Bioanalysis and Quadrupole-Time of Flight-Mass Spectrometry Driven In Vitro Metabolite Profiling of a New Boronic Acid-Based Anticancer Molecule.

(E/Z)-(4-(3-(2-((4-chlorophenyl)amino)-4-(dimethylamino)thiazol-5-yl)-2-(ethoxy carbonyl)-3-oxoprop-1-en-1-yl)phenyl) boronic acid, a newly developed molecule having anticancer activity serves as a potential candidate for the further drug development process. In this study, to ascertain the anticancer potential of the molecule, we screened it against different cell lines and compared the activity against the standard drug doxorubicin. The molecule showed promising activity at a low concentration against almost all cell lines used in the study. Apart from that, the molecule was characterized for its pKa and a precise reverse phase high-performance liquid chromatography bioanalytical method has been developed. The method was validated according to the United States of Food and Drug Administration bioanalytical guideline and was found to produce linear response over the calibration range of 0.8-25 µg/mL. Inter- and intra-day accuracy were found to be in the range of 93.44-99.74%, whereas precision [% coefficient of variation (CV)] for inter- and intra-day was ranged between 1.63 and 5.79%, and 0.87 and 6.96%, respectively. The bioanalytical stability testing was carried out in different conditions including 8 h benchtop, 12 h autosampler and three freeze-thaw cycles. The analyte was stable in all the tested stability conditions. Finally, an in vitro metabolite identification study was conducted using quadrupole-time of flight-mass spectrometer, and two metabolites have been identified.

Development of an HPLC Method for the Determination of Meropenem/Vaborbactam in Biological and Aqueous Matrixes.

A HPLC method was developed and validated to analyze meropenem and vaborbactam simultaneously in murine plasma and saline matrixes. A 60-µL volume of extracted sample was injected onto a 5-µm BDS Phenyl-Hypersil C18 reversed-phase column and analyzed with a UV detector set at 298 nm for the first 4.9 min and switched to 240 nm. The mobile phase contained a mixture of methanol and 25-mM sodium phosphate buffer set at a flow rate of 1.0 mL/min for the 16 min run time. Cefuroxime was used as the internal standard. The standard curves were linear over a range of 0.25-50 µg/mL. The precision and accuracy for 0.25 µg/mL (LLQ) in plasma for both compounds were <4.8% and >98.9%, respectively. Interday and intraday precision and accuracy for all QC plasma samples for both compounds were <6.2% and >95.7%, respectively. This methodology details a reproducible assay for both compounds using a single extraction with good accuracy and precision.

Evaluation of Hemodialysis Effect on Pharmacokinetics of Meropenem/Vaborbactam in End-Stage Renal Disease Patients Using Modeling and Simulation.

The objectives of this study were to evaluate the effect of hemodialysis (HD) on the pharmacokinetics (PK) of meropenem/vaborbactam, an approved beta-lactam/beta-lactamase inhibitor combination, and provide the rationale for the recommended timing of meropenem/vaborbactam administration relative to HD in end-stage renal disease (ESRD) patients. Population PK models were developed separately for meropenem and vaborbactam in subjects with normal renal function and different degrees of renal impairment, including those receiving HD. Simulations were performed to evaluate the exposure of meropenem and vaborbactam in ESRD patients who received a fixed dose of 0.5 g/0.5 g meropenem/vaborbactam every 12 hours as a 3-hour intravenous infusion under various drug administration schedules relative to HD. The probability of target attainment (PTA) analyses were conducted with pharmacokinetic/pharmacodynamic (PK/PD) targets of meropenem and vaborbactam. Simulations showed that HD reduces the accumulation of vaborbactam, but the exposure of vaborbactam is still above the PK/PD target regardless of whether meropenem/vaborbactam is administered predialysis or postdialysis. For meropenem, drug infusion completed right prior to initiation of HD may substantially reduce exposure leading to poor PTA results. In contrast, drug infusion completed at least 2 hours prior to initiation of HD is not predicted to result in efficacy loss based on PTA analysis. The results of simulation indicate that meropenem/vaborbactam infusion completed at least 2 hours prior to initiation of HD or administered immediately after the end of HD can avoid potential efficacy loss in ESRD patients.

