Maximum Serum Concentration Research Articles

Efficacy of ceftiofur N-acyl homoserine lactonase niosome in the treatment of multi-resistant Klebsiella pneumoniae in broilers

In this study, the efficiency of the ceftiofur N-acyl homoserine lactonase niosome against multi-resistant Klebsiella pneumoniae in broilers was evaluated. Fifty-six K. pneumoniae isolates previously recovered from different poultry and environmental samples were screened for the ahlK gene. The lactonase enzyme was extracted from eight quorum-quenching isolates. The niosome was formulated, characterized, and tested for minimal inhibitory concentration (MIC) and cytotoxicity. Fourteen-day-old chicks were assigned to six groups: groups Ӏ and П served as negative and positive controls, receiving saline and K. pneumoniae solutions, respectively. In groups Ш and IV, ceftiofur and niosome were administrated intramuscularly at a dose of 10 mg/kg body weight for five consecutive days, while groups V and VI received the injections following the K. pneumoniae challenge. Signs, mortality, and gross lesions were recorded. Tracheal swabs were collected from groups П, V, and VI for counting K. pneumoniae. Pharmacokinetic parameters were evaluated in four treated groups at nine-time points. The niosome was spherical and 56.5 ± 4.41 nm in size. The viability of Vero cells was unaffected up to 5 × MIC (2.4 gml−1). The niosome-treated challenged group showed mild signs and lesions with lower mortality and colony count than the positive control group. The maximum ceftiofur serum concentrations in treated groups were observed 2 h following administration. The elimination half-life in niosome-treated groups was longer than that reported in ceftiofur-treated groups. This is the first report of the administration of N-acyl homoserine lactonase for the control of multi-resistant K. pneumoniae infections in poultry.

Safety, Virology, Pharmacokinetics, and Clinical Experience of High-Dose Intravenous Sotrovimab for the Treatment of Mild to Moderate COVID-19: An Open-Label Clinical Trial.

Five hundred milligrams of intravenous (IV) sotrovimab has been shown to be well tolerated and efficacious against pre-Omicron strains in treating patients with mild to moderate coronavirus disease 2019 (COVID-19) at high risk for disease progression. This was an open-label, single-arm substudy of phase 3 COMET-TAIL (NCT04913675) assessing the safety and tolerability of a 2000 mg IV dose of sotrovimab. Symptomatic patients (aged ≥18 years) with COVID-19 at high risk for progression were enrolled from June 30 through July 11, 2022, when Omicron BA.5, BA.2.12.1, and BA.4 were the predominant circulating variants in the United States. The primary end point was the occurrence of adverse events (AEs), serious AEs (SAEs), AEs of special interest, and COVID-19 disease-related events (DREs) through day 8. Safety, pharmacokinetics, viral load, and hospitalization >24 hours for acute management of illness or death through day 29 were assessed. All participants (n = 81) were Hispanic, 58% were female, and 51% were aged ≥55 years. Through day 8, no AEs, including infusion-related reactions or hypersensitivity, were reported; 2 participants reported DREs (mild cough, n = 2). One SAE (acute myocardial infarction), which was considered unrelated to sotrovimab or COVID-19 by the investigator, occurred on day 27 and was the only hospitalization reported. Maximum serum concentration (geometric mean) was 745.9 µg/mL. Viral load decreased from baseline through day 29; only 2 (3%) participants had a persistently high viral load (≥4.1 log10 copies/mL) at day 8. Two thousand milligrams of IV sotrovimab was well tolerated, with no safety signals observed. ClinicalTrials.gov Identifier: NCT04913675.

What is the right gentamicin dose for multiple trauma patients? A Monte Carlo simulation exploration study.

The appropriate dose of gentamicin is important to prevent and treat infections. The study aimed to determine the optimal dose of gentamicin to achieve the probability of pharmacokinetic/pharmacodynamic (PK) targets for efficacy and safety in multiple trauma patients. PK parameters of gentamicin in multiple trauma patients were gathered to develop a one-compartment PK model for prediction. The Monte Carlo simulation method was performed. The 24-h area under the concentration time curve to the minimum inhibitory concentration ratio (AUC24h/MIC) ≥50 was defined for the infection prevention target. AUC24h/MIC ≥110 or the maximum serum concentration to MIC ratio ≥8-10 was for the treatment of serious Gram-negative infection target. The risk of nephrotoxicity was the minimum serum concentration ≥2 mg/L. The optimal dose of gentamicin was determined when the efficacy target was >90% and the risk of nephrotoxicity was lowest. The optimal gentamicin dose to prevent infection when the MIC was <1 mg/L was 6-7 mg/kg/day. A higher dose of gentamicin up to 10 mg/kg/day could not reach the target for treating serious Gram-negative infection when the expected MIC was ≥1 mg/L. The probability of nephrotoxicity was minimal at 0.2-4% with gentamicin doses of 5-10 mg/kg/day for 3 days. Once daily gentamicin doses of 6-7 mg/kg are recommended to prevent infections in patients with multiple trauma. Gentamicin monotherapy could not be recommended for serious infections. Further clinical studies are required to confirm our results.

