mk-8776 and Leukemia--Myeloid--Acute

Acute myeloid leukemia (AML) is a relapsed and refractory hematological malignancy with a lower morbidity but higher mortality. In addition to hematopoietic stem cell transplantation, chemotherapy is used as the front-line treatment. However, the diversity of available agents and the inconsistency of outcomes of relevant trials render treatment decision-making tough. Network meta-analysis (NMA) is an efficient statistical framework that makes a comprehensive comparison and provides a valuable clinical reference.. All the potential trials were retrieved from the medical database and screened according to the inclusion and exclusion criteria. The main characteristics of each trial as well as the primary outcomes, including complete remission (CR), overall response rate (ORR), overall survival (OS), and event-free survival (EFS), were extracted. In addition, the network graph was plotted to illustrate the connections among the trials involved. Comparison results in the network were exhibited in a forest plot. Furthermore, the surface under the cumulative ranking curve (SUCRA) was introduced to rank the treatments for each endpoint.. A total of 11 trials were selected from 1,625 identifications. No significant difference in the common treatment was observed for the endpoints CR and ORR. In terms of OS, CPX-351 (HR: 0.77, 95% CrI: 0.63, 0.94) and HiDAC plus MK-8776 (HR: 0.80, 95% CrI: 0.68, 0.93) showed a superiority over the common salvage regimen in the short term, while HiDAC plus MK-8776 (HR: 0.80, 95% CrI: 0.70, 0.93) and Ara-C plus vosaroxin (HR: 0.86, 95% CrI: 0.74, 0.99) outperformed the common salvage regimen for the 3-year OS. In addition, clofarabine plus Ara-C (HR: 0.61, 95% CrI: 0.53, 0.69) and CPX-351 (HR: 0.71, 95% CrI: 0.60, 0.83) were confirmed to be efficacious in enhancing the rate of EFS.. Referring to the network outcome and SUCRA value, clofarabine plus Ara-C (CR: 79.05%, ORR: 80.02%) and Ara-C plus vosaroxin (CR: 75.42%, ORR: 73.43%) were potentially the top two choices for both CR and ORR. CPX-351 (1-year OS: 91.36%), HiDAC plus MK-8776 (3-year OS: 94.23%) and clofarabine plus Ara-C (1-year EFS: 97.34%) yielded the highest probabilities to be the optimal choices for 1-year OS, 3-year OS and 1-year EFS, respectively.

Topics: Bayes Theorem; Cytarabine; Disease-Free Survival; Histone Deacetylase Inhibitors; Humans; Leukemia, Myeloid, Acute; Naphthyridines; Neoplasm Recurrence, Local; Odds Ratio; Pyrazoles; Pyrimidines; Remission Induction; Salvage Therapy; Survival Rate; Thiazoles

Cytosine arabinoside (AraC) remains the backbone of most treatment regimens for acute myeloid leukemia (AML). Incorporation of AraC into DNA activates checkpoint kinase 1 (Chk1), leading to cell-cycle arrest and diminished AraC cytotoxicity, which can be reversed by the selective Chk1 inhibitor MK-8776. Building on a Phase I trial, we conducted a phase II trial comparing timed sequential AraC with or without MK-8776.. Patients with relapsed or primary refractory AML were randomized 1:1 to receive either AraC with MK-8776 (Arm A); or AraC alone (Arm B).. 32 patients were treated: 14 assigned to Arm A and 18 to Arm B. There were 5 (36%) complete responses (CR/CRi) and 1 (7%) partial response (PR) in Arm A, and 8 (44%) CR/CRis and 1 (6%) PR in Arm B. Median survival did not differ significantly between the two groups (5.9months in Arm A vs. 4.5 months in Arm B). MK-8776 led to a robust increase in DNA damage in circulating leukemic blasts as measured by increased γ-H2AX (16.9%±6.1% prior and 36.4%±6.8% at one hour after MK-8776 infusion, p=0.016).. Response rates and survival were similar between the two groups in spite of evidence that MK-8776 augmented DNA damage in circulating leukemic blasts. Better than expected results in the control arm using timed sequential AraC and truncated patient enrollment may have limited the ability to detect clinical benefit from the combination.

