abt-199 and Leukemia--Myelogenous--Chronic--BCR-ABL-Positive

Venetoclax (VEN), a small-molecule inhibitor of B cell leukemia/lymphoma-2, is now FDA approved (November 2018) for use in acute myeloid leukemia (AML), specific to newly diagnosed elderly or unfit patients, in combination with a hypomethylating agent (HMA; including azacitidine or decitabine) or low-dose cytarabine. A recent phase-3 study compared VEN combined with either azacitidine or placebo, in the aforementioned study population; the complete remission (CR) and CR with incomplete count recovery (CRi) rates were 28.3% and 66.4%, respectively, and an improvement in overall survival was also demonstrated. VEN-based chemotherapy has also shown activity in relapsed/refractory AML (CR/CRi rates of 33-46%), high-risk myelodysplastic syndromes (CR 39% in treatment naïve, 5-14% in HMA failure), and blast-phase myeloproliferative neoplasm (CR 25%); in all instances, an additional fraction of patients met less stringent criteria for overall response. Regardless, venetoclax-induced remissions were often short-lived (less than a year) but long enough to allow some patients transition to allogeneic stem cell transplant. Herein, we review the current literature on the use of VEN-based combination therapy in both acute and chronic myeloid malignancies and also provide an outline of procedures we follow at our institution for drug administration, monitoring of adverse events and dose adjustments.

Topics: Antineoplastic Combined Chemotherapy Protocols; Azacitidine; Bridged Bicyclo Compounds, Heterocyclic; Clinical Trials, Phase III as Topic; Cytarabine; Decitabine; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid, Acute; Randomized Controlled Trials as Topic; Sulfonamides

Dasatinib, a potent Bcr-Abl tyrosine kinase inhibitor, is approved for the treatment of chronic-phase chronic myeloid leukemia (CML-CP) in the frontline and salvage settings. Notable side effects include pleural effusions and myelosuppression. Dasatinib at 50 mg daily has previously been reported to be active and better tolerated than the approved 100-mg daily dose. The aim of this study was to update the long-term follow-up results of dasatinib at 50 mg daily as frontline therapy for CML-CP.. Eighty-three patients with newly diagnosed CML-CP received dasatinib at 50 mg daily. Eligibility and response criteria were standards used in previous protocols.. After a minimum follow-up of 12 months, 81 patients were evaluable. Two patients came off the study in less than 3 months. The rates of BCR-ABL1 transcript levels (International Standard) at ≤10% and ≤1% at 3 months were 96% and 77%, respectively. The cumulative rates for a complete cytogenetic response by 6 and 12 months were 77% and 95%, respectively. The cumulative rates for a major molecular response, a molecular response with a 4.0-log reduction, and a molecular response with a 4.5-log reduction by 12 months were 81%, 55%, and 49%, respectively. Twenty-one patients (25%) had treatment interruptions for a median of 13 days (range, 4-64 days). Five patients (6%) developed pleural effusions; 4 of these patients (80%) required a dose reduction. Two patients (2%) failed to achieve any cytogenetic or molecular response and were taken off the study. At a median follow-up of 24 months, none of the patients had disease transformation to an accelerated or blastic phase. The 2-year event-free and overall survival rates were 100%.. These updated results continue to support 50 mg of dasatinib daily as an effective and safe dose for early CML-CP.

Topics: Adult; Aged; Aged, 80 and over; Bridged Bicyclo Compounds, Heterocyclic; Dasatinib; Disease-Free Survival; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Fusion Proteins, bcr-abl; Humans; Imatinib Mesylate; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid, Chronic-Phase; Male; Middle Aged; Protein Kinase Inhibitors; Sulfonamides; Treatment Outcome

Topics: Antineoplastic Combined Chemotherapy Protocols; Blast Crisis; Bridged Bicyclo Compounds, Heterocyclic; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid; Leukemia, Myeloid, Acute