Boronic acid functionalized fibrous cellulose for the selective enrichment of glycopeptides.

Enrichment of glycoproteins has been important because of their dynamicity and role in biological systems. Study of glycoproteins is complex because of the simultaneous glycosylation and deglycosylation inside the body. Often employed affinities for glycopeptides are hydrazide, boronic acid, or physiosorbed lectin on support materials. Cellulose, a natural polysaccharide, has rich surface chemistry, stable structure, low cost and availability in different variants. In present study, fibrous cellulose is oxidized using periodate to modify with boronic acid. Attachment of boronic acid is confirmed by Fourier transform infrared spectroscopy. Particle size and morphology of boronic acid@fibrous cellulose is studied by scanning electron microscopy. The enrichment efficiency is evaluated by using horseradish peroxidase as model protein. Boronic acid@fibrous cellulose is selective up to 1:250 for spiked horseradish peroxidase in bovine serum albumin digest, sensitive down to 0.1 femtomol and recovering 88.15% glycopeptides. Moreover, protein binding capacity is determined as 213 mg/g and 41% sequence coverage of horseradish peroxidase protein with all eight glycosylation sites detected. Total of 18 glycopeptides are enriched from immunoglobulin digest showing ability of boronic acid@fibrous cellulose to enrich glycoproteins from multiglycoforms. Enrichment from human serum recovers 18% extracellular and 72% secreted glycoproteins via bottom-up approach and online tools.

A validated LC-MSMS method for the simultaneous quantification of meropenem and vaborbactam in human plasma and renal replacement therapy effluent and its application to a pharmacokinetic study.

A simple method for the simultaneous quantification of meropenem and the recently approved ß-lactamase inhibitor, vaborbactam, in human plasma and renal replacement therapy effluent (RRTE) was developed and validated. This antibiotic combination protects a primary ß-lactam, meropenem, with a new ß-lactamase inhibitor, and expands the limited options for treatment of multidrug-resistant Gram-negative infections. Meropenem, vaborbactam, and the internal standards [2H6]-meropenem and sulbactam in plasma and RRTE were processed using acetonitrile followed by a chromatographic separation on a Poroshell HPH-C18 column with a gradient elution of the mobile phases and monitored using mass spectrometry detection. The calibration range was 0.05 to 100 µg mL-1 for both meropenem and vaborbactam. The intra-day and inter-day precision and accuracy were less than 15% for both meropenem and vaborbactam and the recovery from plasma was 96% for both meropenem and vaborbactam and the recovery from RRTE was 93% and 103% for meropenem and vaborbactam, respectively. This methodology was successfully applied to an ex vivo characterisation study of the effects of renal replacement therapy modalities on the pharmacokinetics of meropenem and vaborbactam (Antimicrob Agents Chemother 62(10), 2018). Graphical abstract.

Single-Dose Pharmacokinetics and Safety of Meropenem-Vaborbactam in Subjects with Chronic Renal Impairment.

