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Background Glioblastoma (GBM) is an incurable disease with few approved therapeutic interventions. Radiation therapy (RT) and temozolomide (TMZ) remain the standards of care. The efficacy and optimal deployment schedule of the orally bioavailable small-molecule tumor checkpoint controller lisavanbulin alone, and in combination with, standards of care were assessed using a panel of IDH-wildtype GBM patient-derived xenografts. Methods Mice bearing intracranial tumors received lisavanbulin +/−RT +/−TMZ and followed for survival. Lisavanbulin concentrations in plasma and brain were determined by liquid chromatography with tandem mass spectrometry, while flow cytometry was used for cell cycle analysis. Results Lisavanbulin monotherapy showed significant benefit (P < .01) in 9 of 14 PDXs tested (median survival extension 9%-84%) and brain-to-plasma ratios of 1.3 and 1.6 at 2- and 6-hours postdose, respectively, validating previous data suggesting significant exposure in the brain. Prolonged lisavanbulin dosing from RT start until moribund was required for maximal benefit (GBM6: median survival lisavanbulin/RT 90 vs. RT alone 69 days, P = .0001; GBM150: lisavanbulin/RT 143 days vs. RT alone 73 days, P = .06). Similar observations were seen with RT/TMZ combinations (GBM39: RT/TMZ/lisavanbulin 502 days vs. RT/TMZ 249 days, P = .0001; GBM26: RT/TMZ/lisavanbulin 172 days vs. RT/TMZ 121 days, P = .04). Immunohistochemical analyses showed a significant increase in phospho-histone H3 with lisavanbulin treatment (P = .01). Conclusions Lisavanbulin demonstrated excellent brain penetration, significant extension of survival alone or in RT or RT/TMZ combinations, and was associated with mitotic arrest. These data provide a strong clinical rationale for testing lisavanbulin in combination with RT or RT/TMZ in GBM patients.

Elevations of liver enzymes have been observed in clinical trials with BAL30072, a novel antibiotic. In vitro assays have identified potential mechanisms for the observed hepatotoxicity, including electron transport chain (ETC) inhibition and reactive oxygen species (ROS) generation. DILIsym, a quantitative systems pharmacology (QSP) model of drug-induced liver injury, has been used to predict the likelihood that each mechanism explains the observed toxicity. DILIsym was also used to predict the safety margin for a novel BAL30072 dosing scheme; it was predicted to be low. DILIsym was then used to recommend potential modifications to this dosing scheme; weight-adjusted dosing and a requirement to assay plasma alanine aminotransferase (ALT) daily and stop dosing as soon as ALT increases were observed improved the predicted safety margin of BAL30072 and decreased the predicted likelihood of severe injury. This research demonstrates a potential application for QSP modeling in improving the safety profile of candidate drugs.

BAL30072 is a new monocyclic β-lactam antibiotic under development which provides a therapeutic option for the treatment of severe infections caused by multi-drug-resistant Gram-negative bacteria. Despite the absence of liver toxicity in preclinical studies in rats and marmosets and in single dose clinical studies in humans, increased transaminase activities were observed in healthy subjects in multiple-dose clinical studies. We, therefore, initiated a comprehensive program to find out the mechanisms leading to hepatocellular injury using HepG2 cells (human hepatocellular carcinoma cell line), HepaRG cells (inducible hepatocytes derived from a human hepatic progenitor cell line), and human liver microtissue preparations. Our investigations demonstrated a concentration- and time-dependent reduction of the ATP content of BAL30072-treated HepG2 cells and liver microtissues. BAL30072 impaired oxygen consumption by HepG2 cells at clinically relevant concentrations, inhibited complexes II and III of the mitochondrial electron transport chain, increased the production of reactive oxygen species (ROS), and reduced the mitochondrial membrane potential. Furthermore, BAL 30072 impaired mitochondrial fatty acid metabolism, inhibited glycolysis, and was associated with hepatocyte apoptosis. Co-administration of N-acetyl-L-cysteine partially protected hepatocytes from BAL30072-mediated toxicity, underscoring the role of oxidative damage in the observed hepatocellular toxicity. In conclusion, BAL30072 is toxic for liver mitochondria and inhibits glycolysis at clinically relevant concentrations. Impaired hepatic mitochondrial function and inhibition of glycolysis can explain liver injury observed in human subjects receiving long-term treatment with this compound.

BackgroundBAL101553 (lisavanbulin), the lysine prodrug of BAL27862 (avanbulin), exhibits broad anti-proliferative activity in human cancer models refractory to clinically relevant microtubule-targeting agents.MethodsThis two-part, open-label, phase 1/2a study aimed to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of 2-h infusion of BAL101553 in adults with advanced or recurrent solid tumours. The MTD was determined using a modified accelerated titration design in phase I. Patients received BAL101553 at the MTD and at lower doses in the phase 2a expansion to characterise safety and efficacy and to determine the recommended phase 2 dose (RP2D).ResultsSeventy-three patients received BAL101553 at doses of 15–80 mg/m2(phase 1,n = 24; phase 2a,n = 49). The MTD was 60 mg/m2; DLTs observed at doses ≥60 mg/m2were reversible Grade 2–3 gait disturbance with Grade 2 peripheral sensory neuropathy. In phase 2a, asymptomatic myocardial injury was observed at doses ≥45 mg/m2. The RP2D for 2-h intravenous infusion was 30 mg/m2. The overall disease control rate was 26.3% in the efficacy population.ConclusionsThe RP2D for 2-h infusion of BAL101553 was well tolerated. Dose-limiting neurological and myocardial side effects were consistent with the agent’s vascular-disrupting properties.Clinical trial registrationEudraCT: 2010-024237-23.

Objective/methods Two openlabel, single-dose, randomized crossover studies and one open-label, multiple-dose, parallel group study in healthy volunteers were conducted with the prodrug, isavuconazonium sulfate, to determine absolute bioavailability of the active triazole, isavuconazole (EudraCT 2007-004949-15; n = 14), and the effect of food (EudraCT 2007- 004940-63; n = 26), and pH (NCT02128893; n = 24) on the absorption of isavuconazole. Isavuconazonium sulfate 744 mg designed to deliver 400 mg of the active triazole isavuconazole was administered in the absolute bioavailability (oral or intravenous (IV) (2-hour infusion)) and food-effect studies (oral). In the pH-effect study, isavuconazonium sulfate 372 mg designed to deliver 200 mg of isavuconazole was administered orally three times daily (t.i.d.) for 2 days, followed by a single daily oral dose for 3 days, in the presence of steady state esomeprazole dosed orally at 40 mg/day. Results Isavuconazole was well tolerated in each study. Bioavailability: Geometric least squares mean ratios (GLSMR; oral/IV) for isavuconazole AUC∞, and Cmax were 98% (90% confidence interval (CI): 94, 101) and 78% (90% CI: 72, 85), respectively. Food-effect: GLSMR (fed/fasted) for AUC∞ and Cmax of isavuconazole in plasma were 110% (90% CI: 102, 118) and 92% (90% CI: 86, 98), respectively. Median tmax was 5 hours with food and 3 hours under fasted conditions. pH-effect: GLSMR for isavuconazole AUCtau and Cmax were 108% (90% CI: 89, 130) and 105% (90% CI: 89, 124), respectively. Conclusions Orally administered isavuconazonium sulfate effectively delivers isavuconazole, as evidenced by the fact that oral isavuconazole is bioequivalent to the IV formulation. Dose adjustments are not required when switching between oral and IV formulations, regardless of food or drugs that increase gastric pH.

This report describes the phase 1 trials that evaluated the metabolism of the novel triazole antifungal isavuconazole by cytochrome P450 3A4 (CYP3A4) and isavuconazole's effects on CYP3A4-mediated metabolism in healthy adults. Coadministration of oral isavuconazole (100 mg once daily) with oral rifampin (600 mg once daily; CYP3A4 inducer) decreased isavuconazole area under the concentration-time curve (AUCτ ) during a dosing interval by 90% and maximum concentration (Cmax ) by 75%. Conversely, coadministration of isavuconazole (200 mg single dose) with oral ketoconazole (200 mg twice daily; CYP3A4 inhibitor) increased isavuconazole AUC from time 0 to infinity (AUC0-∞ ) and Cmax by 422% and 9%, respectively. Isavuconazole was coadministered (200 mg 3 times daily for 2 days, then 200 mg once daily) with single doses of oral midazolam (3 mg; CYP3A4 substrate) or ethinyl estradiol/norethindrone (35 μg/1 mg; CYP3A4 substrate). Following coadministration, AUC0-∞ increased 103% for midazolam, 8% for ethinyl estradiol, and 16% for norethindrone; Cmax increased by 72%, 14%, and 6%, respectively. Most adverse events were mild to moderate in intensity; there were no deaths, and serious adverse events and adverse events leading to study discontinuation were rare. These results indicate that isavuconazole is a sensitive substrate and moderate inhibitor of CYP3A4.

