Hypomethylating Therapy Does Not Improve Outcome of Therapy-Related Myeloid Neoplasm Including TP53 Mutated and Complex Karyotype Subgroups

Abstract

Introduction: Therapy related myeloid neoplasm (t-MN) is a rare but devastating complication of cytotoxic therapy used for management of unrelated malignancy or autoimmune diseases. Therapeutic options for t-MN are limited and although hypomethylating agents (HMA) are frequently used, the benefit of it in t-MN is unclear. There are no prospective trials of HMA in t-MN and published experience is based on retrospective analysis of small number of cases (n=42 to 54). The aim of this study was to assess the efficacy of HMA therapy in t-MN patients and evaluate predictors for it.Methods: t-MN patients managed with first line HMA therapy were analyzed. This study was approved by the participating institutional review board. Criteria for inclusion were a pathologically confirmed diagnosis of t-MN based on WHO 2016 criteria, age >18 years, and ≥1 cycle of decitabine or azacitidine.Patient characteristics were summarized by frequency (percentage). Overall survival was calculated from the time of starting azacitidine to last follow up or death date using Kaplan-Meier analysis. Multivariable analysis was performed using Cox proportional hazard model. Statistical analysis was performed using R program and significance was defined as P<0.05.Results: Of the 554 t-MN patients analyzed, 184 (33%) patients were treated with HMA as the first line therapy and were included in the study. Median age at t-MN diagnosis was 70 (IQR 64-75) years and 112 (60%) patients were male. At the time of diagnosis, 84% (n=154) and 16% (n=30) patients were classified as t-MDS and t-AML and 47% (87/184) and 46% (49/107) of the evaluable patients had complex karyotype and TP53 somatic mutations (TP53 Mut) respectively. Azacitidine (n=145, 79%) was most frequently used HMA followed by decitabine (n=39, 21%). Median survival of the whole cohort since t-MN diagnosis was 13.2 months.At the time of analysis further treatment details were available for 78 patients and outcome of these patients were compared with primary MDS (p-MDS) and oligoblastic AML managed at the same institute. Completion of six-cycles of HMA (50% vs. 62%; P=0.07) and overall response rate (47 vs. 50%, P=0.22) was not significantly different between t-MN and p-MDS. However, median OS of t-MN was significantly poor compared to p-MDS (10 vs. 20 months, P=0.0004; Figure 1A).In t-MN patients treated with HMA as the first-line agent, median OS was significantly shorter in t-AML compared to t-MDS (7 vs.10 months, P=0.04; Figure 1B). Median OS was significantly shorter in patients with TP53 Mut and complex karyotype (Figure 1C-D). In Cox proportional hazard analysis, t-AML and complex karyotype were independently associated with poor outcome.Conclusion: This study demonstrates significantly poor outcome of t-MN patients treated with HMA therapy as first line. The outcome is particularly poor in t-AML and patients with complex karyotype and TP53 Mut. Hence there is urgent need for clinical trials of novel therapies for t-MN. [Display omitted] DisclosuresSharplin: Kite Gilead: Honoraria; Novartis: Other: Travel Support. Ross: Keros Therapeutics: Consultancy, Honoraria; Bristol Myers Squib: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Hiwase: Novartis: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees.