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Summary The prognostic value of minimal residual disease (MRD) measured by fusion‐gene transcript (FGT) detection was investigated in 76 infants (aged ≤1 year) with acute lymphoblastic leukaemia (ALL) with lysine methyltransferase 2A (KMT2A) rearrangements. Either at the end of induction or at later time‐points, FGT‐MRD‐positivity was associated with poor outcome. FGT‐MRD‐positivity after first consolidation or first high‐risk block detected 46·5% of infants with extremely poor outcome [disease‐free survival (SE) 0·06 (0·06), cumulative incidence of relapse (SE) 0·91 (0·05)], which was also confirmed in multivariable analysis. Thus, FGT‐MRD measurement at a single time‐point clearly identifies infants with ALL who are curable with conventional chemotherapy and those who would benefit only from other treatment approaches.

We compared the efficacy and safety of eltrombopag (ELTR) combined with immunosuppressive therapy (IST) and IST alone in treatment-naïve children with severe (SAA) and very severe (vSAA) aplastic anemia. Ninety-eight pediatric patients were randomized to receive horse antithymocyte globulin and cyclosporin A with (n=49) or without (n=49) ELTR. The primary endpoint was the overall response rate (ORR) at 4 months. After 4 months, nonresponders were crossed over to the alternative group. In all patients, the ORR in ELTR+IST and IST groups was similar (65% vs. 53%, p=0.218); however, the complete response (CR) rate was significantly higher in ELTR+IST group (31% vs. 12%, p=0.027). In severity subgroups, the ORR was 89% vs. 57% (p=0.028) in favor of IST+ELTR in SAA, but it did not differ in patients with vSAA (52% vs. 50%, p=0.902). At 6 months after the crossover, 61% of initial ELTR(-) patients achieved a response compared to 17% of initial ELTR(+) patients (p=0.016). No significant difference in ELTR+IST and IST groups was observed in the 3-year OS (89% vs. 91%, p=0.673) or the 3-year EFS (53% vs. 41%, p=0.326). There was no unexpected toxicity related to ELTR. Adding ELTR to standard IST was well tolerated and increased the CR rate. The greatest benefit from ELTR combined with IST was observed in patients with SAA, but not in those with vSAA. The second course of IST resulted in a high ORR in initial ELTR(-) patients who added ELTR and had limited efficacy among patients who received ELTR upfront. Clinicaltrials.gov #NCT03413306.

Summary This study aimed to evaluate the concordance between minimal residual disease (MRD) results obtained by multicolour flow cytometry (MFC) and polymerase chain reaction for fusion gene transcripts (FGTs) in infants with acute lymphoblastic leukaemia (ALL) associated with rearrangement of the KMT2A gene (KMT2A‐r). A total of 942 bone marrow (BM) samples from 123 infants were studied for MFC‐MRD and FGT‐MRD. In total, 383 samples (40.7%) were concordantly MRD‐negative. MRD was detected by the two methods in 441 cases (46.8%); 99 samples (10.5%) were only FGT‐MRD‐positive and 19 (2.0%) were only MFC‐MRD‐positive. A final concordance rate of 87.4% was established. Most discordance occurred if residual leukaemia was present at levels close to the sensitivity limits. Neither the type of KMT2A fusion nor a new type of treatment hampering MFC methodology had an influence on the concordance rate. The prognostic value of MFC‐MRD and FGT‐MRD differed. MFC‐MRD was able to identify a rapid response at early time‐points, whereas FGT‐MRD was a reliable relapse predictor at later treatment stages. Additionally, the most precise risk definition was obtained when combining the two methods. Because of the high comparability in results, these two rather simple and inexpensive approaches could be good options of high clinical value.

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