Vaborbactam is a member of a new class of ß-lactamase inhibitors with inhibitory activity against serine carbapenemases (e.g., Klebsiella pneumoniae carbapenemase) that has been developed in combination with meropenem. The pharmacokinetics of the combination was evaluated in 41 subjects with chronic renal impairment in a phase 1, open-label, single-dose study. Subjects were assigned to one of five groups based on renal function: normal (creatinine clearance of ≥90 ml/min), mild (estimated glomerular filtration rate [eGFR] of 60 to 89 ml/min/1.73 m2), moderate (eGFR of 30 to <60), or severe (eGFR of <30) impairment plus end-stage renal disease (ESRD) patients on hemodialysis. Subjects received a single intravenous dose of 1 g of meropenem plus 1 g of vaborbactam by 3-h infusion. The ESRD group received two doses (on and off dialysis) separated by a washout. Pharmacokinetic parameters were estimated by standard noncompartmental methods. For both meropenem and vaborbactam, the area under the concentration-time curve was larger and the elimination half-life was longer with decreasing renal function. Meropenem and vaborbactam total plasma clearance (CLt) rates were similar and decreased with decreasing renal function. Slopes of the linear relationship between eGFR and CLt were similar, indicating a similar proportional reduction in CLt with decreasing renal function. Hemodialysis significantly increased drug clearance of meropenem (mean of 2.21-fold increase in CLt, P < 0.001) and vaborbactam (mean of 5.11-fold increase, P = 0.0235) relative to drug administration off dialysis, consistent with dose recovery rates of 38.3% and 52.9% for meropenem and vaborbactam, respectively, in dialysate. Plasma clearance of meropenem and vaborbactam is reduced with renal impairment, requiring dose adjustment. Hemodialysis removes both drugs. (This study has been registered at ClinicalTrials.gov under identifier NCT02020434.).

Meropenem-RPX7009 Concentrations in Plasma, Epithelial Lining Fluid, and Alveolar Macrophages of Healthy Adult Subjects.

The steady-state concentrations of meropenem and the ß-lactamase inhibitor RPX7009 in plasma, epithelial lining fluid (ELF), and alveolar macrophage (AM) concentrations were obtained in 25 healthy, nonsmoking adult subjects. Subjects received a fixed combination of meropenem (2 g) and RPX7009 (2 g) administered every 8 h, as a 3-h intravenous infusion, for a total of three doses. A bronchoscopy and bronchoalveolar lavage were performed once in each subject at 1.5, 3.25, 4, 6, or 8 h after the start of the last infusion. Meropenem and RPX7009 achieved a similar time course and magnitude of concentrations in plasma and ELF. The mean pharmacokinetic parameters ± the standard deviations of meropenem and RPX7009 determined from serial plasma concentrations were as follows: Cmax = 58.2 ± 10.8 and 59.0 ± 8.4 µg/ml, Vss = 16.3 ± 2.6 and 17.6 ± 2.6 liters; CL = 11.1 ± 2.1 and 10.1 ± 1.9 liters/h, and t1/2 = 1.03 ± 0.15 and 1.27 ± 0.21 h, respectively. The intrapulmonary penetrations of meropenem and RPX7009 were ca. 63 and 53%, respectively, based on the area under the concentration-time curve from 0 to 8 h (AUC0-8) values of ELF and total plasma concentrations. When unbound plasma concentrations were considered, ELF penetrations were 65 and 79% for meropenem and RPX7009, respectively. Meropenem concentrations in AMs were below the quantitative limit of detection, whereas median concentrations of RPX7009 in AMs ranged from 2.35 to 6.94 µg/ml. The results from the present study lend support to exploring a fixed combination of meropenem (2 g) and RPX7009 (2 g) for the treatment of lower respiratory tract infections caused by meropenem-resistant Gram-negative pathogens susceptible to the combination of meropenem-RPX7009.

LC-UV/MS methods for the analysis of prochelator-boronyl salicylaldehyde isonicotinoyl hydrazone (BSIH) and its active chelator salicylaldehyde isonicotinoyl hydrazone (SIH).

