A Randomized, Double-Blind, Placebo-Controlled Study of the PI3Kδ Inhibitor Parsaclisib Plus Ruxolitinib in Participants With Myelofibrosis Who Have Suboptimal Response to Ruxolitinib

  • End date
    Mar 31, 2025
  • participants needed
  • sponsor
    Incyte Corporation
Updated on 25 October 2022


The purpose of the study is to compare the efficacy and safety of parsaclisib when combined with ruxolitinb versus placebo combined with ruxolitinib in participants with myelofibrosis who have suboptimal response while receiving ruxolitinib monotherapy.


Prospective participants must be on stable doses of ruxolitinib ranging from 5 mg BID to 25 mg BID and will have been on that dose for at least the last 8 weeks prior to Day 1. At least 3 months duration of prior ruxolitinib is required. Participants must meet Protocol-defined criteria for suboptimal response to ruxolitinib monotherapy. After participants have been determined to be eligible for the study and completed the baseline symptom diary assessment for 7 days, they will be randomized to 1 of 2 treatment groups, with stratification for platelet count (≥ 100 × 10^9/L vs 50 to < 100 × 10^9/L inclusive) and DIPSS risk category (high vs intermediate-2 vs intermediate-1).

Once a participant has completed the week 24 assessments, the participant's treatment assignment will then be unblinded and if found to be placebo, the participant will have the opportunity to crossover to begin receiving parsaclisib, together with continued ruxolitinib, as long as hematology parameters are adequate.

Condition Myelofibrosis, Primary Myelofibrosis, Post Essential Thrombocythemia Myelofibrosis, Post Polycythemia Vera Myelofibrosis
Treatment Placebo, Ruxolitinib, Parsaclisib
Clinical Study IdentifierNCT04551053
SponsorIncyte Corporation
Last Modified on25 October 2022


Yes No Not Sure

Inclusion Criteria

Diagnosis of PMF, PPV-MF, or PET-MF
DIPSS risk category of intermediate-1, intermediate-2, or high
Treated with ruxolitinib for ≥ 3 months with a stable dose for at least the last 8 weeks prior to Day 1
Palpable spleen of ≥ 5 cm below the left costal margin on physical examination at the screening visit
Active symptoms of MF at the screening visit, as demonstrated by the presence of a TSS of ≥ 10 using the Screening Symptom Form
Participants with an ECOG performance status score of 0, 1, or 2
Screening bone marrow biopsy specimen and pathology report(s) available that was obtained within the prior 2 months or willingness to undergo a bone marrow biopsy at screening/baseline; willingness to undergo bone marrow biopsy at Week 24 and every 24 weeks there after. Screening/baseline biopsy specimen must show diagnosis of MF
Life expectancy of at least 24 weeks
Willingness to avoid pregnancy or fathering children

Exclusion Criteria

Prior therapy with any drug that inhibits PI3K (examples of drugs targeting this pathway include but are not limited to INCB040093, idelalisib, duvelisib, buparlisib, copanlisib, and umbralisib)
Use of experimental drug therapy for MF or any other standard drug used for MF (whether for treatment of MF or another indication) with the exception of ruxolitinib, within 3 months of starting study drug, and/or lack of recovery from all toxicities from previous therapy (except ruxolitinib) to Grade 1 or better
Inability to swallow food or any condition of the upper gastrointestinal tract that precludes administration of oral medications
Recent history of inadequate bone marrow reserve
Inadequate liver and renal function at screening
Active bacterial, fungal, parasitic, or viral infection that requires therapy
Active HBV or HCV infection that requires treatment or at risk for HBV reactivation
Known HIV infection
Uncontrolled, severe, or unstable cardiac disease that in the investigator's opinion may jeopardize the safety of the participant or compliance with the Protocol
Active invasive malignancy over the previous 2 years
Splenic irradiation within 6 months before receiving the first dose of study drug
Concurrent use of any prohibited medications
Active alcohol or drug addiction that would interfere with the ability to comply with the study requirements
Use of any potent CYP3A4 inhibitors or inducers within 14 days or 5 half lives(whichever is longer) before the first dose of study drug or anticipated during the study
Inadequate recovery from toxicity and/or complications from a major surgery before starting therapy
Currently breastfeeding or pregnant
Any condition that would, in the investigator's judgment, interfere with full participation in the study, including administration of study drug and attending required study visits; pose a significant risk to the participant; or interfere with interpretation of study data
History of Grade 3 or 4 irAEs from prior immunotherapy
Receipt of any live vaccine within 30 days of the first dose of study drug
Unwillingness to receive RBC transfusions to treat low hemoglobin levels
Known hypersensitivity or severe reaction to parsaclisib or ruxolitinib or excipients of parsaclisib/matching placebo or ruxolitinib formulations
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