Patients with acute myeloid leukemia (AML) and a FLT3 internal tandem duplication (ITD) have poor outcomes to current treatment. A phase 2 hypothesis-generating trial was conducted to determine whether the addition of the multitargeted kinase inhibitor midostaurin to intensive chemotherapy followed by allogeneic hematopoietic cell transplantation (alloHCT) and single-agent maintenance therapy of 12 months is feasible and favorably influences event-free survival (EFS) compared with historical controls. Patients 18 to 70 years of age with newly diagnosed AML and centrally confirmed FLT3-ITD were eligible: 284 patients were treated, including 198 younger (18-60 years) and 86 older (61-70 years) patients. Complete remission (CR) rate, including CR with incomplete hematological recovery (CRi) after induction therapy, was 76.4% (younger, 75.8%; older, 77.9%). The majority of patients in CR/CRi proceeded to alloHCT (72.4%). Maintenance therapy was started in 97 patients (34%): 75 after alloHCT and 22 after consolidation with high-dose cytarabine (HiDAC). Median time receiving maintenance therapy was 9 months after alloHCT and 10.5 months after HiDAC; premature termination was mainly a result of nonrelapse causes (gastrointestinal toxicity and infections). EFS and overall survival at 2 years were 39% (95% confidence interval [CI], 33%-47%) and 34% (95% CI, 24%-47%) and 53% (95% CI, 46%-61%) and 46% (95% CI, 35%-59%) in younger and older patients, respectively. EFS was evaluated in comparison with 415 historical controls treated within 5 prospective trials. Propensity score-weighted analysis revealed a significant improvement of EFS by midostaurin (hazard ratio [HR], 0.58; 95% CI, 0.48-0.70; P < .001) overall and in older patients (HR, 0.42; 95% CI, 0.29-0.61). The study was registered at www.clinicaltrials.gov as #NCT01477606.

The azanucleosides azacitidine and decitabine are currently used for the treatment of acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) in patients not only eligible for intensive chemotherapy but are also being explored in other hematologic and solid cancers. Based on their capacity to interfere with the DNA methylation machinery, these drugs are also referred to as hypomethylating agents (HMAs). As DNA methylation contributes to epigenetic regulation, azanucleosides are further considered to be among the first true “epigenetic drugs” that have reached clinical application. However, intriguing new evidence suggests that DNA hypomethylation is not the only mechanism of action for these drugs. This review summarizes the experience from more than 10 years of clinical practice with azanucleosides and discusses their molecular actions, including several not related to DNA methylation. A particular focus is placed on possible causes of primary and acquired resistances to azanucleoside treatment. We highlight current limitations for the success and durability of azanucleoside-based therapy and illustrate that a better understanding of the molecular determinants of drug response holds great potential to overcome resistance.

We performed serial measurable residual disease (MRD) monitoring in bone marrow (BM) and peripheral blood (PB) samples of 155 intensively treated patients with RUNX1-RUNX1T1-positive AML using an RT-qPCR-based assay with a sensitivity of up to 10^-6. We assessed both reduction of RUNX1-RUNX1T1 transcript levels and achievement of MRD negativity (MRD^neg) for impact on prognosis. Achievement of MR^2.5 (>2.5 log reduction) after treatment cycle 1 and achievement of MR^3.0 after treatment cycle 2 were significantly associated with a reduced risk of relapse (P=0.034 and P=0.028, respectively). After completion of therapy, achievement of MRD^neg in both, BM and PB, was an independent favorable prognostic factor for cumulative incidence of relapse (4-year CIR BM: 17% vs 36%, P=0.021; PB: 23% vs 55%; P=0.001) and overall survival (4-year OS rate BM: 93% vs 70%, P=0.007; PB: 87% vs 47%; P<0.0001). Finally, during follow-up serial RT-qPCR analyses allowed prediction of relapse in 77% of patients exceeding a cut-off value of 150 RUNX1-RUNX1T1 transcript levels in BM, and in 84% of patients exceeding a value of 50 RUNX1-RUNX1T1 transcript levels in PB. KIT mutation was a significant factor predicting for lower CR rate and inferior outcome, but its prognostic impact was outweighed by RUNX1-RUNX1T1 transcript levels during treatment. Virtually all relapses occurred within one year after end of treatment with a very short latency from molecular to morphologic relapse, necessitating MRD assessment at short intervals during this time period. Based on our data we here propose a refined practical guideline for MRD assessment in RUNX1-RUNX1T1-positive AML. Key Points MRD assessment in t(8;21) AML allows identifications of patients at high relapse risk at defined time points during treatment and follow-up. MRD^neg at EOT is the most valuable favorable factor for relapse risk and OS, and serial MRD analyses define cut-offs predicting relapse.

