Pharmacotherapeutic advances for chronic myelogenous leukemia: beyond tyrosine kinase inhibitors.

INTRODUCTION: Despite the notable success of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML), a subset of patients experiences resistance, or relapse after discontinuation. This challenge is attributed to the Ph+ leukemia stem cells (LSCs) pool not fully involved in the inhibition process due to the current therapeutic approach. AREAS COVERED: Current pharmacological advancements in CML therapy focus on targeting LSCs, intervening in self-renewal pathways, and exploiting biological vulnerabilities. Beyond BCR::ABL1 inhibition, innovative approaches include immunotherapy, epigenetic modulation, and interference with microenvironmental mechanisms. EXPERT OPINION: Diverse therapeutic strategies beyond TKIs are under investigation. Immunotherapy with interferon-α (IFN-α) shows some biological effects, although further research is needed for optimal application in enhancing discontinuation rates. Other compounds were able to mobilize Ph+ LSCs from the bone marrow niche (DPP-IV inhibitor vildagliptin or PAI-1 inhibitor TM5614) increasing the LSC clearance or target the CD26, a Ph+ specific surface receptor. It is noteworthy that the majority of these alternative strategies still incorporate TKIs. In conclusion, novel therapeutic perspectives are emerging for CML, holding the potential for substantial advancements in disease treatment.

NG2 Molecule Expression in Acute Lymphoblastic Leukemia B Cells: A Flow-Cytometric Marker for the Rapid Identification of KMT2A Gene Rearrangements.

Background: B-lineage acute lymphoblastic leukemias (B-ALL) harboring rearrangements of the histone lysine [K]-Methyltransferase 2A (KMT2A) gene on chromosome 11q23 (KMT2A-r) represent a category with dismal prognosis. The prompt identification of these cases represents an urgent clinical need. Considering the correlation between rat neuron glial-antigen 2 (NG2) chondroitin-sulfate-proteoglycan molecule expression and KMT2A-r, we aimed to identify an optimized cytofluorimetric diagnostic panel to predict the presence of KMT2A-r. Materials and Methods: We evaluated 88 NG2+ B-ALL cases identified with an NG2 positivity threshold >10% from a cohort of 1382 newly diagnosed B-ALLs referred to the Division of Hematology of 'Sapienza' University of Rome. Results: Eighty-five of 88 (96.6%) NG2+ B-ALLs harbored KMT2A-r and were mainly pro-B ALL (77/85; 91%). Only 2 B-ALLs with KMT2A-r showed NG2 expression below 10%, probably due to the steroid therapy administered prior to cytofluorimetric analysis.Compared to KMT2A-r-cases, KMT2A r+ B-ALLs showed a higher blast percentage, significantly higher mean fluorescence intensity (MFI) of CD45, CD38, and CD58, and significantly lower MFI of CD34, CD22, TdT, and CD123.The study confirmed differences in CD45, CD34, CD22, and TdT MFI within the same immunologic EGIL group (European Group for the immunological classification of leukemias), indicating no influence of the B-ALLs EGIL subtype on the KMT2A-r+ B-ALLs immunophenotype. Conclusions: Our data demonstrate the association between NG2 and KMT2A-r in B-ALLs identify a distinctive immunophenotypic pattern, useful for rapid identification in diagnostic routines of these subtypes of B-ALLs with a poor prognosis that benefits from a specific therapeutic approach.

Neutrophil to lymphocyte ratio in myelofibrosis patients treated with ruxolitinib may predict prognosis and rate of discontinuation.

BACKGROUND: Myelofibrosis (MF) is a clonal Philadelphia chromosome negative myeloproliferative neoplasm (Ph-MPN). MF is featured by an inflammatory condition that can also drive the progression of disease. Ruxolitinib (ruxo) is the-first-in-class Jak1/2 inhibitor approved for treatment of MF, proved to reduce spleen volume and decrease symptom burden. In various malignancies neutrophil-to-lymphocyte ratio (NLR) has been indicated as predictor of progression free survival (PFS) and overall survival (OS). NLR might reflect the balance between systemic inflammation and immunity and is emerging as a prognostic biomarker in several neoplasms, including the hematological ones. METHODS: We analyzed a cohort of 140 MF patients treated with ruxo to validate baseline NLR (as a continuous variable and as a cut-off 2) as predictor of OS and of ruxo treatment discontinuation. RESULTS: We found that both baseline NLR as a continuous variable [HR 0.8 (95% CI: 0.7-0.9) (p = .006)] and NLR (<2 vs. ≥2) [HR 3.4 (95% CI: 1.6-7.0) (p = .001)] were significantly associated with OS. Censoring for patients undergone allotransplant, baseline NLR <2 was predictive of an earlier ruxo any-other-cause discontinuation [HR 3.7 (95%CI 1.7-8.3) (p < .001)]. CONCLUSIONS: NLR before starting ruxo treatment may be used as a simple and early predictor of OS and earlier ruxo discontinuation in clinical practice.