Patients with synchronous malignancies can be problematic to diagnose and manage because workup and therapeutic targeting for each individual malignancy must be coordinated carefully. This report presents a patient with concurrent chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL) managed with concomitant venetoclax and imatinib. Because imatinib is a moderate cytochrome P450 3A4 inhibitor, close monitoring is required when using with a substrate of 3A4 such as venetoclax. Although the target dose of venetoclax is 400 mg, it was capped at 100 mg due to the interaction. Despite the interaction and possible enhancement of toxicities, the patient has tolerated therapy well, and both diseases have responded to this novel approach. In addition, because aberrant BCL-2 activity has been implicated in CML, the use of venetoclax may contribute to success in the management of this patient's CML. This case report represents the safe concomitant use of venetoclax and imatinib in a patient with synchronous CML and CLL.

Topics: Antineoplastic Agents; Humans; Imatinib Mesylate; Leukemia, Lymphocytic, Chronic, B-Cell; Leukemia, Myelogenous, Chronic, BCR-ABL Positive

Topics: Blast Crisis; Bridged Bicyclo Compounds, Heterocyclic; Fusion Proteins, bcr-abl; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Sulfonamides

Venetoclax has shown synergism with BCR-ABL1 tyrosine kinase inhibitors (TKIs) in preclinical studies for patients with Philadelphia chromosome-positive (Ph+) leukemias. This combination may suggest a novel treatment strategy for Ph + leukemias.. We conducted a retrospective study to summarize the activity of combining venetoclax and BCR-ABL1 TKI-based therapies in Ph + leukemias.. A total of 18 patients with Ph + leukemias were enrolled in this study. At the time of venetoclax and TKI-based therapy, 5 patients were initially diagnosed, with Ph + acute myeloid leukemia (AML) (n = 1) and mixed phenotype acute leukemia (MPAL) (n = 4), 7 patients had chronic myeloid leukemia at blastic phase (CML-BP), and the remaining 6 patients had relapsed or refractory to prior therapy. The overall response rate (ORR) was 88.9% (9 CR, 2 CRi, 4 MLFS, 1 PR), and a major molecular response (MMR) (or better) was achieved in 7 (38.8%) of all patients. With a median follow-up of 7.0 months (range, 2.3-15.6), 15 (83.3%) were in continuous CR at the time of this analysis, with a 1-year OS of 85.6%, 1-year LFS of 76.7%, and 1-year CIR of 22.4%. Moreover, 10 of 18 patients were treated with venetoclax, TKI and hypomethylating agent (HMA) regimens, which also associated with a high ORR rate (6 CR, 1 CRi, 3 MLFS), and can be used for induction or salvage therapy.. Venetoclax and TKI-based combination regimens may be a feasible approach for Ph + leukemias, and prospective studies are needed to properly assess the safety, tolerability and efficacy of this regimen.

Topics: Fusion Proteins, bcr-abl; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Philadelphia Chromosome; Protein Kinase Inhibitors; Retrospective Studies; Tyrosine Kinase Inhibitors

Although some studies have hinted at the therapeutic potential of daunorubicin (DNR) in chronic myeloid leukemia (CML), the mechanism by which DNR induces CML cell death is unclear. Therefore, this study aimed to investigate DNR-induced cell death signaling pathways in CML cell lines K562 and KU812. DNR-triggered apoptosis in K562 cells was characterized by inhibition of MCL1 expression, while restoration of MCL1 expression protected K562 cells from DNR-mediated cytotoxicity. In addition, DNR induced NOX4-dependent ROS production, leading to the activation of p38 MAPK and inactivation of Akt and ERK. Activated p38 MAPK stimulated protein phosphatase 2A-dependent dephosphorylation of CREB. Since Akt-mediated activation of ERK reduced β-TrCP mRNA stability, the inactivation of Akt-ERK axis increased β-TrCP expression, which in turn promoted proteasomal degradation of Sp1. Inhibition of CREB phosphorylation and Sp1 expression simultaneously reduced MCL1 transcription and protein expression. DNR-induced MCL1 suppression was not reliant on its ability to induce DNA damage. In addition, DNR induced the expression of drug exporter ABCB1 in K562 cells through the p38 MAPK/NFκB-mediated pathway, while imatinib or ABT-199 inhibited the DNR-induced effect. The combination of imatinib or ABT-199 with DNR showed synergistic cytotoxicity in K562 cells by increasing intracellular DNR retention. Cumulatively, our data indicate that DNR induces MCL1 downregulation in K562 cells by promoting p38 MAPK-mediated dephosphorylation of CREB and inhibiting the Akt-ERK axis-mediated Sp1 protein stabilization. Furthermore, experimental evidence indicates that DNR-induced death of KU812 cells occurs through a similar pathway.

