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RecruitingInterventionalPhase 1

A Phase 1, Open-Label, Multi-Center, Safety and Efficacy Study of PRT12396 in Participants With Polycythemia Vera and Myelofibrosis

NCT ID: NCT07469891Sponsor: Prelude TherapeuticsLast updated: 2026-06-09

Summary

This is a first-in-human, open-label, multi-center Phase 1 study designed to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of PRT12396 in participants with high-risk polycythemia vera (PV) and myelofibrosis (MF), and to determine the maximum tolerated dose (MTD) and recommended dose(s) for expansion (RDE\[s\]). The study consists of a dose-escalation phase followed by a dose-expansion phase to further evaluate selected dose level(s).

Detailed description

This first-in-human, open-label, multi-center Phase 1 study is designed to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of PRT12396 in participants with high-risk polycythemia vera (PV) and myelofibrosis (MF). Eligible MF populations include participants with intermediate-1, intermediate-2, or high-risk primary MF, as well as post-polycythemia vera MF or post-essential thrombocythemia MF, with evidence of disease burden based on splenomegaly. The study is conducted in two parts: Part 1 (dose escalation) evaluates escalating oral doses of PRT12396 to evaluate safety and tolerability and to determine the maximum tolerated dose (MTD) and recommended dose(s) for expansion (RDE\[s\]). Part 2 (dose expansion) enrolls additional participants at selected dose level(s) to further characterize the safety, tolerability, pharmacokinetics, and preliminary efficacy of PRT12396 in the PV and MF populations. Approximately up to 100 participants are planned for enrollment across both parts of the study.

Arms & interventions

  • DrugPRT12396

    PRT12396 is an investigational oral capsule administered twice daily at the assigned dose level or RDE. Capsules are swallowed whole with water and may be taken one hour before or two hours after meals.

Outcome measures

Primary

  • Dose limiting toxicity (DLT) of PRT12396

    Incidence of dose limiting toxicities, defined according to protocol-specified criteria

    Time frame: Through cycle 1 (4 weeks)

  • Incidence and severity of Adverse events

    Incidence and severity of treatment-emergent adverse events (AEs), graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), Version 6.0

    Time frame: Through study completion, an average of 2 years

  • Adverse Events Leading to Dose Modifications or Discontinuation

    Incidence of AEs leading to dose reductions, dose interruptions, treatment discontinuations, and clinically significant laboratory abnormalities

    Time frame: Through study completion, an average of 2 years

  • Maximum tolerated dose (MTD) and Recommended Dose(s) for Expansion (RDE[s]) of PRT12396

    Determination of the maximum tolerated dose (MTD) and recommended dose(s) for expansion (RDE\[s\]) based on evaluation of DLTs, safety, and tolerability data

    Time frame: Through study completion, an average of 2 years

Secondary

  • Hematologic Response Rate (PV)

    Time frame: Through study completion, an average of 2 years

  • Duration of Hematologic Response (PV)

    Time frame: Through study completion, an average of 2 years

  • Hematocrit Control Without Phlebotomy Requirements (PV)

    Time frame: Through study completion, an average of 2 years

  • Spleen Response (MF)

    Time frame: Through study completion, an average of 2 years

  • Change from Baseline in Hemoglobin (MF)

    Time frame: Through study completion, an average of 2 years

  • Change from Baseline in Platelet Count (MF)

    Time frame: Through study completion, an average of 2 years

  • Change from Baseline in Absolute Neutrophil Count (MF)

    Time frame: Through study completion, an average of 2 years

  • Transfusion Independence (MF)

    Time frame: Through study completion, an average of 2 years

  • Maximum Observed Plasma Concentration (Cmax)

    Time frame: Up to Cycle 4 Day 1 (each cycle is 4 weeks)

  • Time To Maximum Concentration (Tmax)

    Time frame: Up to Cycle 4 Day 1 (each cycle is 4 weeks)

  • Area under the plasma concentration versus time curve (AUC)

    Time frame: Up to Cycle 4 Day 1 (each cycle is 4 weeks)

  • Terminal Elimination Half-life (T1/2)

    Time frame: Cycle 1 Day 1

  • Steady State Trough Concentrations

    Time frame: Up to Cycle 4 Day 1 (each cycle is 4 weeks)

  • Clearance

    Time frame: Cycle 1 Day 1

  • Accumulation

    Time frame: Up to Cycle 4 Day 1 (each cycle is 4 weeks)

  • Myeloproliferative Neoplasm Symptom Assessment Form Total Symptom Score (MPN-SAF TSS)

    Time frame: Through study completion, an average of 2 years

  • Patient Global Impression of Change (PGI-C)

    Time frame: Through study completion, an average of 2 years

Eligibility criteria

Sex: AllAge: 18 Years and olderHealthy volunteers: No
Inclusion Criteria: * Willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations (including contraception requirements), and other study procedures. * Confirmed diagnosis of PV or MF according to WHO 2016 or revised ICC/WHO 2022 criteria * Documented presence of a JAK2 V617 mutation * Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 * Estimate life expectancy of ≥12 weeks per investigator assessment. * Negative serum or urine pregnancy test and agree to use contraception or maintain true abstinence. * Adequate organ function and bone marrow reserves (hematology, renal, and hepatic) Exclusion Criteria: * History of another malignancy within 3 years prior to enrollment, except for malignancy considered cured with low risk of recurrence. * Clinically significant anemia due to nutritional deficiency or hemolytic disorders. * Active or uncontrolled infection requiring systemic therapy or hospitalization. * Any other medical or psychiatric conditions that, in the Investigator's judgment, would increase risk or interfere with study participation or interpretation of results. * Clinically significant or uncontrolled medical conditions, including active infection or cardiovascular disease, that would increase risk or interfere with study participation. * Unresolved toxicity \> Grade 1 from prior anticancer therapy, except for alopecia or peripheral neuropathy ≤ Grade 2. * Pregnancy or breastfeeding * Known sensitivity or contraindication to any component of study, or the excipients of study treatment. * Prior systemic therapy for PV or MF, prior or planned allogeneic hematopoietic stem-cell transplantation, recent major surgery, prior splenectomy or prior splenic irradiation, or use of hematopoietic growth factors within protocol-defined washout periods. * Use of strong or moderate cytochrome P450 (CYP) 3A4 inhibitor or inducer, sensitive CYP3A substrates with narrow therapeutic range, or acid-reducing agents that cannot be discontinued prior to study treatment. * Participation in another interventional clinical study.

Study locations (5)

Colorado Blood Cancer Institute

Denver, Colorado, 80218

Recruiting

BRCR Global - Coral Springs

Coral Springs, Florida, 33065

Recruiting

START Midwest, LLC

Grand Rapids, Michigan, 49546

Recruiting

Thomas Jefferson University, Sidney Kimmel Cancer Center, Clinical Trials Office

Philadelphia, Pennsylvania, 19107

Recruiting

Tristar BMT

Nashville, Tennessee, 37203

Recruiting