A high proportion of patients with acute myeloid leukemia who achieve minimal residual disease (MRD) negative status ultimately relapse because a fraction of pathological clones remains undetected by standard methods. We designed and validated a high-throughput sequencing method for MRD assessment of cell clonotypes with mutations of NPM1, IDH1/2 and/or FLT3-SNVs. For clinical validation, 106 follow-up samples from 63 patients in complete remission were studied by NGS, evaluating the level of mutations detected at diagnosis. The predictive value of MRD status by NGS, multiparameter flow cytometry, or quantitative PCR was determined by survival analysis. The method achieved a sensitivity of 10-4 for SNV mutations and 10-5 for insertions/deletions and could be used in acute myeloid leukemia patients who carry any mutation (86% in our diagnosis data set). NGS-determined MRD positive status was associated with lower disease-free survival (hazard ratio [HR] 3.4, p=0.005) and lower overall survival (HR 4.2, p<0.001). Multivariate analysis showed that MRD positive status by NGS was an independent factor associated with risk of death (HR 4.54, p =0.005) and the only independent factor conferring risk of relapse (HR 3.76, p =0.012). This NGS based method simplifies and standardizes MRD evaluation, with high applicability in acute myeloid leukemia. It also improves upon flow cytometry and quantitative PCR to predict acute myeloid leukemia outcome and could be incorporated in clinical settings and clinical trials.

The need for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in adults with Philadelphia chromosome-negative (Ph-neg) acute lymphoblastic leukemia (ALL) with high-risk (HR) features and adequate measurable residual disease (MRD) clearance remains unclear. The aim of the ALL-HR-11 trial was to evaluate the outcomes of HR Ph-neg adult ALL patients following chemotherapy or allo-HSCT administered based on end-induction and consolidation MRD levels. Patients aged 15-60 years (y) with HR-ALL in complete response (CR) and MRD levels (centrally assessed by 8-color flow cytometry) &lt;0.1% after induction and &lt;0.01% after early consolidation, were assigned to receive delayed consolidation and maintenance therapy up to 2y in CR. The remaining patients were allocated to allo-HSCT. CR was attained in 315/348 patients (91%), with MRD &lt;0.1% after induction in 220/289 patients (76%). By intention-to treat, 218 patients were assigned to chemotherapy and 106 to allo-HSCT. The 5-year (±95%CI) cumulative incidence of relapse (CIR), overall survival (OS) and event-free survival (EFS) probabilities for the whole series were 43%±7%, 49%±7% and 40±6%, respectively, with CIR and OS rates of 45±8% and 59±9% for patients assigned to chemotherapy and of 40±12% and 38±11% for those assigned to allo-HSCT, respectively. Our results show that avoiding allo-HSCT does not hamper the outcomes of HR Ph-neg adult ALL patients up to 60y with adequate MRD response after induction and consolidation. Better post-remission alternative therapies are especially needed for patients with poor MRD clearance. ClinicalTrials.gov (NCT01540812)

Summary This study aimed to standardize a simple molecular method for evaluating the response to treatment in multiple myeloma (MM) patients after high dose chemotherapy. Fifty three patients enrolled in the GEM2000 protocol were studied for minimal residual disease (MRD) using both fluorescent‐polymerase chain reaction (F‐PCR) and flow cytometry. Most patients had achieved complete remission or very good response after autologous stem cell transplantation. The molecular analysis of immunoglobulin gene rearrangements at diagnosis and during the follow‐up was carried out by F‐PCR according to the Biomed‐2 protocols. F‐PCR could be used in 91% of the patients and the results were similar to flow cytometry. F‐PCR was able to identify a group of patients with a better prognosis [progression‐free survival (PFS) 67·86% in patients with negative F‐PCR vs. 28%; P = 0·001], even amongst patients who achieved a complete response with negative immunofixation (PFS 75% vs. 25%; P = 0·002). Multivariate analysis identified the F‐PCR result as the only variable to show a prognostic value when PFS was analysed. F‐PCR of DHJ and light chain rearrangements of immunoglobulin genes is a feasible method for evaluating MRD in MM patients after intensive therapy. Achieving molecular response by F‐PCR shows prognostic value.

High-dose chemotherapy supported by autologous stem cell transplantation (HDT/ASCT) has contributed to modify the natural history of follicular lymphoma (FL); however, an overall survival (OS) benefit has been demonstrated at relapse only after a rituximab-free chemotherapy regimen. A total of 655 patients with FL were reported to the Spanish GELTAMO (Grupo Español de Linfomas y Trasplantes de Médula Ósea) registry and underwent first ASCT between 1989 and 2007. A total of 203 patients underwent ASCT in first complete response (CR1), 174 in second complete response (CR2), 28 in third complete response (CR3), 140 in first partial response (PR1), 81 in subsequent PR, and 29 with resistant/refractory disease; 184 patients received rituximab before ASCT. With a median follow-up of 12 years from ASCT, median progression-free survival (PFS) and overall survival (OS) were 9.7 and 21.3 years, respectively. Actuarial 12-year PFS and OS were 63% (95% confidence interval [CI], 58%-68%) and 73% (95% CI, 68%-78%), respectively, for patients in CR (with a plateau in the curve beyond 15.9 years), 25% (95% CI, 19%-28%) and 49% (95% CI 42%-56%), respectively, for patients in PR, and 23% (95% CI, 8%-48%) and 28% (95% CI, 9%-45%), respectively, for patients with resistant/refractory disease (P < .001). In patients who received rituximab before ASCT, the estimated 9-year PFS and OS from ASCT were 59.5% (95% CI, 51%-67%) and 75% (95% CI, 68%-83%), respectively. Interestingly, for patients who underwent transplantation in CR ≥2 or PR ≥2 who had received rituximab before ASCT (n = 90), 9-year PFS and OS were 61% (95% CI, 51%-73%) and 75% (95% CI, 65%-80%), respectively, with no relapses occurring beyond 5.1 years after ASCT. The cumulative incidence of second malignancies in the global series was 6.7% at 5 years and 12.8% at 10 years. This analysis strongly suggests that ASCT is a potentially curative option for eligible patients with FL. In the setting of relapse, it is of especial interest in pretransplantation rituximab-sensitive patients with FL.

Native or pegylated (PEG) asparaginase (ASP) are commonly used in treatment of acute lymphoblastic leukemia (ALL), but have been scarcely compared in the same trial in adult patients. Native vs. PEG-ASP administered according to availability in each center were prospectively evaluated in adults with high-risk ALL. Ninety-one patients received native ASP and 35 PEG-ASP in induction. No significant differences were observed in complete remission, minimal residual disease levels after induction and after consolidation, disease-free survival, and overall survival. No significant differences in grades 3-4 toxicity were observed in the induction period, although a trend for higher hepatic toxicity was observed in patients receiving PEG-ASP. In this trial the type of ASP did not influence patient response and outcome.