Dasatinib for the treatment of Philadelphia chromosome-positive leukaemias

Dasatinib and FLAG-IDA Is an Effective Therapy for Initial Myeloid Blast Crisis but Involves a High Risk of Opportunistic Infections

Blast crisis (BC) continues to be the major challenge in the treatment of chronic myeloid leukemia. Best results have been observed in a few patients who were successfully transplanted after returning to chronic phase. Recent studies focus on the combination of chemotherapy with imatinib, but results remain unsatisfactory. Since dasatinib induces deeper and faster responses, a reasonable strategy might be to combine it with chemotherapy, taking into account the alterations in T-cell response induced by dasatinib. However, there are no published studies or case reports supporting the use of dasatinib as first line treatment for initial myeloid BC, and very little is known about infectious complications associated with this drug. Based on this, we present the case of a patient diagnosed with an initial nonlymphoid phenotype BC, who achieved molecular response (MR^4.5) with dasatinib and FLAG-IDA, but he suffered a pulmonary aspergillosis, CMV infection, and a CMV reactivation, prior to an allogeneic hematopoietic stem cell transplantation (HSCT). In conclusion, dasatinib and FLAG-IDA is an effective therapy for initial BC. However, a warning call is needed owing to the high risk of opportunistic infections, such as CMV.

The Hippo pathway as a drug target in gastric cancer

The Hippo tumor suppressor pathway is critical for balancing cellular differentiation and proliferation in response to cell-cell contact, mechanical signals and diffusible signals such as lysophosphatidic acid. Hippo pathway signaling is frequently dysregulated in gastric cancer (GC), as well as many other kinds of solid tumors, contributing to multiple aspects of malignant progression including unchecked cell division and metastasis. Considering the importance of this Hippo pathway in cancer, its pharmacological disruption may be of huge benefit in the fight against this disease. In this review, we summarize the components of the Hippo pathway, its crosstalk with other major oncogenic signaling pathways, common mechanisms of its dysregulation, as well as potential therapeutic approaches of targeting this pathway for cancer treatment, specifically in a GC context.

The discovery of medicines for rare diseases

There is a pressing need for new medicines (new molecular entities; NMEs) for rare diseases as few of the 6800 rare diseases (according to the NIH) have approved treatments. Drug discovery strategies for the 102 orphan NMEs approved by the US FDA between 1999 and 2012 were analyzed to learn from past success: 46 NMEs were first in class; 51 were followers; and five were imaging agents. First-in-class medicines were discovered with phenotypic assays (15), target-based approaches (12) and biologic strategies (18). Identification of genetic causes in areas with more basic and translational research such as cancer and in-born errors in metabolism contributed to success regardless of discovery strategy. In conclusion, greater knowledge increases the chance of success and empirical solutions can be effective when knowledge is incomplete.

Systematic review of dasatinib in chronic myeloid leukemia

Dasatinib is a dual tyrosine kinase inhibitor active against ABL and Src family kinases, and is approved for the treatment of chronic myeloid leukemia (CML) patients in chronic, accelerated, or blast phase with resistance or intolerance to imatinib therapy, for newly diagnosed chronic phase patients, and for adults with Philadelphia chromosome-positive acute lymphoblastic leukemia who have become resistant to or intolerant of other treatments. This review presents clinical data regarding different trials involving CML patients in different phases of the disease. Six-year follow-up of the Phase III dose-optimization study are described, showing overall survival of 71% with the current approved dose of 100 mg once daily. Three-year results of the randomized Phase III DASISION (DASatinib vs Imatinib Study In Treatment-Naïve CML patients) trial confirmed that dasatinib 100 mg once daily was superior to standard-dose imatinib in terms of achieving a faster and deeper molecular response, with similar activity regardless of baseline prognostic score.

