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 PACE (Ponatinib Ph+ ALL and CML Evaluation), a phase 2 trial of ponatinib that included patients with chronic-phase chronic myeloid leukemia (CP-CML) resistant to multiple prior tyrosine kinase inhibitors (TKIs), ponatinib showed deep and durable responses, but arterial occlusive events (AOEs) emerged as notable adverse events. Post hoc analyses indicated that AOEs are dose dependent. We assessed the benefit/risk ratio across 3 ponatinib starting doses in the first prospective study to evaluate a novel, response-based, dose-reduction strategy for TKI treatment. Adults with CP-CML resistant to or intolerant of at least 2 prior BCR-ABL1 TKIs or with a BCR-ABL1 T315I mutation were randomly assigned 1:1:1 to 3 cohorts receiving ponatinib 45, 30, or 15 mg once daily. In patients who received 45 or 30 mg daily the dose was reduced to 15 mg upon response (BCR-ABL1IS transcript levels ≤1%). The primary end point was response at 12 months. From August 2015 through May 2019, 283 patients were randomly assigned to the cohorts: 282 (94 per dose group) received treatment (data cutoff, 31 May 2020). The primary end point (98.3% confidence interval) was achieved in 44.1% (31.7-57.0) in the 45-mg cohort, 29.0% (18.4-41.6) in the 30-mg cohort, and 23.1% (13.4-35.3) in the 15-mg cohort. Independently confirmed grade 3 or above treatment-emergent AOEs occurred in 5, 5, and 3 patients in the 45-, 30-, and 15-mg cohorts, respectively. All cohorts showed benefit in this highly resistant CP-CML population. Optimal benefit/risk outcomes occurred with the 45-mg starting dose, which was decreased to 15 mg upon achievement of a response. This trial is registered on www.clinicaltrials.gov as NCT02467270.

Blast phase (BP) of chronic myeloid leukemia (CML) still represents an unmet clinical need with a dismal prognosis. Due to the rarity of the condition and the heterogeneity of the biology and clinical presentation, prospective trials and concise treatment recommendations are lacking. Here we present the analysis of the European LeukemiaNet Blast Phase Registry, an international collection of the clinical presentation, treatment and outcome of blast phases which had been diagnosed in CML patients after 2015. Data reveal the expected heterogeneity of the entity, lacking a clear treatment standard. Outcomes remain dismal, with a median overall survival of 23.8 months (median follow up 27.8 months). Allogeneic stem cell transplantation (alloSCT) increases the rate of deep molecular responses. De novo BP and BP evolving from a previous CML do show slightly different features, suggesting a different biology between the two entities. Data show that outside clinical trials and in a real-world setting treatment of blast phase is individualized according to disease- and patient-related characteristics, with the aim of blast clearance prior to allogeneic stem cell transplantation. AlloSCT should be offered to all patients eligible for this procedure.

The efficacy of and disease control afforded by tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia in chronic phase (CML-CP) have led to increased longevity and thus the continued pursuit of alternative therapies that are efficacious and maximize tolerability. The 24- and 96-week analyses from ASCEMBL demonstrated superior efficacy, safety, and tolerability of asciminib when compared with bosutinib in later-line therapy, thereby meeting the primary and key secondary objectives. With nearly 4 years of follow-up, data from ASCEMBL continued to demonstrate the superior efficacy, safety, and tolerability of asciminib over bosutinib. At week 156, the major molecular response (MMR) rates remained higher with asciminib (33.8%) than with bosutinib (10.5%); the difference in MMR rates between arms, after adjusting for baseline major cytogenetic response, was 23.2% (95% confidence interval, 13.14-33.18; 2-sided P < .001). Asciminib continued to cause fewer grade ≥3 adverse events (AEs; 59.6% vs 68.4%) and fewer AEs that led to treatment discontinuation (8.3% vs 27.6%) than bosutinib. This updated analysis also includes patients who switched to asciminib because of a lack of efficacy with bosutinib. Two of the 25 patients who switched achieved MMR by the end of study, suggesting that earlier incorporation of asciminib, before other TKIs, may improve responses, albeit modestly. These long-term results further solidify asciminib as the therapy of choice for patients with CML-CP who were previously treated with ≥2 previous TKIs. This trial was registered at clinicaltrials.gov as #NCT03106779.

The development of National clinical guidelines on diagnosis and treatment of Ph-negative myeloproliferative neoplasms provides the knowledge basis for decision making in diagnosis, therapy, prevention, and rehabilitation in compliance with evidence-based medicine principles in order to ensure appropriate medical care in a particular clinical setting. The clinical guidelines underly the choice of optimal methods of diagnosis, therapy, prevention, and rehabilitation as part of a patient’s medical care, the development of criteria for the assessment of medical care quality, medical care standards, medical care procedures, setting standards on equipment and management of diagnostic and therapeutic procedures, and provision of continuous medical education and advanced training for healthcare professionals. In 2013, a working group was formed to develop and formulate clinical guidelines on the treatment of myeloproliferative neoplasms. These guidelines were first published in 2014, afterwards they were revised and republished. The dynamic development of current hematology presupposes constant updating of knowledge and implementation of new diagnosis and treatment methods in clinical practice. In this context, clinical guidelines present a dynamic document to be continuously amended, expanded, and updated in accordance with scientific findings and new requirements of specialists who are directly involved in treatment activities. The present edition is an upgraded version of clinical guidelines with updated information on classification, diagnosis, prognosis, current methods of therapy, and their efficacy and tolerability assessment. The guidelines are intended for oncologists, hematologists, healthcare executives, and medical students.

Introduction. Recommendations cover the current state of diagnosis and treatment of mastocytosis.Aim — а consolidation of the Russian experts’ opinion on treatment for adult mastocytosis.Main findings. The recommendations have been developed taking into account foreign literature, national experience and world clinical evidence on therapy for systemic and cutaneous mastocytoses, mast cell leukaemia and other mastocytosis forms. The significance of bone marrow and peripheral blood molecular genetic testing for the presence of KITD816V gene variants is demonstrated. The treatment regimens described are based on midostaurin, imatinib, cladribine, hydroxycarbamide, interferon alfa and haematopoietic stem cell transplantation. Prognosis in different forms of mastocytosis is provided.