Topics: Adult; Aged; Antineoplastic Agents; Checkpoint Kinase 1; Cytarabine; Drug Resistance, Neoplasm; Female; Humans; Leukemia, Myeloid, Acute; Male; Middle Aged; Neoplasm Recurrence, Local; Pyrazoles; Pyrimidines

The nucleoside analog cytarabine, an inhibitor of DNA replication fork progression that results in DNA damage, is currently used in the treatment of acute myeloid leukemia (AML). We explored the prognostic value of the expression of 72 genes involved in various aspects of DNA replication in a set of 198 AML patients treated by cytarabine-based chemotherapy. We unveiled that high expression of the DNA replication checkpoint gene CHEK1 is a prognostic marker associated with shorter overall, event-free, and relapse-free survivals and determined that the expression of CHEK1 can predict more frequent and earlier postremission relapse. CHEK1 encodes checkpoint kinase 1 (CHK1), which is activated by the kinase ATR when DNA replication is impaired by DNA damage. High abundance of CHK1 in AML patient cells correlated with higher clonogenic ability and more efficient DNA replication fork progression upon cytarabine treatment. Exposing the patient cells with the high abundance of CHK1 to SCH900776, an inhibitor of the kinase activity of CHK1, reduced clonogenic ability and progression of DNA replication in the presence of cytarabine. These results indicated that some AML cells rely on an efficient CHK1-mediated replication stress response for viability and that therapeutic strategies that inhibit CHK1 could extend current cytarabine-based treatments and overcome drug resistance. Furthermore, monitoring CHEK1 expression could be used both as a predictor of outcome and as a marker to select AML patients for CHK1 inhibitor treatments.

Topics: Checkpoint Kinase 1; Cytarabine; DNA Replication; Drug Resistance, Neoplasm; Female; Humans; Leukemia, Myeloid, Acute; Male; Neoplasm Proteins; Pyrazoles; Pyrimidines

Incorporation of cytarabine into DNA activates checkpoint kinase 1 (Chk1), which stabilizes stalled replication forks, induces S-phase slowing, and diminishes cytarabine cytotoxicity. The selective Chk1 inhibitor SCH 900776 abrogates cytarabine-induced S-phase arrest and enhances cytarabine cytotoxicity in acute leukemia cell lines and leukemic blasts in vitro. To extend these findings to the clinical setting, we have conducted a phase I study of cytarabine and SCH 900776.. Twenty-four adults with relapsed and refractory acute leukemias received timed sequential, continuous infusion cytarabine 2 g/m(2) over 72 hours (667 mg/m(2)/24 hours) beginning on day 1 and again on day 10. SCH 900776 was administered as a 15- to 30-minute infusion on days 2, 3, 11, and 12. The starting dose of SCH 900776 was 10 mg/m(2)/dose.. Dose-limiting toxicities consisting of corrected QT interval prolongation and grade 3 palmar-plantar erythrodysesthesia occurred at 140 mg flat dosing (dose level 5, equivalent to 80 mg/m(2)). Complete remissions occurred in 8 of 24 (33%) patients, with 7 of 8 at 40 mg/m(2) or higher. SCH 900776 did not accumulate at any dose level. Marrow blasts obtained pretreatment and during therapy showed increased phosphorylation of H2Ax after SCH 900776 beginning at 40 mg/m(2), consistent with unrepaired DNA damage.. These data support a randomized phase II trial of cytarabine +/- SCH 900776 at a recommended flat dose of 100 mg (equivalent to 56 mg/m(2)) for adults with poor-risk leukemias. The trial (SP P05247) was registered at www.clinicaltrials.gov as NCT00907517.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Bone Marrow; Checkpoint Kinase 1; Cytarabine; Drug Resistance, Neoplasm; Female; Histones; Humans; Leukemia, Myeloid, Acute; Male; Maximum Tolerated Dose; Middle Aged; Phosphorylation; Protein Kinases; Protein Processing, Post-Translational; Pyrazoles; Pyrimidines; Treatment Outcome; Young Adult