Activity and safety of dasatinib as second-line treatment or in newly diagnosed chronic phase chronic myeloid leukemia patients

Dasatinib is an oral dual tyrosine kinase inhibitor active against ABL1 and SRC family kinases. The US FDA approved it for the treatment of chronic myeloid leukemia (CML) patients in chronic, accelerated, or blastic phase with resistance or intolerance to imatinib therapy. Dasatinib is also indicated for the treatment of adults with Philadelphia chromosome-positive acute lymphoblastic leukemia who have become resistant to or intolerant of other treatments. The agent is now also approved for newly diagnosed chronic phase (CP) patients. This article reviews the pharmacokinetic and pharmacodynamic properties of dasatinib as well as clinical data limited to CP-CML patients. Four-year follow-up of a phase III dose-optimization trial confirmed that better progression-free survival (66%) and overall survival (82%) were obtained with a dose of 100 mg once daily (od) than with the standard 70 mg twice daily dosing (65% and 75%, respectively). The 100 mg od dosing schedule was also associated with the highest benefit-risk ratio for CP patients with resistant, intolerant, or suboptimal response. Recent results of a phase III trial in newly diagnosed patients demonstrated that dasatinib 100 mg od has superiority in terms of confirmed cytogenetic and molecular responses, with faster responses and high activity in high Sokal risk patients compared with standard-dose imatinib.

The Importance of Descriptor-Based Clusterization in QSAR Models Development: Tyrosine Kinases Inhibitors as a Key Study

Quantitative Structure Activity Relationship (QSAR) is a well known cheminformatic tool for the discovery of novel biologically active compounds. However, when large and heterogeneous datasets are mined, it is not possible to derive a QSAR equation able to predict in a satisfactory manner the activity of the compounds. Thus, QSAR models are often inadequate for virtual screening purpose. Herein we present a novel approach to multitarget classification QSAR models, useful to assess the selectivity profile of the tyrosine kinases inhibitors. A descriptor-based clusterization process was employed, that allowed the generation of models with high accuracies and independent from the chemical classification of the compounds (i.e. from the scaffold type). The herein proposed methodology can lead to QSAR models useful for virtual screening processes.

Simultaneous exposure of transformed cells to SRC family inhibitors and CHK1 inhibitors causes cell death

The present studies were initiated to determine in greater molecular detail the regulation of CHK1 inhibitor lethality in transfected and infected breast cancer cells and using genetic models of transformed fibrobalsts. Multiple MEK1/2 inhibitors (PD184352, AZD6244 (ARRY-142886)) interacted with multiple CHK1 inhibitors (UCN-01 (7-hydroxystaurosporine), AZD7762) to kill mammary carcinoma cells and transformed fibroblasts. In transformed cells, CHK1 inhibitor -induced activation of ERK1/2 was dependent upon activation of SRC family non-receptor tyrosine kinases as judged by use of multiple SRC kinase inhibitors (PP2, Dasatinib; AZD0530), use of SRC/FYN/YES deleted transformed fibroblasts or by expression of dominant negative SRC. Cell killing by SRC family kinase inhibitors and CHK1 inhibitors was abolished in BAX/BAK -/- transformed fibroblasts and suppressed by over expression of BCL-XL. Treatment of cells with BCL-2/BCL-XL antagonists promoted SRC inhibitor + CHK1 inhibitor -induced lethality in a BAX/BAK-dependent fashion. Treatment of cells with [SRC + CHK1] inhibitors radio-sensitized tumor cells. These findings argue that multiple inhibitors of the SRC-RAS-MEK pathway interact with multiple CHK1 inhibitors to kill transformed cells.

Charlson comorbidity index and adult comorbidity evaluation-27 scores might predict treatment compliance and development of pleural effusions in elderly patients with chronic myeloid leukemia treated with second-line dasatinib

BACKGROUND

Comorbidities may affect survival and choice of treatment among cancer patients. In fact, comorbidities have been identified as significant determinants of response to therapy in older patients with acute myeloid leukemia, breast cancer, head and neck cancer, and lung cancer. The Charlson comorbidity index and adult comorbidity evaluation-27 are lists of comorbidities with a weight assigned from 1 to 6 for the former and from 0 to 3 for the latter score, derived from relative risk estimates of a proportional hazard regression model using clinical data.

