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CompletedNCT02158858Updated Jun 4, 2026Results posted

A Phase 1/2 Study of CPI-0610 With and Without Ruxolitinib in Patients With Hematologic and Myeloproliferative Malignancies

A Phase 1/2 interventional study of Pelabresib and Ruxolitinib in Myelofibrosis, Leukemia, Myelocytic, Acute and Myelodysplastic/Myeloproliferative Neoplasm, sponsored by Constellation Pharmaceuticals. Completed at 48 sites in 9 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-04.

Sponsored by Constellation Pharmaceuticals · Phase 1/2, Interventional, and Treatment

Phase
Phase 1/2
Study type
Interventional
Enrollment
336
Allocation
Non-randomized
Ages
18 Years and older
Sex
All
01

Study summary

Phase 1 Part: This was an open-label, sequential dose escalation study of pelabresib (CPI-0610) in patients who had previously been treated for Acute Leukemia, Myelodysplastic/Myeloproliferative Neoplasms.

Phase 2 Part: This was an open-label study of pelabresib (CPI-0610), administered with and without Ruxolitinib, in patients diagnosed with Myeloproliferative Neoplasms (Myelofibrosis and Essential Thrombocythemia).

Pelabresib (CPI-0610) was a small molecule inhibitor of bromodomain and extra-terminal (BET) proteins.

02

Conditions studied

  • Myelofibrosis
  • Leukemia, Myelocytic, Acute
  • Myelodysplastic/Myeloproliferative Neoplasm
  • Myelodysplastic Syndrome (MDS)
  • Preleukemia
  • Primary Myelofibrosis
  • Myeloproliferative Disorders
  • Bone Marrow Disease
  • Hematological Disease
  • Precancerous Conditions
  • Neoplasms
  • Leukemia
  • Neoplasms by Histologic Type
  • Essential Thrombocytosis

Keywords

  • Phase 1
  • Phase 2
  • Oncology
  • BET Inhibitor
  • Ruxolitinib
  • Pelabresib (CPI-0610)
03

Who can participate

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

Eligibility criteria

Phase I (Dose Escalation) - Inclusion and Exclusion Criteria:

  1. Inclusion Criteria (Phase I):

    • Age: Adults ≥18 years.
    • Diagnosis: Histologically or cytologically confirmed diagnosis of one of the following hematologic malignancies:

      • Acute myelogenous leukemia (AML)
      • Acute lymphocytic leukemia (ALL)
      • Acute undifferentiated or biphenotypic leukemia
      • Chronic myeloid leukemia (CML) in blast crisis
      • Myelodysplastic syndrome (MDS)
      • Myelodysplastic/myeloproliferative neoplasms (MDS/MPN)
      • Myelofibrosis (MF)
    • Performance Status: ECOG ≤2.
    • Organ Function:

      • Serum total bilirubin ≤1.5 × ULN
      • AST/ALT ≤2.5 × ULN (up to 5 × ULN if due to leukemic infiltration)
      • Serum creatinine ≤2.0 × ULN or CrCl ≥30 mL/min
    • Hematology (MF only):

      • Platelet count ≥50 × 10⁹/L and ANC ≥1 × 10⁹/L (MF not on ruxolitinib)
      • Platelet count ≥75 × 10⁹/L and ANC ≥1 × 10⁹/L (MF on ruxolitinib)
    • Other:

      • DIPSS-plus risk category of intermediate-2 or high (MF only)
      • Serum glucose ≤160 mg/dL (or HbA1C ≤7%)
      • Fully recovered from major surgery and acute toxic effects of prior therapy
      • Negative pregnancy test for women of childbearing potential
      • Agreement to use appropriate contraception
      • Written informed consent
  2. Exclusion Criteria (Phase I):

    • Untreated newly diagnosed acute leukemia (unless AML with myelodysplasia-related changes and 20-30% blasts)
    • Relapsed/refractory acute leukemia where further induction chemotherapy is beneficial
    • Acute leukemia relapse \<6 months after allogeneic SCT
    • CML in blast crisis treated with only one TKI
    • Very low/low risk MDS without prior treatment
    • CNS involvement by leukemia (unless resolved)
    • Active HIV, Hepatitis B or C infection
    • GI impairment affecting absorption (unresolved nausea, vomiting, diarrhea >CTCAE grade 1)
    • Significant cardiac disease (recent MI/angina, high cTn, QTcF >470 ms, LVEF \<50%, uncontrolled arrhythmia, etc.)
    • Severe/uncontrolled comorbidities
    • Recent systemic anti-cancer therapy (other than hydroxyurea/radiotherapy) \<2 weeks prior
    • Ongoing or recent JAK inhibitor use (\<2 weeks prior, MF only)
    • Recent therapeutic antibody (\<4 weeks) or investigational agent (\<2 weeks or \<5 half-lives)
    • Use of strong CYP450 inhibitors/inducers or drugs with Torsades de Pointes risk
    • Immunosuppressive treatment that cannot be discontinued
    • Pregnant/lactating women
    • Inadequate contraception
    • Inability/unwillingness to comply with protocol

Phase II (Expansion) - Inclusion \& Exclusion Criteria:

  1. Inclusion Criteria (Phase II):

    1. MF Arms (Prior JAKi, Add-on JAKi, JAKi Naïve)

      • Age: Adults ≥18 years
      • Diagnosis: Confirmed primary MF or MF evolved from ET or PV
      • Risk: DIPSS intermediate-2 or higher
      • Platelets:

        • ≥75 × 10⁹/L (Arms 1 \& 2)
        • ≥100 × 10⁹/L (Arm 3, JAKi naïve)
      • ANC: ≥1 × 10⁹/L
      • Spleen Volume: ≥450 cm³ by MRI/CT (non-TD cohorts) OR
      • Transfusion Dependence: Average ≥2 RBC transfusions/month (total ≥6 in prior 12 weeks) for TD cohorts
      • Peripheral Blood Blasts: \<10%
      • Symptoms: At least 2 symptoms measurable (score ≥1 for Arms 1 \& 2; score ≥3 or total ≥10 for Arm 3) using MFSAF v4.0
      • Treatment History:

        • Arm 1 (Prior JAKi): Previously treated with JAKi and intolerant, resistant, refractory, or lost response, or ineligible for JAKi
        • Arm 2 (Add-on JAKi): On ruxolitinib ≥6 months, stable dose ≥8 weeks, not adequately controlled
        • Arm 3 (JAKi Naïve): No prior JAKi, eligible for ruxolitinib
      • Performance Status: ECOG ≤2
      • Organ Function: Serum direct bilirubin \<2 × ULN, AST/ALT ≤2.5 × ULN (up to 5 × ULN if due to liver involvement), CrCl ≥45 mL/min
      • Other: Fully recovered from major surgery/acute toxic effects, effective contraception, written informed consent
    2. ET Arm (High-Risk ET)

      • Age: Adults ≥18 years
      • Diagnosis: Confirmed ET (WHO 2016 criteria)
      • High-Risk: At least one of:

        • Age >60 years
        • Platelets >1500 × 10⁹/L
        • Prior thrombosis, erythromelalgia, or migraine (disease-related)
        • Prior hemorrhage related to ET
        • Diabetes/hypertension requiring therapy >6 months
      • Symptoms: ≥2 symptoms with average score ≥3 or total score ≥15 (MPN-SAF)
      • Platelets: >600 × 10⁹/L
      • Resistant/Intolerant to HU: As defined by ELN
      • Performance Status: ECOG ≤2
      • Life Expectancy: >24 weeks
      • ANC: ≥1 × 10⁹/L
      • Organ Function: Serum direct bilirubin \<2 × ULN, AST/ALT ≤2.5 × ULN, CrCl ≥45 mL/min
      • Other: Fully recovered from major surgery/acute toxic effects, effective contraception, written informed consent
  2. Exclusion Criteria (Phase II)

    • Prior splenectomy (MF non-TD cohorts)
    • Splenic irradiation within 3 months
    • Active or chronic HIV, Hepatitis B/C infection
    • Active clinically significant infection (until recovery ≥2 weeks)
    • Anemia deemed clinically significant (iron/B12/folate deficiency, hemolytic anemia)
    • Major bleeding event (≥2 g/dL Hgb drop or ≥2 units transfused in last 6 months)
    • Liver cirrhosis Child-Pugh B or C
    • GI impairment affecting absorption (unresolved nausea, vomiting, diarrhea >CTCAE grade 1)
    • Rare hereditary problems of galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption (Arm 3)
    • Hypersensitivity to ruxolitinib formulation (Arm 3)
    • History of PML (Arm 3)
    • Significant cardiac disease (recent MI/angina, QTcF >500 ms [>450 ms in France/Germany], uncontrolled arrhythmia, etc.)
    • Ongoing uncontrolled hypertension
    • Severe/uncontrolled comorbidities
    • Systemic anticancer treatment (other than ruxolitinib for Arm 2, HU/ANA up to 24h prior) \<2 weeks or \<5 half-lives prior
    • Prior treatment with any BET inhibitor
    • Hematopoietic growth factor or androgenic steroids \<4 weeks prior
    • Systemic corticosteroids ≥10 mg prednisone equivalent within 4 weeks (exceptions for short courses)
    • Concurrent/second malignancy (except certain adequately treated cancers)
    • Pregnant/lactating women, or planning pregnancy within protocol-defined window
    • Inability/unwillingness to comply with protocol
04

Study design

Phase
Phase 1 / Phase 2
Primary purpose
Treatment
Allocation
Non-randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
336 participants (actual)

Study arms

  • Experimental
    Phase 1

    Patients were enrolled in sequential cohorts (acute leukemia, including acute myelogenous leukemia (AML), acute lymphocytic leukemia (ALL), and acute undifferentiated or biphenotypic leukemia; chronic myelogenous leukemia (CML) in blast crisis; myelodysplastic syndrome (MDS); myelodysplastic/myeloproliferative neoplasms (MDS/MPN); or myelofibrosis (MF)) and received escalating doses of pelabresib (CPI-0610).

