Morphologic Leukemia-Free State in Acute Myeloid Leukemia Is Sufficient for Successful Allogeneic Hematopoietic Stem Cell Transplant
Authors: Pabon Cindy M. , Li Zhiguo , Hennig Therese , De Castro Carlos , Neff Jadee , Horwitz Mitchell E. , Leblanc Thomas W. , Long Gwynn D. , Lopez Richard D. , Sung Anthony D. , Chao Nelson J. , Gasparetto Cristina , Sarantopoulos Stefanie , Adams Donna B. , Erba Harry P. , Rizzieri David A 
Published: February 2021

Allogeneic hematopoietic cell transplant (HCT) improves survival in patients with relapsed or high risk acute myeloid leukemia (AML). Complete remission (CR) is typically a pre-requisite for transplantation, though many do not achieve a formal CR. The traditional AML treatment starts with induction chemotherapy, followed by assessment of response to guide next steps. Response criteria definitions differ between that of the National Comprehensive Cancer Network (NCCN), utilized by the majority of clinicians, and the Center for International Blood and Marrow Research (CIBMTR) data registry utilized by transplant centers, making interpretation of the impact of HCT difficult. Definitions for morphologic complete remission (CR) are the same, however complete remission with incomplete hematologic recovery (CRi) differs and the CIBMTR does not recognize the morphologic leukemia-free state (MLFS), thus mis-identifying such patients and preventing clear treatment guidelines for this population. We conducted a retrospective study, identifying a cohort of 35 AML patients at our center who underwent allogeneic HCT while in MLFS, to evaluate characteristics in patient demographics, disease status, treatment(s), and outcomes. From our cohort, the median overall survival (OS) was 14 months, however 37% were alive and in remission with median follow-up of survivors of five years. Twenty three percent had progression of disease following transplant. Non-relapse mortality (NRM) was 35% with leading cause of death being infection. Our study reveals that transplant can induce long-term survival in patients with acute leukemia who are in MLFS at the start of induction, similar to data for patients with high risk disease in early relapse or in later remissions. Early transplantation while in MLFS and not waiting for full count recovery may protect patients from toxicities of further chemotherapeutic agents or prevent unnecessary delays that may allow for infections or other barriers to arise, and requires further study.

Disclosures
Leblanc: American Cancer Society, BMS, Duke University, NINR/NIH, Jazz Pharmaceuticals, Seattle Genetics: Research Funding; UpToDate: Patents & Royalties: Royalties; Agios, AbbVie, and Bristol Myers Squibb/Celgene: Speakers Bureau; AstraZeneca: Research Funding; AbbVie, Agios, Amgen, AstraZeneca, CareVive, BMS/Celgene, Daiichi-Sankyo, Flatiron, Helsinn, Heron, Otsuka, Medtronic, Pfizer, Seattle Genetics, Welvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Rizzieri:Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite: Honoraria, Speakers Bureau; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Stemline: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Mustang: Membership on an entity's Board of Directors or advisory committees; Celltrion: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AROG: Membership on an entity's Board of Directors or advisory committees; abbvie: Membership on an entity's Board of Directors or advisory committees; Teva: Membership on an entity's Board of Directors or advisory committees; Acrobiotech: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees.