Structure-based analysis and biological characterization of imatinib derivatives reveal insights towards the inhibition of wild-type BCR-ABL and its mutants

Efficacy and safety of flumatinib in the treatment of newly diagnosed chronic myeloid leukemia in the chronic phase: A real-world single-center retrospective study, with a focus on premature drug discontinuation

PURPOSE

To assess the real-world efficacy and safety of flumatinib as first-line and post-line treatments for chronic myeloid leukemia in the chronic phase (CML-CP).

RESULTS

Among 141 patients receiving flumatinib as first-line and post-line treatment, the 12-month major molecular response (MMR) rates were 69.4% and 67.6%, respectively. The median time to response was 6 and 10.5 months, respectively. In post-line treatment, the early molecular response (EMR) of flumatinib as second-line is significantly superior to that of third-line treatment (3-month EMR rate: 79.2% vs. 39.3%, P<0.001; 3-month MMR rate: 45.8% vs. 21.4%, P=0.033). Contrastively, patients who switched to flumatinib due to intolerance had significantly higher MMR rates at 3, 6, and 12 months compared to patients who switched due to inadequate response (60.6% vs. 24.2%, P=0.003; 66.7% vs. 36.0%, P=0.027; 84.2% vs. 50.0%, P=0.038). Premature drug discontinuation was observed in 28.4% of the patients. Grades 3-4 hematologic adverse events (AEs) were identified as independent risk factors for premature drug discontinuation. Patients who discontinued treatment and those who previously received only imatinib therapy had a poorer molecular response and failure-free survival.

CONCLUSIONS

Flumatinib demonstrates favorable efficacy and safety. Treatment discontinuation can result in a poorer molecular response and long-term prognosis.

Philadelphia chromosome-positive acute myeloid leukemia successfully treated by allogeneic hematopoietic stem cell transplantation: A case report and review of the literature

RATIONAL

The Philadelphia chromosome (Ph) is seen in most patients with chronic myeloid leukemia and some patients with acute lymphoblastic leukemia. However, Ph-positive acute myeloid leukemia (Ph + AML) is a rare entity with a poor prognosis and a short median survival period. To date, there have been few clinical reports on this disease. And the treatment regimen of this disease has not been uniformly determined.

PATIENT CONCERNS

We report a case of a Ph + AML. A 32-year-old male who was admitted to our hospital with weakness for 2 months.

DIAGNOSIS

Philadelphia chromosome-positive acute myeloid leukemia.

INTERVENTIONS

The patient achieved complete remission by the administration of a tyrosine kinase inhibitor, combined with low-intensity chemotherapy and a B-cell lymphoma 2 inhibitor. Then, allogeneic hematopoietic stem cell transplantation (allo-HSCT) from his sister was successfully performed.

OUTCOMES

The patient has been in a continuous remission state for 6 months after transplantation.

LESSONS

We reported a rare Ph + AML case, successfully treated with allo-HSCT. This case provided strong support for treating Ph + AML with allo-HSCT.

Clinical efficacy and safety of flumatinib versus dasatinib combined with multi-drug chemotherapy in adults with Philadelphia-positive acute lymphoblastic leukemia

INTRODUCTION

Flumatinib, a highly selective ABL kinase inhibitor, exhibits stronger inhibition of intracellular BCR-ABL tyrosine kinase activity, compared to Imatinib. However, there is limited research comparing the real-world efficacy and safety of flumatinib and dasatinib in patients with Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL).

OBJECTIVE

Investigating the differences in therapeutic efficacy and safety between flumatinib and dasatinib in combination with multi-drug chemotherapy for the treatment of newly diagnosed Ph+ ALL.

METHOD

In this study, we assessed 43 patients with newly diagnosed Ph+ ALL (20 in the flumatinib group, 23 in the dasatinib group).

RESULTS

There were no significant differences in gender, age, fusion gene type, initial blood routine, bone marrow blast cell ratio or chromosome karyotype between the two groups. Within 1 month, there were no significant differences in the complete response (CR), major molecular response (MMR) or minimal residual disease (MRD) negativity rate between the flumatinib and dasatinib groups. Similarly, within 3 months, there were no significant differences in CR or MMR rates between the two groups. However, the rates of complete molecular response (CMR) and MRD negativity within 3 months were significantly higher in the flumatinib group, compared to the dasatinib group (P < 0.05). Additionally, the flumatinib group exhibited fewer adverse reactions compared to the dasatinib group.

CONCLUSION

These findings suggest that flumatinib is a safe and effective tyrosine kinase inhibitor (TKI) for achieving CMR and MRD negativity in patients with Ph+ ALL, as supported by this small series of patients.

High BCR::ABL1 Expression Defines CD34+ Cells with Significant Alterations in Signal Transduction, Short-Proliferative Potential and Self-Renewal Ability

Purpose

Chronic Myeloid Leukemia (CML) is a clonal disorder of the hematopoietic stem cell caused by expression of the BCR::ABL1 oncoprotein. High BCR::ABL1 levels have been associated to proliferative advantage of leukemic cells, blast crisis progression and tyrosine kinase inhibitors (TKIs) inefficacy. We have previously shown that high BCR::ABL1/GUSIS transcripts measured at diagnosis are associated with inferior responses to standard dose Imatinib (IM). However, the mechanisms underlying the higher rates of disease progression and development of TKIs resistance dependent on elevated BCR::ABL1 levels remain unclear.

Methods

Leukemic cells were collected from CML patients showing, at diagnosis, high or low BCR::ABL1/GUSIS. BCR::ABL1 expression levels were measured using real-time PCR. Short-term culture and long-term culture-initiating cells assays were employed to investigate the role of BCR::ABL1 gene-expression levels on proliferation, clonogenicity, signal transduction, TKIs responsiveness and self-renewal ability. Cell division was performed by carboxyfluorescein-succinimidyl ester (CFSE) assay.

Results

We found that BCR::ABL1 oncogene expression levels correlate in both PMNs and CD34+ cells. Furthermore, high oncogene levels increased both proliferation and anti-apoptotic signaling via ERK and AKT phosphorylation. Moreover, high BCR::ABL1 expression reduced the clonogenicity of leukemic CD34+ cells and increased their sensitivity to high doses IM but not to those of dasatinib. Furthermore, we observed that high BCR::ABL1 levels are associated with a reduced self-renewal of primitive leukemic cells and, also, that these cells showed comparable TKIs responsiveness with cells expressing lower BCR::ABL1 levels. Interestingly, we found a direct correlation between high BCR::ABL1 levels and reduced number of quiescent leukemic cells caused by increasing their cycling.

Conclusion

Higher BCR::ABL1 levels improving the proliferation, anti-apoptotic signaling and reducing self-renewal properties cause an increased expansion of leukemic clone.

Basic and clinical study of efficacy and adverse effects of flumatinib in Ph+ ALL

Objective: To investigate the efficacy and safety of chemotherapy in treating Ph+ ALL based on flumatinib. Methods: The clinical data of 29 patients with Ph+ ALL receiving flumatinib-based chemotherapy in Sichuan Provincial People's Hospital from January 2020 to January 2023 were collected for analysis, with the concentrations of TKI in the peripheral blood, bone marrow, and cerebrospinal fluid of some patients monitored, Cytological experiments on SUP-B15 were conducted in a Ph+ ALL cell line. Results: A total of 29 patients were enrolled, showing the induced CR, 3-month CR, and 6-month CR rates of 96.3%, 87.5%, and 86.7%, respectively after flumatinib-based chemotherapy. The negative conversion ratio of MRD was 82.6%, 91.3%, and 95.6% in 1, 2, and 3 months after treatment, respectively, with 4.3% of patients failing the conversion in 3 months after treatment. The rates of MMR were 73.9%, 87.5%, and 93.3% in 1, 3, and 6 months after treatment, and CMR of 52.2%, 62.5%, and 73.3%, respectively. Among the 29 patients, 11 (37.9%) received transplant and the continuous flumatinib for 1 year after transplantation. The deep remission was maintained in all patients up to the time of follow-up, with the median follow-up of 12 months (1-33 months), progression-free survival (PFS) of 11 months (1-33 months), and median overall survival (OS) of 12 months (1-33 months). The adverse reactions mainly referred to myelosuppression, liver insufficiency and infection that were generally tolerable. In terms of blood concentration, the concentration of flumatinib was ordered as bone marrow > serum > cerebrospinal fluid in Ph+ ALL bone marrow. In contrast, the concentration of dasatinib and imatinib was ordered as serum > bone marrow > cerebrospinal fluid. At the same time, flumatinib has a high probability to cross the blood-brain barrier, while the concentration of cerebrospinal fluid in the patients using Dasatinib was lower compared to the lower limit of detection in this study. Compared with Imatinib and Dasatinib, flumatinib exerted the most potent inhibitory effect on Ph+ ALL cell lines according to pharmacodynamic analysis of SUP-B15 cells. Conclusion: Flumatinib combined with chemotherapy could achieve good efficacy and safety in treating Ph+ ALL, with flumatinib in a high probability of crossing the blood-brain barrier. Flumatinib could be a superior choice to Dasatinib and Imatinib in cell experiments.

Efficacy of Flumatinib in CML Patients with F359V/C Mutation

The BCR-ABL mutation is the main cause of tyrosine kinase inhibitors(TKI) resistance. The second-generation TKI can overcome most of the mutations. However, both dasatinib and nilotinib have a unique set of mutants with reduced sensitivity. All TKIs are associated with adverse events, which lead to treatment discontinuation and affect the quality of life of patients. Flumatinib showed higher activity against BCR-ABL mutants in vitro. Drug-related adverse events of flumatinib were mainly grade 1 or grade 2 events. There is no study that reported the efficacy of flumatinib against F359V/C mutation.We report two cases of chronic myelocytic leukemia(CML) patients with F359V/C mutation resistance to Imatinib therapy. One patient with F359V mutation was shifted to Dasatinib. Repeated massive pleural effusion and anemia occurred after Dasatinib treatment, forcing drug dosage reduction or withdrawal, affecting drug efficacy and quality of life of patient. Two patients were shifted to Flumatinib. MR4 was achieved and F359V/C mutation was not detected after treatment with Flumatinib. There was no significant side effect. The patients had a high quality of life. Flumatinib is effective against F359V/C mutation, has less drugrelated adverse reactions. Flumatinib may be a better choice for patients with F359V/C mutation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12288-022-01585-3.

Electronic and structural study of T315I mutated form in DFG-out conformation of BCR-ABL inhibitors

In this work, the four main drugs for the treatment of chronic myeloid leukemia were analyzed, being imatinib, dasatinib, nilotinib and ponatinib followed by four derivative molecules of nilotinib and ponatinib. For these derivative molecules, the fluorine atoms were replaced by hydrogen and chlorine atoms in order to shade light to the structural effects on this set of inhibitors. Electronic studies were performed at density functional theory level with the B3LYP functional and 6-311+G(d,p) basis set. The frontier molecular orbitals, gap HOMO-LUMO, and NBO were analyzed and compared to docking studies for mutant T315I tyrosine kinase protein structure code 3IK3, in the DFG-out conformation. Structural similarities were pointed out, such as the presence of groups common to all inhibitors and modifications raised up on new generations of imatinib-based inhibitors. One of them is the trifluoromethyl group present in nilotinib and later included in ponatinib, in addition to the 1-methylpiperazin-1-ium group that is present in imatinib and ponatinib. The frontier molecular orbitals of imatinib and ponatinib are contributing to the same amino acid residues, and the ineffectiveness of imatinib against the T315I mutation was discussed.Communicated by Ramaswamy H. Sarma.

Quantitative structure-activity relationship modeling for predication of inhibition potencies of imatinib derivatives using SMILES attributes

Chronic myelogenous leukemia (CML) which is resulted from the BCR-ABL tyrosine kinase (TK) chimeric oncoprotein, is a malignant clonal disorder of hematopoietic stem cells. Imatinib is used as an inhibitor of BCR-ABL TK in the treatment of CML patients. The main object of the present manuscript is focused on constructing quantitative activity relationships (QSARs) models for the prediction of inhibition potencies of a large series of imatinib derivatives against BCR-ABL TK. Herren, the inbuilt Monte Carlo algorithm of CORAL software is employed to develop QSAR models. The SMILES notations of chemical structures are used to compute the descriptor of correlation weights (CWs). QSAR models are established using the balance of correlation method with the index of ideality of correlation (IIC). The data set of 306 molecules is randomly divided into three splits. In QSAR modeling, the numerical value of R², Q², and IIC for the validation set of splits 1 to 3 are in the range of 0.7180-0.7755, 0.6891-0.7561, and 0.4431-0.8611 respectively. The numerical result of [Formula: see text] > 0.5 for all three constructed models in the Y-randomization test validate the reliability of established models. The promoters of increase/decrease for pIC₅₀ are recognized and used for the mechanistic interpretation of structural attributes.