    Drug: Pelabresib

  • Experimental
    Phase 2 (Arm 1): Prior JAKi Monotherapy Arm (MF patients treated with pelabresib alone)

    * Cohort 1A: Was open to patients with MF who were Transfusion Dependent (TD) and who had previously been treated with a JAKi and were intolerant, resistant, refractory, or had lost response to the JAKi, or were ineligible to be treated with a JAKi (pelabresib (CPI-0610) alone). * Cohort 1B: Was open to patients with MF who were not TD and who had previously been treated with a JAKi and were intolerant, resistant, refractory, or had lost response to the JAKi, or were ineligible to be treated with a JAKi (pelabresib (CPI-0610) alone).

    Drug: Pelabresib

  • Experimental
    Phase 2 (Arm 2): Prior JAKi Combination Arm

    * Cohort 2A: Was open to patients with MF who were Transfusion Dependent (TD) and were taking ruxolitinib but had disease that was not adequately controlled by ruxolitinib (pelabresib (CPI-0610) + Ruxolitinib). * Cohort 2B: Was open to patients with MF who were not TD and were taking ruxolitinib but had disease that was not adequately controlled by ruxolitinib (pelabresib (CPI-0610) + Ruxolitinib).

    Drug: Pelabresib · Drug: Ruxolitinib

  • Experimental
    Phase 2 (Arm 3): JAKi Naïve Combination Arm

    Was open to patients with MF who had not previously received a JAKi (pelabresib (CPI-0610) + Ruxolitinib).

    Drug: Pelabresib · Drug: Ruxolitinib

  • Experimental
    Phase 2 (Arm 4): Essential Thrombocythemia (ET) Monotherapy Arm

    Was open to high-risk patients with ET who were resistant or intolerant to hydroxyurea (HU) (pelabresib (CPI-0610) alone).

    Drug: Pelabresib

Interventions

  • DrugPelabresib

    CPI-0610 was administered orally once daily for 14 consecutive days, followed by a 7-day break (1 cycle = 21 days)

    Also known as: CPI-0610, DAK539

  • DrugRuxolitinib

    Ruxolitinib was given orally, twice daily (BID), on a continuous basis for 21 consecutive days of each 21-day cycle.

05

What researchers measure

Primary outcomes

  1. Phase 1: Frequency of Dose-limiting Toxicities (DLTs)

    A dose-limiting toxicity (DLT) was defined as an adverse event or abnormal laboratory value assessed by the Investigator as unrelated to disease progression, intercurrent illness, or concomitant medications that occurred within the first cycle of treatment (21-day cycle) with pelabresib (CPI-0610), and that met any of the criteria specified in the protocol.

    Time frame: Up to 21 days

  2. Phase 2 (Cohorts 1B, 2B, and Arm 3): Number of Participants With Splenic Response Rate (SVR35) at Week 24

    Splenic Response Rate (SVR35) at Week 24 was defined as the proportion of participants who demonstrated a reduction of at least 35% in spleen size from baseline, as measured by imaging techniques (MRI or CT), following 24 weeks of treatment.

    Time frame: Week 24 (Cycle 9 Day 1)

  3. Phase 2 (Cohorts 1A and 2A): Number of Participants Enrolled as Transfusion Dependent (TD) With Conversion Rate From Red Blood Cell (RBC) Transfusion Dependence (TD) to Transfusion Independence (TI)

    Conversion rate was defined as the proportion of participants who converted from transfusion dependence (TD) to transfusion independence (TI). TD was characterized by receiving an average of at least 2 units of red blood cell (RBC) transfusions per month-amounting to a minimum of 6 units over the 12 weeks prior to enrollment-while TI was defined as the absence of RBC transfusions during any consecutive 12-week period.

    Time frame: Any 12 consecutive weeks (rolling window) during active treatment with pelabresib (CPI-0610), from first dose through treatment discontinuation (up to approximately 8 years for Phase II)

  4. Phase 2 (Arm 4): Number of Participants With Complete Hematological Response (CHR) Rate

    Complete Hematological Response (CHR) Rate was defined as the proportion of participants who fulfilled the criteria for CHR, based on the modified European LeukemiaNet (ELN) guidelines (Barosi et al 2009): platelet count ≤400 × 10⁹/L, white blood cell (WBC) count ≤10 × 10⁹/L, confirmation of laboratory values after one treatment cycle, and normal spleen size determined by palpation or imaging.

    Time frame: Over 2 consecutive cycles (rolling window) (1 cycle = 21 days)

Secondary outcomes

  1. Phase 1: Number of Adverse Events and Serious Adverse Events as Assessed by CTCAE Criteria

    The distribution of adverse events was performed through the analysis of frequencies for treatment-emergent adverse events (TEAEs) and serious adverse events (TESAEs), based on the monitoring of relevant clinical and laboratory safety parameters. Treatment-emergent adverse events (TEAEs) in this study were defined as events that began after the first dose of study treatment and continued until 30 days after the last dose, or events that were present prior to the first dose and increased in severity based on preferred term within 30 days following the last dose of pelabresib (CPI-0610).

    Time frame: Up to approximately 6 months

  2. Phase 2 (All Arms): Number of Adverse Events and Serious Adverse Events as Assessed by CTCAE Criteria

    The distribution of adverse events was performed through the analysis of frequencies for treatment-emergent adverse events (TEAEs) and serious adverse events (TESAEs), based on the monitoring of relevant clinical and laboratory safety parameters. Treatment-emergent adverse events (TEAEs) in this study were defined as events that began after the first dose of study treatment and continued until 30 days after the last dose, or events that were present prior to the first dose and increased in severity based on preferred term within 30 days following the last dose of pelabresib (CPI-0610).

    Time frame: Up to approximately 387 weeks

  3. Phase 2 (All Arms): Symptom Improvement From the Patient Global Impression of Change (PGIC) at 12 and 24 Weeks

    The Patient Global Impression of Change (PGIC) was a single-question, patient-reported assessment that asked individuals to rate their overall change in myeloproliferative neoplasm (MPN) symptoms since starting study treatment. The participants selected one of seven options, ranging from 'Very much improved' to 'Very much worse'. 'No Change from Baseline' indicated stable symptoms (no improvement or worsening), negative change from Baseline indicated a reduction in symptom severity (improvement), and positive change from Baseline indicated an increase in symptom severity (worsening).

    Time frame: Week 12 (Cycle 5 Day 1), Week 24 weeks (Cycle 9 Day 1)

  4. Phase 2 (Arms 1, 2 and 3): Percent Change From Baseline in Total Symptom Score (TSS) From the Myelofibrosis Symptom Assessment Form (MFSAF v4.0) at 12 and 24 Weeks

    The MFSAF (Myelofibrosis Symptom Assessment Form) was completed by participants every day for 7 days before Day 1 of each treatment cycle, including the 7 days before starting Cycle 1. It used a 24-hour recall format, asking participants to rate the worst severity of seven symptoms (fatigue, night sweats, pruritus, abdominal discomfort, pain under the ribs on the left side, early satiety, and bone pain) during the past 24 hours. Each symptom was rated on a scale from 0 (Absent) to 10 (Worst Imaginable). The Total Symptom Score (TSS) was the sum of 7 symptoms (range: 0-70). 'No Change from Baseline' indicated stable symptoms (no improvement or worsening), negative change from Baseline indicated a reduction in symptom severity (improvement), and positive change from Baseline indicated an increase in symptom severity (worsening).

    Time frame: Baseline, Week 12 (Cycle 5 Day 1), Week 24 (Cycle 9 Day 1)

  5. Phase 2 (Arms 1, 2 and 3): Number of Participants Who Achieved a ≥ 50% Reduction in Total Symptom Score (TSS) at 12 and 24 Weeks

    The proportion of study participants who experienced a reduction of at least 50% in their Total Symptom Score (TSS), as assessed using the Myelofibrosis Symptom Assessment Form (MFSAF v4.0), was evaluated at both 12 and 24 weeks relative to their baseline score.

    Time frame: Week 12 (Cycle 5 Day 1), Week 24 (Cycle 9 Day 1)

  6. Phase 2 (Arms 1, 2 and 3): Number of Participants With Overall Splenic Response Rate (Overall SVR35)

    Overall Splenic Response Rate (SVR35) was defined as the proportion of participants who achieved a reduction of at least 35% in spleen size from baseline, as measured by imaging (MRI or CT), at any point between Cycle 1 Day 1 and the End of Study Visit, whichever occurred first.

    Time frame: Through Phase II completion, an average of 6 years

  7. Phase 2 (Arms 1, 2 and 3): Duration of Overall Splenic Response (Overall SVR35)

    Duration of Overall Splenic Response (overall SVR35) was defined as the time from the first occurrence of a at least 35% reduction in spleen volume from baseline until the earliest of the following: a reduction of less than 35% from baseline combined with an increase of more than 25% from the nadir in spleen volume (as measured by MRI or CT), or death. The nadir was defined as the lowest spleen volume recorded after baseline and up to the evaluation point at which the initial splenic response was achieved.

