Development, validation, and application of an LC-MS/MS method for the determination of the AXL/FLT3 inhibitor gilteritinib in mouse plasma.

A simple, fast and precise LC-MS/MS method for the quantitation of the tyrosine kinase inhibitor gilteritinib was developed and validated for micro-volumes of mouse plasma. The assay procedure involved a one-step extraction of gilteritinib and the internal standard [2H5]-gilteritinib with acetonitrile. An Accucore aQ column was used to separate analytes using a gradient elution delivered at a flow rate of 0.4 mL/min, and a total run time of 2.5 min. Validation studies with quality control samples processed on consecutive days revealed that values for intra-day and inter-day precision were <7.04%, with an accuracy of 101-108%. Linear responses were observed over the entire calibration curve range (up to 500 ng/mL), and the lower limit of quantification was 5 ng/mL. The developed method was successfully used to examine the pharmacokinetics of oral gilteritinib in wild-type mice and mice lacking the organic cation transporters OCT1, OCT2, and MATE1 to further understand mechanisms contributing to drug-drug interactions and causes of inter-individual pharmacokinetic variability.

Simultaneous quantification of seven repurposed COVID-19 drugs remdesivir (plus metabolite GS-441524), chloroquine, hydroxychloroquine, lopinavir, ritonavir, favipiravir and azithromycin by a two-dimensional isotope dilution LC-MS/MS method in human serum.

BACKGROUND: The present COVID-19 pandemic has prompted worldwide repurposing of drugs. The aim of the present work was to develop and validate a two-dimensional isotope-dilution liquid chromatrography tandem mass spectrometry (ID-LC-MS/MS) method for accurate quantification of remdesivir and its active metabolite GS-441524, chloroquine, hydroxychloroquine, lopinavir, ritonavir, favipiravir and azithromycin in serum; drugs that have gained attention for repurposing in the treatment of COVID-19. METHODS: Following protein precipitation, samples were separated with a two-dimensional ultra-high performance liquid chromatography (2D-UHPLC) setup, consisting of an online solid phase extraction (SPE) coupled to an analytical column. For quantification, stable isotope-labelled analogues were used as internal standards for all analytes. The method was validated on the basis of the European Medicines Agency bioanalytical method validation protocol. RESULTS: Detuning of lopinavir and ritonavir allowed simultaneous quantification of all analytes with different concentration ranges and sensitivity with a uniform injection volume of 5 µL. The method provided robust validation results with inaccuracy and imprecision values of ≤ 9.59 % and ≤ 11.1 % for all quality controls. CONCLUSION: The presented method is suitable for accurate and simultaneous quantification of remdesivir, its metabolite GS-441525, chloroquine, hydroxychloroquine, lopinavir, ritonavir, favipiravir and azithromycin in human serum. The quantitative assay may be an efficient tool for the therapeutic drug monitoring of these potential drug candidates in COVID-19 patients in order to increase treatment efficacy and safety.

Determination of the concentration of gilteritinib in human plasma using HPLC.

Gilteritinib, an oral inhibitor of FMS-like tyrosine kinase 3 (FLT3), is a standard treatment for FLT3-mutated acute myeloid leukemia. We developed a simple HPLC-UV-based method for determining the concentration of gilteritinib in human plasma. The analysis requires the extraction of a 200-µL plasma sample and the precipitation of proteins by solid-phase extraction. Gilteritinib was isocratically separated within 10 min using a mobile phase of acetonitrile:0.5% monopotassium phosphate (KH2 PO4 , pH 3.5, 28:72, v/v) on a Capcell Pack C18 MG II (250 × 4.6 mm) column at a flow rate of 1.0 mL/min and monitored at 250 nm. The calibration curve was found to be linear within a plasma concentration range of 25-2500 ng/mL, with the coefficient of determination (r2 ) being 0.9997. The coefficients of intra-day and inter-day validation were 2.3-3.7 and 1.3-5.2%, respectively. The accuracy and recovery of the assay were -9.6 to 0.1 and >81.8%, respectively. This HPLC-UV method for determining the plasma concentration of gilteritinib is simple and can be effectively applied to routine drug monitoring.

An LC-MS/MS Bioanalytical Assay for the Determination of Gilteritinib in Rat Plasma and Application to a Drug-Drug Interaction Study.