Topics: Antibiotics, Antineoplastic; ATP Binding Cassette Transporter, Subfamily B; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Cyclic AMP Response Element-Binding Protein; Daunorubicin; Drug Synergism; Humans; Imatinib Mesylate; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; MAP Kinase Signaling System; Myeloid Cell Leukemia Sequence 1 Protein; NADPH Oxidase 4; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Reactive Oxygen Species; Sp1 Transcription Factor; Sulfonamides

The BCL2-inhibitor, Venetoclax (VEN), has shown significant anti-leukemic efficacy in combination with the DNMT-inhibitor, Azacytidine (AZA). To explore the mechanisms underlying the selective sensitivity of mutant leukemia cells to VEN and AZA, we used cell-based isogenic models containing a common leukemia-associated mutation in the epigenetic regulator ASXL1. KBM5 cells with CRISPR/Cas9-mediated correction of the ASXL1

Topics: Antineoplastic Agents; Azacitidine; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Epigenesis, Genetic; Gene Expression Regulation, Leukemic; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Mutation; Point Mutation; Repressor Proteins; Sulfonamides

The aim of this study was to investigate the mechanism of YM155 cytotoxicity in human chronic myeloid leukemia (CML) cells. YM155-induced apoptosis of human CML K562 cells was characterized by ROS-mediated p38 MAPK activation, mitochondrial depolarization, and survivin and MCL1 downregulation. Moreover, YM155-induced autophagy caused degradation of HuR mRNA and downregulation of HuR protein expression, which resulted in destabilized survivin and MCL1 mRNA. Interestingly, survivin and MCL1 suppression contributed to autophagy-mediated HuR mRNA destabilization in YM155-treated cells. Pretreatment with inhibitors of p38 MAPK or autophagy alleviated YM155-induced autophagy and apoptosis in K562 cells, as well as YM155-induced downregulation of HuR, survivin, and MCL1. Ectopic overexpression of HuR, survivin, or MCL1 attenuated the cytotoxic effect of YM155 on K562 cells. Conversely, YM155 sensitized K562 cells to ABT-199 (a BCL2 inhibitor), and circumvented K562 cell resistance to ABT-199 because of its inhibitory effect on survivin and MCL1 expression. Overall, our data indicate that YM155-induced apoptosis is mediated by inducing autophagic HuR mRNA degradation, and reveal the pathway responsible for YM155-induced downregulation of survivin and MCL1 in K562 cells. Our findings also indicate a similar pathway underlying YM155-induced death in human CML MEG-01 cells.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagy; Bridged Bicyclo Compounds, Heterocyclic; Cell Proliferation; Down-Regulation; Drug Resistance, Neoplasm; ELAV-Like Protein 1; Humans; Imidazoles; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Myeloid Cell Leukemia Sequence 1 Protein; Naphthoquinones; RNA Stability; RNA, Messenger; Sulfonamides; Survivin