Elucidation of Ligand/Protein Interactions between BCR-ABL Tyrosine Kinase and Some Commercial Anticancer Drugs Via DFT Methods

In this study, the interactions of 7 commercially available BCR-ABL tyrosine kinase enzyme inhibitors with amino acids in the active site of the relevant enzyme were investigated quantum mechanically. Here a per-residue study was carried out. Interaction energies were calculated by using the coordinates of the critical residues in the binding site of the enzyme and the drug molecules docked in this region. DFT methods were used during the QM processes. All interaction energies were calculated via M06-2X functional and 6-31G (d,p) basis set in vacuum. Based on the results obtained, it was tried to be determined which of the important residues in the binding cavity of the enzyme could better interact with the examined ligands. It is thought that this study may contribute to the development of tyrosine kinase enzyme inhibitors.

Flumatinib versus Imatinib for Newly Diagnosed Chronic Phase Chronic Myeloid Leukemia: A Phase III, Randomized, Open-label, Multi-center FESTnd Study

PURPOSE

Flumatinib has been shown to be a more potent inhibitor of BCR-ABL1 tyrosine kinase than imatinib. We evaluated the efficacy and safety of flumatinib versus imatinib, for first-line treatment of chronic phase Philadelphia chromosome-positive chronic myeloid leukemia (CML-CP).

PATIENTS AND METHODS

In this study, 394 patients were randomized 1:1 to flumatinib 600 mg once daily (n = 196) or imatinib 400 mg once daily (n = 198) groups.

RESULTS

The rate of major molecular response (MMR) at 6 months (primary endpoint) was significantly higher with flumatinib than with imatinib (33.7% vs. 18.3%; P = 0.0006), as was the rate of MMR at 12 months (52.6% vs. 39.6%; P = 0.0102). At 3 months, the rate of early molecular response (EMR) was significantly higher in patients receiving flumatinib than in those receiving imatinib (82.1% vs. 53.3%; P < 0.0001). Compared with patients receiving imatinib, more patients receiving flumatinib achieved molecular remission 4 (MR4) at 6, 9, and 12 months (8.7% vs. 3.6%, P = 0.0358; 16.8% vs. 5.1%, P = 0.0002; and 23.0% vs. 11.7%, P = 0.0034, respectively). No patients had progression to accelerated phase or blast crisis in the flumatinib arm versus 4 patients in the imatinib arm by 12 months. Adverse events of edema, pain in extremities, rash, neutropenia, anemia, and hypophosphatemia were more frequent in imatinib arm, whereas diarrhea and alanine transaminase elevation were more frequent in flumatinib arm.

CONCLUSIONS

Patients receiving flumatinib achieved significantly higher rates of responses, and faster and deeper responses compared with those receiving imatinib, indicating that flumatinib can be an effective first-line treatment for CML-CP. This trial was registered at www.clinicaltrials.gov as NCT02204644.See related commentary by Müller, p. 3.

Insulin-like growth factor-binding proteins play a significant role in the molecular response to imatinib in chronic myeloid leukemia patients

Imatinib (IM) is successfully used in the majority of patients with chronic myeloid leukemia (CML), but some patients develop resistance to drug treatment. Insufficient apoptosis results in uncontrolled cell proliferation, which is closely associated with the occurrence of drug resistance. Therefore, it is crucial to identify new biomarkers related to drug resistance. This aim of the present study was to investigate the profile of apoptosis-related proteins in K562 and K562/G (IM-resistant K562 cells) cells, in order to identify new biomarkers. A human apoptosis antibody array was used to screen 46 proteins in the two cells lines, among which 20 proteins were found to be differentially expressed between K562 and K562/G cells. The major proteins included secreted caspase-8, insulin-like growth factor-binding protein (IGFBP)-1, IGFBP-2, IGFBP-3, caspase-3 and p27. IGFBP-1 IGFBP-2 and IGFBP-3 were selected for the follow-up study. Subsequently, reverse transcription-quantitative PCR analysis and western blotting were used to detect the expression levels of the IGFBPs. The results revealed that the expression levels of IGFBP-2 and IGFBP-3 in K562/G cells were significantly decreased compared with those in K562 cells, whereas the IGFBP-1 level was higher. Moreover, no significant correlation was observed between IGFBP-1 or IGFBP-2 and the level of the BCR-ABL fusion protein, whereas decreasing IGFBP-3 levels were associated with increasing BCR-ABL levels. These results suggested that IGFBP-1, IGFBP-2 and IGFBP-3 could be useful novel biomarkers for IM resistance in CML.