European Medicines Agency Authorizes Oryzon’s Phase II IDEAL Trial Of Iadademstat In Essential Thrombocythemia

Oryzon Genomics, S.A. announced that the European Medicines Agency has authorized its Clinical Trial Application (CTA) to begin a Phase II study of iadademstat for the treatment of essential thrombocythemia (ET). Iadademstat is a potent and selective LSD1 inhibitor currently in clinical development across oncology and hematology indications. The Phase II trial, named IDEAL (IaDademstat treatment for EssentiAL thrombocythemia), will be conducted in Spain in adult ET patients who are resistant or intolerant to hydroxyurea.

The multicenter, single-arm study will evaluate safety, tolerability, and efficacy, specifically measuring the reduction in abnormal platelet counts. Secondary endpoints include durable clinical hematologic response rates, confirmation of pharmacokinetic and pharmacodynamic profiles, and the duration of hematologic remissions. Treatment will be administered for up to 24 weeks, with an optional 24-week extension for patients who continue to benefit.

Dr. Carlos Buesa, Oryzon’s CEO, said, “The initiation of the IDEAL study reinforces our strategy to broaden the clinical utility of iadademstat beyond acute leukemia into additional hematologic indications with significant unmet medical need. Iadademstat is by far the most potent LSD1 inhibitor in clinical development, with more than 100-fold greater potency than any other LSD1 inhibitor currently in development. We believe the mechanistic profile of LSD1 inhibition uniquely positions iadademstat to address the underlying biology of essential thrombocythemia, and we look forward to advancing this important program, with the potential to demonstrate efficacy across the full spectrum of myeloproliferative diseases.”

Essential thrombocythemia is the most common myeloproliferative neoplasm and carries risks of serious complications such as stroke, myocardial infarction, and pulmonary embolism. While current therapies primarily focus on platelet reduction and symptom management, many patients develop resistance or intolerance to first-line treatments like hydroxyurea. LSD1 inhibition has demonstrated the ability to interfere with megakaryocyte differentiation into platelets, supporting its therapeutic potential in ET. Positive Phase II data with another LSD1 inhibitor in high-risk ET further validate this mechanism.

Dr Ana Limón, Oryzon’s Senior Vice-president of Clinical Development and Global Medical Affairs added, “LSD1 inhibition alters the natural biology of myeloid diseases by reversing differentiation blocks and reducing the prevalence of leukemic stem cells. Early intervention in ET could potentially prevent progression to post-ET myelofibrosis or secondary AML. The IDEAL study will explore this potential of iadademstat, in addition to assessing its dose-dependent effects on platelet counts and thrombotic events in ET patients who are resistant or intolerant to standard-of-care treatment with hydroxyurea.”

Beyond ET, iadademstat is under active investigation in multiple oncology programs. In the Phase Ib ALICE-2 trial combining iadademstat with venetoclax and azacitidine in first-line acute myeloid leukemia (AML), preliminary results presented at the American Society of Hematology (ASH) 2025 meeting showed a 100% overall response rate and 90% strict complete remission rate. Additional studies include the FRIDA trial in combination with gilteritinib for relapsed/refractory FLT3-mutated AML, as well as programs conducted under a Cooperative Research and Development Agreement with the National Cancer Institute. The company is also evaluating iadademstat in sickle cell disease and other hematologic and solid tumor indications.