Summary Background Isavuconazole is a novel triazole with broad-spectrum antifungal activity. The SECURE trial assessed efficacy and safety of isavuconazole versus voriconazole in patients with invasive mould disease. Methods This was a phase 3, double-blind, global multicentre, comparative-group study. Patients with suspected invasive mould disease were randomised in a 1:1 ratio using an interactive voice–web response system, stratified by geographical region, allogeneic haemopoietic stem cell transplantation, and active malignant disease at baseline, to receive isavuconazonium sulfate 372 mg (prodrug; equivalent to 200 mg isavuconazole; intravenously three times a day on days 1 and 2, then either intravenously or orally once daily) or voriconazole (6 mg/kg intravenously twice daily on day 1, 4 mg/kg intravenously twice daily on day 2, then intravenously 4 mg/kg twice daily or orally 200 mg twice daily from day 3 onwards). We tested non-inferiority of the primary efficacy endpoint of all-cause mortality from first dose of study drug to day 42 in patients who received at least one dose of the study drug (intention-to-treat [ITT] population) using a 10% non-inferiority margin. Safety was assessed in patients who received the first dose of study drug. This study is registered with ClinicalTrials.gov, number NCT00412893. Findings 527 adult patients were randomly assigned (258 received study medication per group) between March 7, 2007, and March 28, 2013. All-cause mortality from first dose of study drug to day 42 for the ITT population was 19% with isavuconazole (48 patients) and 20% with voriconazole (52 patients), with an adjusted treatment difference of −1·0% (95% CI −7·8 to 5·7). Because the upper bound of the 95% CI (5·7%) did not exceed 10%, non-inferiority was shown. Most patients (247 [96%] receiving isavuconazole and 255 [98%] receiving voriconazole) had treatment-emergent adverse events (p=0·122); the most common were gastrointestinal disorders (174 [68%] vs 180 [69%]) and infections and infestations (152 [59%] vs 158 [61%]). Proportions of patients with treatment-emergent adverse events by system organ class were similar overall. However, isavuconazole-treated patients had a lower frequency of hepatobiliary disorders (23 [9%] vs 42 [16%]; p=0·016), eye disorders (39 [15%] vs 69 [27%]; p=0·002), and skin or subcutaneous tissue disorders (86 [33%] vs 110 [42%]; p=0·037). Drug-related adverse events were reported in 109 (42%) patients receiving isavuconazole and 155 (60%) receiving voriconazole (p Interpretation Isavuconazole was non-inferior to voriconazole for the primary treatment of suspected invasive mould disease. Isavuconazole was well tolerated compared with voriconazole, with fewer study-drug-related adverse events. Our results support the use of isavuconazole for the primary treatment of patients with invasive mould disease. Funding Astellas Pharma Global Development, Basilea Pharmaceutica International.

Data regarding treatment of rare invasive fungal diseases (IFDs) are scarce. We documented the efficacy and safety of isavuconazole for treatment of uncommonly diagnosed IFDs. VITAL was a single-arm, international, open-label study evaluating the efficacy and safety of isavuconazole (200 mg orally or intravenously every 8 hours for 48 hours, then once daily). The primary outcome was overall response at Day 42; key secondary outcomes were overall responses at Day 84 and end of treatment (EOT), mortality at Days 42 and 84, and safety. This analysis includes patients with IFD caused by rare or unidentified pathogens. Twenty-six patients with IFDs caused by rare moulds (n = 17), non-Candida yeasts (n = 2), or unidentified moulds (n = 7) were enrolled (median treatment duration [range], 114.5 [1-496]) days. Overall treatment success was observed in 11/26 (42.3%), 10/26 (38.5%), and 15/26 (57.7%) patients at Days 42, 84, and EOT, respectively. All-cause mortality rates were 2/26 patients (7.7%) at Day 42 and 4/26 patients (15.4%) at Day 84; another two patients died after Day 84. All patients had ≥1 treatment-emergent adverse event (TEAE); 15 patients (57.7%) had serious TEAEs, and TEAEs led to discontinuation of isavuconazole in four patients (15.4%). Isavuconazole may be efficacious for treatment of a range of rare IFDs.

Elevations of liver enzymes have been observed in clinical trials with BAL30072, a novel antibiotic. In vitro assays have identified potential mechanisms for the observed hepatotoxicity, including electron transport chain (ETC) inhibition and reactive oxygen species (ROS) generation. DILIsym, a quantitative systems pharmacology (QSP) model of drug‐induced liver injury, has been used to predict the likelihood that each mechanism explains the observed toxicity. DILIsym was also used to predict the safety margin for a novel BAL30072 dosing scheme; it was predicted to be low. DILIsym was then used to recommend potential modifications to this dosing scheme; weight‐adjusted dosing and a requirement to assay plasma alanine aminotransferase (ALT) daily and stop dosing as soon as ALT increases were observed improved the predicted safety margin of BAL30072 and decreased the predicted likelihood of severe injury. This research demonstrates a potential application for QSP modeling in improving the safety profile of candidate drugs.

Ceftobiprole is a broad‐spectrum cephalosporin. The objective of this study was to test the hypothesis that the pharmacokinetics (PK) and exposure of ceftobiprole in Asian subjects are similar to those in non‐Asian subjects. Three approaches were followed. The first compared the individual PK estimates between the 2 subgroups derived from a population PK model previously built. Next, it was determined whether “Asian subject” was a significant covariate. Finally, a pharmacodynamic analysis was performed by comparing measures of exposure and target attainment. No significant differences were found between PK parameter estimates for Asian and non‐Asian subjects, with median values (range) for clearance of 4.82 L/h (2.12–10.47) and 4.97 L/h (0.493–20.6), respectively (P = .736). “Asian subject” was not a significant covariate in the population PK model. There were no significant differences between the measures of exposure. The geometric mean ratio for the fAUC was 1.022 (90%CI, 0.91–1.15), indicating bioequivalence. Taking a target of 60% coverage of the dose interval, more than 90% of the population in both subgroups was adequately exposed. This analysis demonstrated that there are no PK or pharmacodynamic differences between Asian and non‐Asian subjects for a ceftobiprole dose of 500 mg every 8 hours as a 2‐hour infusion.

Isavuconazole is a novel broad-spectrum triazole antifungal agent. This open-label dose escalation study assessed the safety and pharmacokinetics of intravenous isavuconazole prophylaxis in patients with acute myeloid leukemia who had undergone chemotherapy and had preexisting/expected neutropenia. Twenty-four patients were enrolled, and 20 patients completed the study. The patients in the low-dose cohort ( n = 11) received isavuconazole loading doses on day 1 (400/200/200 mg, 6 h apart) and day 2 (200/200 mg, 12 h apart), followed by once-daily maintenance dosing (200 mg) on days 3 to 28. The loading and maintenance doses were doubled in the high-dose cohort ( n = 12). The mean ± standard deviation plasma isavuconazole areas under the concentration-time curves for the dosing period on day 7 were 60.1 ± 22.3 μg · h/ml and 113.1 ± 19.6 μg · h/ml for the patients in the low-dose and high-dose cohorts, respectively. The adverse events in five patients in the low-dose cohort and in eight patients in the high-dose cohort were considered to be drug related. Most were mild to moderate in severity, and the most common adverse events were headache and rash ( n = 3 each). One patient in the high-dose cohort experienced a serious adverse event (unrelated to isavuconazole treatment), and two patients each in the low-dose and high-dose cohorts discontinued the study due to adverse events. Of the 20 patients who completed the study, 18 were classified as a treatment success. In summary, the results of this analysis support the safety and tolerability of isavuconazole administered at 200 mg and 400 mg once-daily as prophylaxis in immunosuppressed patients at high risk of fungal infections. (This study is registered at ClinicalTrials.gov under registration number NCT00413439.)