    Time frame: From first onset of splenic response until loss of response, assessed up to approximately 6 years

  8. Phase 2 (Cohorts 1A and 2A): Number of Participants With Splenic Response Rate (SVR35) at 12 and 24 Weeks

    Splenic Response Rate (SVR35) at 12 and 24 weeks was defined as the proportion of participants who achieved a reduction of at least 35% in spleen size from baseline, as determined by imaging (MRI or CT), following 12 and 24 weeks of treatment, respectively.

    Time frame: Week 12 (Cycle 5 Day 1), Week 24 weeks (Cycle 9 Day 1)

  9. Phase 2 (Cohorts 1A and 2A): Duration of Red Blood Cell (RBC) Transfusion Independence (TI) in Participants Who Enroll as Transfusion Dependent (TD)

    Duration of Red Blood Cell (RBC) Transfusion Independence (TI) was defined as the longest continuous period during which participants, having achieved at least 12 weeks of transfusion independence, remained free from RBC transfusions.

    Time frame: From first onset of TI to earliest onset of loss of TI, assessed up to approximately 6 years

  10. Phase 2 (Cohorts 1A and 2A): Early Anemic Response Rate in Participants Who Enroll as Transfusion Dependent (TD)

    Early anemic response rate was defined as the proportion of participants who achieved an average increase of at least 1 g/dL in hemoglobin concentration over any rolling 8-week (56-day) period following baseline. This calculation was performed after applying the 14/3 day rule, which stipulates that hemoglobin measurements must be spaced at least 14 days apart, and that at least 3 such measurements are required within the 8-week window to ensure a reliable average. Importantly, this increase had to occur without any red blood cell (RBC) transfusions during the treatment period and up to the time of the latest hemoglobin assessment for each patient.

    Time frame: Through Phase II completion, an average of 6 years

  11. Phase 2 (Cohorts 1B, 2B, and Arm 3): Number of Participants With Splenic Response Rate (SVR35) at 12 Weeks

    Splenic Response Rate (SVR35) at Week 12 was defined as the proportion of participants who achieved a reduction of at least 35% in spleen size from baseline, as measured by imaging (MRI or CT), following 12 weeks of treatment.

    Time frame: Week 12 (Cycle 5 Day 1)

  12. Phase 2 (Cohorts 1B, 2B, and Arm 3): Anemic Response Rate in Participants Who Enroll as Non-transfusion-dependent (Non-TD)

    Anemic response was defined as a sustained average increase in hemoglobin concentration of at least 1.5 g/dL over any rolling 12-week (84-day) period following baseline. This calculation excluded periods involving red blood cell (RBC) transfusions and was performed after applying the 14/3-day rule for valid hemoglobin assessments. The response had to be maintained through to the most recent available hemoglobin measurement for each patient.

    Time frame: Through Phase II completion, an average of 6 years

  13. Phase 2 (Arm 4): Percentage of Participants Who Achieve a ≥50% Reduction From Baseline in the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) Total Score

    The Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) is a patient-reported questionnaire designed to measure symptom burden in participants with myeloproliferative neoplasms (MPNs). Participants rate the severity of several symptoms (such as fatigue, night sweats, itching, abdominal discomfort, bone pain, early satiety, and others) over the past 24 hours. Each symptom is scored on a scale from 0 (absent/as good as it can be) to 10 (worst imaginable/as bad as it can be). The total score is the sum of all individual symptom scores, providing an overall measure of symptom burden. A 50% reduction in the MPN-SAF total score at 12 or 24 weeks means the patient's overall symptom burden has improved by half compared to their baseline (pre-treatment) score.

    Time frame: Baseline, 12 weeks (Cycle 5, Day 1), 24 weeks (Cycle 9, Day 1)

  14. Phase 2 (Arm 4): Partial Hematological Response Rate (PHR)

    Partial Hematological Response Rate (PHR) was defined as the proportion of participants who met the following criteria over two consecutive cycles up to the last administration of study treatment: * Platelet count \> 400-600 x 10\^9/L * WBC count within normal range (i.e., ≤ 10 x 10\^9/L) * Laboratory results confirmed after 1 cycle (after 3weeks)

    Time frame: Over 2 consecutive cycles (rolling window) (1 cycle = 21 days)

  15. Phase 2 (Arm 4): Overall Hematological Response Rate (OHR)

    Confirmed Overall Hematological Response (OHR) Rate was defined as the proportion of participants with either a confirmed complete or a partial hematological response at any time.

    Time frame: Through Phase II completion, an average of 6 years

  16. Phase 2 (Arm 4): Duration of Overall Hematological Response Rate (OHR)

    Duration of Overall Hematological Response (OHR) Rate was defined as the time from when the overall hematological response was first met until the time at which the overall hematological response was lost, i.e., the criteria for an overall hematological response (CHR or PHR) were not observed or death occurred, whichever came first.

    Time frame: Through Phase II completion, an average of 6 years

  17. Phase 2 (Arm 4): Rate of Hemorrhagic and Thromboembolic (TE) Events

    Rate of hemorrhagic and thromboembolic (TE) events was defined as the proportion of participants with hemorrhagic or thromboembolic events throughout the study.

    Time frame: Through Phase II completion, an average of 6 years

  18. Phase 2 (All Arms): Maximum Observed Plasma Concentration (Cmax) of Pelabresib

    Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. Cmax was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  19. Phase 2 (All Arms): Time to Reach Maximum Concentration (Tmax) of Pelabresib

    Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. Tmax was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (predose, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  20. Phase 2 (All Arms): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Pelabresib

    Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. Ctrough was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (predose, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  21. Phase 2 (All Arms): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Pelabresib

    Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. AUClast was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  22. Phase 2 (All Arms): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Pelabresib

    Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. AUC0-8,ss was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  23. Phase 2 (All Arms): Time of Last Measurable Concentration (Tlast) of Pelabresib

    Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. Tlast was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  24. Phase 2 (Arm 2 - Cohort 2A): Maximum Observed Plasma Concentration (Cmax) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Cmax was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  25. Phase 2 (Arm 2 - Cohort 2A): Time to Reach Maximum Concentration (Tmax) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Tmax was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  26. Phase 2 (Arm 2 - Cohort 2A): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Ctrough was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (predose, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  27. Phase 2 (Arm 2 - Cohort 2A): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUClast was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  28. Phase 2 (Arm 2 - Cohort 2A): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUC0-8,ss was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  29. Phase 2 (Arm 2 - Cohort 2B): Maximum Observed Plasma Concentration (Cmax) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Cmax was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  30. Phase 2 (Arm 2 - Cohort 2B): Time to Reach Maximum Concentration (Tmax) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Tmax was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  31. Phase 2 (Arm 2 - Cohort 2B): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Ctrough was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  32. Phase 2 (Arm 2 - Cohort 2B): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUClast was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  33. Phase 2 (Arm 2 - Cohort 2B): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUC0-8,ss was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  34. Phase 2 (Arm 3): Maximum Observed Plasma Concentration (Cmax) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Cmax was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  35. Phase 2 (Arm 3): Time to Reach Maximum Concentration (Tmax) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Tmax was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  36. Phase 2 (Arm 3): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Ctrough was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (predose, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  37. Phase 2 (Arm 3): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUClast was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

  38. Phase 2 (Arm 3): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Ruxolitinib

    Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUC0-8,ss was listed and summarized using descriptive statistics.

    Time frame: Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.

06

Results

Posted Jun 4, 2026

Participant flow

This study was conducted at 54 centers across 9 countries (Belgium, Canada, France, Germany, Italy, Netherlands, Poland, United Kingdom, United States)

Participant flow — Overall Study
MilestonePhase 1 (24 mg Capsule PO Daily)Phase 1 (48 mg Capsule PO Daily)Phase 1 (120 mg Capsule PO Daily)Phase 1 (170 mg Capsule PO Daily)Phase 1 (230 mg Capsule PO Daily)Phase 1 (300 mg Capsule PO Daily)Phase 1 (400 mg Capsule PO Daily)Phase 1 (225 mg Tablet PO Daily)Phase 1 (275 mg Tablet PO Daily)Phase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Started355334786485259288421
Completed000000000000000
Not completed355334786485259288421
Withdrew: Disease progression13323231059137121
Withdrew: Adverse event011102131107176144
Withdrew: Withdrawal by subject1110001325863104
Withdrew: Death000000011434180
Withdrew: Other protocol defined stopping criteria100000100210230
Withdrew: Physician decision0000001022013146103
Withdrew: Transitioned to pelabresib extension study0000000002730149
Withdrew: Cell transplant0000000000423130

Outcome measures

PrimaryPhase 1: Frequency of Dose-limiting Toxicities (DLTs)

A dose-limiting toxicity (DLT) was defined as an adverse event or abnormal laboratory value assessed by the Investigator as unrelated to disease progression, intercurrent illness, or concomitant medications that occurred within the first cycle of treatment (21-day cycle) with pelabresib (CPI-0610), and that met any of the criteria specified in the protocol.

Time frame:
Up to 21 days
Reported as:
Count of participants · Participants
Phase 1: Frequency of Dose-limiting Toxicities (DLTs)
ParticipantsPhase 1 (24 mg Capsule PO Daily)Phase 1 (48 mg Capsule PO Daily)Phase 1 (120 mg Capsule PO Daily)Phase 1 (170 mg Capsule PO Daily)Phase 1 (230 mg Capsule PO Daily)Phase 1 (300 mg Capsule PO Daily)Phase 1 (400 mg Capsule PO Daily)Phase 1 (225 mg Tablet PO Daily)Phase 1 (275 mg Tablet PO Daily)
Phase 1: Frequency of Dose-limiting Toxicities (DLTs)000000124
PrimaryPhase 2 (Cohorts 1B, 2B, and Arm 3): Number of Participants With Splenic Response Rate (SVR35) at Week 24

Splenic Response Rate (SVR35) at Week 24 was defined as the proportion of participants who demonstrated a reduction of at least 35% in spleen size from baseline, as measured by imaging techniques (MRI or CT), following 24 weeks of treatment.

