Omission of Maintenance in Patients with High-Risk Acute Promyelocytic Leukemia (APL) in the Era of ATRA/Arsenic Consolidation

Abstract Introduction: The role of maintenance treatment in patients with high-risk Acute Promyelocytic Leukemia (APL) in the era of ATO/ATRA is unclear. Methods: We retrospectively reviewed electronic medical records of patients with high-risk Acute Promyelocytic Leukemia (APL) and identified patients who did not receive maintenance. Results: We have identified 9 patients with high-risk APL who did not receive maintenance therapy. Five patients were females and 8 were white. The median age was 47-year-old (range 26-77 year old). The median WBC was 41,500 (range 14,700-167,500). The median blast percentage was 81% (range 1%-91%). The median platelet count was 28,000 (range 7,000-60,000). One patient received G-CSF prior to diagnosis of APL but the majority of cells on presentation were blasts. Two patients had additional cytogenetics changes apart from presence of t(15;17)(q22;21). Three patients had FLT3 ITD detected. All patients received ATRA during induction. Moreover, during induction 8 patients received Arsenic and all but one received Idarubicin. Seven of the 8 received Idarubicin according to Australasian APLM4 study. Bone marrow biopsies following induction were negative for PML/RARA by FISH analysis. RT-PCR for PML/ RARA was obtained at the time of the bone marrow (BM) biopsy in 8 patients and was negative. One patient had assessment close to the time of BM biopsy from peripheral blood and was negative. The median time from diagnosis to post Induction bone marrow was 49 days (range 32-56 days). All patients received 4 cycle of consolidation with ATRA and ATO according to Italian-German APL 0406 trial ( Lo-Coco et al., NEJM 2013). Three patients received Intrathecal chemotherapy for prophylaxis. Six of 9 had end-of-treatment bone marrow, which were negative for relapse. All patients were subsequently followed by RT-PCR for PML/RARA for molecular relapse. At last follow-up, all patients are alive and were in molecular remission. The median follow-up from diagnosis was 916 day (range 429-1674). Conclusion: We report our experience of high-risk APL patients in our institution who did not receive maintenance. None of the patients relapsed and our data suggest that patients that do not undergo maintenance in the era of ATO/Arsenic consolidation may remain in remission. Disclosures Erba: Takeda/Millenium: Research Funding; Pfizer: Consultancy, Other: grant; Celgene: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Takeda/Millenium: Research Funding; Pfizer: Consultancy, Other: grant; Incyte: Consultancy, Speakers Bureau; Amgen: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Astellas: Research Funding; Incyte: Consultancy, Speakers Bureau; Jazz: Consultancy, Speakers Bureau; Astellas: Research Funding; Seattle Genetics: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Amgen: Research Funding; Novartis: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Astellas: Research Funding; Agios: Consultancy, Speakers Bureau; Agios: Consultancy, Speakers Bureau; Glycomimetics: Consultancy, Other: Chair, Data and Safety Monitoring Committee; Novartis: Consultancy, Speakers Bureau; Amgen: Research Funding; Amgen: Research Funding; Glycomimetics: Consultancy, Other: Chair, Data and Safety Monitoring Committee; Astellas: Research Funding; Seattle Genetics: Consultancy, Research Funding; Janssen: Research Funding; Janssen: Research Funding; MacroGenics: Consultancy; MacroGenics: Consultancy; Pfizer: Consultancy, Other: grant; Juno: Research Funding; Juno: Research Funding; Pfizer: Consultancy, Other: grant; Agios: Consultancy, Speakers Bureau; Agios: Consultancy, Speakers Bureau; Seattle Genetics: Consultancy, Research Funding; Incyte: Consultancy, Speakers Bureau; Seattle Genetics: Consultancy, Research Funding; Incyte: Consultancy, Speakers Bureau; Jazz: Consultancy, Speakers Bureau; Takeda/Millenium: Research Funding; Immunogen: Consultancy, Research Funding; Jazz: Consultancy, Speakers Bureau; Takeda/Millenium: Research Funding; Celgene: Consultancy, Speakers Bureau; Immunogen: Consultancy, Research Funding; MacroGenics: Consultancy; Glycomimetics: Consultancy, Other: Chair, Data and Safety Monitoring Committee; MacroGenics: Consultancy; Celgene: Consultancy, Speakers Bureau; Juno: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Glycomimetics: Consultancy, Other: Chair, Data and Safety Monitoring Committee; Juno: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Immunogen: Consultancy, Research Funding; Jazz: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Immunogen: Consultancy, Research Funding. Papadantonakis: Agios pharmaceuticals: Honoraria, Other: advisory board.