Quantitative whole-body autoradiography was used to assess the distribution and tissue penetration of isavuconazole in rats following single and repeated oral-dose administration of radiolabeled isavuconazonium sulfate, the prodrug of isavuconazole. Following a single-dose administration of radiolabeled isavuconazonium sulfate (labeled on the active moiety), radioactivity was detectable within 1 h postdose in 56 of 65 tissue/fluid specimens. The highest maximum concentrations ( C max ) were observed in bile and liver (66.6 and 24.7 μg eq/g, respectively). The lowest C max values were in bone and eye lens (0.070 and 0.077 μg eq/g, respectively). By 144 h postdose, radioactivity was undetectable in all tissues/fluids except liver (undetectable at 336 h) and adrenal gland tissues (undetectable at 672 h). Following daily administration for up to 21 days, 1-h-postdose C max values were the highest on or before day 14 in all except seven tissues/fluids, of which only rectum mucosa and small intestine mucosa had C max values >25% higher than all other 1-h-postdose values. For 24-h-postdose C max values, only large intestine, large intestine mucosa, and urine had the highest C max values at day 21. The penetration of single oral doses of unlabeled isavuconazole (25 mg/kg of body weight isavuconazonium sulfate) and voriconazole (50 mg/kg) into rat brain (assessed using liquid chromatography-tandem mass spectrometry) was also compared. Brain concentration/plasma concentration ratios reached approximately 1.8:1 and 2:1, respectively. These data suggest that isavuconazole penetrates most tissues rapidly, reaches a steady state in most or all tissues/fluids within 14 days, does not accumulate in tissues/fluids over time, and achieves potentially efficacious concentrations in the brain.

A systematic comparison between two labeling approaches for the investigation of the in vitro metabolic pattern of pharmaceutical drugs was performed by examining the use of (i) radiolabeled drugs analyzed with LC-MS-offline radiodetection and (ii) stable-isotope labeled drugs, used in a defined mixture with the unlabeled drug and analyzed by LC-MS with recognition of the specific isotopic pattern. (14)C was used for the radioisotope-approach and deuterium for the stable-isotope approach. Olanzapine, diclofenac and ketoconazole were chosen as model drugs, as they are commercially available in their non-, radio- and stable-isotope labeled forms. For all three model drugs, liver microsome- and hepatocyte-incubations (both from rat) were performed with various concentrations and incubation times for both, the radio- and the stable-isotope approaches. The metabolic pattern, including structure elucidation of all detected metabolites, was performed independently for all individual compounds and incubations. Subsequently, the metabolic patterns of the radio-, and the stable-isotope approaches were compared. In conclusion, all metabolites found with the radioisotope approach could also be found with the stable-isotope approach. Although the stable-isotope approach does not provide a quantitative result, it can be considered to be a highly suited analytical alternative for early in vitro metabolism investigations, especially when radiolabeled drug analogues are not yet available and quantitative results are not yet necessary.

Carbapenem resistance in Gram-negative bacteria, mediated by restricted net influx and carbapenem-hydrolysing β-lactamases, is a growing problem. The monosulfactam antibiotic BAL30072 is stable to most carbapenemases, suggesting that it could be complementary to carbapenems. We have investigated the antimicrobial activity of BAL30072 combined with imipenem, meropenem and doripenem.The in vitro activities of the combinations were evaluated using broth microdilution susceptibility and agar disc diffusion tests, broth dilution chequerboard titration and time-kill studies, using strains of Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter with carbapenem MICs ≥ 2 mg/L.The combinations were effective against 70%-80% of the isolates tested in the presence of 1 mg/L of each antibiotic, whereas the carbapenems were ineffective and BAL30072 alone was effective against 20%-40% of the strains. Synergistic effects were observed with many Enterobacteriaceae and P. aeruginosa, but were less common among the Acinetobacter, although additive effects, where the activity of one partner compensated for lack of activity of the other, were common. None of the combinations exhibited an antagonistic effect in all tests, in contrast to other β-lactams where negative interactions were frequently observed. Animal models of septicaemia demonstrated that the synergy observed in vitro with BAL30072 and meropenem can translate into greater in vivo efficacy.BAL30072/carbapenem combinations were effective against a broader range of multidrug-resistant Gram-negative bacteria than either of the single agents. Additive and synergistic effects were observed in Enterobacteriaceae and P. aeruginosa, and this enhanced activity was frequently associated with suppression of resistance development. The in vitro activity translated into improved in vivo efficacy.

An approach was developed that uses enzyme inhibitors to support the assessment of the pathways that are responsible for the conversion of intravenously administered ester and amide prodrugs in different biological matrices. The methodology was applied to ceftobiprole medocaril (BAL5788), the prodrug of the cephalosporin antibiotic, ceftobiprole. The prodrug was incubated in plasma, postmitochondrial supernatant fractions from human liver (impaired and nonimpaired), kidney, and intestine as well as erythrocytes, in the presence and absence of different enzyme inhibitors (acetylcholinesterase, pseudocholinesterase, retinyl palmitoyl hydrolase, serine esterases, amidases, and cholinesterase). Hydrolysis was rapid, extensive, and not dependent on the presence of β-nicotinamide-adenine dinucleotide phosphate (reduced form) in all matrices tested, suggesting the involvement of carboxylesterases but not P450 enzymes. Hydrolysis in healthy human plasma was rapid and complete and only partially inhibited in the presence of paraoxonase inhibitors or in liver from hepatic impaired patients, suggesting involvement of nonparaoxonase pathways. The results demonstrate the utility of this approach in confirming the presence of multiple conversion pathways of intravenously administered prodrugs and in the case of BAL5788 demonstrated that this prodrug is unlikely to be affected by genetic polymorphisms, drug interactions, or other environmental factors that might inhibit or induce the enzymes involved in its conversion.

Isavuconazole, administered as the prodrug isavuconazonium sulfate, was recently approved by the U.S. Food and Drug Administration and the European Medicines Agency for the treatment of adults with invasive aspergillosis and mucormycosis. The objective of this analysis was to develop a population pharmacokinetic model using NONMEM (version 7.2) for subjects with hepatic impairment, using intravenous and oral administration data from two hepatic studies, and to simulate concentration profiles to steady state, thus evaluating the need for dose adjustment. A two-compartment model with Weibull absorption function and first-order elimination process adequately described plasma isavuconazole concentrations. The population mean clearance in healthy subjects was 2.5 liters/h (5th and 95th percentiles: 2.0 and 3.1). The mean clearance values for subjects with mild and moderate hepatic impairment decreased approximately to 1.55 liters/h (5th and 95th percentiles: 1.3 and 1.8 liters/h) and 1.32 liters/h (5th and 95th percentiles: 1.05 and 1.35), respectively. Peripheral volume of distribution increased with body mass index. Simulations of mean concentration time profiles to steady state showed less than a 2-fold increase in mean trough concentrations for subjects with mild and moderate hepatic impairment compared with healthy subjects. After administration of the single dose, safety data for subjects with mild and moderate hepatic impairment were generally comparable to those for healthy subjects in both studies. Due to the

BAL30376 is a triple combination comprising a siderophore monobactam, BAL19764 ; a novel bridged monobactam, BAL29880 , which specifically inhibits class C β-lactamases; and clavulanic acid, which inhibits many class A and some class D β-lactamases. The MIC 90 was ≤4 μg/ml (expressed as the concentration of BAL19764 ) for most species of the Enterobacteriaceae family, including strains that produced metallo-β-lactamases and were resistant to all of the other β-lactams tested. The MIC 90 for Stenotrophomonas maltophilia was 2 μg/ml, for multidrug-resistant (MDR) Pseudomonas aeruginosa it was 8 μg/ml, and for MDR Acinetobacter and Burkholderia spp. it was 16 μg/ml. The presence of the class C β-lactamase inhibitor BAL29880 contributed significantly to the activity of BAL30376 against strains of Citrobacter freundii , Enterobacter species, Serratia marcescens , and P. aeruginosa . The presence of clavulanic acid contributed significantly to the activity against many strains of Escherichia coli and Klebsiella pneumoniae that produced class A extended-spectrum β-lactamases. The activity of BAL30376 against strains with metallo-β-lactamases was largely attributable to the intrinsic stability of the monobactam BAL19764 toward these enzymes. Considering its three components, BAL30376 was unexpectedly refractory toward the development of stable resistance.