Time frame:
Week 24 (Cycle 9 Day 1)
Reported as:
Number · Percentage of Participants
Phase 2 (Cohorts 1B, 2B, and Arm 3): Number of Participants With Splenic Response Rate (SVR35) at Week 24
Percentage of ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Phase 2 (Cohorts 1B, 2B, and Arm 3): Number of Participants With Splenic Response Rate (SVR35) at Week 2419.2 (9.6 to 32.5)21.4 (8.3 to 41.0)67.9 (56.8 to 77.6)
PrimaryPhase 2 (Cohorts 1A and 2A): Number of Participants Enrolled as Transfusion Dependent (TD) With Conversion Rate From Red Blood Cell (RBC) Transfusion Dependence (TD) to Transfusion Independence (TI)

Conversion rate was defined as the proportion of participants who converted from transfusion dependence (TD) to transfusion independence (TI). TD was characterized by receiving an average of at least 2 units of red blood cell (RBC) transfusions per month-amounting to a minimum of 6 units over the 12 weeks prior to enrollment-while TI was defined as the absence of RBC transfusions during any consecutive 12-week period.

Time frame:
Any 12 consecutive weeks (rolling window) during active treatment with pelabresib (CPI-0610), from first dose through treatment discontinuation (up to approximately 8 years for Phase II)
Reported as:
Number · Percentage of Participants
Phase 2 (Cohorts 1A and 2A): Number of Participants Enrolled as Transfusion Dependent (TD) With Conversion Rate From Red Blood Cell (RBC) Transfusion Dependence (TD) to Transfusion Independence (TI)
Percentage of ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A
Phase 2 (Cohorts 1A and 2A): Number of Participants Enrolled as Transfusion Dependent (TD) With Conversion Rate From Red Blood Cell (RBC) Transfusion Dependence (TD) to Transfusion Independence (TI)25.6 (13.5 to 41.2)26.1 (14.3 to 41.1)
PrimaryPhase 2 (Arm 4): Number of Participants With Complete Hematological Response (CHR) Rate

Complete Hematological Response (CHR) Rate was defined as the proportion of participants who fulfilled the criteria for CHR, based on the modified European LeukemiaNet (ELN) guidelines (Barosi et al 2009): platelet count ≤400 × 10⁹/L, white blood cell (WBC) count ≤10 × 10⁹/L, confirmation of laboratory values after one treatment cycle, and normal spleen size determined by palpation or imaging.

Time frame:
Over 2 consecutive cycles (rolling window) (1 cycle = 21 days)
Reported as:
Number · Percentage of Participants
Phase 2 (Arm 4): Number of Participants With Complete Hematological Response (CHR) Rate
Percentage of ParticipantsPhase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (Arm 4): Number of Participants With Complete Hematological Response (CHR) Rate57.1 (34.0 to 78.2)
SecondaryPhase 1: Number of Adverse Events and Serious Adverse Events as Assessed by CTCAE Criteria

The distribution of adverse events was performed through the analysis of frequencies for treatment-emergent adverse events (TEAEs) and serious adverse events (TESAEs), based on the monitoring of relevant clinical and laboratory safety parameters. Treatment-emergent adverse events (TEAEs) in this study were defined as events that began after the first dose of study treatment and continued until 30 days after the last dose, or events that were present prior to the first dose and increased in severity based on preferred term within 30 days following the last dose of pelabresib (CPI-0610).

Time frame:
Up to approximately 6 months
Reported as:
Count of participants · Participants
Phase 1: Number of Adverse Events and Serious Adverse Events as Assessed by CTCAE Criteria
ParticipantsPhase 1 (24 mg Capsule PO Daily)Phase 1 (48 mg Capsule PO Daily)Phase 1 (120 mg Capsule PO Daily)Phase 1 (170 mg Capsule PO Daily)Phase 1 (230 mg Capsule PO Daily)Phase 1 (300 mg Capsule PO Daily)Phase 1 (400 mg Capsule PO Daily)Phase 1 (225 mg Tablet PO Daily)Phase 1 (275 mg Tablet PO Daily)
Participants with at least 1 TEAE355334786
Participants with ≥ Grade 3 TEAEs243324786
Participants with any drug-related TEAE335333675
Participants with any drug-related TEAEs of ≥ CTCAE Grade 3111000534
Participants with any serious TEAEs143124666
Participants with any drug-related serious TEAEs001000103
Participants with any TEAEs leading to drug discontinuation022102243
SecondaryPhase 2 (All Arms): Number of Adverse Events and Serious Adverse Events as Assessed by CTCAE Criteria

The distribution of adverse events was performed through the analysis of frequencies for treatment-emergent adverse events (TEAEs) and serious adverse events (TESAEs), based on the monitoring of relevant clinical and laboratory safety parameters. Treatment-emergent adverse events (TEAEs) in this study were defined as events that began after the first dose of study treatment and continued until 30 days after the last dose, or events that were present prior to the first dose and increased in severity based on preferred term within 30 days following the last dose of pelabresib (CPI-0610).

Time frame:
Up to approximately 387 weeks
Reported as:
Count of participants · Participants
Phase 2 (All Arms): Number of Adverse Events and Serious Adverse Events as Assessed by CTCAE Criteria
ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Participants with at least 1 TEAE485159288421
Participants with ≥ Grade 3 TEAEs384049216610
Participants with at least 1 TEAE related to pelabresib454453277420
Participants with ≥ Grade 3 TEAEs related to pelabresib27213314416
Participants with any serious TEAEs18232918405
Participants with any serious TEAEs related to pelabresib4326162
Participants with any TEAEs leading to interruption of pelabresib20163213399
Participants with any TEAEs leading in reduction of pelabresib1610157386
Participants with any TEAEs leading to discontinuation of pelabresib1212177223
Participants with any TEAEs leading to study discontinuation1111189225
SecondaryPhase 2 (All Arms): Symptom Improvement From the Patient Global Impression of Change (PGIC) at 12 and 24 Weeks

The Patient Global Impression of Change (PGIC) was a single-question, patient-reported assessment that asked individuals to rate their overall change in myeloproliferative neoplasm (MPN) symptoms since starting study treatment. The participants selected one of seven options, ranging from 'Very much improved' to 'Very much worse'. 'No Change from Baseline' indicated stable symptoms (no improvement or worsening), negative change from Baseline indicated a reduction in symptom severity (improvement), and positive change from Baseline indicated an increase in symptom severity (worsening).

Time frame:
Week 12 (Cycle 5 Day 1), Week 24 weeks (Cycle 9 Day 1)
Reported as:
Count of participants · Participants
Phase 2 (All Arms): Symptom Improvement From the Patient Global Impression of Change (PGIC) at 12 and 24 Weeks
ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
PGIC status at Week 12 — Improvement283622186613
PGIC status at Week 12 — No change7215494
PGIC status at Week 12 — Worsening4510352
PGIC status at Week 24 — Improvement20292716588
PGIC status at Week 24 — No change103126153
PGIC status at Week 24 — Worsening254064
SecondaryPhase 2 (Arms 1, 2 and 3): Percent Change From Baseline in Total Symptom Score (TSS) From the Myelofibrosis Symptom Assessment Form (MFSAF v4.0) at 12 and 24 Weeks

The MFSAF (Myelofibrosis Symptom Assessment Form) was completed by participants every day for 7 days before Day 1 of each treatment cycle, including the 7 days before starting Cycle 1. It used a 24-hour recall format, asking participants to rate the worst severity of seven symptoms (fatigue, night sweats, pruritus, abdominal discomfort, pain under the ribs on the left side, early satiety, and bone pain) during the past 24 hours. Each symptom was rated on a scale from 0 (Absent) to 10 (Worst Imaginable). The Total Symptom Score (TSS) was the sum of 7 symptoms (range: 0-70). 'No Change from Baseline' indicated stable symptoms (no improvement or worsening), negative change from Baseline indicated a reduction in symptom severity (improvement), and positive change from Baseline indicated an increase in symptom severity (worsening).

Time frame:
Baseline, Week 12 (Cycle 5 Day 1), Week 24 (Cycle 9 Day 1)
Reported as:
Mean · Score on a scale
Phase 2 (Arms 1, 2 and 3): Percent Change From Baseline in Total Symptom Score (TSS) From the Myelofibrosis Symptom Assessment Form (MFSAF v4.0) at 12 and 24 Weeks
Score on a scalePhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Percent Change from baseline to Week 12-38.77 ± 38.637-30.98 ± 35.394-27.18 ± 75.391-29.70 ± 36.106-39.91 ± 69.251
Percent Change from baseline to Week 24-32.69 ± 36.474-39.82 ± 42.228-38.93 ± 61.818-44.73 ± 35.224-47.43 ± 52.460
SecondaryPhase 2 (Arms 1, 2 and 3): Number of Participants Who Achieved a ≥ 50% Reduction in Total Symptom Score (TSS) at 12 and 24 Weeks

The proportion of study participants who experienced a reduction of at least 50% in their Total Symptom Score (TSS), as assessed using the Myelofibrosis Symptom Assessment Form (MFSAF v4.0), was evaluated at both 12 and 24 weeks relative to their baseline score.