Salicylaldehyde isonicotinoyl hydrazone (SIH) is an intracellular iron chelator with well documented potential to protect against oxidative injury both in vitro and in vivo. However, it suffers from short biological half-life caused by fast hydrolysis of the hydrazone bond. Recently, a concept of boronate prochelators has been introduced as a strategy that might overcome these limitations. This study presents two complementary analytical methods for detecting the prochelator-boronyl salicylaldehyde isonicotinoyl hydrazone-BSIH along with its active metal-binding chelator SIH in different solution matrices and concentration ranges. An LC-UV method for determination of BSIH and SIH in buffer and cell culture medium was validated over concentrations of 7-115 and 4-115 µM, respectively, and applied to BSIH activation experiments in vitro. An LC-MS assay was validated for quantification of BSIH and SIH in plasma over the concentration range of 0.06-23 and 0.24-23 µM, respectively, and applied to stability studies in plasma in vitro as well as analysis of plasma taken after i.v. administration of BSIH to rats. A Zorbax-RP bonus column and mobile phases containing either phosphate buffer with EDTA or ammonium formate and methanol/acetonitrile mixture provided suitable conditions for the LC-UV and LC-MS analysis, respectively. Samples were diluted or precipitated with methanol prior to analysis. These separative analytical techniques establish the first validated protocols to investigate BSIH activation by hydrogen peroxide in multiple matrices, directly compare the stabilities of the prochelator and its chelator in plasma, and provide the first basic pharmacokinetic data of this prochelator. Experiments reveal that BSIH is stable in all media tested and is partially converted to SIH by H2O2. The observed integrity of BSIH in plasma samples from the in vivo study suggests that the concept of prochelation might be a promising strategy for further development of aroylhydrazone cytoprotective agents.

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.

Population pharmacokinetic analysis of dutogliptin, a selective dipeptidyl peptidase-4 inhibitor.

Dutogliptin is a selective dipeptidyl peptidase-4 inhibitor shown to be efficacious and safe in patients with type 2 diabetes mellitus (T2DM). Population pharmacokinetic (PK) analysis of dutogliptin was performed based on data collected in 561 healthy subjects and patients with T2DM enrolled in Phase I and II studies to assess sources of variability and support dosing rationale. The effect of extrinsic (formulations, fed/fasting conditions, potential drug-drug interaction with metformin) and intrinsic (baseline characteristics, markers of renal function, renal impairment category, and disease status) covariates was evaluated using non-linear mixed effect modeling. Plasma concentrations of dutogliptin were best fitted with a two-compartment model with a first-order rate constant of absorption (Ka) and a lag time. No differences were observed between healthy subjects and patients with T2DM. Apparent clearance (CL/F) and terminal elimination half-life of dutogliptin were 176 L/h and 12.2 hours, respectively. Typical CL/F values in patients with mild and moderate renal impairment were 121 and 79 L/h, respectively. No drug-drug interaction was observed with metformin. These results suggest that a reduction in dosing from 400 to 200 mg daily is warranted in T2DM patients with moderate renal impairment. No dose adjustments were deemed necessary for other evaluated patient characteristics and coadministration with metformin.

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.

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.

Pharmacokinetics and safety of bortezomib in patients with advanced malignancies and varying degrees of liver dysfunction: phase I NCI Organ Dysfunction Working Group Study NCI-6432.

PURPOSE: The proteasome inhibitor bortezomib undergoes oxidative hepatic metabolism. This study (NCI-6432; NCT00091117) was conducted to evaluate bortezomib pharmacokinetics and safety in patients with varying degrees of hepatic impairment, to inform dosing recommendations in these special populations. EXPERIMENTAL DESIGN: Patients received bortezomib on days 1, 4, 8, and 11 of 21-day cycles. Patients were assigned to four hepatic function groups based on the National Cancer Institute Organ Dysfunction Working Group classification. Those with normal function received bortezomib at the 1.3 mg/m(2) standard dose. Patients with severe, moderate, and mild impairment received escalating doses from 0.5, 0.7, and 1.0 mg/m(2), respectively, up to a 1.3 mg/m(2) maximum. Serial blood samples were collected for 24 hours postdose on days 1 and 8, cycle 1, for bortezomib plasma concentration measurements. RESULTS: Sixty-one patients were treated, including 14 with normal hepatic function and 17, 12, and 18 with mild, moderate, and severe impairment, respectively. Mild hepatic impairment did not alter dose-normalized bortezomib exposure (AUC(0-tlast)) or C(max) compared with patients with normal function. Mean dose-normalized AUC(0-tlast) was increased by approximately 60% on day 8 in patients with moderate or severe impairment. CONCLUSIONS: Patients with mild hepatic impairment do not require a starting dose adjustment of bortezomib. Patients with moderate or severe hepatic impairment should be started at a reduced dose of 0.7 mg/m(2).

