Omeros reports primate data for OncotoX-AML program
Omeros reported initial nonhuman primate data for OncotoX-AML in acute myeloid leukemia. One treatment course reduced myeloid progenitor cells by up to 99% and was well tolerated.
Omeros Corporation announced the successful completion of its initial study in nonhuman primates evaluating the efficacy and safety of its OncotoX-AML cancer therapeutic platform. Administration of only one course of OncotoX-AML treatment to immunocompetent primates demonstrated marked, selective, reversible, and dose-related reduction in myeloid progenitor cells by up to 99 percent, and the treatment was well tolerated without broader or lasting hematologic changes while preserving hematopoietic stem cells.
OncotoX-AML is first targeting acute myeloid leukemia, an aggressive and highly fatal bone marrow and blood cancer. The therapeutic is an engineered biologic designed to selectively kill both AML blasts and relapse-related leukemia stem cells, and its mechanism of action is independent of myeloid cell genetic mutations, including TP53, NPM1, KMT2A, and FLT3, collectively found in approximately 90 percent of AML patients.
The company said there were no observed safety signals or meaningful changes in blood chemistry values often seen with current AML treatments. In preclinical studies using patient-derived AML cells, OncotoX-AML molecules preferentially and efficiently killed myeloid cancer cells regardless of their respective mutational signature.
In multiple in vivo murine-human xenograft models, OncotoX-AML treatment consistently demonstrated superior efficacy compared to the combination of venetoclax and azacitidine. Across these models, OncotoX-AML eradicated all disseminated tumors, extending survival in all animals to over 100 days without evidence of tumor recurrence, compared to a median survival increase of 8 days with venetoclax and azacitidine.
The company said it is now initiating IND-enabling studies to bring OncotoX-AML to the clinic, targeting a first-in-human trial for late 2027. AML is estimated to have been responsible for over 11,000 U.S. deaths in 2025.