Time frame:
Week 12 (Cycle 5 Day 1), Week 24 (Cycle 9 Day 1)
Reported as:
Number · Percentage of Participants
Phase 2 (Arms 1, 2 and 3): Number of Participants Who Achieved a ≥ 50% Reduction in Total Symptom Score (TSS) at 12 and 24 Weeks
Percentage of ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
MFSAF TSS50 response at week 1233.3 (20.0 to 49.0)31.3 (18.7 to 46.3)36.2 (24.0 to 49.9)33.3 (16.5 to 54.0)52.4 (41.1 to 63.6)
MFSAF TSS50 response at week 2415.6 (6.5 to 29.5)34.7 (21.7 to 49.6)36.2 (24.0 to 49.9)40.7 (22.4 to 61.2)56.1 (44.7 to 67.0)
SecondaryPhase 2 (Arms 1, 2 and 3): Number of Participants With Overall Splenic Response Rate (Overall SVR35)

Overall Splenic Response Rate (SVR35) was defined as the proportion of participants who achieved a reduction of at least 35% in spleen size from baseline, as measured by imaging (MRI or CT), at any point between Cycle 1 Day 1 and the End of Study Visit, whichever occurred first.

Time frame:
Through Phase II completion, an average of 6 years
Reported as:
Number · Percentage of Participants
Phase 2 (Arms 1, 2 and 3): Number of Participants With Overall Splenic Response Rate (Overall SVR35)
Percentage of ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Phase 2 (Arms 1, 2 and 3): Number of Participants With Overall Splenic Response Rate (Overall SVR35)16.7 (7.0 to 31.4)28.8 (17.1 to 43.1)30.8 (18.7 to 45.1)25.0 (10.7 to 44.9)79.8 (69.6 to 87.7)
SecondaryPhase 2 (Arms 1, 2 and 3): Duration of Overall Splenic Response (Overall SVR35)

Duration of Overall Splenic Response (overall SVR35) was defined as the time from the first occurrence of a at least 35% reduction in spleen volume from baseline until the earliest of the following: a reduction of less than 35% from baseline combined with an increase of more than 25% from the nadir in spleen volume (as measured by MRI or CT), or death. The nadir was defined as the lowest spleen volume recorded after baseline and up to the evaluation point at which the initial splenic response was achieved.

Time frame:
From first onset of splenic response until loss of response, assessed up to approximately 6 years
Reported as:
Median · Weeks
Phase 2 (Arms 1, 2 and 3): Duration of Overall Splenic Response (Overall SVR35)
WeeksPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Phase 2 (Arms 1, 2 and 3): Duration of Overall Splenic Response (Overall SVR35)24.1 (12.4 to NA)73.1 (27.1 to 106.4)180.9 (73.0 to NA)228.4 (36.1 to NA)197.6 (95.7 to NA)
SecondaryPhase 2 (Cohorts 1A and 2A): Number of Participants With Splenic Response Rate (SVR35) at 12 and 24 Weeks

Splenic Response Rate (SVR35) at 12 and 24 weeks was defined as the proportion of participants who achieved a reduction of at least 35% in spleen size from baseline, as determined by imaging (MRI or CT), following 12 and 24 weeks of treatment, respectively.

Time frame:
Week 12 (Cycle 5 Day 1), Week 24 weeks (Cycle 9 Day 1)
Reported as:
Number · Percentage of Participants
Phase 2 (Cohorts 1A and 2A): Number of Participants With Splenic Response Rate (SVR35) at 12 and 24 Weeks
Percentage of ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A
SVR35 at week 129.3 (2.6 to 22.1)9.4 (3.1 to 20.7)
SVR35 at week 240 (0 to NA)16.4 (7.8 to 28.8)
SecondaryPhase 2 (Cohorts 1A and 2A): Duration of Red Blood Cell (RBC) Transfusion Independence (TI) in Participants Who Enroll as Transfusion Dependent (TD)

Duration of Red Blood Cell (RBC) Transfusion Independence (TI) was defined as the longest continuous period during which participants, having achieved at least 12 weeks of transfusion independence, remained free from RBC transfusions.

Time frame:
From first onset of TI to earliest onset of loss of TI, assessed up to approximately 6 years
Reported as:
Median · Weeks
Phase 2 (Cohorts 1A and 2A): Duration of Red Blood Cell (RBC) Transfusion Independence (TI) in Participants Who Enroll as Transfusion Dependent (TD)
WeeksPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A
Phase 2 (Cohorts 1A and 2A): Duration of Red Blood Cell (RBC) Transfusion Independence (TI) in Participants Who Enroll as Transfusion Dependent (TD)35.8 (15.3 to NA)68.0 (34.7 to NA)
SecondaryPhase 2 (Cohorts 1A and 2A): Early Anemic Response Rate in Participants Who Enroll as Transfusion Dependent (TD)

Early anemic response rate was defined as the proportion of participants who achieved an average increase of at least 1 g/dL in hemoglobin concentration over any rolling 8-week (56-day) period following baseline. This calculation was performed after applying the 14/3 day rule, which stipulates that hemoglobin measurements must be spaced at least 14 days apart, and that at least 3 such measurements are required within the 8-week window to ensure a reliable average. Importantly, this increase had to occur without any red blood cell (RBC) transfusions during the treatment period and up to the time of the latest hemoglobin assessment for each patient.

Time frame:
Through Phase II completion, an average of 6 years
Reported as:
Number · Percentage of Participants
Phase 2 (Cohorts 1A and 2A): Early Anemic Response Rate in Participants Who Enroll as Transfusion Dependent (TD)
Percentage of ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A
Phase 2 (Cohorts 1A and 2A): Early Anemic Response Rate in Participants Who Enroll as Transfusion Dependent (TD)18.6 (8.4 to 33.4)21.7 (10.9 to 36.4)
SecondaryPhase 2 (Cohorts 1B, 2B, and Arm 3): Number of Participants With Splenic Response Rate (SVR35) at 12 Weeks

Splenic Response Rate (SVR35) at Week 12 was defined as the proportion of participants who achieved a reduction of at least 35% in spleen size from baseline, as measured by imaging (MRI or CT), following 12 weeks of treatment.

Time frame:
Week 12 (Cycle 5 Day 1)
Reported as:
Number · Percentage of Participants
Phase 2 (Cohorts 1B, 2B, and Arm 3): Number of Participants With Splenic Response Rate (SVR35) at 12 Weeks
Percentage of ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Phase 2 (Cohorts 1B, 2B, and Arm 3): Number of Participants With Splenic Response Rate (SVR35) at 12 Weeks15.4 (6.9 to 28.1)10.7 (2.3 to 28.2)66.7 (55.5 to 76.6)
SecondaryPhase 2 (Cohorts 1B, 2B, and Arm 3): Anemic Response Rate in Participants Who Enroll as Non-transfusion-dependent (Non-TD)

Anemic response was defined as a sustained average increase in hemoglobin concentration of at least 1.5 g/dL over any rolling 12-week (84-day) period following baseline. This calculation excluded periods involving red blood cell (RBC) transfusions and was performed after applying the 14/3-day rule for valid hemoglobin assessments. The response had to be maintained through to the most recent available hemoglobin measurement for each patient.

Time frame:
Through Phase II completion, an average of 6 years
Reported as:
Number · Percentage of Participants
Phase 2 (Cohorts 1B, 2B, and Arm 3): Anemic Response Rate in Participants Who Enroll as Non-transfusion-dependent (Non-TD)
Percentage of ParticipantsPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Phase 2 (Cohorts 1B, 2B, and Arm 3): Anemic Response Rate in Participants Who Enroll as Non-transfusion-dependent (Non-TD)47.1 (32.9 to 61.5)21.4 (8.3 to 41.0)35.4 (25.0 to 47.0)
SecondaryPhase 2 (Arm 4): Percentage of Participants Who Achieve a ≥50% Reduction From Baseline in the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) Total Score

The Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) is a patient-reported questionnaire designed to measure symptom burden in participants with myeloproliferative neoplasms (MPNs). Participants rate the severity of several symptoms (such as fatigue, night sweats, itching, abdominal discomfort, bone pain, early satiety, and others) over the past 24 hours. Each symptom is scored on a scale from 0 (absent/as good as it can be) to 10 (worst imaginable/as bad as it can be). The total score is the sum of all individual symptom scores, providing an overall measure of symptom burden. A 50% reduction in the MPN-SAF total score at 12 or 24 weeks means the patient's overall symptom burden has improved by half compared to their baseline (pre-treatment) score.

Time frame:
Baseline, 12 weeks (Cycle 5, Day 1), 24 weeks (Cycle 9, Day 1)
Reported as:
Number · Percentage of Participants
Phase 2 (Arm 4): Percentage of Participants Who Achieve a ≥50% Reduction From Baseline in the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) Total Score
Percentage of ParticipantsPhase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
MPN-SAF TSS50 response at week 1225.0 (8.7 to 49.1)
MPN-SAF TSS50 response at week 2420.0 (5.7 to 43.7)
SecondaryPhase 2 (Arm 4): Partial Hematological Response Rate (PHR)

Partial Hematological Response Rate (PHR) was defined as the proportion of participants who met the following criteria over two consecutive cycles up to the last administration of study treatment: * Platelet count \> 400-600 x 10\^9/L * WBC count within normal range (i.e., ≤ 10 x 10\^9/L) * Laboratory results confirmed after 1 cycle (after 3weeks)

Time frame:
Over 2 consecutive cycles (rolling window) (1 cycle = 21 days)
Reported as:
Number · Percentage of Participants
Phase 2 (Arm 4): Partial Hematological Response Rate (PHR)
Percentage of ParticipantsPhase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (Arm 4): Partial Hematological Response Rate (PHR)38.1 (18.1 to 61.6)
SecondaryPhase 2 (Arm 4): Overall Hematological Response Rate (OHR)

Confirmed Overall Hematological Response (OHR) Rate was defined as the proportion of participants with either a confirmed complete or a partial hematological response at any time.

