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Concept: Mesylate

172

Effective treatment of reactive arthritis would ideally achieve both control of inflammation and eradication of persisting arthritogenic pathogens. We use a model of experimental Chlamydia trachomatis-induced arthritis (CtIA) to evaluate the effectiveness of nafamostat mesilate (NM), a serine protease inhibitor with complement-modifying effects and anticoagulant properties. To date clinical use of NM has largely been in Asia and has been primarily confined to inflammatory states such as pancreatitis.

Concepts: Mesylate, Microbiology, Reactive arthritis, Clinical trial, Effect, Effectiveness, Serine protease, Protease

27

BACKGROUND: A large number of chronic myeloid leukemia (CML) patients are treated with imatinib mesylate outside of clinical trials, which may not be representative of common clinical practice. The age of CML patients enrolled within controlled clinical studies is lower with respect to patients included in population-based registries. PATIENTS AND METHODS: To describe the safety and tolerability of imatinib in very elderly CML patients in chronic phase, 211 chronic-phase CML patients aged >75 years were retrospectively analyzed using data collected from 31 institutions in Italy. RESULTS: The median age at imatinib start was 78.6 years [interquartile range (IR) 76.3-81.4], median time from diagnosis to imatinib start was 1.2 months (IR 0.5-3.7). The starting dose of imatinib was 400 mg/day in 144 patients (68.2 %), >400 mg/day in 4 patients (2.0 %), and <400 mg/day in 63 patients (29.8 %); overall, 94 patients (44.5 %) needed a dose reduction and 27 (12.7 %) discontinued imatinib for toxicity. Grade 3-4 hematologic and extrahematologic toxicities were observed in 40 (18.9 %) and 45 (21.3 %) patients, respectively. After a median observation of 29.8 months (IR 13.0-55.6), 203/211 patients had at least 6 months of observation on imatinib or discontinued before and were evaluable for response and outcome; of them, 183 patients (90.2 %) achieved a complete hematologic response (CHR). Among these 183 patients in CHR, 14 refused any other karyotypic or molecular evaluation, 24 achieved CHR only, and 145 (71.4 %) achieved a cytogenetic response (CyR) of any grade, which was complete (CCyR) in 129 (63.5 %). Among the 129 patients with CCyR, 95 (46.7 %) achieved a major molecular response (MMolR). By multivariate regression analysis, late chronic phase (p = 0.001) and grade 3-4 extrahematologic toxicity (p = 0.007) maintained a negative independent prognostic impact for CCyR, while late chronic phase (p = 0.026), grade 3-4 extrahematologic toxicity (p = 0.007), and lower initial dose of imatinib (p = 0.044) maintained a negative independent prognostic impact for MMolR. The 2-year and 4-year overall survival were 92.6 % (95 % CI 88.7-96.5) and 78.0 % (95 % CI 71.2-84.8), respectively. CONCLUSIONS: Results from this large cohort of patients show that no upper age limit should be applied for the administration of imatinib to patients with chronic-phase CML; the very elderly, including those with concomitant severe diseases, should be offered this treatment. The role of a reduced starting dose of imatinib warrants further studies.

Concepts: Mesylate, Regression analysis, Blood disorders, Philadelphia chromosome, Imatinib, Leukemia, Clinical trial, Chronic myelogenous leukemia

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OBJECTIVES: The validity of the three currently used chronic myeloid leukemia (CML) scoring systems (Sokal CML prognostic scoring system, Euro/Hasford CML scoring system, and the EUTOS CML prognostic scoring system) were compared in the CML patients receiving frontline imatinib mesylate. PATIENTS AND METHODS: One hundred and fourty-three chronic phase CML patients (71 males, 72 females) taking imatinib as frontline treatment were included in the study. The median age was 44 (16-82) years. Median total and on-imatinib follow-up durations were 29 (3.8-130) months and 25 (3-125) months, respectively. RESULTS: The complete hematological response (CHR) rate at 3 months was 95%. The best cumulative complete cytogenetic response (CCyR) rate at 24 months was 79.6%. Euro/Hasford scoring system was well-correlated with both Sokal and EUTOS scores (r = 0.6, P < 0.001 and r = 0.455, P < 0.001). However, there was only a weak correlation between Sokal and EUTOS scores (r = 0.2, P = 0.03). The 5-year median estimated event-free survival for low and high EUTOS risk patients were 62.6 (25.7-99.5) and 15.3 (7.4-23.2) months, respectively (P < 0.001). This performance was better than Sokal (P = 0.3) and Euro/Hasford (P = 0.04) scoring systems. Overall survival and CCyR rates were also better predicted by the EUTOS score. DISCUSSION: EUTOS CML prognostic scoring system, which is the only prognostic system developed during the imatinib era, predicts European LeukemiaNet (ELN)-based event-free survival better than Euro/Hasford and Sokal systems in CML patients receiving frontline imatinib mesylate. This observation might have important clinical implications.

Concepts: Scores, Mesylate, Philadelphia chromosome, Leukemia, Imatinib, Chronic myelogenous leukemia

25

After identification of activating mutations of the KIT gene in gastrointestinal stromal tumor (GIST)-the most common sarcomaof the gastrointestinal tract-a phase 2 study demonstrated efficacy of imatinib mesylate in patients with metastatic GIST harboring a KIT exon 11 mutation. Initial results of long-term follow-up have found a survival benefit in this subgroup of patients.