Pharmacokinetics and antiviral activity of PHX1766, a novel HCV protease inhibitor, using an accelerated Phase I study design.

BACKGROUND: PHX1766 is a novel HCV NS3/4 protease inhibitor with robust potency and high selectivity in replicon studies (50% maximal effective concentration 8 nM). Two clinical trials investigated the safety, tolerability, pharmacokinetics and antiviral activity of PHX1766 in healthy volunteers (HV) and chronic hepatitis C patients, by use of a dose-adaptive overlapping clinical trial design. METHODS: Two randomized, double-blind, placebo-controlled clinical trials were conducted. Single doses of PHX1766 or placebo were administered to 25 HV and six HCV genotype 1-infected patients (50 mg once daily -1,000 mg once daily, 250 mg twice daily and 100 mg of a new formulation of PHX1766 once daily). Multiple doses of PHX1766 or placebo were administered to 32 HV and seven HCV genotype 1-infected patients (50 mg once daily -800 mg twice daily). RESULTS: Oral administration of PHX1766 was safe and well tolerated at all dose levels with rapid absorption (time at which concentration maximum is reached of 1-4 h) and with mean terminal half-lives of 4-23 h. Multiple doses of PHX1766 800 mg twice daily in HCV patients produced an area under the plasma concentration-time curve from time of drug administration to the last time point with a measurable concentration after dosing accumulation ratio of 2.3. The mean maximal observed HCV RNA decline was 0.6 log(10) IU/ml in the first 24 h in the single-dose protocol and 1.5 log(10) IU/ml after 6 days of PHX1766 dosing. CONCLUSIONS: An overlapping, dose-adaptive single-dose and multiple-dose escalating design in HV and HCV-infected patients proved to be highly efficient in identifying a therapeutic dose. Although in vitro replicon studies indicated a robust HCV RNA viral decline of PHX1766, the study in HCV patients demonstrated only modest viral load reduction.

Effect of cytochrome P450 3A4 inducers on the pharmacokinetic, pharmacodynamic and safety profiles of bortezomib in patients with multiple myeloma or non-Hodgkin's lymphoma.

BACKGROUND AND OBJECTIVE: Bortezomib, an antineoplastic agent with proteasome inhibitory activity, is extensively metabolized by the hepatic microsomal cytochrome P450 (CYP) enzymes CYP3A4 and CYP2C19. Drugs that affect these enzymes may therefore have an impact on the pharmacological profile of bortezomib. This study evaluated the effects of co-administration of a potent CYP3A4 inducer (rifampicin [rifampin]) and a weak CYP3A4 inducer (dexamethasone) on the pharmacokinetic, pharmacodynamic and safety profiles of bortezomib. PATIENTS AND METHODS: Patients aged ≥18 years with relapsed or refractory multiple myeloma or non-Hodgkin's lymphoma received intravenous bortezomib 1.3 mg/m2, administered on days 1, 4, 8 and 11 of a 21-day cycle, for 3 cycles. In stage 1, patients were randomized (1 : 1) to receive bortezomib alone or in combination with oral rifampicin 600 mg once daily on days 4-10 during cycle 3 only. If the mean area under the plasma concentration-time curve (AUC) of bortezomib was reduced by ≥30% during rifampicin co-administration, then stage 2 was initiated, in which patients received bortezomib with dexamethasone 40 mg once daily on days 1-4 and days 9-12 during cycle 3 only. Blood samples were collected on days 11 through 14 of cycles 2 and 3 before and after bortezomib administration, at prespecified time points, for pharmacokinetic and pharmacodynamic (proteasome inhibition) assessments. RESULTS: Twelve patients in the bortezomib-alone arm, six patients in the bortezomib plus rifampicin arm and seven patients in the bortezomib plus dexamethasone arm were included in the pharmacokinetics-evaluable set. Rifampicin reduced the mean AUC from 0 to 72 hours (AUC(72h)) of bortezomib by approximately 45% (223 ng · h/mL in cycle 2 vs 123 ng · h/mL in cycle 3), while dexamethasone had no effect (mean AUC(72h): 179 ng · h/mL in cycle 2 vs 170 ng · h/mL in cycle 3). Proteasome inhibition parameters in peripheral blood were unaffected by rifampicin or dexamethasone. Safety profiles were similar across the treatment arms and consistent with previous experience of bortezomib. CONCLUSIONS: In patients with multiple myeloma or non-Hodgkin's lymphoma, co-administration of rifampicin decreased the exposure to bortezomib but did not affect the proteasome inhibition or safety profiles; co-administration of dexamethasone did not affect the exposure to bortezomib, proteasome inhibition or safety profiles. Concomitant administration of bortezomib with strong CYP3A4 inducers such as rifampicin is not recommended, as it may result in a reduction of the clinical effect, whereas concomitant administration of weak CYP3A4 inducers such as dexamethasone does not affect the pharmacological profile of bortezomib.

