A Phase 1 Study of AJ1-11095 in Patients With Primary Myelofibrosis (PMF), Post-Polycythemia Vera Myelofibrosis (PPV-MF), or Post-Essential Thrombocythemia Myelofibrosis (PET-MF) Who Have Been Failed by a Type I JAK2 Inhibitor (JAK2i)

Inclusion Criteria:

1. 18 years of age or older.

2. Diagnosis of PMF, post-PV MF, or post-ET MF.

3. DIPSS Intermediate-2 or High-risk MF with ≤10% blasts, regardless of JAK2 mutationstatus.

4. Estimated spleen volume ≥450cm3.

5. MFSAF v.4.0 TSS ≥10, or at least 2 of 7 MFSAF-assessed symptoms with scores ≥3.

6. ECOG PS of 0, 1, 2, or 3.

7. Prior therapy with at least 1 type I JAK2 inhibitor, and either failed to achieve aresponse or relapsed after achieving a response.

8. ANC ≥1.0×10^9/L.

9. Platelet count ≥75×10^9/L.

10. eGFR ≥45 mL/min/1.73m2.

11. Serum total bilirubin ≤2.0 × upper limit of normal (ULN).

12. AST and ALT ≤3.0 × ULN.

13. QTcF ≤480 msec.

Exclusion Criteria:

1. Prior splenectomy.

2. Splenic irradiation within 3 months prior to first dose of study drug.

3. Ongoing use of systemic corticosteroids at dose equivalent to >10mg/day ofprednisone.

4. Uncontrolled intercurrent illness such as an acute infection.

5. Chronic active or acute hepatitis B or C infection.

6. Chemotherapy in the previous 4 weeks prior to first dose of study drug (Hydrea ispermitted until 5 days before starting protocol therapy).

7. Use of a Type I JAK2 inhibitor must have been discontinued for at least 5 days or 5half-lives prior to dosing (whichever is longer).

8. Use of erythropoiesis stimulating agents (unless stable for >8 weeks).

9. Peripheral neuropathy ≥ Grade 2 (NCI CTCAE v 5.0).

10. Unable or unwilling to undergo CT or MRI for spleen size imaging.

11. Pregnant or breastfeeding.

12. Requirement for therapy with a medication that is a strong CYP3A4 inhibitor as aconcomitant medication.