Concepts: Evolution, DNA repair, Mesylate, Oncology, DNA, Imatinib, Cancer, Gastrointestinal stromal tumor

4

GISTs can be successfully treated with imatinib mesylate (Gleevec), however, complete remissions are rare and patients frequently achieve disease stabilization in the presence of residual tumor masses. The clinical observation that discontinuation of treatment can lead to tumor progression suggests that residual tumor cells are in fact quiescent and hence able to re-enter the cell division cycle. In line with this notion, we have previously shown that imatinib induces GIST cell quiescence in vitro through the APCCDH1-SKP2-p27Kip1 signaling axis. Here, we provide evidence that imatinib induces GIST cell quiescence in vivo and that this process also involves the DREAM complex, a multi-subunit complex that has recently been identified as a additional key regulator of quiescence. Importantly, inhibition of DREAM complex formation by depletion of the DREAM regulatory kinase DYRK1A or its target LIN52 was found to enhance imatinib-induced cell death. Our results show that imatinib induces apoptosis in a fraction of GIST cells while at the same time a subset of cells undergoes quiescence involving the DREAM complex. Inhibition of this process enhances imatinib-induced apoptosis, which opens the opportunity for future therapeutic interventions to target the DREAM complex for more efficient imatinib responses.

Concepts: In vitro, Binary fission, Mesylate, Cell division, Cell cycle, Gastrointestinal stromal tumor, Imatinib, Cancer

1

Imatinib mesylate can induce rapid tumor regression, increase tumor antigen presentation, and inhibit tumor immunosuppressive mechanisms. CTLA-4 blockade and imatinib synergize in mouse models to reduce tumor volume via intratumoral accumulation of CD8+ T cells. We hypothesized that imatinib combined with ipilimumab would be tolerable and may synergize in patients with advanced cancer.

Concepts: Mesylate, Neoplasm, Cancer, Imatinib, Tyrosine kinase, The Canon of Medicine, Oncology, Immune system

0

In exploring the cause of Imatinib mesylate (IM) resistance among chronic myeloid leukemia (CML) patients who do not harbouring BCR-ABL dependent mechanism, BCR-ABL independent pathways are the most possible pathways that should be explored. In BCR-ABL independent pathway, SOCS1 plays an important role as it helps to regulate optimal JAK/STAT activity.

Concepts: Mesylate, DNA methylation, Gene expression, Philadelphia chromosome, DNA, Leukemia, Imatinib, Chronic myelogenous leukemia

0

Despite the excellent efficacy and improved clinical responses obtained with imatinib mesylate (IM), development of resistance in a significant proportion of chronic myeloid leukemia (CML) patients on IM therapy have emerged as a challenging problem in clinical practice. Resistance to imatinib can be due to heterogeneous array of factors involving BCR/ABL-dependent and BCR/ABL-independent pathways. Although BCR/ABL mutation is the major contributory factor for IM resistance, reduced bio-availability of IM in leukemic cells is also an important pharmacokinetic factor that contributes to development of resistance to IM in CML patients. The contribution of polymorphisms of the pharmacogenes in relation to IM disposition and treatment outcomes have been studied by various research groups in numerous population cohorts. However, the conclusions arising from these studies have been highly inconsistent. This review encompasses an updated insight into the impact of pharmacogenetic variability on treatment response of IM in CML patients.

Concepts: Cancer, Blood disorders, Pharmacology, Mesylate, Philadelphia chromosome, Imatinib, Leukemia, Chronic myelogenous leukemia

0

Imatinib mesylate (IM) is an anti-neoplasic drug used for the treatment of cancer. Recently new guidelines specify daily doses and concentration limits for genotoxic impurities (GTIs) in pharmaceutical final products. So, in this work an analytical method by UHPLC-MS/MS was developed, validated and applied to characterize IM tablets for two GTIs: N-(2-methyl-5-aminophenyl)-4-(3-pyridyl)-2-pyrimidine amine (Imp. 1), and N-[4-methyl-3-(4-methyl-3-yl-pyrimidin-2-ylamino)-phenyl]-4- chloromethyl benzamide (Imp. 2), simultaneously. Additionally, dissolution data of IM tablets were compared using a methodology recommended by FDA. The UHPLC method utilizes an Acquity BEH C18 (150 x 2,1 mm, 1,7 um) maintained at 40°C. The mobile phase consisted of ammonium formate 0.063% (phase A) and acetonitrile plus 0.05% formic acid (phase B) in gradient elution. A sensitive method for determination of previously mentioned GTIs in IM tablets was successfully developed and applied. Overall, the formulations analyzed in this work showed low levels of Imp. 1 and Imp. 2. However, sample named D1 showed very high levels of Imp. 1 and failed to meet the requirements established by the FDA for dissolution data. Periodic verification of GTIs in pharmaceutical formulations is important to minimize safety risks, so analytical methods to determine it need be available and implemented in routine analysis.

Concepts: Acetic acid, Mesylate, Formamide, Pharmaceutical formulation, Formates, Pharmacology, Imatinib, Analytical chemistry

0

Only limited data are available concerning the long-term outcomes of imatinib treatment among Japanese or Asian patients with advanced or recurrent gastrointestinal stromal tumors (GIST). Our multicenter study, which was conducted in northern Kanto, Japan, aimed to assess the efficacy of imatinib mesylate against advanced or recurrent GIST.

Concepts: Japan, Asia, Mesylate, Imatinib, Gastrointestinal stromal tumor