A Phase 1 Study of PRT12396 in Participants With Select Myeloproliferative Neoplasms

Prior treatment

• Unresolved toxicity Grade \>1 from prior anticancer therapy, except for alopecia or peripheral neuropathy Grade ≤2.
• 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.

Other illness

• 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.

Other

• Pregnancy or breastfeeding
• Known sensitivity or contraindication to any component of study, or the excipients of study treatment.
• Participation in another interventional clinical study.

• 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 0-1
• 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)