Patients with chronic myeloid leukemia in chronic phase (CML-CP) resistant/intolerant to ≥2 tyrosine kinase inhibitors (TKIs) are at high risk of experiencing poor outcomes because of disease biology and inadequate efficacy and/or safety of current therapies. Asciminib, a first-in-class BCR-ABL1 inhibitor Specifically Targeting the ABL Myristoyl Pocket (STAMP), has the potential to overcome resistance/intolerance to approved TKIs. In this phase 3, open-label study, patients with CML-CP previously treated with ≥2 TKIs were randomized (2:1) to receive asciminib 40 mg twice daily vs bosutinib 500 mg once daily. Randomization was stratified by major cytogenetic response (MCyR) status at baseline. The primary objective was to compare the major molecular response (MMR) rate at week 24 for asciminib vs bosutinib. A total of 233 patients were randomized to asciminib (n = 157) or bosutinib (n = 76). Median follow-up was 14.9 months. The MMR rate at week 24 was 25.5% with asciminib and 13.2% with bosutinib. The difference in MMR rate between treatment arms, after adjusting for MCyR at baseline, was 12.2% (95% confidence interval, 2.19-22.30; 2-sided P = .029). Fewer grade ≥3 adverse events (50.6% vs 60.5%) and adverse events leading to treatment discontinuation (5.8% vs 21.1%) occurred with asciminib than with bosutinib. The study showed a superior efficacy of asciminib compared with that of bosutinib, together with a favorable safety profile. These results support the use of asciminib as a new therapy in patients with CML-CP who are resistant/intolerant to ≥2 prior TKIs. This trial was registered at www.clinicaltrials.gov as #NCT03106779.

In chronic myeloid leukemia (CML) patients, tyrosine kinase inhibitors (TKIs) may select for drug-resistant BCR-ABL1 kinase domain (KD) mutants. Although Sanger sequencing (SS) is considered the gold standard for BCR-ABL1 KD mutation screening, next-generation sequencing (NGS) has recently been assessed in retrospective studies. We conducted a prospective, multicenter study (NEXT-in-CML) to assess the frequency and clinical relevance of low-level mutations and the feasibility, cost, and turnaround times of NGS-based BCR-ABL1 mutation screening in a routine setting. A series of 236 consecutive CML patients with failure (n = 124) or warning (n = 112) response to TKI therapy were analyzed in parallel by SS and NGS in 1 of 4 reference laboratories. Fifty-one patients (22 failure, 29 warning) who were negative for mutations by SS had low-level mutations detectable by NGS. Moreover, 29 (27 failure, 2 warning) of 60 patients who were positive for mutations by SS showed additional low-level mutations. Thus, mutations undetectable by SS were identified in 80 out of 236 patients (34%), of whom 42 (18% of the total) had low-level mutations somehow relevant for clinical decision making. Prospective monitoring of mutation kinetics demonstrated that TKI-resistant low-level mutations are invariably selected if the patients are not switched to another TKI or if they are switched to a inappropriate TKI or TKI dose. The NEXT-in-CML study provides for the first time robust demonstration of the clinical relevance of low-level mutations, supporting the incorporation of NGS-based BCR-ABL1 KD mutation screening results in the clinical decision algorithms.

The Gruppo Italiano Malattie EMatologiche dell’Adulto (GIMEMA) Leucemia Acuta Linfoblastica (LAL) 2317 protocol investigated the frontline chemotherapy-blinatumomab combination in adult Philadelphia chromosome/BCR::ABL1 rearrangement–negative (Ph–) CD19+ B-lineage acute lymphoblastic leukemia (B-ALL) to improve minimal residual disease (MRD) response and clinical outcome. Two cycles of IV blinatumomab were administered after chemotherapy cycles 3 and 6. The primary end point was the rate of molecular MRD negativity after blinatumomab 1. One hundred forty-nine patients were enrolled (median age, 41 years [range, 18-65]); 132 entered remission, 122 received blinatumomab, and 109 had a pre– and post–blinatumomab 1 MRD assessment. MRD negativity increased from 72% to 93% (P < .001) after blinatumomab, with 23 of 30 MRD-positive patients (73%) becoming MRD negative, fulfilling the primary end point. At a median follow-up of 38.1 months (range, 0.5-62.8), the median overall survival (OS) and disease-free survival (DFS) were not reached, and the estimated 3-year OS and DFS were 71% and 65%, respectively, with an excellent outlook for the patients aged 18 to 40 years who achieved an early MRD negativity (DFS, 92%). Pre-blinatumomab MRD predicted a worse outcome, especially in genetically high-risk patients. Notably, the 3-year survival of blinatumomab-treated patients was 82%. Survival and relapse rates were 91% and 15% in patients assigned to standard chemotherapy, 59% and 35% in patients assigned to hematopoietic stem cell transplantation, and 69% and 19% in transplant recipients, respectively. Blinatumomab toxicity was manageable, with only 8 permanent discontinuations. This chemotherapy-blinatumomab risk-oriented program yielded remarkable results that need further improvement in higher-risk patients displaying early MRD persistence. Blinatumomab should be considered as a standard component of induction/consolidation for adult Ph– B-ALL. This trial was registered at www.ClinicalTrials.gov as #NCT03367299.

CML is a hematopoietic stem-cell disorder emanating from breakpoint cluster region/Abelson murine leukemia 1 (BCR/ABL) translocation. Introduction of different TKIs revolutionized treatment outcome in CML patients, but CML LSCs seem insensitive to TKIs and are detectable in newly diagnosed and resistant CML patients and in patients who discontinued therapy. It has been reported that CML LSCs aberrantly express some CD markers such as CD26 that can be used for the diagnosis and for targeting. In this study, we confirmed the presence of CD26+ CML LSCs in newly diagnosed and resistant CML patients. To selectively target CML LSCs/progenitor cells that express CD26 and to spare normal HSCs/progenitor cells, we designed a venetoclax-loaded immunoliposome (IL-VX). Our results showed that by using this system we could selectively target CD26+ cells while sparing CD26− cells. The efficiency of venetoclax in targeting CML LSCs has been reported and our system demonstrated a higher potency in cell death induction in comparison to free venetoclax. Meanwhile, treatment of patient samples with IL-VX significantly reduced CD26+ cells in both stem cells and progenitor cells population. In conclusion, this approach showed that selective elimination of CD26+ CML LSCs/progenitor cells can be obtained in vitro, which might allow in vivo reduction of side effects and attainment of treatment-free, long-lasting remission in CML patients.