BACKGROUND: Gilteritinib, a novel, potent FLT3/AXL inhibitor, was recently approved in Japan and USA for the treatment of adult patients who have relapsed or refractory acute myeloid leukemia (AML) with a FLT3 mutation. PURPOSE AND METHODS: In this study, we aimed to develop and validate a sensitive and simple ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the quantification of gilteritinib in plasma and to investigate whether CYP3A4 inhibitors (fluconazole and itraconazole) could influence the pharmacokinetics of gilteritinib from a drug-drug interaction study in rats. Sample preparation was done by a simple protein crash with acetonitrile containing the internal standard (IS) pirfenidone, followed by UPLC-MS/MS quantification. RESULTS: The assay was successfully validated in a 1-500 ng/mL calibration range for gilteritinib, where the lower limit of quantification (LLOQ) was set at 1 ng/mL. The intra-day and inter-day precisions for gilteritinib were less than 10.6%, and the accuracies were in the range of -14.5% to 11.1%. Recovery and matrix effect of the analyte and IS were acceptable, and the analyte was stable during the assay and storage in plasma samples. The validated UPLC-MS/MS method was successfully applied to a drug-drug interaction study between gilteritinib and CYP3A4 inhibitors (fluconazole and itraconazole) in rats. Itraconazole significantly increased the exposure of gilteritinib, and affected the pharmacokinetics of gilteritinib in rats, not fluconazole. CONCLUSION: A further clinical study should be conducted to investigate the effect of itraconazole on the metabolism of gilteritinib in subjects.

A phase 2 study of an oral mTORC1/mTORC2 kinase inhibitor (CC-223) for non-pancreatic neuroendocrine tumors with or without carcinoid symptoms.

Second-generation mammalian target of rapamycin (mTOR) inhibitors such as CC-223 may have theoretical advantages over first-generation drugs by inhibiting TOR kinase in mTOR complex 1 (mTORC1) and 2 (mTORC2), potentially improving clinical efficacy for well-differentiated neuroendocrine tumors (NET).Enrolled patients had metastatic, well-differentiated NET of non-pancreatic gastrointestinal or unknown origin, with/without carcinoid symptoms, had failed ≥1 systemic chemotherapy, and were taking a somatostatin analog (SSA). Oral once-daily CC-223 was administered in 28-day cycles starting at 45 mg (n = 24), with a subsequent cohort starting at 30 mg (n = 23). Objectives were to evaluate tolerability, preliminary efficacy, and pharmacokinetic and biomarker profiles of CC-223. Forty-seven patients completed the study, with mean treatment duration of 378 days and mean dose of 26 mg; 26% of patients remained on the starting dose. Most frequent grade ≥3 toxicities were diarrhea (38%), fatigue (21%), and stomatitis (11%). By investigator, 3 of 41 evaluable patients (7%) showed partial response (PR) and 34 (83%) had stable disease (SD) for a disease control rate (DCR) of 90% (95% confidence interval [CI] 76.9-97.3%). Duration of PR was 125-401 days; median SD duration was 297 days (min-max, 50-1519 days). Median progression-free survival was 19.5 months (95% CI 10.4-28.5 months). Carcinoid symptoms of flushing, diarrhea, or both improved in 50%, 41%, and 39% of affected patients, respectively. For the first time, this study describes that a second-generation mTOR pathway inhibitor can result in highly durable tumor regression and control of NET carcinoid symptoms. The manageable safety profile, high DCR, and durable response, coupled with reduction in carcinoid symptoms refractory to SSA, make CC-223 a promising agent for further development.

Novel Bruton tyrosine kinase inhibitor acalabrutinib quantification by validated LC-MS/MS method: An application to pharmacokinetic study in Sprague Dawley rats.

USFDA has approved a novel Bruton tyrosine kinase (BTK) inhibitor acalabrutinib (ACA) for the treatment of mantle cell lymphoma in adults. ACA is more potent and selective with fewer side effects compared to other Bruton tyrosine kinase inhibitors. In the current work a highly sensitive, selective and specific LC-MS/MS method for the estimation of acalabrutinib (ACA) in rat plasma was developed. Agilent Eclipse Plus C 8 column (50 mm × 4.6 mm, µm), with gradient elution using 10 mM ammonium formate and acetonitrile as mobile phase at a flow rate of 0.6 mL/min was used for the chromatographic separation. The ion transitions were quantified in positive mode with MRM transition of 466.1→372.3 for ACA and 236.8→194.0 for internal standard (IS). Solid phase extraction process was used as sample preparation approach. The method was validated according to USFDA bioanalytical guidelines. The method provided good linearity over the range of 0.2-199.14 ng/mL for ACA with short run time of 4 min. The method offers very high sensitivity (0.2 ng/mL) and was free from matrix interferences. The validated LC-MS/MS method was successfully applied for in vivo pharmacokinetic study in Sprague Dawley rats. The Cmax of ACA was found to be 25.56 ng/mL reaching at time of 0.5 h. The developed analytical method can also be utilized for bioequivalence studies and/or for pharmacokinetic studies in clinics.

Population Pharmacokinetics of the BTK Inhibitor Acalabrutinib and its Active Metabolite in Healthy Volunteers and Patients with B-Cell Malignancies.