Summary Background. Previous studies have shown that concomitant administration of food may enhance the bioavailability of oral retinoids. Aim. To assess the influence of food on the pharmacokinetics (PK) of alitretinoin after a single oral dose. Methods. This was a single-dose, open-label, randomized, crossover study, which enrolled 30 healthy men, aged 18–44 years. Subjects received sequential doses of alitretinoin 40 mg either after fasting (treatment A) or 5 min after completion of a standard breakfast (treatment B), with the dosing sequence randomized (A/B or B/A). The washout period between the two doses was 1 week. Plasma concentrations over time were plotted and standard PK variables [area under the curve (AUC) of plasma concentration vs. time, maximum plasma concentration (Cmax), time to maximum plasma concentration (tmax) and elimination half-life (t1/2)] were determined. Results. Drug exposure was markedly increased when alitretinoin was taken with food compared with fasting, and there were significant increases in mean Cmax (82.8 vs.25.4 ng/mL, respectively) and AUC (220.2 vs. 55.7 ng·h/mL). The delaying effect of food on tmax was less marked (median of 3.0 vs. 2.0 h). Administration with food also increased exposure to drug metabolites. Variability in exposure was markedly reduced if alitretinoin was taken with vs. without food (percentage coefficient of variation 40% vs. 74% for AUC; 49% vs. 85% for Cmax). Alitretinoin was generally well tolerated, with typical retinoid adverse reactions, mostly comprising headache. Conclusions. Intake of alitretinoin with food substantially increased the bioavailability of alitretinoin, but variability in exposure was reduced. Consequently, oral alitretinoin should be taken with food as outlined in the manufacturer’s summary of product characteristics.

P>Background. Recent studies have found that alitretinoin can induce clinically significant responses in subjects with severe chronic hand eczema (CHE) unresponsive to topical corticosteroids. Aims. To assess the pharmacokinetics (PK), efficacy and safety of alitretinoin 10 or 30 mg once daily. Methods. This was a randomized, double-blind study, which enrolled 32 subjects aged 18-75 years with CHE unresponsive to potent topical corticosteroids. Subjects received alitretinoin 10 mg (n = 16) or 30 mg (n = 16) once daily for 12 or 24 weeks. Standard PK variables [area under the curve (AUC) of plasma concentration vs. time, maximum plasma concentration (C-max), time to maximum plasma concentration (t(max)), elimination half-life (t(1/2)), total systemic clearance (CL/F) and volume of distribution (Vd/F)] were determined for alitretinoin and metabolites. Efficacy was assessed using the Physician's Global Assessment (PGA) scale. Results. Chronic administration of alitretinoin for up to 24 weeks did not result in accumulation or time-dependent changes in the disposition of alitretinoin. Exposure was found to be proportional to dose. Systemic exposure (AUC) to alitretinoin was proportional to dose for 10 and 30 mg alitretinoin; 62.8% of subjects achieved clear/almost clear hands in the 30 mg group and 12.5% in the 10 mg group. Alitretinoin was well tolerated. Conclusions. Chronic administration of alitretinoin for 12-24 weeks did not lead to accumulation or time-dependent changes in drug exposure. Alitretinoin was effective and well tolerated in the treatment of subjects with moderate or severe CHE unresponsive to potent topical corticosteroids.

Summary Background. Based on in vitro data with isolated cytochrome P450 (CYP) isoenzymes, alitretinoin interacts only with CYP3A4, and the potential for drug–drug interactions is considered negligible. Aim. To confirm in humans the lack of potential interactions between CYP3A4 and alitretinoin in vivo. Methods. This was a multiple-dose, open-label, parallel-group, single-centre study, which enrolled 54 healthy male volunteers aged 18–45 years. Subjects were divided into three groups, with 18 in each group: group 1 received either alitretinoin 30 mg and ketoconazole 200 mg, group 2 alitretinoin 30 mg and simvastatin 40 mg, and group 3 alitretinoin 30 mg and ciclosporin A 300-mg. Results. At the highest therapeutic dose of 30 mg, alitretinoin had no significant effect on the pharmacokinetics (PK) of ketoconazole and ciclosporin A. There was a significant but not clinically relevant effect of simvastatin on the area under the curve (AUC) of plasma concentration vs. time and on maximum plasma concentration (Cmax) after repeated administration of alitretinoin. Exposure to simvastatin concomitantly with alitretinoin was decreased by 16% for AUC and 23% for Cmax. The CYP3A4 ± PgP substrates of simvastatin and ciclosporin A did not affect the single or repeated dose PK of alitretinoin. The strong CYP3A4/PgP inhibitor ketoconazole led to significant increases in both AUC and Cmax values for alitretinoin. Conclusions. Single and repeated doses of alitretinoin do not alter the PK of ciclosporin A and ketoconazole. Simvastatin levels were slightly but significantly reduced by co-administration of alitretinoin. Substrates of CYP3A4 did not affect the PK of alitretinoin. However, ketoconazole significantly increased the plasma levels of alitretinoin, therefore, co-administration with CYP3A4 inhibitors such as ketoconazole may require a dose reduction of alitretinoin.

Summary Background. Alitretinoin, like all retinoids, is teratogenic, and can only be given to women of childbearing potential if pregnancy is excluded and a strict contraceptive programme is followed. Aim. This study was designed to determine whether alitretinoin in the semen of men treated with alitretinoin poses a teratogenic risk to their female partners. Methods. In total, 24 healthy men aged 18–45 years received alitretinoin 20 mg (n = 12) or 40 mg (n = 12), once daily for 14 days. Subjects in the 40 mg dose group provided ejaculate at baseline, on day 1, before and approximately 4 h after dosing on day 2, and at follow-up on study day 21 (± 2). Results. Alitretinoin and 4-oxo-alitretinoin were detected in 11 of the 12 semen samples. The highest level of alitretinoin in semen was 7.92 ng/mL. Assuming an ejaculate volume of 10 mL, the amount of drug transferred in semen would be about 80 ng, 1/375 000 of a single 30 mg capsule. Complete absorption of 80 ng of alitretinoin from semen, presuming a volume of distribution confined to 5 L of circulating blood in the partner, would lead to an increase in plasma alitretinoin concentration of 0.016 ng/mL, which appears to be negligible compared with measured endogenous plasma levels. Increases in plasma levels of related retinoids are also negligible. Conclusions. Alitretinoin in the semen of men receiving up to 40 mg of oral alitretinoin per day is unlikely to be associated with teratogenic risk in their female partners. Barrier contraception is therefore not required for men taking alitretinoin.

BACKGROUND: Alitretinoin (9-cis retinoic acid) is currently registered in many European countries and in Canada as the only licensed treatment for severe chronic hand eczema unresponsive to potent topical corticosteroids. Alitretinoin like all retinoids is teratogenic and women of child-bearing potential must strictly adhere to pregnancy-prevention measures. AIM: To investigate the influence of alitretinoin on the pharmacokinetics (PK) of ethinyl estradiol/norgestimate (Ortho Tri-Cyclen 28((R))) a commonly prescribed combination oral contraceptive. METHODS: In total 16 healthy premenopausal women received three consecutive cycles of the triphasic contraceptive ethinyl estradiol/norgestimate together with concomitant oral alitretinoin 40 mg once daily during cycle 2. Steady-state PK (noncompartmental analysis) of ethinyl estradiol 17-deacetyl norgestimate alitretinoin and its main metabolite 4-oxo-alitretinoin were assessed alone and in combination. RESULTS: The PK profiles of ethinyl estradiol and 17-deacetyl norgestimate were similar when contraceptives were given alone or with alitretinoin and the area under the plasma concentration vs. time curve and the maximum concentration met the conventional criteria for PK equivalence. Similarly the influence of ethinyl estradiol/norgestimate on systemic exposure to alitretinoin and 4-oxo-alitretinoin was not clinically relevant. Alitretinoin was well tolerated when given either alone or with ethinyl estradiol/norgestimate. CONCLUSIONS: There was no clinically relevant influence of alitretinoin on the PK of ethinyl estradiol/norgestimate and no influence of ethinyl estradiol/norgestimate on systemic exposure to alitretinoin and 4-oxo-alitretinoin. Consequently oral contraception with ethinyl estradiol/norgestimate is an appropriate primary method of birth control during alitretinoin treatment for women of childbearing potential. (c) 2011 The Author(s). Clinical and Experimental Dermatology (c) 2011 British Association of Dermatologists.