Time frame:
Through Phase II completion, an average of 6 years
Reported as:
Number · Percentage of Participants
Phase 2 (Arm 4): Overall Hematological Response Rate (OHR)
Percentage of ParticipantsPhase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (Arm 4): Overall Hematological Response Rate (OHR)66.7 (43.0 to 85.4)
SecondaryPhase 2 (Arm 4): Duration of Overall Hematological Response Rate (OHR)

Duration of Overall Hematological Response (OHR) Rate was defined as the time from when the overall hematological response was first met until the time at which the overall hematological response was lost, i.e., the criteria for an overall hematological response (CHR or PHR) were not observed or death occurred, whichever came first.

Time frame:
Through Phase II completion, an average of 6 years
Reported as:
Median · Weeks
Phase 2 (Arm 4): Duration of Overall Hematological Response Rate (OHR)
WeeksPhase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (Arm 4): Duration of Overall Hematological Response Rate (OHR)21.1 (9.1 to 33.1)
SecondaryPhase 2 (Arm 4): Rate of Hemorrhagic and Thromboembolic (TE) Events

Rate of hemorrhagic and thromboembolic (TE) events was defined as the proportion of participants with hemorrhagic or thromboembolic events throughout the study.

Time frame:
Through Phase II completion, an average of 6 years
Reported as:
Number · Percentage of Participants
Phase 2 (Arm 4): Rate of Hemorrhagic and Thromboembolic (TE) Events
Percentage of ParticipantsPhase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (Arm 4): Rate of Hemorrhagic and Thromboembolic (TE) Events61.9 (38.4 to 81.9)
SecondaryPhase 2 (All Arms): Maximum Observed Plasma Concentration (Cmax) of Pelabresib

Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. Cmax was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · ng/mL
Phase 2 (All Arms): Maximum Observed Plasma Concentration (Cmax) of Pelabresib
ng/mLPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (All Arms): Maximum Observed Plasma Concentration (Cmax) of Pelabresib1280 ± 29.11350 ± 37.01210 ± 40.01190 ± 29.01070 ± 26.32130 ± 24.7
SecondaryPhase 2 (All Arms): Time to Reach Maximum Concentration (Tmax) of Pelabresib

Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. Tmax was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (predose, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Median · Hour
Phase 2 (All Arms): Time to Reach Maximum Concentration (Tmax) of Pelabresib
HourPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (All Arms): Time to Reach Maximum Concentration (Tmax) of Pelabresib1.94 (0.85 to 4.02)1.58 (0.83 to 3.63)1.90 (0.50 to 4.00)1.81 (0.92 to 3.13)1.71 (0.50 to 3.87)2.08 (1.07 to 6.00)
SecondaryPhase 2 (All Arms): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Pelabresib

Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. Ctrough was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (predose, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · ng/mL
Phase 2 (All Arms): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Pelabresib
ng/mLPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (All Arms): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Pelabresib120 ± 489.0201 ± 107.0244 ± 151.0162 ± 84.0240 ± 79.1174 ± 112.0
SecondaryPhase 2 (All Arms): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Pelabresib

Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. AUClast was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · h*ng/mL
Phase 2 (All Arms): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Pelabresib
h*ng/mLPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (All Arms): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Pelabresib5660 ± 36.75610 ± 35.55190 ± 40.94760 ± 26.74380 ± 26.89590 ± 28.7
SecondaryPhase 2 (All Arms): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Pelabresib

Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. AUC0-8,ss was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · h*ng/mL
Phase 2 (All Arms): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Pelabresib
h*ng/mLPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (All Arms): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Pelabresib6200 ± 35.36470 ± 31.75320 ± 38.14930 ± 28.84540 ± 25.310800 ± 29.0
SecondaryPhase 2 (All Arms): Time of Last Measurable Concentration (Tlast) of Pelabresib

Pharmacokinetic (PK) parameters were calculated based on Pelabresib plasma concentrations and actual sampling time points. Tlast was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Median · Hour
Phase 2 (All Arms): Time of Last Measurable Concentration (Tlast) of Pelabresib
HourPhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))
Phase 2 (All Arms): Time of Last Measurable Concentration (Tlast) of Pelabresib7.08 (4.50 to 9.00)7.07 (2.58 to 8.08)7.19 (6.10 to 8.05)7.12 (7.00 to 8.17)7.08 (5.07 to 8.58)7.08 (5.88 to 10.08)
SecondaryPhase 2 (Arm 2 - Cohort 2A): Maximum Observed Plasma Concentration (Cmax) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Cmax was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · ng/mL
Phase 2 (Arm 2 - Cohort 2A): Maximum Observed Plasma Concentration (Cmax) of Ruxolitinib
ng/mLPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A
Cohort 2A, 5 mg65.9 ± 56.5
Cohort 2A, 7.5 mg142.0 ± 31.0
Cohort 2A, 10 mg108.0 ± 29.3
Cohort 2A, 15 mg310.0 ± 88.9
Cohort 2A, 20 mg325.0 ± 37.7
SecondaryPhase 2 (Arm 2 - Cohort 2A): Time to Reach Maximum Concentration (Tmax) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Tmax was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Median · Hour
Phase 2 (Arm 2 - Cohort 2A): Time to Reach Maximum Concentration (Tmax) of Ruxolitinib
HourPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A
Cohort 2A, 5 mg0.92 (0.50 to 2.00)
Cohort 2A, 7.5 mg1.00 (0.50 to 2.02)
Cohort 2A, 10 mg0.76 (0.50 to 1.50)
Cohort 2A, 15 mg1.55 (0.67 to 3.50)
Cohort 2A, 20 mg0.53 (0.33 to 1.58)
SecondaryPhase 2 (Arm 2 - Cohort 2A): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Ctrough was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (predose, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · ng/mL
Phase 2 (Arm 2 - Cohort 2A): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Ruxolitinib
ng/mLPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A
Cohort 2A, 5 mgNA ± NA
Cohort 2A, 7.5 mg14.7 ± 74.9
Cohort 2A, 10 mg13.4 ± 81.6
Cohort 2A, 15 mg74.6 ± 94.7
Cohort 2A, 20 mg19.8 ± 54.2
SecondaryPhase 2 (Arm 2 - Cohort 2A): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUClast was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · h*ng/mL
Phase 2 (Arm 2 - Cohort 2A): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Ruxolitinib
h*ng/mLPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A
Cohort 2A, 5 mg230 ± 63.3
Cohort 2A, 7.5 mg390 ± 34.0
Cohort 2A, 10 mg347 ± 44.7
Cohort 2A, 15 mg1240 ± 64.7
Cohort 2A, 20 mg829 ± 42.3
SecondaryPhase 2 (Arm 2 - Cohort 2A): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUC0-8,ss was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · h*ng/mL
Phase 2 (Arm 2 - Cohort 2A): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Ruxolitinib
h*ng/mLPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A
Cohort 2A, 5 mg239 ± 64.5
Cohort 2A, 7.5 mg369 ± 35.9
Cohort 2A, 10 mg375 ± 47.2
Cohort 2A, 15 mgNA ± NA
Cohort 2A, 20 mg887 ± 42.3
SecondaryPhase 2 (Arm 2 - Cohort 2B): Maximum Observed Plasma Concentration (Cmax) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Cmax was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · ng/mL
Phase 2 (Arm 2 - Cohort 2B): Maximum Observed Plasma Concentration (Cmax) of Ruxolitinib
ng/mLPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2B
Cohort 2B, 5 mg69.5 ± 27.8
Cohort 2B, 15 mgNA ± NA
Cohort 2B, 20 mgNA ± NA
Cohort 2B, 25 mgNA ± NA
SecondaryPhase 2 (Arm 2 - Cohort 2B): Time to Reach Maximum Concentration (Tmax) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Tmax was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Median · Hour
Phase 2 (Arm 2 - Cohort 2B): Time to Reach Maximum Concentration (Tmax) of Ruxolitinib
HourPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2B
Cohort 2B, 5 mg1.57 (0.47 to 1.60)
Cohort 2B, 15 mg0.48 (NA to NA)
Cohort 2B, 20 mg0.53 (NA to NA)
Cohort 2B, 25 mg0.40 (NA to NA)
SecondaryPhase 2 (Arm 2 - Cohort 2B): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Ctrough was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · ng/mL
Phase 2 (Arm 2 - Cohort 2B): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Ruxolitinib
ng/mLPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2B
Cohort 2B, 5 mg8.49 ± 28.4
Cohort 2B, 15 mgNA ± NA
Cohort 2B, 20 mgNA ± NA
Cohort 2B, 25 mgNA ± NA
SecondaryPhase 2 (Arm 2 - Cohort 2B): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUClast was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · h*ng/mL
Phase 2 (Arm 2 - Cohort 2B): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Ruxolitinib
h*ng/mLPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2B
Cohort 2B, 5 mg207 ± 3.08
Cohort 2B, 15 mgNA ± NA
Cohort 2B, 20 mgNA ± NA
Cohort 2B, 25 mgNA ± NA
SecondaryPhase 2 (Arm 2 - Cohort 2B): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUC0-8,ss was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · ng/mL
Phase 2 (Arm 2 - Cohort 2B): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Ruxolitinib
ng/mLPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2B
Cohort 2B, 5 mg214 ± 3.67
Cohort 2B, 15 mgNA ± NA
Cohort 2B, 20 mgNA ± NA
Cohort 2B, 25 mgNA ± NA
SecondaryPhase 2 (Arm 3): Maximum Observed Plasma Concentration (Cmax) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Cmax was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · ng/mL
Phase 2 (Arm 3): Maximum Observed Plasma Concentration (Cmax) of Ruxolitinib
ng/mLPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Cohort 3, 5 mgNA ± NA
Cohort 3, 10 mg190 ± 28.6
Cohort 3, 15 mg213 ± 34.7
Cohort 3, 20 mgNA ± NA
SecondaryPhase 2 (Arm 3): Time to Reach Maximum Concentration (Tmax) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Tmax was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Median · Hour
Phase 2 (Arm 3): Time to Reach Maximum Concentration (Tmax) of Ruxolitinib
HourPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Cohort 3, 5 mg0.72 (NA to NA)
Cohort 3, 10 mg0.62 (0.28 to 7.00)
Cohort 3, 15 mg0.95 (0.22 to 3.87)
Cohort 3, 20 mg1.25 (NA to NA)
SecondaryPhase 2 (Arm 3): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. Ctrough was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (predose, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · ng/mL
Phase 2 (Arm 3): Predose (Trough) Concentration at the End of a Dosing Interval (Ctrough) of Ruxolitinib
ng/mLPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Cohort 3, 5 mgNA ± NA
Cohort 3, 10 mg25.3 ± 99.2
Cohort 3, 15 mg31.4 ± 58.1
Cohort 3, 20 mgNA ± NA
SecondaryPhase 2 (Arm 3): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUClast was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · h*ng/mL
Phase 2 (Arm 3): Area Under the Concentration-Time Curve From Time Zero to the Last Observed Concentration (AUClast) of Ruxolitinib
h*ng/mLPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Cohort 3, 5 mgNA ± NA
Cohort 3, 10 mg519 ± 54.8
Cohort 3, 15 mg677 ± 33.9
Cohort 3, 20 mgNA ± NA
SecondaryPhase 2 (Arm 3): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Ruxolitinib