INTRODUCTION: Bruton tyrosine kinase (BTK) is a key component of B-cell receptor signalling, critical for cell proliferation. Acalabrutinib, a selective, covalent BTK inhibitor, recently received an accelerated approval in relapsed/refractory mantle cell lymphoma. This analysis characterized the population pharmacokinetics (PK) of acalabrutinib and its metabolite ACP-5862. METHODS: Data were obtained from six phase I/II trials in adult patients with B-cell malignancy and seven phase I trials in healthy volunteers. Pooled concentration-time data, at dose levels ranging from 15 to 400 mg, were analysed using non-linear mixed-effects modelling. Base model parameters were scaled with body weight and normalized to 70 kg (fixed exponents: 0.75 and 1 for clearance and volumes, respectively). A full covariate approach was used to evaluate any relevant effects of dose, health group/disease status, hepatic and renal impairment, use of acid-reducing agents, race and sex. RESULTS: A total of 11,196 acalabrutinib and 1068 ACP-5862 concentration-time samples were available. The PK of both analytes were well described using two-compartment disposition models. Acalabrutinib absorption was characterized using sequential zero- and first-order constants and a lag time. Apparent clearance (CL/F) of acalabrutinib was 169 L/h (95% CI 159-175). Relative to the 100 mg dose group, the 15 and 400 mg dose groups showed a 1.44-fold higher and 0.77-fold lower CL/F, respectively. The clearance for ACP-5862 was 21.9 L/h (95% CI 19.5-24.0). The fraction metabolized was fixed to 0.4. The central and peripheral volumes of distribution were 33.1 L (95% CI 24.4-41.0) and 226 L (95% CI 149-305) for acalabrutinib, and 38.5 L (95% CI 31.6-49.2) and 38.4 L (95% CI 32.3-47.9) for ACP-5862. None of the investigated covariates led to clinically meaningful changes in exposure. CONCLUSION: The PK of acalabrutinib and its metabolite ACP-5862 were adequately characterized. Acalabrutinib CL/F decreased with increasing dose, but the trend was small over the 75-250 mg range. No dose adjustment was necessary for intrinsic or extrinsic covariates.

Application of TQSM polypharmacokinetics and its similarity approach to ascertain Q-marker by analyses of transitivity in vivo of five candidates in Buyanghuanwu injection.

BACKGROUND: It is well-known that the public still have been facing on a severe issue about the inconsistency of quality and therapeutic efficacy of traditional medicines. Recently, Professor Chang-Xiao Liu has created a new promising concept for identifying relevant quality-markers (Q-marker) from herbs, their formulas and manufacturing products. Therefore, building up a new approach is necessary for us to bridge over quality to efficacy of pharmaceutical products. STUDY DESIGN: In this paper, five candidate Q-markers, astragaloside IV, paeonflorin, amygdalin, tetramethylpyrazine, ferulic acid in Buyanghuanwu injection (BYHWI) had been designed to carry out in rat by using single and polypharmacokinetic models for total quanta to ascertain adequate Q-marker. METHODS: The Q-marker transitivity in vivo was studied with polypharmacokinetic model and its similarity approach, which were modeled with TQSM principle. The Q-marker was ascertained with transitive similarity and bioavailability in polypharmacokinetics. Their concentrations in plasma sample of white rat were determined by RP-HPLC. Data analyses were used by the DAS software for singles and myself-written-program with EXCEL for multiples. RESULTS: In BYHWI, five candidate Q-marker pharmacokinetic profiles were singly fixed to two compartmental models in rat using classical compartmental analysis, but there were tremendous differences among which the candidate parameters were fluctuated from nearly 3552 folds to equivalency. The theoretical value of TQSM polypharmacokinetic parameters such as AUCT, MRTT, VRTT, CLT, VT over the mixure of five drugs were 110.8 ±â€¯51.91 mg min ml-1, 176.0 ±â€¯36.5 min, 39,921 ±â€¯4311 min2, 0.3116 ±â€¯0.02347 ml min-1 kg-1, 54.83 ±â€¯7.683 ml kg-1 respectively. The TQSM polypharmacokinetic parameters in astragaloside Ⅳ ordered by AUCT, MRTT, VRTT, CLT, VT were 110.8 ±â€¯51.91 mg min ml-1, 176.0 ±â€¯36.5 min, 39,921 ±â€¯4311 min2, 0.3116 ±â€¯0.02347 ml min-1 kg-1, 54.83 ±â€¯7.683 ml kg-1, respectively, which were closed to the theoretical values. TQSM similarity versus astragaloside Ⅳ was 0.9661. CONCLUSION: The results represented that the optimum Q-marker in BYHWI is astragaloside Ⅳ, whose transitivity in vivo similarity was close to the behavior of polypharmacokinetics with maximum bioavailability to the total quanta. It is feasible for Q-marker in CMMs to screen on the comparison of single pharmacokinetic behavior and bioavailability to the total quanta.