DESIGN AND METHODS

We retrospectively evaluated the Charlson index and adult comorbidity evaluation-27 score in a cohort of 125 elderly (> 60 years) patients with chronic phase chronic myeloid leukemia who received dasatinib after showing resistance or intolerance to imatinib with the aim of establishing associations between comorbidities and the development of pleural effusions or compliance with the drug treatment.

RESULTS

We found a significant association between the Charlson index as well as the adult comorbidity evaluation-27 score and the rate of drug reduction or suspension: with regards to the Charlson index, 49% of score 0 patients had a dose reduction compared to 63% of patients with score 1, 74% of those with score 2 and 100% of patients with score 3-5 (P=0.03); with regards to the adult comorbidity evaluation-27 score, 45% of patients had score 0-1 and 69% of patients with score 2-3 had a dose reduction. Of the 65 patients with Charlson score 0, 29% had at least one suspension of treatment (79% for hematologic and 21% for non-hematologic toxicity), compared to 46% of patients with score 1 (37% for hematologic and 69% for non-hematologic toxicity), 58% of patients with score 2 (36% for hematologic and 64% for non-hematologic toxicity) and 100% of patients with score 3 or 4 (all patients for both types of toxicity). High adult comorbidity index-27 scores identified patients at high risk of grade 3/4 hematologic toxicity. Forty-one patients (32.8%) experienced pleural effusion during treatment: the highest scores for both indices were associated with an increased risk of pleural effusions.

CONCLUSIONS

In elderly patients with chronic myeloid leukemia treated with dasatinib, the rate of drug reduction or suspension and the incidence of pleural effusions seem to be associated with the presence of comorbidities: stratification according to the Charlson index and adult comorbidity evaluation-27 score before dasatinib therapy may enable the identification of patients at risk of major toxicities.

Rapid clonal shifts in response to kinase inhibitor therapy in chronic myelogenous leukemia are identified by quantitation mutation assays

Treatment of CML with the tyrosine kinase inhibitor (TKI) imatinib mesylate results in the emergence of point mutations within the kinase domain (KD) of the BCR-ABL1 fusion transcript. The introduction of next-generation TKIs that can overcome the effects of some BCR-ABL1 KD mutations requires quantitative mutation profiling methods to assess responses. We report the design and validation of such quantitative assays, using pyrosequencing and mutation-specific RT-PCR techniques, to allow sequential monitoring and illustrate their use in tracking specific KD mutations (e.g. G250E, T315I, and M351T) following changes in therapy. Pyrosequencing and mutation-specific RT-PCR allows sequential monitoring of specific mutations and identification of rapid clonal shifts in response to kinase inhibitor therapy in CML. Rapid reselection of TKI-resistant clones occurs following therapy switch in CML.

Pleural/pericardic effusions during dasatinib treatment: incidence, management and risk factors associated to their development

IMPORTANCE OF THE FIELD

Despite the beneficial effect of imatinib treatment in chronic myeloid leukemia patients, some patients develop resistance and/or intolerance and need a switch to second-generation tyrosine kinase inhibitors. Dasatinib is indicated for chronic myeloid leukemia patients with resistance or intolerance to imatinib; it has 325-fold increase potency compared to imatinib and is active in mutated and unmutated resistant patients. Pleural/pericardic effusions are frequent complications during treatment with dasatinib, and usually are reported to require dose reduction or drug discontinuation. Changing the dasatinib regimen from 70 mg twice daily to 100 mg once daily reduces the risk of pleural effusions.

AREA COVERED IN THIS REVIEW

In this article, we review the incidence of the phenomenon observed in different dasatinib trials (Phase I - III) and the currently suggested management. We also describe the identified pathogenetic mechanisms related to the development and discuss the associated risk factors.

WHAT THE READER WILL GAIN

The aim of this paper is to provide healthcare professionals with clear guidance on the management of pleural effusions associated with dasatinib treatment. Recommendations are based on the published data and clinical experience from a number of different centers.

