Ajax Therapeutics Secures Orphan Drug Designation From FDA For AJ1-11095 Advancing Therapy Options In Myelofibrosis
FDA grants Orphan Drug Designation to Ajax Therapeutics’ AJ1-11095. A first-in-class type II JAK2 inhibitor advancing treatment options for myelofibrosis patients.
Breaking News
Dec 12, 2025
Simantini Singh Deo

Ajax Therapeutics, Inc., a biopharmaceutical company focused on developing next-generation JAK inhibitors for patients with myeloproliferative neoplasms (MPNs), announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation to AJ1-11095 for the treatment of myelofibrosis. Myelofibrosis is a serious and debilitating blood cancer that affects an estimated 20,000 people in the United States.
AJ1-11095 is notable for being the first JAK2 inhibitor in clinical development that targets the type II conformation of the JAK2 kinase, unlike all currently approved JAK2 inhibitors, which bind the type I conformation. The therapy is now being studied in an ongoing Phase 1 clinical trial involving patients with myelofibrosis who have previously been treated with a type I JAK2 inhibitor but did not respond or eventually lost their response (NCT06343805).
David Steensma, MD, FACP, Chief Medical Officer at Ajax Therapeutics, said that receiving Orphan Drug Designation marks a significant step in the clinical progress of AJ1-11095. He emphasized that this designation highlights the urgent need for new, effective treatment approaches for people living with myelofibrosis. He added that the recognition supports Ajax’s ongoing work to advance AJ1-11095 as a potential option for patients who require better treatment outcomes or who have not benefited from currently available therapies.