Effect of gemfibrozil and rifampicin on the pharmacokinetics of selexipag and its active metabolite in healthy subjects.

AIMS: Based on in vitro data, there is evidence to suggest that cytochrome P450 (CYP) 2C8 is involved in the metabolism of selexipag and its active metabolite, ACT-333679. The present study evaluated the possible pharmacokinetic interactions of selexipag with gemfibrozil, a strong CYP2C8 inhibitor, and rifampicin, an inducer of CYP2C8. METHODS: The study consisted of two independent parts, each conducted according to an open-label, randomized, crossover design. The pharmacokinetics and safety of selexipag and ACT-333679 were studied following single-dose administration either alone or in the presence of multiple-dose gemfibrozil (part I) or rifampicin (part II) in healthy male subjects. RESULTS: Gemfibrozil had comparatively small effects on selexipag (less than 2-fold difference in any pharmacokinetic variable) but, with respect to ACT-333679, increased the maximum plasma concentration (Cmax ) 3.6-fold [90% confidence interval (CI) 3.1, 4.3] and the area under the plasma concentration-time curve from zero to infinity (AUC0-∞ ) 11.1-fold (90% CI 9.2, 13.4). The marked increased exposure to ACT-333679, which mediates the majority of the pharmacological activity of selexipag, was accompanied by significantly more adverse events such as headache, nausea and vomiting. Coadministration of rifampicin increased the Cmax of selexipag 1.8-fold (90% CI 1.4, 2.2) and its AUC0-∞ 1.3-fold (90% CI 1.1, 1.4); its effects on ACT-333679 were to increase its Cmax 1.3-fold (90% CI 1.1, 1.6), shorten its half-life by 63% and reduce its AUC0-∞ by half (90% CI 0.45, 0.59). CONCLUSION: Concomitant administration of selexipag and strong inhibitors of CYP2C8 must be avoided, whereas when coadministered with inducers of CYP2C8, dose adjustments of selexipag should be envisaged.

Simultaneous quantification of volitinib and gefitinib in rat plasma by HPLC-MS/MS for application to a pharmacokinetic study in rats.

A rapid, simple, and accurate procedure was developed and validated for the simultaneous quantification of two anticancer agents, volitinib and gefitinib in rat plasma by high-performance liquid chromatography with tandem mass spectrometry. The samples were separated by gradient elution from a cyano column within five minutes, using 0.1% formic acid in acetonitrile and 10 mM ammonium formate solution (pH 3.0) as mobile phase. When plasma samples were deproteinated by adding methanol, the analytes in the extract were detected in the positive ionization mode with the tracer ion mass of 346.1 → 145.1 for volitinib and 446.8 → 128.1 for gefitinib. The assay was determined to be valid in the concentration ranges of 2 to 1000 ng/mL for volitinib, and of 1 to 500 ng/mL for gefitinib. Intra- and interday accuracies ranged from 88.0 to 104.7% for volitinib and from 90.3 to 101%, for gefitinib. The precision of the assay ranged from 2.1 to 9.71% for volitinib and 2.31 to 12.1% for gefitinib. This method was successfully applied to a pharmacokinetic study of volitinib and gefitinib after the administration of an intravenous or oral dose, indicating that the developed assay can be used to simultaneously determine the concentrations of volitinib and gefitinib in rat plasma.

Selective inhibition of FLT3 by gilteritinib in relapsed or refractory acute myeloid leukaemia: a multicentre, first-in-human, open-label, phase 1-2 study.