Acute myeloid leukemia (AML) is an aggressive hematologic neoplasm, and patients with an internal tandem duplication (ITD) mutation of the FMS-like tyrosine kinase-3 (FLT3) receptor gene have a poor prognosis. FLT3-ITD interacts with DOCK2, a G effector protein that activates Rac1/2. Previously, we showed that knockdown of DOCK2 leads to decreased survival of FLT3-ITD leukemic cells. We further investigated the mechanisms by which Rac1/DOCK2 activity affects cell survival and chemotherapeutic response in FLT3-ITD leukemic cells. Exogenous expression of FLT3-ITD led to increased Rac1 activity, reactive oxygen species, phosphorylated STAT5, DNA damage response factors and cytarabine resistance. Conversely, DOCK2 knockdown resulted in a decrease in these factors. Consistent with the reduction in DNA damage response factors, FLT3-ITD cells with DOCK2 knockdown exhibited significantly increased sensitivity to DNA damage response inhibitors. Moreover, in a mouse model of FLT3-ITD AML, animals treated with the CHK1 inhibitor MK8776 + cytarabine survived longer than those treated with cytarabine alone. These findings suggest that FLT3-ITD and Rac1 activity cooperatively modulate DNA repair activity, the addition of DNA damage response inhibitors to conventional chemotherapy may be useful in the treatment of FLT3-ITD AML, and inhibition of the Rac signaling pathways via DOCK2 may provide a novel and promising therapeutic target for FLT3-ITD AML.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Biomarkers, Tumor; Cell Cycle; Cell Proliferation; Cytarabine; DNA Repair Enzymes; Drug Synergism; Female; fms-Like Tyrosine Kinase 3; Gene Expression Regulation, Neoplastic; GTPase-Activating Proteins; Guanine Nucleotide Exchange Factors; Humans; Leukemia, Myeloid, Acute; Mice; Mice, Inbred NOD; Mice, SCID; Pyrazoles; Pyrimidines; rac1 GTP-Binding Protein; Tandem Repeat Sequences; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Topics: Antigens, CD34; Drug Delivery Systems; Female; Humans; Leukemia, Myeloid, Acute; Male; Neoplasm Proteins; Neoplastic Stem Cells; Pyrazoles; Pyrimidines

Kinase inhibitors are important cancer therapeutics. Polypharmacology is commonly observed, requiring thorough target deconvolution to understand drug mechanism of action. Using chemical proteomics, we analyzed the target spectrum of 243 clinically evaluated kinase drugs. The data revealed previously unknown targets for established drugs, offered a perspective on the "druggable" kinome, highlighted (non)kinase off-targets, and suggested potential therapeutic applications. Integration of phosphoproteomic data refined drug-affected pathways, identified response markers, and strengthened rationale for combination treatments. We exemplify translational value by discovering SIK2 (salt-inducible kinase 2) inhibitors that modulate cytokine production in primary cells, by identifying drugs against the lung cancer survival marker MELK (maternal embryonic leucine zipper kinase), and by repurposing cabozantinib to treat FLT3-ITD-positive acute myeloid leukemia. This resource, available via the ProteomicsDB database, should facilitate basic, clinical, and drug discovery research and aid clinical decision-making.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cytokines; Drug Discovery; fms-Like Tyrosine Kinase 3; Humans; Leukemia, Myeloid, Acute; Lung Neoplasms; Mice; Molecular Targeted Therapy; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Proteomics; Xenograft Model Antitumor Assays

