Ajax Therapeutics Receives Orphan Drug Designation for Myelofibrosis Candidate
Thursday, December 11, 2025
Ajax Therapeutics has received Orphan Drug Designation from the U.S. Food and Drug Administration for AJ1-11095, a next-generation JAK2 inhibitor being developed for myelofibrosis.
AJ1-11095 was created through structure-based drug design and advanced computational methods to selectively bind the Type II conformation of JAK2. Preclinical studies have shown potential to reverse bone marrow fibrosis, reduce mutant allele burden, and maintain activity in cells that develop resistance to long-term Type I JAK2 inhibition.
Myelofibrosis is a rare cancer characterised by enlarged spleen, bone marrow scarring, anaemia, and symptoms such as fatigue, night sweats, itching, and abdominal discomfort. Although Type I JAK2 inhibitors are widely used to relieve symptoms and reduce spleen size, they do not target the root cause of the disease.
Many patients eventually discontinue treatment due to limited benefit, loss of response, side effects, or disease progression.
The rare blood cancer affects around 20,000 people in the United States.
AJ1-11095 is the first JAK2 inhibitor in clinical development that targets the Type II conformation of the JAK2 kinase. Existing approved JAK2 inhibitors work through the Type I conformation. The therapy is currently being assessed in a Phase 1 study for patients who previously received a Type I JAK2 inhibitor but did not respond or later lost response (NCT06343805).
The designation marks a key step for the company as it progresses AJ1-11095 through clinical development.
The need for more effective treatment options remains significant, particularly for patients who no longer benefit from standard therapies.
Source: globenewswire.com