TAKE HOME MESSAGE

Literature evidences support the fact that with adequate management and monitoring of patients with predisposing factors, pleural effusions can be easily managed.

Realizing individualized medicine: the road to translating proteomics from the laboratory to the clinic

The sequencing of the human genome has brought great promise and potential for the future of medicine, as well as providing a strong momentum for the burgeoning field of individualized medicine. Tests based on genetic information can be used to allow physicians to target therapies for those patients most likely to benefit from specific therapies and identify potential risk before the onset of disease. While advances in genomics-based molecular diagnostics are progressing, producing some useful US FDA-approved/-cleared diagnostic tests, protein-based molecular diagnostics have not met its promised potential. This article will provide an overview of protein-based analysis technologies, identify their strengths and limitations, discuss barriers to protein-based biomarker development and identify issues which must be addressed in order to successfully transfer the field of proteomics from the laboratory to the clinic.

Pharmacogenetic testing and therapeutic drug monitoring are complementary tools for optimal individualization of drug therapy

Genetic factors contribute to the phenotype of drug response, but the translation of pharmacogenetic outcomes into drug discovery, drug development or clinical practice has proved to be surprisingly disappointing. Despite significant progress in pharmacogenetic research, only a few drugs, such as cetuximab, dasatinib, maraviroc and trastuzumab, require a pharmacogenetic test before being prescribed. There are several gaps that limit the application of pharmacogenetics based upon the complex nature of the drug response itself. First, pharmacogenetic tests could be more clinically applicable if they included a comprehensive survey of variation in the human genome and took into account the multigenic nature of many phenotypes of drug disposition and response. Unfortunately, much of the existing research in this area has been hampered by limitations in study designs and the nonoptimal selection of gene variants. Secondly, although responses to drugs can be influenced by the environment, only fragmentary information is currently available on how the interplay between genetics and environment affects drug response. Third, the use of a pharmacogenetic test as a standard of care for drug therapy has to overcome significant scientific, economic, commercial, political and educational barriers, among others, in order for clinically useful information to be effectively communicated to practitioners and patients. Meanwhile, the lack of efficacy is in this process is quite as costly as drug toxicity, especially for very expensive drugs, and there is a widespread need for clinically and commercially robust pharmacogenetic testing to be applied. In this complex scenario, therapeutic drug monitoring of parent drugs and/or metabolites, alone or combined with available pharmacogenetic tests, may be an alternative or complementary approach when attempts are made to individualize dosing regimen, maximize drug efficacy and enhance drug safety with certain drugs and populations (e.g. antidepressants in older people).

Nilotinib for the treatment of chronic myeloid leukemia: An evidence-based review

Introduction:

Chronic myelogenous leukemia (CML) is a progressive and often fatal hematopoietic neoplasm. The Bcr-Abl tyrosine kinase inhibitor imatinib mesylate represented a major therapeutic advance over conventional CML therapy, with more than 90% of patients obtaining complete hematologic response, and 70%–80% of patients achieving a complete cytogenetic response. Despite the high efficacy of imatinib, a minority of patients in chronic phase CML and more patients in advanced phases are resistant to imatinib, or develop resistance during treatment. This is attributed, in 40% to 50% of cases, to the development of mutations in the Bcr-Abl tyrosine kinase domain that impair imatinib binding. Attempts to circumvent resistance led to the discovery of nilotinib (Tasigna), a novel, potent and selective oral Bcr-Abl kinase inhibitor.

Aims:

To review the evidence for the use of nilotinib in the management of CML.

Evidence review:

Preclinical and clinical investigations demonstrate that nilotinib effectively overcomes imatinib resistance, and has further improved the treatment of CML.

Place in therapy:

Nilotinib is currently indicated for patients with CML in chronic and accelerated phases following imatinib failure. Randomized studies are ongoing to assess the efficacy of nilotinib in patients with newly diagnosed CML.