Safety and Efficacy of TKIs in very Elderly Patients (≥75 Years) with Chronic Myeloid Leukemia.

BACKGROUND: While the outcomes of chronic phase chronic myeloid leukemia (CP-CML) patients aged over 65 years have been extensively evaluated in real-life experiences, limited data exist for the very elderly population (i.e., aged ≥ 75 years), especially for next-generation tyrosine kinase inhibitors (TKIs). In this retrospective study, we sought to evaluate the safety and efficacy of TKIs in this particular setting of patients. METHODS: We conducted a retrospective analysis of a multicenter cohort of 123 newly diagnosed CP-CML very elderly patients. RESULTS: The median age at diagnosis was 80 years (range: 75-96). In the first line, 86.1% of patients received imatinib, 7.1% dasatinib, 5.6% nilotinib, and 0.81% received bosutinib. A total of 31 patients (25.2%) switched to second-line therapy, nine patients to a third line, and one patient to a fourth line of therapy. Resistance to treatment was the primary reason for switching therapy in both the first (64.5%) and second lines (77.7%). At diagnosis, reduced doses were administered in 36.5% of patients, in 61.2% in the second line, and in all patients in subsequent lines of therapy. In the first-line setting, 71.9% of patients achieved an early molecular response (EMR, i.e., 3-month BCR::ABL1IS < 10%); at 6, 12, and 24 months, MR3 was reached by 35.7%, 55.7%, and 75.0% of patients, respectively, with 16.6%, 35.7%, and 51.7% achieving a deep molecular response (DMR) at the same time points. Treatment-free remission (TFR) was successfully attempted in 11 patients. During the follow-up period, adverse events (AEs) were observed in 78.8% of patients, including 22 cases of cardiovascular AEs. Toxicity grade ≥ 3 was more commonly observed in patients treated with standard doses of TKIs compared to reduced doses (p = 0.033). Overall, the median follow-up was 46.62 months (range: 1.8-206.2), and 43 patients died due to non-CML-related causes. Three patients died due to disease progression to advanced (n = 1) and blastic (n = 2) phases. The 5-year overall survival (OS) for the entire cohort was 71.9% (95% CI: 0.63-0.81), with no significant difference between the patients treated with standard doses of TKIs compared to those treated with reduced doses (p = 0.35). CONCLUSIONS: TKIs appear to be safe and effective even in very elderly CML patients, and dose optimization strategies yield satisfactory molecular responses for adequate disease control with an improved safety profile.

Validation of imatinib therapy failure score (IMTF) in chronic phase chronic myeloid leukemia in real life practice.

The outcome of chronic myeloid leukemia (CML) patients improved in the last decade. Clinical prognostic scoring systems aim to provide information about survival in the long-term, without determining from baseline the subset of patients who require a strictly monitoring because at increased risk of failure. Imatinib, the first-generation tyrosine kinase inhibitor (TKI), is still widely used as frontline treatment: recently, the imatinib therapy failure (IMTF) score was proposed to identify the failure free survival. Aim of our study was to validate this index in a large cohort of patients treated with imatinib.

Management of Chronic Myeloid Leukemia Patients in Later Lines: The Role of Ponatinib and New Compounds.

Limited therapeutic options and poor response probability still represent some unresolved issue in later lines chronic myeloid leukemia (CML) patients. In addition, sequential treatment is associated with reduced overall survival and may select new mutation, including the T315I, further reducing the therapeutic chances: outside the United States, ponatinib and allogenic stem cell transplant are the only available options. In the last decade, ponatinib improved outcomes in third-line patients, although limited by the risk of severe adverse occlusive events. Dose optimization strategies with lower doses of ponatinib in selected patients have shown to reduce toxicity while retaining efficacy, but higher doses are needed in T315I patients for an adequate disease control. Recently approved by FDA, the first-of-its-kind STAMP inhibitor asciminib has proven safe and effective, obtaining deep and stable molecular responses even in heavily pretreated patients and with T315I mutation. Unfortunately, a significant proportion of patients remain intolerant or refractory, making it crucial to develop new therapeutic options. Among these, novel agents such as vodobatinib and olverembatinib have provided promising result in clinical trials, representing valuable therapeutic possibilities in intolerant or refractory patients. Therefore, a more complex therapeutic paradigm is expected in the near future.