Pharmacokinetic (PK) parameters were calculated based on ruxolitinib plasma concentrations and actual sampling time points. AUC0-8,ss was listed and summarized using descriptive statistics.

Time frame:
Cycle 1 Day 14 (30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 8 hours post-dose). 1 cycle = 21 days.
Reported as:
Geometric mean · h*ng/mL
Phase 2 (Arm 3): Area Under the Concentration-Time Curve From Time Zero to 8 Hours Post-dose at Steady State (AUC0-8,ss) of Ruxolitinib
h*ng/mLPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)
Cohort 3, 5 mgNA ± NA
Cohort 3, 10 mg587 ± 45.5
Cohort 3, 15 mg696 ± 34.7
Cohort 3, 20 mgNA ± NA

Adverse events

Collected over Adverse events were collected for each participant from the first dose of study treatment through 30 days after the last dose of pelabresib (CPI-0610). The duration of adverse event collection varied by participant and phase, with a maximum follow-up of approximately 2 years in Phase I and approximately 8 years in Phase II. Deaths were collected for each participant from study initiation through study completion, with an average follow-up of up to approximately 10 years.. Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Phase 1 (24 mg Capsule PO Daily)0/3 (0%)1/3 (33.3%)3/3 (100%)
Phase 1 (48 mg Capsule PO Daily)1/5 (20%)4/5 (80%)5/5 (100%)
Phase 1 (120 mg Capsule PO Daily)2/5 (40%)3/5 (60%)5/5 (100%)
Phase 1 (170 mg Capsule PO Daily)0/3 (0%)1/3 (33.3%)3/3 (100%)
Phase 1 (230 mg Capsule PO Daily)1/3 (33.3%)2/3 (66.7%)3/3 (100%)
Phase 1 (300 mg Capsule PO Daily)1/4 (25%)4/4 (100%)4/4 (100%)
Phase 1 (400 mg Capsule PO Daily)1/7 (14.3%)6/7 (85.7%)7/7 (100%)
Phase 1 (225 mg Tablet PO Daily)1/8 (12.5%)6/8 (75%)8/8 (100%)
Phase 1 (275 mg Tablet PO Daily)1/6 (16.7%)6/6 (100%)6/6 (100%)
Phase 1 (Overall)8/44 (18.2%)33/44 (75%)44/44 (100%)
Phase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1A6/48 (12.5%)18/48 (37.5%)48/48 (100%)
Phase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1B3/52 (5.8%)23/52 (44.2%)50/52 (96.2%)
Phase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2A3/59 (5.1%)29/59 (49.2%)58/59 (98.3%)
Phase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2B3/28 (10.7%)18/28 (64.3%)28/28 (100%)
Phase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)7/84 (8.3%)40/84 (47.6%)84/84 (100%)
Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))0/21 (0%)5/21 (23.8%)21/21 (100%)
Phase 2 (Overall)22/292 (7.5%)133/292 (45.5%)289/292 (99%)
Most frequent serious events
Showing 10 of 181
Most frequent serious events
EventPhase 1 (24 mg Capsule PO Daily)Phase 1 (48 mg Capsule PO Daily)Phase 1 (120 mg Capsule PO Daily)Phase 1 (170 mg Capsule PO Daily)Phase 1 (230 mg Capsule PO Daily)Phase 1 (300 mg Capsule PO Daily)Phase 1 (400 mg Capsule PO Daily)Phase 1 (225 mg Tablet PO Daily)Phase 1 (275 mg Tablet PO Daily)Phase 1 (Overall)Phase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))Phase 2 (Overall)
VomitingGastrointestinal disorders0/30/50/50/30/30/40/70/83/63/440/480/520/591/280/840/211/292
Febrile neutropeniaBlood and lymphatic system disorders1/32/51/50/30/30/42/71/82/69/440/480/520/590/281/840/211/292
FatigueGeneral disorders0/32/50/50/31/30/40/70/81/64/440/480/520/590/280/840/210/292
AnaemiaBlood and lymphatic system disorders0/30/50/51/30/30/41/70/80/62/441/482/522/595/281/840/2111/292
Sinus tachycardiaCardiac disorders0/30/50/51/30/30/40/70/80/61/440/480/520/590/280/840/210/292
DiarrhoeaGastrointestinal disorders0/30/51/51/30/30/40/70/81/63/440/481/520/590/280/840/211/292
NauseaGastrointestinal disorders0/30/50/50/30/30/40/70/82/62/440/480/520/590/280/840/210/292
PyrexiaGeneral disorders0/30/50/51/30/30/41/70/81/63/441/480/521/591/283/840/216/292
Device related infectionInfections and infestations1/30/50/50/30/30/40/71/80/62/440/480/520/590/280/840/210/292
SepsisInfections and infestations0/30/51/50/30/30/40/70/82/63/441/481/520/590/282/840/214/292
Most frequent other events
Showing 10 of 230
Most frequent other events
EventPhase 1 (24 mg Capsule PO Daily)Phase 1 (48 mg Capsule PO Daily)Phase 1 (120 mg Capsule PO Daily)Phase 1 (170 mg Capsule PO Daily)Phase 1 (230 mg Capsule PO Daily)Phase 1 (300 mg Capsule PO Daily)Phase 1 (400 mg Capsule PO Daily)Phase 1 (225 mg Tablet PO Daily)Phase 1 (275 mg Tablet PO Daily)Phase 1 (Overall)Phase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))Phase 2 (Overall)
DiarrhoeaGastrointestinal disorders1/30/51/51/30/34/43/75/82/617/4415/4826/5234/5918/2840/8410/21143/292
NauseaGastrointestinal disorders2/33/54/53/30/32/42/75/82/623/4418/4823/5221/5912/2826/8416/21116/292
FatigueGeneral disorders2/33/54/52/30/30/45/73/81/620/4414/4817/5213/5913/2827/845/2189/292
VomitingGastrointestinal disorders0/32/51/52/30/31/43/71/83/613/447/4810/5210/598/2815/849/2159/292
Platelet count decreasedInvestigations2/30/50/51/30/30/42/72/81/68/445/488/5211/598/2822/842/2156/292
Decreased appetiteMetabolism and nutrition disorders0/31/53/52/32/31/42/75/82/618/447/4813/5213/597/2815/844/2159/292
AnxietyPsychiatric disorders2/31/50/50/30/30/40/70/80/63/440/481/523/591/284/840/219/292
CoughRespiratory, thoracic and mediastinal disorders2/30/51/50/30/30/40/71/82/66/449/4811/5213/5914/2822/844/2173/292
RashSkin and subcutaneous tissue disorders0/31/50/52/30/30/41/70/80/64/442/487/523/594/286/844/2126/292
HaematomaVascular disorders0/30/50/50/32/30/40/70/80/62/440/483/521/593/284/841/2112/292