4-Anilino-7-pyridyl-3-quinolinecarbonitriles as Src kinase inhibitors

A series of 4-anilino-7-pyridyl-3-quinolinecarbonitriles was prepared as Src kinase inhibitors. A systematic SAR study of substitutions on both the pyridine ring and the 3-quinolinecarbonitrile core established the requirements for optimal activity. The lead compound, 17, showed potent activity in both the Src enzyme assay and cell assays, and demonstrated in vivo anti-tumor activity in a xenograft model.

Development and targeted use of nilotinib in chronic myeloid leukemia

The development of imatinib has resulted in sustained hematologic and cytogenetic remissions in all phases of chronic myeloid leukemia (CML). Despite the high efficacy, relapses have been observed and are much more prevalent in patients with advanced disease. The most common mechanism of acquired resistance has been traced to Bcr-Abl kinase domain mutations. Several strategies have been developed to overcome the problem of imatinib resistance, including imatinib dose escalation, novel targeted agents and combination treatments. A second generation of tyrosine kinase inhibitors was developed, which displays increased potency towards Bcr-Abl and is able to target the majority of CML mutant clones. Nilotinib (Tasigna^®, AMN107, Novartis) is a close analog of imatinib with approximately 20-fold higher potency for BCR-ABL kinase inhibition. Preclinical and clinical investigations demonstrate that nilotinib effectively overcomes imatinib resistance, and has induced high rates of hematologic and cytogenetic responses in CML post imatinib failure, with a good tolerance. Nilotinib has been approved for CML patients in chronic and accelerated phases, post imatinib failure.

Dasatinib inhibits recombinant viral antigen-specific murine CD4+ and CD8+ T-cell responses and NK-cell cytolytic activity in vitro and in vivo

OBJECTIVE

Dasatinib (BMS-354825) is a small molecule Src/Abl tyrosine kinase inhibitor approved for the treatment of chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia. Members of the Src family of kinases are involved in the induction of innate and adaptive immunity. The purpose of this study was to evaluate the inhibitory action of dasatinib on antigen-specific CD8(+) and CD4(+) T-cell function, as well as natural killer (NK) cell cytotoxicity.

MATERIALS AND METHODS

To assess dasatinib-mediated inhibition of antigen-specific T-cell proliferation, transgenic CD4(+) and CD8(+) T cells specific for ovalbumin were utilized. Endogenous CD4(+) and CD8(+) T-cell responses were determined following immunization of dasatinib-treated or control mice with a nonreplicating recombinant virus. Clearance of the RMA-S cells, a major histocompatibility complex (MHC) class I-deficient thymoma sensitive to NK-cell lysis, was analyzed in mice undergoing dasatinib treatment.

RESULTS

Dasatinib inhibited antigen-specific proliferation of murine CD4(+) and CD8(+) transgenic T cells in vitro and in vivo. Endogenous antigen-specific helper T-cell recall responses and induction of T-cell-mediated cytotoxicity following immunization with a nonreplicating recombinant virus were also inhibited. So to was the ability of NK cells to eliminate MHC class I-deficient cells in vivo.

CONCLUSIONS

These findings suggest that dasatinib has the potential to modulate the host immune response at clinical doses and highlights scope for off target applications, e.g., therapeutic immunosuppression in the context of autoimmune pathogenesis and allogeneic tissue transplantation.

Kinase domain point mutations in Philadelphia chromosome-positive acute lymphoblastic leukemia emerge after therapy with BCR-ABL kinase inhibitors

BACKGROUND

BCR-ABL kinase domain (KD) mutations are detected in approximately 45% of patients with imatinib-resistant chronic myeloid leukemia. Patterns of KD mutations in Philadelphia chromosome (Ph)-positive acute lympho- blastic leukemia (ALL) are less well studied.

METHODS

The authors assessed KD mutations in patients with recurrent Ph-positive ALL after treatments that included 1 or more kinase inhibitors (n = 24 patients) or no prior kinase inhibitor (KI) therapy (n = 12 patients).