Neoplastic bone marrow invasion:rapid exclusion of hematological disease by flow cytometric routine panels.

Multiparametric flow cytometry is an extensively used technique to assess the presence of different cellular populations in immunology and hematology. During routine immunophenotyping analysis, it is not uncommon to face cells of non-hemopoietic origin, negative for CD45 and other myeloid, megakaryocytic, B and T lineage antigens and positive for at least one antibody among CD56, CD117 and CD138. If cytology cannot identify cell origin, especially in cases of unclear interpretation, the contribution of multiparametric flow cytometry analysis can be crucial. We report 6 patients with a clinical suspicion of hematological disease in which multiparametric flow cytometry was extremely useful to quickly exclude blood disorders in order to initiate patients to the most appropriate diagnostic process.

Ropeginterferon alfa-2b treatment in a young patient with multi-refractory polycythemia vera and double JAK2 gene mutation: a case report.

This case report presents a 3-year-old female patient initially diagnosed with polycythemia vera (PV) in 2001. The patient exhibited elevated red blood cell (RBC) counts, high hemoglobin (Hb) levels, hyperleukocytosis, and moderate thrombocytosis, with sporadic abdominal pain and significant splenomegaly. Despite various treatments, including phlebotomies, hydroxyurea, and alpha-interferon, the patient struggled to maintain optimal hematocrit levels and experienced persistent symptoms. Subsequent genomic analysis revealed a rare JAK2 G301R mutation alongside the canonical JAK2 V617F mutation, potentially contributing to disease severity. In 2023, the patient started Ropeginterferon alfa-2b, leading to improved hematological parameters and symptom relief. The case underscores the challenges in managing PV, particularly in young patients, and highlights the potential clinical significance of additional JAK2 mutations/variants and the potential benefits of Ropeginterferon alfa-2b in achieving better disease control.

CML Resistant to 2nd-Generation TKIs: Mechanisms, Next Steps, and New Directions.

PURPOSE OF REVIEW: The clinical scenario for chronic myeloid leukemia patients rapidly changed after the introduction of tyrosine kinase inhibitors (TKIs). Second-generation TKIs as frontline treatment increased the rate of deep molecular responses without increasing the rate of overall survival. About 20% of patients experience resistance to these agents, needing alternative treatments. Here, we reviewed the possible mechanisms of resistance, available treatment, and new drugs developed to counteract and overcome resistance. RECENT FINDINGS: Results of novel TKIs have been recently reported, especially for the setting of T315I mutated patients, such as olverembatinib and asciminib, or for patients who developed resistance due to other mutations, such as vodobatinib. Most of new TKIs are selected among compounds tested selective on ABL, therefore without possible off-target effects in the long term. New potential treatments are on the horizon in the field of CML, able to rescue patients treated firstly with one or more second-generation TKIs. Results of ongoing trials and real-world evidence dataset will help us to identify the appropriate timing of intervention and to select appropriate candidate to these drugs.

Emerging concepts for assessing and predicting treatment-free remission in chronic myeloid leukemia patients.

INTRODUCTION: In chronic myeloid leukemia (CML) patients who have reached a deep and sustained reduction of residual disease can attempt a discontinuation. The 'treatment-free remission' (TFR) has become a real long-term endpoint for 30-40% of chronic phase patients. AREAS COVERED: In this review, we focus our attention on possible prognostic features who can predict the success of tyrosine kinase inhibitors discontinuation and how we can assess the minimal residual disease (MRD) during the TFR phase. Broad research was made on Medline, Embase and archives from EHA and ASH congresses. EXPERT OPINION: Median duration of TKI therapy and of deep molecular response are the main prognostic factors identified in most trials and real-life experiences on discontinuation. Immunological pathways have been proposed as possible control on successful TFR as also early molecular response dynamics. Appropriate molecular monitoring by RQ-PCR in the TFR phase has been proposed by several international recommendations and digital droplet PCR (ddPCR) seems to have a possible role in the future for a better identification of candidate to this possible therapeutic strategy.