BACKGROUND: Internal tandem duplication mutations in FLT3 are common in acute myeloid leukaemia and are associated with rapid relapse and short overall survival. The clinical benefit of FLT3 inhibitors in patients with acute myeloid leukaemia has been limited by rapid generation of resistance mutations, particularly in codon Asp835 (D835). We aimed to assess the highly selective oral FLT3 inhibitor gilteritinib in patients with relapsed or refractory acute myeloid leukaemia. METHODS: In this phase 1-2 trial, we enrolled patients aged 18 years or older with acute myeloid leukaemia who either were refractory to induction therapy or had relapsed after achieving remission with previous treatment. Patients were enrolled into one of seven dose-escalation or dose-expansion cohorts assigned to receive once-daily doses of oral gilteritinib (20 mg, 40 mg, 80 mg, 120 mg, 200 mg, 300 mg, or 450 mg). Cohort expansion was based on safety and tolerability, FLT3 inhibition in correlative assays, and antileukaemic activity. Although the presence of an FLT3 mutation was not an inclusion criterion, we required ten or more patients with locally confirmed FLT3 mutations (FLT3mut+) to be enrolled in expansion cohorts at each dose level. On the basis of emerging findings, we further expanded the 120 mg and 200 mg dose cohorts to include FLT3mut+ patients only. The primary endpoints were the safety, tolerability, and pharmacokinetics of gilteritinib. Safety and tolerability were assessed in the safety analysis set (all patients who received at least one dose of gilteritinib). Responses were assessed in the full analysis set (all patients who received at least one dose of study drug and who had at least one datapoint post-treatment). Pharmacokinetics were assessed in a subset of the safety analysis set for which sufficient data for concentrations of gilteritinib in plasma were available to enable derivation of one or more pharmacokinetic variables. This study is registered with ClinicalTrials.gov, number NCT02014558, and is ongoing. FINDINGS: Between Oct 15, 2013, and Aug 27, 2015, 252 adults with relapsed or refractory acute myeloid leukaemia received oral gilteritinib once daily in one of seven dose-escalation (n=23) or dose-expansion (n=229) cohorts. Gilteritinib was well tolerated; the maximum tolerated dose was established as 300 mg/day when two of three patients enrolled in the 450 mg dose-escalation cohort had two dose-limiting toxicities (grade 3 diarrhoea and grade 3 elevated aspartate aminotransferase). The most common grade 3-4 adverse events irrespective of relation to treatment were febrile neutropenia (97 [39%] of 252), anaemia (61 [24%]), thrombocytopenia (33 [13%]), sepsis (28 [11%]), and pneumonia (27 [11%]). Commonly reported treatment-related adverse events were diarrhoea (92 [37%] of 252]), anaemia (86 [34%]), fatigue (83 [33%]), elevated aspartate aminotransferase (65 [26%]), and increased alanine aminotransferase (47 [19%]). Serious adverse events occurring in 5% or more of patients were febrile neutropenia (98 [39%] of 252; five related to treatment), progressive disease (43 [17%]), sepsis (36 [14%]; two related to treatment), pneumonia (27 [11%]), acute renal failure (25 [10%]; five related to treatment), pyrexia (21 [8%]; three related to treatment), bacteraemia (14 [6%]; one related to treatment), and respiratory failure (14 [6%]). 95 people died in the safety analysis set, of which seven deaths were judged possibly or probably related to treatment (pulmonary embolism [200 mg/day], respiratory failure [120 mg/day], haemoptysis [80 mg/day], intracranial haemorrhage [20 mg/day], ventricular fibrillation [120 mg/day], septic shock [80 mg/day], and neutropenia [120 mg/day]). An exposure-related increase in inhibition of FLT3 phosphorylation was noted with increasing concentrations in plasma of gilteritinib. In-vivo inhibition of FLT3 phosphorylation occurred at all dose levels. At least 90% of FLT3 phosphorylation inhibition was seen by day 8 in most patients receiving a daily dose of 80 mg or higher. 100 (40%) of 249 patients in the full analysis set achieved a response, with 19 (8%) achieving complete remission, ten (4%) complete remission with incomplete platelet recovery, 46 (18%) complete remission with incomplete haematological recovery, and 25 (10%) partial remission INTERPRETATION: Gilteritinib had a favourable safety profile and showed consistent FLT3 inhibition in patients with relapsed or refractory acute myeloid leukaemia. These findings confirm that FLT3 is a high-value target for treatment of relapsed or refractory acute myeloid leukaemia; based on activity data, gilteritinib at 120 mg/day is being tested in phase 3 trials. FUNDING: Astellas Pharma, National Cancer Institute (Leukemia Specialized Program of Research Excellence grant), Associazione Italiana Ricerca sul Cancro.

A simple and rapid UHPLC-MS/MS method for the quantitation of the dual aurora kinase A/B inhibitor SCH-1473759 in murine plasma.

The Aurora kinase family facilitates cell division through various processes and is overexpressed in a wide variety of human cancers, leading to aneuploidy. For that reason, these enzymes are currently targets of a rising class of anticancer drugs, with some molecules already in therapeutic use. In this study, a new UHPLC-MS/MS method was developed and validated to quantitate a new pan Aurora kinase inhibitor still in preclinical development, SCH-1473759. This bioanalytical method employed a liquid-liquid extraction from plasma using ethyl acetate before evaporation. Calibration range encompassed 0.5-2500ng/mL. The inter- and intra-day accuracy and precision were assessed over five quality control levels; all within limits required by the FDA guidelines. Assay applicability was demonstrated in a first-in-animals study with oral administration, where the maximum plasma concentration (34ng/mL) occurred at 1h, the half-life (1h) was consistent with a previous IV study, and oral bioavailability was poor (F=0.002).

Effect of lopinavir/ritonavir on the pharmacokinetics of selexipag an oral prostacyclin receptor agonist and its active metabolite in healthy subjects.