Tanespimycin and bortezomib combination treatment in patients with relapsed or relapsed and refractory multiple myeloma: results of a phase 1/2 study.

This open-label, dose escalation, multicentre phase 1/2 trial was undertaken to determine the safety and tolerability of the heat shock protein 90 (HSP90) inhibitor tanespimycin (100-340 mg/m(2) )+ bortezomib (0·7-1·3 mg/m(2) ) given on days 1, 4, 8 and 11 in each 21-d cycle. Phase 2 expansion occurred at the highest tested dose of tanespimycin at 340 mg/m(2) and bortezomib at 1·3 mg/m(2) . Seventy-two patients (median age, 60 years) with relapsed or relapsed and refractory multiple myeloma (MM) were enrolled; 63 patients (89%) completed the study. Tanespimycin in combination with bortezomib was well tolerated; few patients experienced significant neutropenia, constipation and anorexia (<10%), and no patients developed severe peripheral neuropathy. Among 67 efficacy-evaluable patients, there were 2 (3%) complete responses and 8 (12%) partial responses, for an objective response rate (ORR) of 27%, including 8 (12%) minimal responses. Response rates were highest among bortezomib-naive patients and proved durable in all patient subgroups, including those with bortezomib-refractory disease. Pharmacodynamic analyses indicated that tanespimycin plus bortezomib effectively inhibited the proteasome, as evidenced by decreased 20S proteasome activity, and inhibited HSP90, as reflected by increased HSP70 expression. The results of this study support additional studies of this combination approach in MM.

Development and validation of a high-performance liquid chromatography-tandem mass spectrometry method for the determination of the novel proteasome inhibitor CEP-18770 in human plasma and its application in a clinical pharmacokinetic study.

CEP-18770, [(1R)-1-{[(2S,3R)-3-hydroxy-2-{[(6-phenyl-2-pyridinyl)carbonyl]amino}butanoyl]amino}-3-methylbutyl]boronic acid, is a novel proteasome inhibitor, now under early clinical evaluation as an anticancer agent. To investigate its clinical pharmacokinetics, a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and validated to measure the drug in human plasma, based on simple protein precipitation with acetonitrile after the addition of irbesartan as internal standard. The method requires a small volume of sample (100 µl) and is rapid and selective, allowing good resolution of peaks in 5 min. It is sensitive, precise and accurate, with overall precision, expressed as coefficient of variation (CV%), always < 10.0%, accuracy in the range 93.8-107.7% and high recovery, close to 100%. The limit of detection is 0.01 ng/ml and the lower limit of quantitation (LLOQ) is 0.20 ng/ml. The assay was validated in the range from the LLOQ up to 50.00 ng/ml. This is the first method developed and validated for analyzing a proteasome inhibitor with a boronic-acid-based structure in human plasma. The method was successfully applied to study the pharmacokinetics of CEP-18770 in cancer patients with solid tumors or multiple myeloma who had received the drug as a short intravenous bolus during the initial Phase I trial.

Phase 1 clinical trial of bortezomib in adults with recurrent malignant glioma.