Philadelphia chromosome-positive (Ph+) advanced leukemias, including acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) in myeloid blast phase (MBP), have poor outcomes. Venetoclax has shown synergism with BCR-ABL1 tyrosine kinase inhibitors (TKI) in preclinical studies. However, clinical activity of venetoclax and TKI-based regimens is unknown.. We conducted a retrospective study on patients with Ph+ AML (n = 7) and CML-MBP (n = 9) who received venetoclax combined with TKI-based regimens at our institution.. Median patient age was 42 years, and the median number of prior therapy cycles was 5 (range 2-8). Nine patients received decitabine-based, and 7 received intensive chemotherapy-based regimens. Ten patients (63%) received ponatinib. The overall response rate (ORR) in 15 evaluable patients was 60% (1 complete remission [CR], 6 CR with incomplete hematologic recovery [CRi], 1 morphologic leukemia-free state, and 1 partial response). The ORR was 43% in Ph+ AML and 75% in CML-MBP. The median overall survival (OS) for all patients was 3.6 months, for AML OS was 2.0 months, and for CML-MBP OS was 10.9 months. The median relapse-free survival for AML and CML-MBP was 3.6 and 3.9 months, respectively. Compared to nonresponders, patients achieving CR/CRi had higher baseline Ph+ metaphases and BCR-ABL1 PCR.. Combination therapy of venetoclax with TKI-based regimens shows encouraging activity in very heavily pretreated, advanced Ph+ leukemias, particularly CML-MBP.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Blast Crisis; Bridged Bicyclo Compounds, Heterocyclic; Disease-Free Survival; Female; Fusion Proteins, bcr-abl; Humans; Imidazoles; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid, Acute; Male; Middle Aged; Protein Kinase Inhibitors; Pyridazines; Retrospective Studies; Sulfonamides; Survival Rate

BCR-ABL+acute lymphoblastic leukemia (ALL) in adults has a poor prognosis with allogeneic stem cell transplantation (SCT) considered the best curative option for suitable patients. We here characterize the curative potential of BH3-mimetics differentially targeting mitochondrial BCL2-family members using a combination therapy approach with dexamethasone and tyrosine kinase inhibitors targeting BCR-ABL. In BCR-ABL + ALL BH3-mimetics act by redistribution of mitochondrial activator BIM, which is strongly required for cytotoxicity of the BCL2-specific BH3-mimetic ABT-199, tyrosine kinase inhibitors (TKIs) and dexamethasone. BIM expression is enhanced by dexamethasone and TKIs and both synergize with ABT-199 in BCR-ABL + ALL. Triple combinations with ABT-199, dexamethasone and TKIs efficiently attenuate leukemia progression both in tissue culture and in primary cell xenotransplantation models. Notably, the dasatinib-containing combination led to treatment- and leukemia-free long-term survival in a BCR-ABL + mouse model. Finally, response to BH3-mimetics can be predicted for individual patients in a clinically relevant setting. These data demonstrate curative targeted and chemotherapy-free pharmacotherapy for BCR-ABL + ALL in a preclinical model. Clinical evaluation, in particular for patients not suitable for allogeneic SCT, is warranted.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bridged Bicyclo Compounds, Heterocyclic; Dasatinib; Dexamethasone; Drug Resistance, Neoplasm; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Mice; Mice, Inbred NOD; Mice, SCID; Mitochondria; Sulfonamides; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

BCR-ABL1-specific tyrosine kinase inhibitors prolong the life of patients with chronic myeloid leukemia (CML) but cannot completely eradicate CML progenitors. The BH3 mimetic, ABT-263, targets prosurvival BCL2 family members, and has activity against CML progenitors. However, the inhibitory effect of ABT-263 on BCL-XL, which mediates platelet survival, produces dose-limiting thrombocytopenia. A second-generation BH3 mimetic, ABT-199, has been developed to specifically bind BCL2 but not BCL-XL. We determined the activity of ABT-199 against CML cell lines, as well as primary CML and normal cord blood (NCB) progenitors. We find that BCL2 expression levels predict sensitivity to ABT-199 in CML and NCB progenitors, and that high NCB BCL2 levels may explain the reported hematologic toxicities in ABT-199-treated patients. Also, while single agent ABT-199 has modest activity against CML progenitors, when combined with imatinib, ABT-199 significantly enhances imatinib activity against CML progenitors at concentrations predicted to avoid hematologic toxicities.

Topics: Aniline Compounds; Antineoplastic Agents; Apoptosis; Benzamides; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Drug Resistance, Neoplasm; Humans; Imatinib Mesylate; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Neoplastic Stem Cells; Piperazines; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-bcl-2; Pyrimidines; Sulfonamides; Tumor Stem Cell Assay