AIMS: This study investigated the effect of a fixed dose combination of lopinavir/ritonavir on the pharmacokinetics (PK) of selexipag and its active metabolite ACT-333679. METHODS: This was an open label, randomized, single centre, two way, crossover study. Twenty healthy male subjects were treated with a single dose of 400 µg selexipag alone and in combination with multiple doses of lopinavir/ritonavir (400/100 mg) twice daily. RESULTS: The results showed that lopinavir/ritonavir approximately doubled the exposure to selexipag. The area under the plasma concentration-time curve from time zero to infinity (AUC(0,∞) and the maximum plasma concentration (Cmax) of selexipag were 2.2- and 2.1-fold higher, respectively, than under selexipag alone, with a 90% confidence interval (CI) of the geometric mean ratio (GMR) of 1.9, 2.7 and 1.7, 2.6, respectively. For ACT-333679, the clinically more relevant component of selexipag, systemic exposure was increased by 8% (GMR of AUC(0,∞) 1.1, 90% CI 0.9, 1.3), when lopinavir/ritonavir was co-administered with selexipag. The most frequently reported adverse event (AE) was headache. A single dose of selexipag, administered either alone or together with multiple doses of lopinavir/ritonavir, was safe and well tolerated. CONCLUSIONS: Lopinavir/ritonavir does not affect the PK parameters of selexipag and ACT-333679 to a clinically relevant extent. Therefore, adaptation of the selexipag dose is not required when co-administered with inhibitors of the organic anion-transporting polypeptide (OATP) 1B1/ 1B3, P-glycoprotein (P-gp) and/or CYP3A4.

An open-label phase 2 trial of entospletinib (GS-9973), a selective spleen tyrosine kinase inhibitor, in chronic lymphocytic leukemia.

Small-molecule inhibitors of kinases involved in B-cell receptor signaling are an important advance in managing lymphoid malignancies. Entospletinib (GS-9973) is an oral, selective inhibitor of spleen tyrosine kinase. This multicenter, phase 2 study enrolled subjects with relapsed or refractory chronic lymphocytic leukemia (CLL; n = 41) or non-Hodgkin lymphoma (n = 145). Participants received 800 mg entospletinib twice daily. We report efficacy outcomes in the CLL cohort (n = 41) and safety outcomes in all cohorts (N = 186). The primary end point was a progression-free survival (PFS) rate at 24 weeks in subjects with CLL. The PFS rate at 24 weeks was 70.1% (95% confidence interval [CI], 51.3%-82.7%); median PFS was 13.8 months (95% CI, 7.7 months to not reached). The objective response rate was 61.0% (95% CI, 44.5%-75.8%), including 3 subjects (7.3%) who achieved nodal response with persistent lymphocytosis. Fifty-four subjects (29.0%) had serious adverse events (SAEs). The most common treatment-emergent SAEs included dyspnea, pneumonia, febrile neutropenia, dehydration, and pyrexia. Common grade 3/4 laboratory abnormalities included neutropenia (14.5%) and reversible alanine aminotransferase/aspartate aminotransferase elevations (13.4%). Entospletinib demonstrates clinical activity in subjects with relapsed or refractory CLL with acceptable toxicity. This trial was registered at www.clinicaltrials.gov as #NCT01799889.

Blood distribution of bortezomib and its kinetics in multiple myeloma patients.

OBJECTIVES: Pharmacokinetic disposition of bortezomib in the blood has not been fully characterized in humans. This study aimed to evaluate the blood distribution of bortezomib and its kinetics in multiple myeloma patients. DESIGN AND METHOD: Eighteen multiple myeloma patients receiving bortezomib-dexamethasone combination therapy were enrolled. Blood specimens were drawn just before bortezomib administration on days 1 and 8 in the second and third cycles and after discontinuation. The relationships between bortezomib concentration and blood components were evaluated. RESULTS: Bortezomib concentration in the blood on day 1 was higher than that on day 8 in the second cycle. No difference was observed in bortezomib blood concentrations between day 8 in the second and third cycles. The bortezomib concentration in the blood and blood cells was 3- and 7-fold higher than that in plasma. Bortezomib concentration in the blood was correlated with the red blood cell count. The half-life of bortezomib in the blood was 23days. CONCLUSION: Bortezomib was taken up into red blood cells to only a limited extent and eliminated in parallel to the red blood cells' lifespan. The turnover of red blood cells can affect the pharmacokinetic disposition of bortezomib in multiple myeloma patients.

Preclinical analyses and phase I evaluation of LY2603618 administered in combination with pemetrexed and cisplatin in patients with advanced cancer.

