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Testing a new drug for patients with myelofibrosis who didn't respond to previous treatments

A Multicenter, Open-Label, Phase 1 Study of AJ1-11095 Administered as Oral Monotherapy 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)

Phase 1 Interventional Ajax Therapeutics, Inc. · NCT06343805

This study is testing a new drug for people with myelofibrosis who haven't had success with previous treatments to see if it’s safe and effective.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment76 (estimated)
Ages18 Years and up
SexAll
SponsorAjax Therapeutics, Inc. Industry-sponsored
Drugs / interventionsChemotherapy, prednisone
Locations21 sites (Palo Alto, California and 20 other locations)
Trial IDNCT06343805 on ClinicalTrials.gov

What this trial studies

This phase 1 clinical trial evaluates the safety and tolerability of AJ1-11095, a type II JAK2 inhibitor, in patients with primary myelofibrosis or secondary myelofibrosis who have previously failed treatment with a type I JAK2 inhibitor. The study employs a 3+3 dose escalation design followed by an expansion phase to determine the maximally tolerated dose and gather additional safety and efficacy data. Participants will be monitored for changes in biomarkers and clinical activity as part of the trial's objectives.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18 and older with primary or secondary myelofibrosis who have previously failed at least one type I JAK2 inhibitor.

Not a fit: Patients who have undergone splenectomy or have uncontrolled intercurrent illnesses may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for patients with myelofibrosis who have not responded to existing therapies.

How similar studies have performed: While this approach is novel in the context of type II JAK2 inhibitors, similar studies with type I JAK2 inhibitors have shown varying degrees of success.

Eligibility criteria

Show full inclusion / exclusion criteria 
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 mutation status.
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 a response 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 of prednisone.
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 is permitted 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 5 half-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 a concomitant medication.

Where this trial is running

Palo Alto, California and 20 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Primary MyelofibrosisPost-Essential Thrombocythemia MyelofibrosisPost-Polycythemia Vera MyelofibrosisPMFPPV-MFPET-MF
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.