Gecacitinib Pre-, During- and Post-HSCT for Patients With Primary or Secondary Myelofibrosis

Inclusion criteria

• Aged 18-75 years, regardless of gender;
• Diagnosis of primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV-MF), or post-essential thrombocythemia myelofibrosis (post-ET-MF) according to the 2022 WHO diagnostic criteria;
• Meeting the criteria for intermediate-risk or high-risk groups per the DIPSS-plus classification;
• Scheduled to undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT), including transplants from HLA-matched or mismatched related or unrelated donors;
• ECOG performance status ≤2 and Karnofsky performance status ≥60%;
• Capable of understanding and signing the informed consent form, and able to comply with study and follow-up procedures.

Exclusion criteria

• Patients using other JAK inhibitors (except for Gecacitinib) at the time of screening may be enrolled if they switch to Gecacitinib treatment prior to screening.
• Patients who have previously undergone allogeneic hematopoietic stem cell transplantation or organ transplantation.
• Disease progression to accelerated or blast phase (peripheral blood or bone marrow blast percentage ≥10% at any time prior to transplantation).
• Presence of significant medical conditions or marked organ dysfunction that cannot be adequately controlled and may affect the completion of this study:

• Congestive heart failure classified as New York Heart Association (NYHA) Class III-IV, or documented history of diastolic or systolic dysfunction (e.g., LVEF <40% measured by echocardiography), or uncontrolled or unstable angina or myocardial infarction.
• Uncontrolled diabetes (>250 mg/dL or >13.9 mmol/L).
• Hypertension that cannot be reduced to the following range despite combination antihypertensive therapy (systolic blood pressure <160 mmHg, diastolic blood pressure <100 mmHg).
• Peripheral neuropathy (≥ Grade 2 per NCI-CTC AE v5.0 criteria).
• Serum creatinine >1.5 × ULN.
• ALT or AST >2.5 × ULN, or DBIL or TBIL >2.0 × ULN.
• Patients with any bacterial, viral, or fungal infection not adequately controlled.
• HIV-positive at screening, or active hepatitis B virus infection (HBsAg-positive with HBV-DNA positivity or above the normal reference range), or HCV antibody-positive with HCV-RNA positivity.
• History of tuberculosis or positive interferon-gamma release assay at screening.
• Suspected hypersensitivity to Gecacitinib Hydrochloride, drugs of the same class, or any of their excipients.
• Pregnant or breastfeeding women, or patients unwilling to use effective contraception during Gecacitinib treatment and for one week after the last dose.
• Patients with any other comorbidities that may interfere with the study or a history of prior malignancies.
• Patients unable to take oral tablets.