LY2603618 is an inhibitor of checkpoint kinase 1 (CHK1), an important regulator of the DNA damage checkpoints. Preclinical experiments analyzed NCI-H2122 and NCI-H441 NSCLC cell lines and in vitro/in vivo models treated with pemetrexed and LY2603618 to provide rationale for evaluating this combination in a clinical setting. Combination treatment of LY2603618 with pemetrexed arrested DNA synthesis following initiation of S-phase in cells. Experiments with tumor-bearing mice administered the combination of LY2603618 and pemetrexed demonstrated a significant increase of growth inhibition of NCI-H2122 (H2122) and NCI-H441 (H441) xenograft tumors. These data informed the clinical assessment of LY2603618 in a seamless phase I/II study, which administered pemetrexed (500 mg/m(2)) and cisplatin (75 mg/m(2)) and escalating doses of LY2603618: 130-275 mg. Patients were assessed for safety, toxicity, and pharmacokinetics. In phase I, 14 patients were enrolled, and the most frequently reported adverse events included fatigue, nausea, pyrexia, neutropenia, and vomiting. No DLTs were reported at the tested doses. The systemic exposure of LY2603618 increased in a dose-dependent manner. Pharmacokinetic parameters that correlate with the maximal pharmacodynamic effect in nonclinical xenograft models were achieved at doses ≥240 mg. The pharmacokinetics of LY2603618, pemetrexed, and cisplatin were not altered when used in combination. Two patients achieved a confirmed partial response (both non-small cell lung cancer), and 8 patients had stable disease. LY2603618 administered in combination with pemetrexed and cisplatin demonstrated an acceptable safety profile. The recommended phase II dose of LY2603618 was 275 mg.

Precolumn o-phthalaldehyde-N-acetyl-L-cysteine derivatization followed by RP-HPLC separation and fluorescence detection of sitagliptin enantiomers in rat plasma.

An indirect reversed-phase high-performance liquid chromatographic separation and fluorescence detection of sitagliptin enantiomers in rat plasma was developed and validated. Deproteinized rat plasma containing racemic sitagliptin was derivatized with o-phthalaldehyde and N-acetyl-L-cysteine under alkaline conditions, converted to diastereomers, and separated on a Lichrospher 100 RP-18e column using 20 mM phosphate buffer and methanol (45:55 v/v) as a mobile phase under isocratic mode of elution at a flow rate of 1.0 mL/min. Fluorescence detection was performed at 330 and 450 nm as excitation and emission wavelengths, respectively. The method was linear in the range of 50-5000 ng/ mL for both enantiomers. The intra- and interday accuracy and precision were within the predefined limits of ≤15% at all concentrations. The method was successfully applied to a pharmacokinetic study of sitagliptin after 5 mg/kg oral administration to Wistar rats. Robustness of the method was evaluated using design of experiments.

Simultaneous analysis of anticancer agents bortezomib, imatinib, nilotinib, dasatinib, erlotinib, lapatinib, sorafenib, sunitinib and vandetanib in human plasma using LC/MS/MS.

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, performed by electrospray ionization in positive mode using a triple quadrupole mass spectrometry, has been developed and validated for the simultaneous determination of bortezomib (BORT), dasatinib (DASA), imatinib (IMAT), nilotinib (NILO), erlotinib (ERLO), lapatinib (LAPA), sorafenib (SORA), sunitinib (SUNI) and vandetanib (VAND) in human plasma. Separation is achieved on an Hypersil Gold(®) PFP column using a gradient elution of 10mM ammonium formate containing 0.1% formic acid (A) and acetonitrile containing 0.1% formic acid (B) at a flow rate of 0.3 mL/min. After addition of the internal standard and protein precipitation, the supernatant is diluted 2-fold in a mixture A and B (50/50, v/v). Two selected reaction monitoring transitions are used for each analyte: one is used for quantitation, the second one is used for confirmation. The standard curves are ranged from 2 ng/mL to 250 ng/mL for BORT, DASA and SUNI and from 50 ng/mL to 3500 ng/mL for the others and were fitted to a 1/x weighted linear regression model. The lowest limits of quantification were 2 ng/mL for BORT, DASA and SUNI and 50 ng/mL for the other TKIs. The method also showed satisfactory results in terms of sensitivity, specificity, precision (intra- and inter-day RSD from 3.7% to 13.8%), accuracy (from 86.8% to 113.5%), recovery as well as stability of the analytes under various conditions. The method also may contribute to better understand the relationship between pharmacokinetics and pharmacodynamics of TKIs in hematological malignancies and solid tumors.

Biological characterization of ETP-46321 a selective and efficacious inhibitor of phosphoinositide-3-kinases.

