Secondary Acute Myeloid Leukemia from a Previous Chronic Myeloproliferative Neoplasm: A Study of Grelam-Chile Concerning Chilean Patients on Behalf of AML Pethema Registry

Introduction: Secondary Acute Myeloid Leukemia (sAML) from Chronic Myeloproliferative Neoplasm (chMPN) is associated with an unfavorable prognosis and is characterized by a unique set of cytogenetic and molecular features distinct from de novo AML. The only cure for these patients is allogeneic Stem Cell Transplantation (SCT), which usually is not possible given the advanced age and comorbidities from this patient population. Methods: We present a retrospective analysis of sAML Chilean patients due to chMPN from the multicentric epidemiological registry of AML of the PETHEMA Spanish Group. Results: There are 802 AML Chilean patients incorporated in the online PETHEMA platform. 158 are sAMLand 26 are secondary to chMPN. Compared with the sAML group, patients with previous chMPN were mainly male (56% vs. 76%, respectively), had a larger white blood cell count (32,720 mm3 vs. 61,130 mm3), and had splenomegaly (P <0.05). There was no difference in age (median 62,35 years old), peripheral blood blasts (media 28,8%), fibrinogen (287 mg/dl), or other laboratory tests (p>0.05). Regardless of the type of chMPN: Chronic Myeloid Leukemia: 8 patients: Chronic myelomonocytic leukemia: 5, Primary Myelofibrosis: 5, Chronic Myeloproliferative Syndrome not specified subtype: 6, Polycythemia Vera/essential Thrombocytosis 2. 50% received previously chemotherapy, mainly Tyrosine Kinase Inhibitors (7) and hydroxycarbamide (7). Regardless sAML % had an abnormal karyotype. Treatment used, it was Anthracycline/Daunorubicin (38%), azacytidine with or without Venetoclax (19%), and palliative care (23%). In the first induction, the rate of Complete response (CR), or complete response with incomplete hematological response (iCR), was reached in only 3 patients, and these had negative MRD. From the patients with partial responses, 9 patients received a second line of treatment, mainly azacytidine. After that, three more patients reached CR. Only one patient received allogeneic SCT. The average stay in the hospital was 41,4 days, and Overall survival (OS) was 12,2 months (OS in all sAML was 14,2 months, N.S. p>0.05). The mortality rate was 84%, and the main cause was progressive disease in 60% of those cases. Conclusion: We present our local experience with this type of sAML. The outcome remains poor; it seems that allogeneic SCT is the only cure, but most patients cannot reach it. More research is needed to improve the high rates of mortality for this patient population.