Baseline characteristics

Age, Continuous
Age, Continuous(Years)Phase 1 (24 mg Capsule PO Daily)Phase 1 (48 mg Capsule PO Daily)Phase 1 (120 mg Capsule PO Daily)Phase 1 (170 mg Capsule PO Daily)Phase 1 (230 mg Capsule PO Daily)Phase 1 (300 mg Capsule PO Daily)Phase 1 (400 mg Capsule PO Daily)Phase 1 (225 mg Tablet PO Daily)Phase 1 (275 mg Tablet PO Daily)Phase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))Total
Median79.0 (37 to 79)65.0 (55 to 76)69.0 (34 to 80)76.0 (69 to 79)80.0 (57 to 82)66.5 (27 to 76)63.0 (59 to 77)65.5 (54 to 82)61.0 (18 to 80)73.0 (60 to 88)69.5 (43 to 85)72.0 (41 to 83)65.5 (49 to 78)68.0 (37 to 85)64.0 (42 to 83)69.1 (18 to 88)
Sex: Female, Male
Sex: Female, Male(Participants)Phase 1 (24 mg Capsule PO Daily)Phase 1 (48 mg Capsule PO Daily)Phase 1 (120 mg Capsule PO Daily)Phase 1 (170 mg Capsule PO Daily)Phase 1 (230 mg Capsule PO Daily)Phase 1 (300 mg Capsule PO Daily)Phase 1 (400 mg Capsule PO Daily)Phase 1 (225 mg Tablet PO Daily)Phase 1 (275 mg Tablet PO Daily)Phase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))Total
Female311310212162918132513128
Male04402457432234115598208
Race (NIH/OMB)
Race (NIH/OMB)(Participants)Phase 1 (24 mg Capsule PO Daily)Phase 1 (48 mg Capsule PO Daily)Phase 1 (120 mg Capsule PO Daily)Phase 1 (170 mg Capsule PO Daily)Phase 1 (230 mg Capsule PO Daily)Phase 1 (300 mg Capsule PO Daily)Phase 1 (400 mg Capsule PO Daily)Phase 1 (225 mg Tablet PO Daily)Phase 1 (275 mg Tablet PO Daily)Phase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1APhase 2 - Arm 1 (MF Participants Previously Treated With JAK Inhibitor Monotherapy) - Cohort 1BPhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2APhase 2 - Arm 2 (Supplement to JAK Inhibitor Combination Arm for MF Participants) - Cohort 2BPhase 2 - Arm 3 (Combination Treatment Arm for JAKi-Naïve MF Participants)Phase 2 - Arm 4 (Monotherapy Arm for Essential Thrombocythemia (ET))Total
American Indian or Alaska Native0000000000000000
Asian0100000001111308
Native Hawaiian or Other Pacific Islander0000000000000000
Black or African American00100110241243019
White344331684424754227519295
More than one race00000200012113212
Unknown or Not Reported0000000000110002
07

Study locations

48 sites
  • Mayo Clinic Arizona
    Phoenix, Arizona 85054, United States
  • UCLA Medical Center
    Los Angeles, California 90095, United States
  • Mayo Clinic Jacksonville
    Jacksonville, Florida 32224, United States
  • Northwestern University - Lurie Comprehensive Cancer Center
    Chicago, Illinois 60611, United States
  • Massachusetts General Hospital Cancer Center
    Boston, Massachusetts 02114, United States
  • University of Michigan Medical Center
    Ann Arbor, Michigan 48109, United States
  • Washington University School of Medicne Neuromuscular Division Department of Neurology Research
    St Louis, Missouri 63110, United States
  • Memorial Sloan Kettering Cancer Center
    New York, New York 10021, United States
  • ICAHN School of Medicine at Mount Sinai
    New York, New York 10029, United States
  • Weill Medical College and New York Presbyterian Hospital
    New York, New York 10065, United States
  • The University of Texas MD Anderson Cancer Center
    Houston, Texas 77030, United States
  • Froedtert & Medical College of Wisconsin
    Milwaukee, Wisconsin 53226, United States
  • UZ Leuven - Campus Gasthuisberg
    Leuven, Viaams Braban 3000, Belgium
  • AZ Sint-Jan Burgge-Oostende AV- Campus Sint-Jan
    Bruges, West-Vlaanderen 8000, Belgium
  • ZNA Stuyvenberg Antwerpen
    Antwerp, 2060, Belgium
  • University of Alberta Hospital
    Edmonton, Alberta T6G 2G3, Canada
  • St. Paul's Hospital
    Vancouver, British Columbia V6Z 2A5, Canada
  • Juravinski Cancer Centre
    Hamilton, Ontario L8V 5C2, Canada
  • Princess Margaret Cancer Centre
    Toronto, Ontario M5G 2M9, Canada
  • Jewish General Hospital
    Montreal, Quebec H3T 1E2, Canada
  • Institut de cancérologie du Gard - Hematologie clinique
    Nîmes, Gard 30029, France
  • CHRU de Lille - Hopital Claude Huriez
    Toulouse, Haute-Garonne 31059, France
  • CHRU de Lille - Hopital Claude Huriez - Maladies du Sang
    Lille, Hauts-de-France 59037, France
  • CHU - Hopital Saint Louis - Centre D'Investigations Clinique
    Paris, 75010, France
  • Institut Gustave Roussy
    Villejuif, Île-de-France Region 94805, France
  • Universitätsklinikum Bonn
    Bonn, North Rhine-Westphalia 53127, Germany
  • Universitätsklinikum Leipzig AöR
    Leipzig, Saxony 04103, Germany
  • Institue of Hematology "L. and A. Seràgnoli"
    Bologna, Emilia-Romagna 40138, Italy
  • Servizio Sanitario Regionale Emilia-Romagna - Azienda Unita Sanitaria Locale (AUSL) di Rimini - Ospedale Infermi di Rimini
    Rimini, Emilia-Romagna 47923, Italy
  • AOU S.Martino, IRCCS, IST-Istituto Nazionale Ricerca Sul Can
    Genoa, Liguria 16132, Italy
  • Ospedale Maggiore Policlinico, Fondazione IRCCS Ca' Granda
    Milan, Lombardy 20122, Italy
  • IRCCS Policlinico San Matteo, Università degli studi di Pavi
    Pavia, Lombardy 27100, Italy
  • Ospedale di Circolo, PO Varese, AO Ospedale di Circolo e Fon
    Varese, Lombardy 21100, Italy
  • Azienda Ospedaliero-Universitaria Careggi
    Florence, 50134, Italy
  • AOU Maggiore della Carità
    Novara, 28100, Italy
  • Maastricht University Medical Center
    Maastricht, Limburg 6229 HX, Netherlands
  • VUmcResearch B.V.
    Amsterdam, North Holland 1081 HV, Netherlands
  • Erasmus Universitair Medisch Centrum Rotterdam
    Rotterdam, South Holland 3015 AA, Netherlands
  • Instytut Hematologii i Transfuzjologii w Warszawie
    Warsaw, Masovian Voivodeship 02-776, Poland
  • Uniwersyteckie Centrum Kliniczne
    Gdansk, Pomeranian Voivodeship 80-952, Poland
  • Oxford University Hospitals
    Headington, Oxford OX3 7LE, United Kingdom
  • Belfast City Hospital
    Belfast, BT9 7AB, United Kingdom
  • University of Cambridge
    Cambridge, CB2 0QQ, United Kingdom
  • University Hospital of Wales
    Cardiff, CF14 4XW, United Kingdom
  • Beatson West of Scotland Cancer Centre
    Glasgow, G12 0YN, United Kingdom
  • University College London Hospital's NHS foundation Trust
    London, NW1 2PG, United Kingdom
  • Guys and St Thomas' Hospital - Haematology
    London, SE1 9RT, United Kingdom
  • The Christie Hospital
    Manchester, M20 4BX, United Kingdom
08

References and documents

Publications

  • Stein EM, Fathi AT, Harb WA, Colak G, Fusco A, Mangan JK. Results from phase 1 of the MANIFEST clinical trial to evaluate the safety and tolerability of pelabresib in patients with myeloid malignancies. Leuk Lymphoma. 2024 Apr;65(4):503-510. doi: 10.1080/10428194.2023.2300710. Epub 2024 Jan 23. PubMed 38259250 ↗
  • Gupta V, Mascarenhas J, Kremyanskaya M, Rampal RK, Talpaz M, Kiladjian JJ, Vannucchi AM, Verstovsek S, Colak G, Dey D, Harrison C. Matching-adjusted indirect comparison of the pelabresib-ruxolitinib combination vs JAKi monotherapy in myelofibrosis. Blood Adv. 2023 Sep 26;7(18):5421-5432. doi: 10.1182/bloodadvances.2023010628. PubMed 37530627 ↗
  • Mascarenhas J, Kremyanskaya M, Patriarca A, Palandri F, Devos T, Passamonti F, Rampal RK, Mead AJ, Hobbs G, Scandura JM, Talpaz M, Granacher N, Somervaille TCP, Hoffman R, Wondergem MJ, Salama ME, Colak G, Cui J, Kiladjian JJ, Vannucchi AM, Verstovsek S, Curto-Garcia N, Harrison C, Gupta V. MANIFEST: Pelabresib in Combination With Ruxolitinib for Janus Kinase Inhibitor Treatment-Naive Myelofibrosis. J Clin Oncol. 2023 Nov 10;41(32):4993-5004. doi: 10.1200/JCO.22.01972. Epub 2023 Mar 7. PubMed 36881782 ↗

Study documents

  • Study protocol · Jan 4, 2018
  • Study protocol · Feb 23, 2024
  • Statistical analysis plan · Feb 19, 2025

Documents are hosted by the registry — open the source record to download them.

Individual participant data

Plan to share: Yes — 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

09

Registry details

Key details

Study ID
NCT02158858
Lead sponsor
Constellation Pharmaceuticals
Collaborators
The Leukemia and Lymphoma Society
Responsible party
Sponsor
First posted
Jun 9, 2014
Start date
Jul 16, 2014
Primary completion
Jan 9, 2025
Completion
Jan 9, 2025
Results posted
Jun 4, 2026
Last update
Jun 4, 2026

Study contacts

Novartis Pharmaceuticals
study director · Novartis Pharmaceuticals

Oversight

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

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