Bomedemstat has efficacy in the treatment of myelofibrosis and may have a special role in treatment of specific AML subtypes, including secondary leukaemias arising from MPN as seen.<h4>Conclusion</h4>We report a case of an older adult with secondary AML transformed from ET, with a remarkable response to LSD1 inhibition with Bomedemstat, with prolonged reduction in blasts demonstrating differentiation to monocytes. The gene discussed is KDM1A; the disease is myeloproliferative disorder.