Seoul, 06591, South Korea
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Barcelona, 08035, Spain
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Las Palmas GC, 35010, Spain
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Basel, 4058, Switzerland
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Bern, 3010, Switzerland
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Geneva, 1211, Switzerland
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Genolier, 1272, Switzerland
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Changhua, 50006, Taiwan
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Kaohsiung City, 80756, Taiwan
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Tainan, 704302, Taiwan
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Taipei, 10002, Taiwan
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Istanbul, Fatih, 34098, Turkey (Türkiye)
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Ankara, Sihhiye Altindag, 06230, Turkey (Türkiye)
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Ankara, 06000, Turkey (Türkiye)
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Izmir, 35060, Turkey (Türkiye)
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Kocaeli, 41380, Turkey (Türkiye)
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Samsun, 55200, Turkey (Türkiye)
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Study Officials
- STUDY DIRECTOR
Novartis Pharmaceuticals
Novartis Pharmaceuticals
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 3
- Allocation
- RANDOMIZED
- Masking
- QUADRUPLE
- Who Masked
- PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
January 15, 2026
First Posted
January 22, 2026
Study Start
May 27, 2026
Primary Completion (Estimated)
May 17, 2028
Study Completion (Estimated)
December 27, 2030
Last Updated
October 2, 2026
Record last verified: 2026-09
Data Sharing
- IPD Sharing
- Will share
Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations. This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com