The in vitro metabolic profile of BAL30630, an antifungal piperazine propanol derivative, which inhibits the 1,3-beta- d -glucansynthase, was investigated by incubation with microsomes of several species and with rat hepatocytes. For the spotting of the metabolites, mixtures of BAL30630 with a stable isotope (deuterium) labeled analogue were incubated. The metabolic pattern comprises several oxidized metabolites. Based on isotope exchange experiments, their structures could be assigned to epoxide- and hydroxylated metabolites. In hepatocyte incubations, several glucuronides formed from these oxidized metabolites could be observed. From the analysis of the metabolic pattern in microsomes, products of carbamate hydrolysis were characterized. This hydrolysis was highly species dependent. In activated incubations and in rat hepatocytes, those metabolites were further oxidized. In incubations without NADPH activation, the resulting hydrolytic metabolites could be enriched without the subsequent oxidation. Final structural elucidation of the metabolites was performed using accurate mass determination and isotope exchange experiments, in which incubations were analyzed by deuterium exchange and capillary HPLC–QTof-MS and MS/MS. The use of non-radioactive, stabile isotope labeled drug analogues in combination with isotope exchange studies was essential in particular for a defined assignment of the functional groups in the structures of the investigated metabolites.

The pharmacokinetics and distribution into bone tissue of ceftobiprole in uninfected New Zealand White rabbits were determined after subcutaneous administration of the prodrug ceftobiprole medocaril. Serum exposure (maximum concentration of the drug in serum, trough concentration, area under the concentration-time curve) to ceftobiprole at 20 and 80 mg/kg was dose proportional, and there was no accumulation of ceftobiprole following repeated (every 6 h [q6h]) injections of the antibiotic. Ceftobiprole titers in the tibial matrix and marrow were 3.2 ± 1.3 μg/g and 11.2 ± 6.5 μg/g, respectively, in uninfected animals treated with 20 mg/kg of the antibiotic and 13.4 ± 7.3 μg/g and 66.3 ± 43.2 μg/g, respectively, in uninfected animals treated with 80 mg/kg of the antibiotic. No differences in ceftobiprole titers were observed between right and left tibiae for either bone matrix or marrow. The efficacies of 4 weeks of treatment with ceftobiprole (40 mg/kg administered subcutaneously [s.c.] q6h), vancomycin (30 mg/kg administered s.c. q12h), or linezolid (60 mg/kg administered orally q8h) were compared, using a rabbit model of methicillin-resistant Staphylococcus aureus tibial osteomyelitis. After treatment with ceftobiprole, the bacterial titers in all infected left tibiae from evaluable rabbits were below the level of detection, whereas only 73% of infected left tibiae from vancomycin- or linezolid-treated animals had bacterial titers below the level of detection; the mean titers of ceftobiprole were 3 to 5 times higher in infected left tibiae than in uninfected right tibiae. These results indicate that ceftobiprole provided effective parenteral treatment of osteomyelitis in this rabbit model.

Background: BAL8557 (WSA) is the water-soluble prodrug of the triazole BAL4815 with in vitro anti-Aspergillus activity. We compared the activity of oral BAL8557 with oral itraconazole, oral voriconazole and intravenous caspofungin in a temporarily neutropenic murine model of disseminated Aspergillus flavus. METHODS: Mice were immunosuppressed using cyclophosphamide, then infected. Mice were treated either 2 h pre-infection (PRE), or 4 or 24 h post-infection (4POST and 24POST, respectively). Treatment was for 10 days followed by 4 days of observation. Surviving mice were killed and liver, kidneys, lungs and brain cultured. BAL8557 groups included doses corresponding to approximately 30, 15, 6 and 3 mg/kg of the active BAL4815; comparators included itraconazole 25 and 10 mg/kg/dose, voriconazole (plus oral grapefruit) 25 and 10 mg/kg/day or caspofungin 1 mg/kg/day. In a simultaneous tissue burden study mice were treated for 3 days, kidneys removed and homogenized and burden measured by quantitative culture and quantitative PCR using fluorescence resonance energy transfer (FRET). RESULTS: Control mice had 83-100% mortality. Over 66% of BAL8557-treated mice survived after >6 mg/kg PRE or >15 mg/kg POST. In the PRE models BAL8557 (6 mg/kg) and caspofungin were 100% protective and itraconazole 67% protective, but voriconazole 10 mg/kg had 100% mortality (P = 0.0016). In the 4POST and 24POST models survival was >66% with BAL8557 30 and 15 mg/kg/dose and similar to voriconazole or itraconazole. In the 24POST groups, sterilization of all organs was achieved in 11/16 survivors treated with BAL8557. The quantitative PCR correlated with kidney fungal burden (r(2) = 0.59). Earlier treatment reduced burdens. CONCLUSIONS: BAL8557 demonstrated impressive antifungal activity against A. flavus in this model, in both survival and tissue burden.

The metabolic profile of BAL4815, an antifungal azole drug, was determined using in vitro rat hepatocyte incubations and subsequent analysis by capillary LC-qTof-MS and MS/MS including accurate mass determination. For the detection of the metabolites, a mixture of the drug and its deuterium-labelled analogue was used for incubations. Metabolic stability of BAL4815 was high in cultured rat hepatocytes. However, several low-abundant metabolites were detected by the use of capillary LC-qTof-MS and manual investigation of the data. The peak intensity of the most abundant metabolite was close to the limit of detection. Except for an apparent oxidation product, the masses of the other detected metabolites could not be assigned to a single and frequently occurring biotransformation. Accurate mass determination and possible elemental compositions suggested that metabolism occurred through a combination of glutathionylation and defluorination. This was verified using accurate mass MS/MS. The use of accurate mass measurements and the derived suggestions for the elemental compositions were essential to elucidate this atypical metabolic pathway. A mass accuracy better than 8 ppm could be achieved for most assigned MS and MS/MS signals with intensities less than 6 cps in the spectra.

BAL8557 is the water-soluble prodrug of BAL4815, a new broad-spectrum antifungal. Healthy male subjects were randomly assigned to four treatment cohorts to receive multiple oral doses or multiple 1-h constant-rate intravenous infusions of BAL8557. Loading doses of BAL8557 were equivalent to 100 mg (followed by once-daily maintenance doses of 50 mg) or 200 mg (followed by once-daily maintenance doses of 100 mg) of BAL4815. In each cohort, six subjects received active drug and two subjects received the placebo. Study duration was 21 days (oral) and 14 days (intravenous). All adverse events reported were mild or moderate, except one severe rhinitis event which was not related to trial medication. After both routes of administration, maximum drug concentration observed in plasma ( C max ) and area under the concentration-time curve (AUC) values of BAL4815 increased proportionally to the administered dose. AUC values reflected a fourfold to fivefold accumulation of active drug in plasma during once-daily dosing, which is in line with the long elimination half-life of BAL4815 determined after the last administration (mean, 84.5 to 117 h). At steady state, the volume of distribution was large and amounted to 308 to 542 liters. Systemic clearance reached only 2.4 to 4.1 liter/h. At the levels obtained in the present study, C max values of 2.56 and 2.55 μg/ml after oral and intravenous administrations, respectively, there was no indication of CYP3A4 induction or inhibition (as revealed by the urinary 6-β-hydroxycortisol/cortisol test). Based on AUC values after oral and intravenous administration, an excellent oral bioavailability can be predicted for BAL4815. Once-daily oral dosing of 50- or 100-mg equivalents of BAL8557 were recently demonstrated to be efficacious in a phase 2 study conducted with patients with esophageal candidiasis. These doses (preceded by adequate loading dose[s]) will be further explored in the treatment of systemic mycoses.