Novel combinations targeting new molecular vulnerabilities are needed to improve the outcome of patients with acute myeloid leukemia. We recently identified WEE1 kinase as a novel target in leukemias. To identify genes that are synthetically lethal with WEE1 inhibition, we performed a short interfering RNA screen directed against cell cycle and DNA repair genes during concurrent treatment with the WEE1 inhibitor MK1775. CHK1 and ATR, genes encoding two replication checkpoint kinases, were among the genes whose silencing enhanced the effects of WEE1 inhibition most, whereas CDK2 short interfering RNA antagonized MK1775 effects. Building on this observation, we examined the impact of combining MK1775 with selective small molecule inhibitors of CHK1, ATR and cyclin-dependent kinases. The CHK1 inhibitor MK8776 sensitized acute myeloid leukemia cell lines and primary leukemia specimens to MK1775 ex vivo, whereas smaller effects were observed with the MK1775/MK8776 combination in normal myeloid progenitors. The ATR inhibitor VE-821 likewise enhanced the antiproliferative effects of MK1775, whereas the cyclin-dependent kinase inhibitor roscovitine antagonized MK1775. Further studies showed that MK8776 enhanced MK1775-mediated activation of the ATR/CHK1 pathway in acute leukemia cell lines and ex vivo. These results indicate that combined cell cycle checkpoint interference with MK1775/MK8776 warrants further investigation as a potential treatment for acute myeloid leukemia.

Topics: Apoptosis; Ataxia Telangiectasia Mutated Proteins; Cell Cycle Proteins; Cell Line, Tumor; Checkpoint Kinase 1; Dose-Response Relationship, Drug; Drug Synergism; Gene Expression Profiling; Gene Silencing; Humans; Leukemia, Myeloid, Acute; Nuclear Proteins; Protein Kinase Inhibitors; Protein Kinases; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; Pyrimidinones; RNA Interference; RNA, Small Interfering; Signal Transduction; Tumor Stem Cell Assay

Previous studies have shown that the replication checkpoint, which involves the kinases ataxia telangiectasia mutated and Rad3 related (ATR) and Chk1, contributes to cytarabine resistance in cell lines. In the present study, we examined whether this checkpoint is activated in clinical acute myelogenous leukemia (AML) during cytarabine infusion in vivo and then assessed the impact of combining cytarabine with the recently described Chk1 inhibitor SCH 900776 in vitro.. AML marrow aspirates harvested before and during cytarabine infusion were examined by immunoblotting. Human AML lines treated with cytarabine in the absence or presence of SCH 900776 were assayed for checkpoint activation by immunoblotting, nucleotide incorporation into DNA, and flow cytometry. Long-term effects in AML lines, clinical AML isolates, and normal myeloid progenitors were assayed using clonogenic assays.. Immunoblotting revealed increased Chk1 phosphorylation, a marker of checkpoint activation, in more than half of Chk1-containing AMLs after 48 hours of cytarabine infusion. In human AML lines, SCH 900776 not only disrupted cytarabine-induced Chk1 activation and S-phase arrest but also markedly increased cytarabine-induced apoptosis. Clonogenic assays demonstrated that SCH 900776 enhanced the antiproliferative effects of cytarabine in AML cell lines and clinical AML samples at concentrations that had negligible impact on normal myeloid progenitors.. These results not only provide evidence for cytarabine-induced S-phase checkpoint activation in AML in the clinical setting, but also show that a selective Chk1 inhibitor can overcome the S-phase checkpoint and enhance the cytotoxicity of cytarabine. Accordingly, further investigation of the cytarabine/SCH 900776 combination in AML appears warranted.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Ataxia Telangiectasia Mutated Proteins; Cell Cycle Checkpoints; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Checkpoint Kinase 1; Cytarabine; Humans; Leukemia, Myeloid, Acute; Protein Kinase Inhibitors; Protein Kinases; Protein Serine-Threonine Kinases; Pyrazoles; Pyrimidines