RESULTS

ABL KD mutations were detected by direct sequencing in 15 of 17 patients (88%) who had recurrent Ph-positive ALL and received prior imatinib (n = 16) or dasatinib (n = 1) treatment and in 6 of 7 patients (86%) who had resistant/recurrent tumors treated with >or=2 KIs compared with 0 of 12 patients with recurrent Ph-positive ALL who never received KIs. A restricted set of mutations was observed, mostly Y253H and T315I, and were detected on average 10 months after KI initiation, and mutations were not detected in the initial tumor samples before KI therapy in 12 patients who were assessed. Using a more sensitive pyrosequencing method, mutations were not detected at codons 315 and 253 in the diagnostic samples from those 12 patients or in 30 patients with Ph-positive ALL who never developed recurrent disease.

CONCLUSIONS

ABL KD mutations, especially at codons 315 and 253, emerged at the time of disease recurrence in the vast majority of patients who had Ph-positive ALL and received maintenance KI therapy. Thus, the authors concluded that ongoing KI exposure may alter the patterns of recurrence and favor the outgrowth of clones with KI-resistant mutations.

Validation of PDGFRbeta and c-Src tyrosine kinases as tumor/vessel targets in patients with multiple myeloma: preclinical efficacy of the novel, orally available inhibitor dasatinib

Inhibition of multiple myeloma (MM) plasma cells in their permissive bone marrow microenvironment represents an attractive strategy for blocking the tumor/vessel growth associated with the disease progression. However, target specificity is an essential aim of this approach. Here, we identified platelet-derived growth factor (PDGF)-receptor beta (PDGFRbeta) and pp60c-Src as shared constitutively activated tyrosine-kinases (TKs) in plasma cells and endothelial cells (ECs) isolated from MM patients (MMECs). Our cellular and molecular dissection showed that the PDGF-BB/PDGFRbeta kinase axis promoted MM tumor growth and vessel sprouting by activating ERK1/2, AKT, and the transcription of MMEC-released proangiogenic factors, such as vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8). Interestingly, pp60c-Src TK-activity was selectively induced by VEGF in MM tumor and ECs, and the use of small-interfering (si)RNAs validated pp60c-Src as a key signaling effector of VEGF loop required for MMEC survival, migration, and angiogenesis. We also assessed the antitumor/vessel activity of dasatinib, a novel orally bioactive PDGFRbeta/Src TK-inhibitor that significantly delayed MM tumor growth and angiogenesis in vivo, showing a synergistic cytotoxicity with conventional and novel antimyeloma drugs (ie, melphalan, prednisone, bor-tezomib, and thalidomide). Overall data highlight the biologic and therapeutic relevance of the combined targeting of PDGFRbeta/c-Src TKs in MM, providing a framework for future clinical trials.

Arsenical-based cancer drugs

Arsenic is a semi-metal or metalloid with two biologically important oxidation states, As(III) and As(V). As(III), in particular, reacts with closely spaced protein thiols, forming stable cyclic dithioarsinite complexes in which both sulfur atoms are bound to arsenic. It is this reaction that is mostly responsible for arsenics cytotoxicity. Arsenic compounds have been used as medicinal agents for many centuries for the treatment of diseases such as psoriasis, syphilis, and rheumatosis. From the 1700's until the introduction of and use of modern chemotherapy and radiation therapy in the mid 1900's, arsenic was a mainstay in the treatment of leukemia. Concerns about the toxicity of arsenical compounds led eventually to their abandonment for the treatment of cancer. The discovery in the 1980's that arsenic trioxide induces complete remission in a high percentage of patients with acute promyelocytic leukemia has awakened interest in this metalloid for the treatment of human disease. In particular, a new class or organoarsenicals are being trialed for the treatment of hematological malignancies and solid tumors. In this review, we discuss the arsenical-based compounds used in the past and present for the treatment of various forms of cancer. Mechanisms of action and selectivity and acute and chronic toxicities are discussed along with the prospects of this class of molecule.