BAL5788 is the water-soluble prodrug of BAL9141, a novel broad-spectrum cephalosporin with potent bactericidal activity against methicillin-resistant Staphylococcus aureus (MRSA) and penicillin-resistant Streptococcus pneumoniae . Safety and pharmacokinetic data from a multiple-dose study with 16 healthy male volunteers are reported. Subjects were randomized to receive BAL5788 at 500 or 750 mg (as BAL9141 equivalents; n = 6 subjects per dose) or placebo ( n = 2 subjects per dose). The doses were given as 200-ml infusions over 30 min once daily on days 1 and 8 and twice daily on days 2 to 7. BAL5788 was well tolerated, with no severe or serious adverse events (AEs) or dosing-related changes in laboratory parameters, electrocardiographic findings, or vital signs. Drug accumulation in plasma was negligible during the dosing period. The results of pharmacokinetic analyses agreed well with data reported from a previous single-ascending-dose study. The elimination half-life of BAL9141 was about 3 h. The volume of distribution at steady state was equal to the volume of the adult extracellular water compartment. BAL9141 was predominantly eliminated in urine, and renal clearance of the free drug corresponded to the normal glomerular filtration rate in adults. After multiple infusions of 750 mg, the mean concentrations of BAL9141 in plasma exceeded the MIC at which 100% of MRSA isolates are inhibited (4 μg/ml) for approximately 7 to 9 h, corresponding to 58 to 75% of a 12-h dosing interval.

BAL9141, a new antimicrobial agent belonging to the class of parenteral pyrrolidinone-3-ylidenemethyl cephalosporins, is active against most gram-positive microorganisms, including methicillin-resistant variants (methicillin-resistant Staphylococcus aureus [MRSA] and methicillin-resistant Staphylococcus epidermidis [MRSE]), as well as against penicillin-resistant pneumococci (PRP) and many gram-negative microorganisms. BAL9141 is administered as the prodrug BAL5788, which is rapidly converted to BAL9141 by plasma esterases. Pharmacokinetic (PK) data obtained in a previous multiple ascending dose study were used to fit a population PK model to using the NPEM2 program, yielding PK parameter estimates and its covariance matrix for BAL9141. These estimates and matrix were used to perform Monte Carlo simulations (MCSs) and obtain unbiased target attainment rates (TARs) for various time periods during which the concentration remains above the MIC ( T >MIC ). Assuming a T >MIC of 40%, TARs of 100% were reached with a dose of 500 mg/liter every 12 h for pathogens with MICs of 2 mg/liter and with a dose of 750 mg/liter every 12 h for pathogens with MICs of 4 mg/liter. Because MICs are ≤2 mg/liter for most strains of MRSA, MRSE, and PRP (with some strains showing an MIC of 4 mg/liter), a dosing regimen of 750 mg every 12 h is proposed for clinical studies. The corresponding provisional breakpoint is S (susceptible) ≤ 4 mg/liter.

BAL5788 is a water-soluble prodrug of BAL9141, a new broad-spectrum cephalosporin with high levels of in vitro activity against methicillin- and vancomycin-resistant staphylococci and penicillin-resistant streptococci. In plasma BAL5788 is rapidly converted to BAL9141. We studied the activity of BAL5788 in a mouse model of acute pneumococcal pneumonia. Leukopenic female Swiss albino mice were challenged intratracheally with 10 7 CFU of clinical Streptococcus pneumoniae strains P-52181 (Pen s Cro s Ctx s ), P-15986 (Pen r Cro s Ctx s ), P-40422 (Pen r Cro r Ctx r ), and P-40984 (Pen r Cro r Ctx r ). Infected mice received subcutaneous (s.c.) injections of BAL5788 or ceftriaxone starting 3 h after pneumococcal challenge. Uninfected nonleukopenic mice received single s.c. doses of BAL5788 to determine the BAL9141 concentration-time profiles in serum and lungs. Untreated control mice died within 5 days postinfection. Ten-day cumulative survival rates for infected mice receiving BAL5788 (total daily doses of BAL9141 equivalents, 2.1 to 75 mg/kg of body weight) ranged from 57 to 100%, whereas with ceftriaxone (total daily doses, 10 to 400 mg/kg), the survival rates varied between 13 and 100%. In mice infected with P-15986, the survival rates achieved with BAL5788 (BAL9141 equivalent, 8.4 mg/kg) and those achieved with ceftriaxone (50 mg/kg) were significantly different (93 versus 13%; P < 0.0001) in favor of BAL5788; the outcomes of the trials with all other strains were not significantly different between the two antibiotics, but markedly lower doses of BAL5788 than ceftriaxone were required to obtain similar survival rates. Pharmacokinetic data showed that BAL9141 was effective against the four pneumococcal strains tested at very low values of the time above the MIC ( T > MIC), which ranged from 9 to 18% of the dosing interval, whereas the values of T > MICs for ceftriaxone ranged from 30 to 50% of the dosing interval.

Cyclothialidine (1, Ro 09-1437) is a potent DNA gyrase inhibitor that was isolated from Streptomyces filipinensis NR0484 and is a member of a new family of natural products. It acts by competitively inhibiting the ATPase activity exerted by the B subunit of DNA gyrase but barely exhibits any growth inhibitory activity against intact bacterial cells, presumably due to insufficient permeation of the cytoplasmic membrane. To explore the antibacterial potential of 1, we developed a flexible synthetic route allowing for the systematic modification of its structure. From a first set of analogues, structure-activity relationships (SAR) were established for different substitution patterns, and the 14-hydroxylated, bicyclic core (X) of 1 seemed to be the structural prerequisite for DNA gyrase inhibitory activity. The variation of the lactone ring size, however, revealed that activity can be found among 11- to 16-membered lactones, and even seco-analogues were shown to maintain some enzyme inhibitory properties, thereby reducing the minimal structural requirements to a rather simple, hydroxylated benzyl sulfide (XI). On the basis of these "minimal structures" a modification program afforded a number of inhibitors that showed in vitro activity against Gram-positive bacteria. The best activities were displayed by 14-membered lactones, and representatives of this subclass exhibit excellent and broad in vitro antibacterial activity against Gram-positive pathogens, including Staphylococcus aureus, Streptococcus pyogenes, and Enterococcus faecalis, and overcome resistance against clinically used drugs. By improving the pharmacokinetic properties of the most active compounds (94, 97), in particular by lowering their lipophilic properties, we were able to identify congeners of cyclothialidine (1) that showed efficacy in vivo.

2532 Background: BAL101553 (prodrug of BAL27862) is a small molecule TCC that binds microtubules and promotes tumor cell death by activation of the spindle assembly checkpoint. In a previous study (NCT01397929, Lopez et al. JCO 34, 2016; abstr 2525), 2-h IV infusion on Days 1, 8, 15 (q28d) of BAL101553 up to 80 mg/m2 (maximum administered dose, MAD) showed vascular toxicities, including transient hypertension, which appeared to be Cmax related. The recommended Phase 2 dose (RP2D) was 30 mg/m2 weekly IV. Based on nonclinical models, antiproliferative effects of BAL27862 are driven by AUC. This trial explores whether once daily oral administration of BAL101553 reduces Cmax-related toxicity and improves the therapeutic window (NCT02490800). Methods: Patients (pts) with advanced solid tumors who failed standard therapy, received QD oral BAL101553 (28-d cycles) in a 3+3 dose-escalation design to determine the MTD. Adverse events were assessed by CTCAEv4 grade (G); tumor response by RECIST 1.1; serial PK on Day 1 of Cycles 1 and 2. Results: In the ongoing study, 19 pts (9M/10F; median age 67 y) received doses of 2, 4, 8, 16 or 30 mg oral BAL101553 QD. The MAD was 30 mg with DLTs of reversible G2 hallucination and asymptomatic, reversible G3 electrolyte imbalances. No DLTs were observed at ≤ 16 mg. Dosing is ongoing between 16 and 30 mg QD to determine the MTD. BAL27862 exposures after oral QD dosing of BAL101553 compared to weekly 2-h infusions suggested high relative oral bioavailability. The BAL27862 weekly AUC at the oral MAD (30 mg QD) compared to the RP2D of 30 mg/m2 for 2-h IV was more than 5-fold higher (19,656 vs 3,584 ng*h/mL) and Cmax was 1.5-fold lower (171 vs 266 ng/mL). Both Cmaxand AUC were dose-proportional, with low/moderate variability. Oral BAL101553 had no effects on blood pressure and showed no vascular toxicity. 5 pts had stable disease (2 pts [cholangiocarcinoma, neuroendocrine pancreatic cancer] > 4 cycles). Conclusions: Daily oral BAL101553 enables higher weekly exposures of BAL27862 with lower Cmax levels compared with a 2-h weekly infusion, due to the absence of Cmax related vascular toxicity. Doses up to 16 mg QD are well tolerated. The MAD has been identified as 30 mg QD; definition of the MTD is ongoing. Clinical trial information: NCT02490800.

