Analysis of Patient-Level Data from 3 Cooperative Group Trials Confirms a Survival Advantage for NPM1m Patients Achieving MRD-Negative CR after Intensive Induction

Background:NPM1 mutations (NPM1m), predominantly tetra-nucleotide insertions in exon 12, are clonal driver events in acute myeloid leukemia (AML) and are found exclusively in leukemic cells, making them ideal for sensitive detection of measurable residual disease (MRD) using quantitative polymerase chain reaction (qPCR)- or next generation sequencing (NGS)-based methods. Over 50 peer-reviewed publications across multiple cooperative group trials have shown that NPM1m AML patients in complete remission (CR), CR with incomplete count recovery (CRi), or CR with partial hematologic recovery (CRh) have significantly better survival if they are MRD negative compared to MRD positive. Based on this body of evidence, the European LeukemiaNet recommends monitoring molecular MRD in NPM1m AML patients during treatment to help guide treatment decisions.

Purpose: To provide further evidence for the value of NPM1 MRD as a surrogate endpoint for prospective, randomized trials in patients receiving novel agents in combination with intensive chemotherapy by evaluating the relationship between MRD negativity in patients with CR after 2 cycles of chemotherapy and event-free survival (EFS) and overall survival (OS) in a pooled analysis of patient-level data from 3 large cooperative group trials. MRD in all 3 studies was assessed using reverse transcriptase-mediated qPCR (RT-qPCR) of NPM1m transcripts normalized to ABL transcripts.

Methods: Deidentified patient data for a total of 1,128 patients who achieved CR, CRi, or CRh, and who had MRD data after 2 cycles of chemotherapy, were provided by the UK National Cancer Research Institute AML Study Group (SG) for the AML17 (N = 539), the AMLSG for the AMLSG 09-09 (N = 497), and the Study Alliance Leukemia (SAL) for the AML2003 (N = 105) trials and standardized using Standard Data Tabulation Models. Data included demographic information, disease history, induction and consolidation treatment received, morphologic response, MRD data after 2 cycles of treatment, relapse, and survival. Cutoffs for MRD negativity were defined according to the definitions used in the individual studies (Ivey A, et al. N Engl J Med. 2016; Kapp-Schwoerer S, et al. Blood. 2020; Shayegi N, et al. Blood. 2013). In addition, sensitivity analyses were conducted using a range of cutoff values. CR was defined as <5% blasts in the bone marrow (BM) with count recovery, occurring within 42 days of the start of the last induction cycle; only these patients were included in the MRD analysis. EFS and OS were estimated using the Kaplan-Meier method and defined according to FDA criteria. Briefly, EFS was measured from day 1 of randomization to the date of treatment failure, hematologic relapse from CR or death from any cause; treatment failure was defined as not achieving CR after two cycles of chemotherapy. OS was measured from day 1 to the date of death from any cause. The absolute risk difference among MRD response status groups in EFS/OS at the 2-month, 1-year, 2-year, 3-year, and 5-year landmarks and their corresponding 95% confidence intervals (CI) were calculated using complementary log-log transformation. Hazard ratios (HR) were fitted using a Cox regression model with EFS/OS as the dependent variable and with MRD-response status and study as independent variables.

Results: Among the 515 patients who achieved a CR within 42 days at the start of chemotherapy Cycle 2, MRD negativity confers a substantial survival advantage with EFS HR (95% CI) = 1.6 (1.1-2.3) when measured in BM and 1.8 (1.4-2.4) in peripheral blood (PB) using the study-defined cutoffs for positive and negative. This advantage is also observed using cutoff definitions of MRD negativity ranging from <10 to <1,000 NPM1m/10⁴ABL transcripts. A survival advantage for OS was also observed with HR (95% CI) = 1.5 (1.0-2.4) and 1.7 (1.2-2.3) in BM and PB, respectively. Analysis of the predictive value of MRD negativity in the 613 patients who achieved CRi/CRh within 42 days of the start of Cycle 2 is underway.

Conclusions: Analysis of pooled patient-level data confirms the survival advantage of achieving MRD-negative CR as previously reported in 3 independent, cooperative group trials using different induction regimens. The prognostic value of MRD negativity in NPM1m AML is consistent across a broad range of cutoff definitions in both BM and PB providing further evidence for the value of NPM1 MRD as a surrogate endpoint for clinical trials.

Döhner:Astellas: Research Funding; Agios: Research Funding; BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kronos: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Döhner:Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Syndax Pharmaceuticals Inc.: Consultancy, Honoraria; Gilead Sciences, Inc.: Consultancy, Honoraria; Astellas Pharma Inc.: Consultancy, Honoraria, Research Funding; Amgen Inc.: Consultancy, Honoraria, Research Funding; Agios Pharmaceuticals: Consultancy, Honoraria, Research Funding; AbbVie Inc.: Consultancy, Honoraria, Research Funding; Servier: Consultancy, Honoraria; Kronos Bio, Inc.: Research Funding; Janssen Pharmaceuticals: Consultancy, Honoraria; Daiichi Sankyo Co, LTD: Consultancy, Honoraria; Pfizer Inc.: Research Funding; Brystol Myers Squibb: Consultancy, Honoraria, Research Funding; AstraZeneca: Honoraria; Berlin-Chemie: Consultancy, Honoraria. Kapp-Schwoerer:Pfizer Inc.: Consultancy; AbbVie Inc.: Consultancy, Honoraria, Other: Travel support; Jazz Pharmaceuticals: Consultancy, Honoraria, Other: Travel support. Russell:Pfizer: Honoraria, Research Funding, Speakers Bureau; Jazz Pharma: Research Funding; Servier: Honoraria; Astellas: Honoraria. Röllig:Celgene Corporation: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; Jazz Pharmaceuticals: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Amgen Inc.: Honoraria; AbbVie Inc.: Consultancy, Honoraria, Research Funding; Pfizer Inc.: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria; Servier: Consultancy. Thiede:Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen Pharmaceuticals: Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AgenDix GmbH: Current Employment, Current equity holder in private company; Kronos Bio, Inc.: Honoraria. Oellerich:Gilead Sciences, Inc.: Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria; Merck KGaA: Consultancy, Research Funding. Elder:PharPoint Research, Inc.: Current Employment. Carvajal:Kronos Bio, Inc.: Current Employment. To:Kronos Bio, Inc.: Current Employment. DiMartino:Kronos Bio, Inc.: Current Employment, Current equity holder in publicly-traded company; Bristol Myers Squibb: Current equity holder in publicly-traded company. Dillon:Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Research Funding; Astellas: Consultancy, Honoraria, Speakers Bureau; Avencell: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Shattuck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.