Ajax Therapeutics Presents Preclinical Data on AJ1-10502, a Next Generation Type II JAK2 Inhibitor, at the American Society of Hematology Annual Meeting

Ajax Therapeutics, Inc., a biopharmaceutical company applying computational chemistry and structure-based technologies to develop novel, selective small molecules for myeloproliferative neoplasms (MPNs), today announced the presentation of preclinical data on the company's next generation Type II JAK2 inhibitor, AJ1-10502, at a poster session held today at the 64th American Society of Hematology (ASH) Annual Meeting and Exposition in New Orleans.

The poster, entitled "The Second Generation Type II JAK2 inhibitor, AJ1-10502, Demonstrates Enhanced Selectivity, Improved Therapeutic Efficacy and Reduced Mutant Cell Fraction Compared to Type I JAK2 inhibitors in Models of Myeloproliferative Neoplasms (MPNs)," highlights the improved efficacy and disease modifying features of Ajax's Type II JAK2 inhibitor, AJ1-10502, when compared to the investigational, first generation Type II inhibitor, CHZ868, and the approved market-leading Type I inhibitor, ruxolitinib, in two different mouse models of MPNs.

In both MPN models studied, AJ1-10502 demonstrated dose dependent improvements in efficacy over ruxolitinib on key blood cell parameters, including reticulocytes and hematocrit, associated with MPNs, as well as superior reductions in spleen weights on par with JAK2 deletion. More importantly, AJ1-10502 caused significant reductions in mutant cell fraction within bone marrow and spleen not observed with ruxolitinib. Distinct from all currently approved JAK2 inhibitors, including ruxolitinib, that bind the Type I conformation of the JAK2 kinase and allow continued JAK/STAT signaling which leads to disease persistence, AJ1-10502 is designed to bind the Type II conformation of the JAK2 kinase. In preclinical studies, investigational Type II JAK2 inhibitors have been shown to overcome disease persistence to ruxolitinib and, most significantly, reduce mutant JAK2 allele burden that drives MPN disease progression. The ASH poster presentation is available on Ajax's website.

"We're very encouraged by the first preclinical data on our Type II JAK2 inhibitor program being presented today at the ASH Annual Meeting," said Craig E. Masse, PhD, Senior Vice President, Discovery Research at Ajax Therapeutics. "Our unique drug discovery capabilities, including state-of-the-art computational and structure-based technologies, have enabled us to develop Type II JAK2 inhibitors, such as AJ1-10502, that target JAK2 with greater precision and potency, while overcoming the limitations of current JAK2 therapies that interact with other JAK-family members and related kinases which limits their efficacy and leads to unwanted side effects."

"It's exciting to see Ajax's next generation Type II JAK2 inhibitor, AJ1-10502, demonstrate enhanced selectivity and efficacy with a much-improved safety profile than first generation Type II inhibitors," said Ross Levine, MD, Chair of Ajax's Scientific Advisory Board and Deputy Physician-in-Chief, Translational Research, Laurence Joseph Dineen Chair in Leukemia Research and Member of the Human Oncology and Pathogenesis Program at Memorial Sloan Kettering Cancer Center. "This data supports our findings that Type II JAK2 inhibitors can significantly reduce the mutant allele burden that drives MPNs which is not observed with Type I JAK2 inhibitors, such as ruxolitinib. We believe that more selective and potent JAK2 inhibitors, like AJ1-10502, could provide much needed new targeted therapies for MPN patients who are not well served by currently approved JAK2 inhibitors."

About Ajax Therapeutics

Ajax Therapeutics, Inc. is pursuing uniquely selective approaches to develop novel first-in-class therapeutics for myeloproliferative neoplasms (MPNs), including Myelofibrosis. By combining the deep cancer and structural biology insights of our founding scientists with the industry's most advanced computational drug discovery and protein structure platforms from our founding partner, Schrödinger, Inc., we aim to discover and develop more precisely designed therapies to address significant unmet needs for patients with MPNs.

Please find more information at www.ajaxtherapeutics.com.

NOTE: Dr. Ross Levine serves on the board of directors of, has provided advisory services for, and has equity interests in Ajax Therapeutics. Dr. Levine also has intellectual property rights and interests that MSK has licensed to Ajax. MSK has intellectual property rights and other financial interests related to Ajax.