Interspecies scaling is used to extrapolate pharmacokinetic parameters from animals to humans, through the application of physiologically based models, by empirical allometric procedures, or using concentration-time transformations. The aim of this study was to compare the accuracies of the last two methods for predicting the pharmacokinetic parameters and concentration-time curves in humans. In the first part of this study, interspecies scaling techniques were applied to a hypothetical drug (extracellular distribution and elimination through glomerular filtration), to examine the influence of various laboratory animals (mouse, rat, cynomolgus monkey and dog) on the parameters predicted for man. The same techniques were also applied to interferon-alpha A, using the literature data for various animal species. The kinetic parameters predicted in man were then compared to the values published for man. Our theoretical example showed that, for allometric scaling, each species has a very different influence on the prediction in human. With the approach using concentration-time transformations, however, each animal species potentially makes a similar contribution to the prediction for man. Based on the pharmacokinetic data published for interferon-alpha A in laboratory animals, allometric equations underestimated the observed values of CL and Vdss in man by 2-3-fold, and the prediction of t1/2 was likely to be unreliable, due to a poor correlation. The use of equivalent time, kallynochron, and apolysichron transformations improved the pharmacokinetic predictions for all three parameters in man. In conclusion, concentration-time transformations make more adequate use of the data available in the different species of laboratory animals, to give better predictions of the pharmacokinetic parameters in man.

2525Background: BAL101553 (prodrug of BAL27862) is a small molecule TCC that binds microtubules and promotes tumor cell death through activation of the mitotic checkpoint. Antiproliferative effects...

TPS2594Background: BAL101553 is the pro-drug of BAL27862, a novel small molecule TCC that promotes tumor cell death by modulating the spindle assembly checkpoint (SAC). In a completed Phase 1 (P1) ...

Alitretinoin is an endogenous retinoid related to vitamin A. Studies have shown that oral alitretinoin is effective and well tolerated in the treatment of severe chronic hand eczema. This review summarizes the clinical pharmacokinetic and pharmacodynamic data from a number of studies involving alitretinoin. These include the effect of food on the pharmacokinetics of alitretinoin, interactions between alitretinoin and ketoconazole, simvastatin or cyclosporin A, the effect of alitretinoin on the pharmacokinetics of a combined oral contraceptive, alitretinoin in seminal fluid after repeated dosing, and the pharmacokinetics of alitretinoin and its metabolites in a clinical setting.

Based on in vitro data with isolated cytochrome P450 (CYP) isoenzymes, alitretinoin interacts only with CYP3A4, and the potential for drug-drug interactions is considered negligible.To confirm in humans the lack of potential interactions between CYP3A4 and alitretinoin in vivo.This was a multiple-dose, open-label, parallel-group, single-centre study, which enrolled 54 healthy male volunteers aged 18-45 years. Subjects were divided into three groups, with 18 in each group: group 1 received either alitretinoin 30 mg and ketoconazole 200 mg, group 2 alitretinoin 30 mg and simvastatin 40 mg, and group 3 alitretinoin 30 mg and ciclosporin A 300-mg.At the highest therapeutic dose of 30 mg, alitretinoin had no significant effect on the pharmacokinetics (PK) of ketoconazole and ciclosporin A. There was a significant but not clinically relevant effect of simvastatin on the area under the curve (AUC) of plasma concentration vs. time and on maximum plasma concentration (C(max)) after repeated administration of alitretinoin. Exposure to simvastatin concomitantly with alitretinoin was decreased by 16% for AUC and 23% for C(max). The CYP3A4 ± PgP substrates of simvastatin and ciclosporin A did not affect the single or repeated dose PK of alitretinoin. The strong CYP3A4/PgP inhibitor ketoconazole led to significant increases in both AUC and C(max) values for alitretinoin.Single and repeated doses of alitretinoin do not alter the PK of ciclosporin A and ketoconazole. Simvastatin levels were slightly but significantly reduced by co-administration of alitretinoin. Substrates of CYP3A4 did not affect the PK of alitretinoin. However, ketoconazole significantly increased the plasma levels of alitretinoin, therefore, co-administration with CYP3A4 inhibitors such as ketoconazole may require a dose reduction of alitretinoin.

Alitretinoin, like all retinoids, is teratogenic, and can only be given to women of childbearing potential if pregnancy is excluded and a strict contraceptive programme is followed.This study was designed to determine whether alitretinoin in the semen of men treated with alitretinoin poses a teratogenic risk to their female partners.In total, 24 healthy men aged 18-45 years received alitretinoin 20 mg (n = 12) or 40 mg (n = 12), once daily for 14 days. Subjects in the 40 mg dose group provided ejaculate at baseline, on day 1, before and approximately 4 h after dosing on day 2, and at follow-up on study day 21 (± 2).Alitretinoin and 4-oxo-alitretinoin were detected in 11 of the 12 semen samples. The highest level of alitretinoin in semen was 7.92 ng/mL. Assuming an ejaculate volume of 10 mL, the amount of drug transferred in semen would be about 80 ng, 1/375,000 of a single 30 mg capsule. Complete absorption of 80 ng of alitretinoin from semen, presuming a volume of distribution confined to 5 L of circulating blood in the partner, would lead to an increase in plasma alitretinoin concentration of 0.016 ng/mL, which appears to be negligible compared with measured endogenous plasma levels. Increases in plasma levels of related retinoids are also negligible.Alitretinoin in the semen of men receiving up to 40 mg of oral alitretinoin per day is unlikely to be associated with teratogenic risk in their female partners. Barrier contraception is therefore not required for men taking alitretinoin.

Previous studies have shown that concomitant administration of food may enhance the bioavailability of oral retinoids.To assess the influence of food on the pharmacokinetics (PK) of alitretinoin after a single oral dose.This was a single-dose, open-label, randomized, crossover study, which enrolled 30 healthy men, aged 18-44 years. Subjects received sequential doses of alitretinoin 40 mg either after fasting (treatment A) or 5 min after completion of a standard breakfast (treatment B), with the dosing sequence randomized (A/B or B/A). The washout period between the two doses was 1 week. Plasma concentrations over time were plotted and standard PK variables [area under the curve (AUC) of plasma concentration vs. time, maximum plasma concentration (C(max)), time to maximum plasma concentration (t(max)) and elimination half-life (t(1/2)] were determined.Drug exposure was markedly increased when alitretinoin was taken with food compared with fasting, and there were significant increases in mean C(max) (82.8 vs.25.4 ng/mL, respectively) and AUC (220.2 vs. 55.7 ng · h/mL). The delaying effect of food on t(max) was less marked (median of 3.0 vs. 2.0 h). Administration with food also increased exposure to drug metabolites. Variability in exposure was markedly reduced if alitretinoin was taken with vs. without food (percentage coefficient of variation 40% vs. 74% for AUC; 49% vs. 85% for C(max)). Alitretinoin was generally well tolerated, with typical retinoid adverse reactions, mostly comprising headache.Intake of alitretinoin with food substantially increased the bioavailability of alitretinoin, but variability in exposure was reduced. Consequently, oral alitretinoin should be taken with food as outlined in the manufacturer's summary of product characteristics.

Alitretinoin (9-cis retinoic acid) is currently registered in many European countries and in Canada as the only licensed treatment for severe chronic hand eczema unresponsive to potent topical corticosteroids. Alitretinoin, like all retinoids, is teratogenic, and women of child-bearing potential must strictly adhere to pregnancy-prevention measures.To investigate the influence of alitretinoin on the pharmacokinetics (PK) of ethinyl estradiol/norgestimate (Ortho Tri-Cyclen 28(®)), a commonly prescribed combination oral contraceptive.In total, 16 healthy premenopausal women received three consecutive cycles of the triphasic contraceptive ethinyl estradiol/norgestimate together with concomitant oral alitretinoin 40 mg once daily during cycle 2. Steady-state PK (noncompartmental analysis) of ethinyl estradiol, 17-deacetyl norgestimate, alitretinoin and its main metabolite 4-oxo-alitretinoin were assessed alone and in combination.The PK profiles of ethinyl estradiol and 17-deacetyl norgestimate were similar when contraceptives were given alone or with alitretinoin, and the area under the plasma concentration vs. time curve and the maximum concentration met the conventional criteria for PK equivalence. Similarly, the influence of ethinyl estradiol/norgestimate on systemic exposure to alitretinoin and 4-oxo-alitretinoin was not clinically relevant. Alitretinoin was well tolerated when given either alone or with ethinyl estradiol/norgestimate.There was no clinically relevant influence of alitretinoin on the PK of ethinyl estradiol/norgestimate, and no influence of ethinyl estradiol/norgestimate on systemic exposure to alitretinoin and 4-oxo-alitretinoin. Consequently, oral contraception with ethinyl estradiol/norgestimate is an appropriate primary method of birth control during alitretinoin treatment for women of childbearing potential.

