Bomedemstat (IMG-7289) Plus Ruxolitinib for Myelofibrosis

Cohort A:

1. Patients refractory to, relapsed or intolerant of ruxolitinib as per one of the below:

• Refractory is defined as \<30% reduction in spleen length or \<10% SVR compared to baseline having received ruxolitinib for ≥12 weeks prior to enrollment, AND on a stable dose for ≥8 weeks prior to starting investigational therapy
• Relapsed is defined as an increase in spleen volume of ≥25% by MRI/CT from nadir, or, ≥100% in palpable spleen length from a baseline of 5 to 10 cm BLCM or, ≥50% increase in spleen length from a baseline spleen length ≥10 cm BLCM

• Intolerance is defined as the development in patients treated with ruxolitinib for ≥28 days of:

  • Red blood cell transfusion requirement of 2 units/month for 2 months
  • Grade 3 thrombocytopenia, anemia, hematoma, and/or hemorrhage while on ruxolitinib treatment

Cohort B:

1. Patients who are JAK inhibitor naïve, AND:

   • Require MF-directed treatment, AND

   • Have measurable disease burden including one of the following:

     • Disease-related symptoms, determined by a MFSAF or MPN-SAF TSS of ≥10, or at least 2 symptoms with scores ≥3
     • Documented splenomegaly by physical exam, with spleen palpated ≥5 cm below the left costal margin

   Both Cohorts A and B:

2. Willing and able to provide informed consent
3. Age ≥18 years
4. Diagnosis of Overt Myelofibrosis (primary, post-ET, or post-PV) per World Health Organization (WHO) diagnostic criteria
5. Intermediate-1, Intermediate-2, or high-risk disease by Dynamic International Prognostic Scoring System (DIPSS)
6. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2
7. Platelet count ≥100 x 10\^9/L prior to dosing on Cycle 1 Day 1
8. Absolute neutrophil count ≥0.5 x 10\^9/L prior to dosing on Cycle 1 Day 1
9. Peripheral blast count ≤10% prior to dosing on Cycle 1 Day 1
10. Able to swallow capsules
11. Women of childbearing potential and fertile men must agree to use an approved method of contraception from Screening until 30 days after the last dose of bomedemstat and ruxolitinib.

Exclusion Criteria:

1. Those with increased risk of bleeding, including any of the following:

   1. Activated partial thromboplastin time (aPTT) ≥1.3 x the local upper limit of normal
   2. International normalized ratio (INR) ≥1.3 x the local upper limit of normal
   3. Known history of a platelet function disorder
   4. Other known bleeding disorder that is active at the time of screening (Von Willebrand's disease, dysfibrinogenemia, hemophilia, etc.)
2. History of splenectomy or prior splenic irradiation
3. Use of an investigational agent within 14 days of study treatment (or at least 7 half-lives of that agent, whichever is longer), prior to the first dose of bomedemstat
4. Current use of monoamine oxidase A and B inhibitors (MAOIs)
5. Uncontrolled, active infection
6. Major surgery within 4 weeks of starting the study drug, or not recovered from side effects of surgery
7. Any other serious medical conditions that could compromise study participation, in the opinion of the investigator
8. Known HIV infection or known, active hepatitis B or hepatitis C infection
9. Concurrent second active and non-stable malignancy (patients with a concurrent second active but stable malignancy, i.e., non-melanoma skin cancers, are eligible)
10. Current use of a prohibited medication (e.g., romiplostim) or expected to require any of these medications during treatment
11. Known immediate or delayed hypersensitivity reaction or idiosyncrasy to drugs chemically related to bomedemstat or LSD1 inhibitors (i.e., monoamine oxidase inhibitors; MAOIs) that contraindicates participation

12. Evidence at the time of Screening of significant renal or hepatic insufficiency (unless due to hemolysis) as defined by any of the following local lab parameters:

    1. Calculated glomerular filtration rate (GFR; using the Cockcroft-Gault equation) \<40 mL/min or serum creatinine >1.5 x the local upper limit of normal
    2. Aspartate transaminase (AST) or alanine aminotransferase (ALT) ≥2.5 x the local upper limit of normal
13. Pregnant or lactating females, or females planning to become pregnant at any time during the study
14. Unwilling or unable to comply with the study protocol