Inhibitors of PI3K signaling are of great therapeutic interest in oncology. The phosphoinositide-3-kinase signaling pathway is activated in a variety of solid and non-solid tumors. We have identified an imidazopyrazine derivative, ETP-46321, as a potent inhibitor of PI3Kα [Formula: see text]. The compound was 6 times less potent towards PI3Kδ and more than 200 and 60 times less potent at inhibiting PI3Kß and PI3Kγ and did not significantly inhibit the related phosphoinositide-3-kinase-related protein kinase family kinases mTOR or DNA PK (IC(50)'s > 5 µM), or an additional 287 protein kinases that were screened. ETP-46321 inhibited PI3K signaling in treated tumor cell lines, induced cell cycle arrest and inhibited VEGF-dependent sprouting of HUVEC cells. The compound was anti-proliferative and synergized with both cytotoxic and targeted therapeutics. The compound induced a reduction in the phosphorylation of Akt in U87 MG xenografts after a single treatment. The growth of colon and lung cancinoma HT-29 and A549 xenografts was delayed by once a day treatment with ETP-46321. The compound synergized with Doxotaxel in a model of ovarian cancer.

Pharmacokinetic, pharmacodynamic and covariate analysis of subcutaneous versus intravenous administration of bortezomib in patients with relapsed multiple myeloma.

BACKGROUND AND OBJECTIVES: The proteasome inhibitor bortezomib is approved for the treatment of multiple myeloma (MM) and, in the US, for the treatment of mantle cell lymphoma following at least one prior therapy; the recommended dose and schedule is 1.3 mg/m(2) on days 1, 4, 8 and 11 of 21-day cycles, and the approved routes of administration in the US prescribing information are by intravenous and, following a recent update, subcutaneous injection. Findings from a phase III study demonstrated that subcutaneous administration of bortezomib, using the same dose and schedule, resulted in similar efficacy with an improved systemic safety profile (including significantly lower rates of peripheral neuropathy) versus intravenous bortezomib in patients with relapsed MM. The objectives of this report were to present a comprehensive analysis of the pharmacokinetics and pharmacodynamics of subcutaneous versus intravenous bortezomib, and to evaluate the impact of the subcutaneous administration site, subcutaneous injection concentration and demographic characteristics on bortezomib pharmacokinetics and pharmacodynamics. PATIENTS AND METHODS: Data were analysed from the pharmacokinetic substudy of the randomized phase III MMY-3021 study and the phase I CAN-1004 study of subcutaneous versus intravenous bortezomib in patients aged ≥18 (MMY-3021) or ≤75 (CAN-1004) years with symptomatic relapsed or refractory MM after 1-3 (MMY-3021) or ≥1 (CAN-1004) prior therapies. Patients received up to eight 21-day cycles of subcutaneous or intravenous bortezomib 1.3 mg/m(2) on days 1, 4, 8 and 11. Pharmacokinetic and pharmacodynamic (20S proteasome inhibition) parameters of bortezomib following subcutaneous or intravenous administration were evaluated on day 11, cycle 1. RESULTS: Bortezomib systemic exposure was equivalent with subcutaneous versus intravenous administration in MMY-3021 [mean area under the plasma concentration-time curve from time zero to the last quantifiable timepoint (AUC(last)): 155 vs. 151 ng·h/mL; geometric mean ratio 0.992 (90 % CI 80.18, 122.80)] and comparable in CAN-1004 (mean AUC(last): 195 vs. 241 ng·h/mL); maximum (peak) plasma drug concentration (C(max)) was lower with subcutaneous administration in both MMY-3021 (mean 20.4 vs. 223 ng/mL) and CAN-1004 (mean 22.5 vs. 162 ng/mL), and time to C(max) (t(max)) was longer with subcutaneous administration in both studies (median 30 vs. 2 min). Blood 20S proteasome inhibition pharmacodynamic parameters were also similar with subcutaneous versus intravenous bortezomib: mean maximum effect (E(max)) was 63.7 versus 69.3 % in MMY-3021 and 57.0 versus 68.8 % in CAN-1004, and mean area under the effect-time curve from time zero to 72 h was 1,714 versus 1,383 %·h in MMY-3021 and 1,619 versus 1,283 %·h in CAN-1004. Time to E(max) was longer with subcutaneous administration in MMY-3021 (median 120 vs. 5 min) and CAN-1004 (median 120 vs. 3 min). Concentration of the subcutaneous injected solution had no appreciable effect on pharmacokinetic or pharmacodynamic parameters. There were no apparent differences in bortezomib pharmacokinetic and pharmacodynamic parameters between subcutaneous administration in the thigh or abdomen. There were also no apparent differences in bortezomib exposure related to body mass index, body surface area or age. CONCLUSION: Subcutaneous administration results in equivalent bortezomib plasma exposure to intravenous administration, together with comparable blood 20S proteasome inhibition pharmacodynamic effects. These findings, together with the non-inferior efficacy of subcutaneous versus intravenous bortezomib demonstrated in MMY-3021, support the use of bortezomib via the subcutaneous route across the settings of clinical use in which the safety and efficacy of intravenous bortezomib has been established.