Monitoring of measurable residual disease (MRD) provides prognostic information in patients with Nucleophosmin1 mutated (NPM1^mut) acute myeloid leukemia (AML) and represents a powerful tool to evaluate treatment effects within clinical trials. We determined NPM1^mut transcript levels (TL) by RQ-PCR and evaluated the prognostic impact of NPM1^mut MRD and the effect of gemtuzumab ozogamicin (GO) on NPM1^mut TL and the cumulative incidence of relapse (CIR) in patients with NPM1^mut AML enrolled in the randomized phase III AMLSG 09-09 trial. 3733 bone marrow (BM) and 3793 peripheral blood (PB) samples from 469 patients were analyzed. NPM1^mut TL log₁₀ reduction ≥3 and achievement of MRD negativity in BM and PB were significantly associated with a lower CIR rate, after two treatment cycles and at end of treatment (EOT). In multivariate analyses, MRD positivity consistently revealed as poor prognostic factor in BM and PB. With regard to treatment effect, the median NPM1^mut TL were significantly lower in the GO-Arm across all treatment cycles, resulting in a significantly higher proportion of patients achieving MRD negativity at EOT (56% vs 41%; P=.01). The betterreduction of NPM1^mut TL after two treatment cycles in MRD-positive patients by the addition of GO led to a significantly lower CIR rate (4-year CIR 29.3% vs 45.7%, P=.009). In conclusion, the addition of GO to intensive chemotherapy in NPM1^mut AML resulted in a significantly better reduction of NPM1^mut TL across all treatment cycles leading to a significantly lower relapse rate. The AMLSG 09-09 trial was registered at www.clinicaltrials.gov as #NCT00893399.

Clonal hematopoiesis (CH) is an age-related condition predisposing to blood cancer and cardiovascular disease (CVD). Murine models demonstrate CH-mediated altered immune function and proinflammation. Low-grade inflammation has been implicated in the pathogenesis of osteoarthritis (OA), the main indication for total hip arthroplasty (THA). THA-derived hip bones serve as a major source of healthy hematopoietic cells in experimental hematology. We prospectively investigated frequency and clinical associations of CH in 200 patients without known hematologic disease who were undergoing THA. Prevalence of CH was 50%, including 77 patients with CH of indeterminate potential (CHIP, defined as somatic variant allele frequencies [VAFs] ≥2%), and 23 patients harboring CH with lower mutation burden (VAF, 1% to 2%). Most commonly mutated genes were DNMT3A (29.5%), TET2 (15.0%), and ASXL1 (3.5%). CHIP is significantly associated with lower hemoglobin, higher mean corpuscular volume, previous or present malignant disease, and CVD. Strikingly, we observed a previously unreported association of CHIP with autoimmune diseases (AIDs; multivariable adjusted odds ratio, 6.6; 95% confidence interval, 1.7-30; P = .0081). These findings underscore the association between CH and inflammatory diseases. Our results have considerable relevance for managing patients with OA and AIDs or mild anemia and question the use of hip bone–derived cells as healthy experimental controls.

We conducted a single-arm, phase 2 trial (German-Austrian Acute Myeloid Leukemia Study Group [AMLSG] 16-10) to evaluate midostaurin with intensive chemotherapy followed by allogeneic hematopoietic-cell transplantation (HCT) and a 1-year midosta urin maintenance therapy in adult patients with acute myeloid leukemia (AML) and fms-related tyrosine kinase 3 (FLT3) internal tandem duplication (ITD). Patients 18 to 70 years of age with newly diagnosed FLT3-ITD-positive AML were eligible. Primary and key secondary endpoints were event-free survival (EFS) and overall survival (OS). Results were compared with a historical cohort of 415 patients treated on 5 prior AMLSG trials; statistical analysis was performed using a double-robust adjustment with propensity score weighting and covariate adjustment. Results were also compared with patients (18-59 years) treated on the placebo arm of the Cancer and Leukemia Group B (CALGB) 10603/RATIFY trial. The trial accrued 440 patients (18-60 years, n = 312; 61-70 years, n = 128). In multivariate analysis, EFS was significantly in favor of patients treated within the AMLSG 16-10 trial compared with the AMLSG control (hazard ratio [HR], 0.55; P < .001); both in younger (HR, 0.59; P < .001) and older patients (HR, 0.42; P < .001). Multivariate analysis also showed a significant beneficial effect on OS compared with the AMLSG control (HR, 0.57; P < .001) as well as to the CALGB 10603/RATIFY trial (HR, 0.71; P = .005). The treatment effect of midostaurin remained significant in sensitivity analysis including allogeneic HCT as a time-dependent covariate. Addition of midostaurin to chemotherapy was safe in younger and older patients. In comparison with historical controls, the addition of midostaurin to intensive therapy led to a significant improvement in outcome in younger and older patients with AML and FLT3-ITD. This trial is registered at clinicaltrialsregistry.eu as Eudra-CT number 2011-003168-63 and at clinicaltrials.gov as NCT01477606.