Recent studies have found that alitretinoin can induce clinically significant responses in subjects with severe chronic hand eczema (CHE) unresponsive to topical corticosteroids.To assess the pharmacokinetics (PK), efficacy and safety of alitretinoin 10 or 30 mg once daily.This was a randomized, double-blind study, which enrolled 32 subjects aged 18-75 years with CHE unresponsive to potent topical corticosteroids. Subjects received alitretinoin 10 mg (n = 16) or 30 mg (n = 16) once daily for 12 or 24 weeks. Standard PK variables [area under the curve (AUC) of plasma concentration vs. time, maximum plasma concentration (C(max)), time to maximum plasma concentration (t(max)), elimination half-life (t(1/2)), total systemic clearance (CL/F) and volume of distribution (Vd/F)] were determined for alitretinoin and metabolites. Efficacy was assessed using the Physician's Global Assessment (PGA) scale.Chronic administration of alitretinoin for up to 24 weeks did not result in accumulation or time-dependent changes in the disposition of alitretinoin. Exposure was found to be proportional to dose. Systemic exposure (AUC) to alitretinoin was proportional to dose for 10 and 30 mg alitretinoin; 62.8% of subjects achieved clear/almost clear hands in the 30 mg group and 12.5% in the 10 mg group. Alitretinoin was well tolerated.Chronic administration of alitretinoin for 12-24 weeks did not lead to accumulation or time-dependent changes in drug exposure. Alitretinoin was effective and well tolerated in the treatment of subjects with moderate or severe CHE unresponsive to potent topical corticosteroids.

The DNA gyrase inhibitor cyclothialidine had been shown to be a valuable lead structure for the discovery of new antibacterial classes able to overcome bacterial resistance to clinically used drugs. Bicyclic lactone derivatives containing in their 12-14-membered ring a thioamide functionality were reported previously to exhibit potent antibacterial activity against gram-positive bacteria. Moderate in vivo efficacy, however, was demonstrated only for derivatives bearing hydrophilic substituents, which were found to have a favorable impact on pharmcokinetics, and to reduce metabolic degradation, in particular glucuronidation. The incorporation of an additional amide unit into the 14-membered monolactam-lactone scaffold of cyclothialidine analogues provided a new "dilactam" subclass of DNA gyrase inhibitors of inherently higher polarity. After adjusting their lipophilicity by methyl-halogen exchange at the benzene ring, compounds of this series did not require the thioamide functionality to exert a decent antibacterial potency and consequently exhibited improved pharmacokinetic properties resulting in a pronounced in vivo efficacy in a mouse septicaemia infection model.

Racemic 2,4-diaminopyrimidine dihydrophthalazine derivatives BAL0030543, BAL0030544, and BAL0030545 exhibited low in vitro MICs toward small, selected panels of Enterococcus faecalis , Enterococcus faecium , Streptococcus pneumoniae , Moraxella catarrhalis , and Mycobacterium avium , though the compounds were less active against Haemophilus influenzae . The constellation of dihydrofolate reductases (DHFRs) present in 20 enterococci and 40 staphylococci was analyzed and correlated with the antibacterial activities of the dihydrophthalazines and trimethoprim. DHFRs encoded by dfrB , dfrA (S1 isozyme), dfrE , and folA were susceptible to the dihydrophthalazines, whereas DHFRs encoded by dfrG (S3 isozyme) and dfrF were not. Studies with the separated enantiomers of BAL0030543, BAL0030544, and BAL0030545 revealed preferential inhibition of susceptible DHFRs by the ( R )-enantiomers. BAL0030543, BAL0030544, and BAL0030545 were well tolerated by mice during 5- and 10-day oral toxicity studies at doses of up to 400 mg/kg of body weight. Using a nonoptimized formulation, the dihydrophthalazines displayed acceptable oral bioavailabilities in mice, and efficacy studies with a septicemia model of mice infected with trimethoprim-resistant, methicillin-resistant Staphylococcus aureus gave 50% effective dose values in the range of 1.6 to 6.25 mg/kg.

Ceftobiprole, a beta-lactam, is the first of a new generation of broad-spectrum cephalosporins in late-stage development with activity against methicillin-resistant Staphylococcus aureus (MRSA) in addition to broad-spectrum bactericidal activity against other Gram-positive and Gram-negative pathogens. The prodrug, ceftobiprole medocaril, is converted rapidly and almost completely to the active drug, ceftobiprole, upon infusion by type A esterases. In humans, ceftobiprole binds minimally (16%) to plasma proteins, and binding is independent of the drug and protein concentrations. Its steady-state volume of distribution (18.4 L) approximates the extracellular fluid volume in humans. Ceftobiprole undergoes minimal hepatic metabolism, and the primary metabolite is the beta-lactam ring-opened hydrolysis product (open-ring metabolite). Systemic exposure of the open-ring metabolite accounts for 4% of ceftobiprole exposure following single-dose administration; approximately 5% of the dose is excreted in the urine as the metabolite. Ceftobiprole does not significantly induce or inhibit relevant cytochrome P450 enzymes and is neither a substrate nor an inhibitor of P-glycoprotein. Ceftobiprole is rapidly eliminated, primarily unchanged, by renal excretion, with a terminal elimination half-life of 3 hours; the predominant mechanism responsible for elimination is glomerular filtration, with approximately 89% of the dose being excreted as the prodrug, active drug (ceftobiprole) and open-ring metabolite. The pharmacokinetics of ceftobiprole are linear following single and multiple infusions of 125-1000 mg. Steady-state drug concentrations are attained on the first day of dosing, with no appreciable accumulation when administered three times daily (every 8 hours) and twice daily (every 12 hours) in subjects with normal renal function. Low intersubject variability has been seen across studies. Ceftobiprole exposure is slightly higher (~15%) in females than in males; this difference has been attributed to bodyweight. However, the pharmacodynamics of ceftobiprole are similar in males and females, and dosing adjustments are not required based on gender. In patients with moderate to severe renal impairment, systemic clearance of ceftobiprole correlated well with creatinine clearance. For these patients, dose adjustments for the treatment of infections caused by target pathogens, including MRSA, should be based on creatinine clearance. Ceftobiprole is undergoing clinical evaluation in phase III trials in patients with complicated skin and skin structure infections, patients with nosocomial pneumonia, and community-acquired pneumonia in hospitalized patients.

The in vitro metabolic pattern of BAL19403, a novel macrolide antibiotic, was investigated by capillary liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOF-MS) in incubations with human microsomes. For the elucidation of the metabolic pathway, BAL19403 labeled with four deuterium atoms (D4) was used, and detection of metabolites performed using mixtures of the unlabeled (H4) BAL19403 and its D4 analogue (1:1) as substrate. All metabolites appeared with similar chromatographic behavior. MS/MS spectra of BAL19403 and its metabolites are dominated by non-informative fragment ions. Therefore, the structure of the metabolites was elucidated mainly by accurate mass measurements with subsequent proposals of elemental compositions. Main biotransformations were N-demethylation, lactone ring hydrolysis, and oxidation. Additionally, N-dealkylation of the aromatic moiety was identified. This dealkylation results not only in formation of an aldehyde, according to the classical pathway, but also in formation of the corresponding alcohol and carboxylic acid. Final elucidation of their structures was possible, since this dealkylation takes place vicinal to the deuterium-labeled part of BAL19403 and interferes with D/H exchange. The degree of D/H exchange, determined by analysis of the metabolite isotopic pattern, was used to elucidate the adjacent functional group. Copyright © 2007 John Wiley & Sons, Ltd.

TPS2611 Background: BAL101553 is the pro-drug of BAL27862, a novel small-molecule microtubule-targeting agent with potent activity in drug-refractory tumor models. It exerts antiproliferative effec...