Bortezomib selectively binds and inhibits the 20S proteasome enzyme's active sites. This study was conducted to determine the side effects and maximum tolerated dose (MTD) of bortezomib in patients with recurrent malignant glioma. Separate dose escalations were conducted in patients taking or not taking enzyme-inducing anti-seizure drugs (+/-EIASD). The starting dose in both groups was 0.9 mg/m(2) intravenously twice weekly for the first three of each 4 week cycle. Imaging assessment of response was carried out and Plasma 20S proteasome activity inhibition and imaging was conducted to monitor efficacy. The 66 patients enrolled had a median age of 51 years, median KPS of 90%, and 77% had glioblastoma multiforme. The MTD in the -EIASD group was 1.70 mg/m(2) based on grade 3 thrombocytopenia, sensory neuropathy and fatigue. In the +EIASD group escalation was terminated at 2.5 mg/m(2) without meeting meet the MTD criteria. However, proteasome inhibition in this group did not change at doses above 1.90 mg/m(2) suggesting that further escalations would be unlikely to increase a biologic effect. Mean proteasome inhibition plateaued in +EIASD patients receiving 2.1 mg/m(2) of bortezomib at 77 ± 12% and in -EIASD patients treated with a dose of 1.7 mg/m(2) at 79 ± 6%. Two partial responses were observed. This study determined that EIASDs effect the MTD of bortezomib and the dose required for maximal inhibition of whole blood 20S proteasome. Some evidence of clinical activity was noted in this phase I study in patients with recurrent high grade gliomas.

Prospective comparison of subcutaneous versus intravenous administration of bortezomib in patients with multiple myeloma.

This phase I study compared pharmacokinetics and pharmacodynamics, and assessed safety and efficacy of intravenous and subcutaneous administration of bortezomib. Relapsed or refractory multiple myeloma patients were randomized to receive bortezomib by standard intravenous bolus (n=12) or subcutaneous injection (n=12) at the recommended dose and schedule (1.3 mg/m2, days 1, 4, 8, 11; eight 21-day cycles). Plasma bortezomib concentration and percent 20S proteasome inhibition were measured at multiple time points on days 1 and 11, cycle 1. Systemic bortezomib exposure was similar between arms. As expected, mean maximum plasma concentration was lower and took longer to reach following subcutaneous administration. Overall 20S proteasome inhibition was similar between arms. Safety profile and response rate for the subcutaneous arm did not appear inferior to the intravenous arm, with good local tolerance of subcutaneous injection. Based on these exploratory findings, subcutaneous administration offers an alternative option to intravenous injection (ClinicalTrials.gov identifier: NCT00291538).

Phase I and II pharmacokinetic and pharmacodynamic study of the proteasome inhibitor bortezomib in Japanese patients with relapsed or refractory multiple myeloma.

The purpose of this phase I and II study was to evaluate the safety, pharmacokinetics, pharmacodynamics, and efficacy of bortezomib in Japanese patients with relapsed or refractory multiple myeloma. This was a dose-escalation study designed to determine the recommended dose for Japanese patients (phase I) and to investigate the antitumor activity and safety (phase II) of bortezomib administered on days 1, 4, 8, and 11 every 21 days. Thirty-four patients were enrolled. A dose-limiting toxicity was febrile neutropenia, which occurred in one of six patients in the highest-dose cohort in phase I and led to the selection of 1.3 mg/m(2) as the recommended dose. Adverse events >or= grade 3 were rare except for hematological toxicities, although there was one fatal case of interstitial lung disease. The overall response rate was 30% (95% confidence interval, 16-49%). Pharmacokinetic evaluation showed a biexponential decline, characterized by a rapid distribution followed by a longer elimination, after dose administration, whereas the area under the concentration-time curve increased proportionately with the dose. Bortezomib was effective in Japanese patients with relapsed or refractory multiple myeloma. A favorable tolerability profile was also seen, although the potential for pulmonary toxicity should be monitored closely. The pharmacokinetic and pharmacodynamic profiles of bortezomib in the present study warrant further investigations, including more relevant administration schedules.