Pharmacokinetics and safety of candidate tocilizumab biosimilar CT-P47 versus reference tocilizumab: a randomized, double-blind, single-dose phase I study

ABSTRACT Background CT-P47 is a candidate tocilizumab biosimilar. This study assessed the pharmacokinetic (PK) equivalence of CT-P47 and European Union-approved reference tocilizumab (EU-tocilizumab) in healthy Asian adults. Research design and methods This double-blind, multicenter, parallel-group trial randomized healthy adults (1:1) to receive a single (162 mg/0.9 mL) subcutaneous dose of CT-P47 or EU-tocilizumab. The primary endpoint (Part 2) was PK equivalence by area under the concentration – time curve (AUC) from time zero to last quantifiable concentration (AUC0–last), AUC from time zero to infinity (AUC0–inf), and maximum serum concentration (Cmax). PK equivalence was concluded if 90% confidence intervals (CIs) for the ratios of geometric least-squares means (gLSMs) were within the 80–125% equivalence margin. Additional PK endpoints, immunogenicity, and safety were evaluated. Results In Part 2, 289 participants were randomized (146 CT-P47; 143 EU-tocilizumab); 284 received study drug. AUC0–last, AUC0–inf, and Cmax were equivalent between CT-P47 and EU-tocilizumab: 90% CIs for the ratios of gLSMs were within the 80–125% equivalence margin. Secondary PK endpoints, immunogenicity, and safety were comparable between groups. Conclusions CT-P47 demonstrated PK equivalence with EU-tocilizumab and was well tolerated, following a single dose in healthy adults. Clinical trial registration www.clinicaltrials.gov identifier is NCT05188378.

Self-Nanoemulsifying Drug Delivery System-Containing the Poorly Absorbed Drug - Valsartan in Post-Bariatric Surgery.

Morbid obesity and its related metabolic syndrome are an important health issue. Recently, sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) have accounted for the most popular bariatric surgeries. Valsartan (VST) is a common hypertension drug, and nano-carriers can increase its solubility and bioavailability. This study aims to explore the nano-VST formula in bariatric surgery subjects. High-fat fed animals were used as obese models. Operations were performed according to a standardized protocol. The drug was administrated by gavage, and blood samples were taken by serial tail vein sampling. Caco-2 cells were used for examining cell viability and drug uptake. A self-nano-emusifying drug delivery system (SNEDDS) formula was composed of sefsol-218, RH-40 and propylene glycol by a specified ratio, while high-performance liquid chromatography (HPLC) was used for determining drug concentrations. Post-operatively, subjects that underwent RYGB lost more body weight compared to the SG group. The SNEDDS did not exhibit cytotoxicity after adequate dilution, and the cytotoxicity was not related to VST dose. A better cellular uptake of SNEDDS was observed in vitro. The SNEDDS formula achieved a diameter of 84 nm in distilled water and 140 nm in simulated gastric fluid. In obese animals, the maximum serum concentration (Cmax) of VST was increased 1.68-folds by SNEDDS. In RYGB with SUS, the Cmax was reduced to less than 50% of the obese group. SNEDDS increased the Cmax to 3.5 folds higher than SUS and resulted in 3.28-folds higher AUC0-24 in the RYGB group. Fluorescence imaging also confirmed a stronger signal of SNEDDS in the gastrointestinal mucosa. SNEDDS accumulated a higher drug concentration than suspension alone in the liver of the obese group. SNEDDS could reverse the VST malabsorption in RYGB. Further studies are mandatory to clarify post-SG change of drug absorption.

LZM008, a proposed tocilizumab biosimilar: Pharmacokinetics, safety, and immunogenicity profiles compared with ACTEMRA® in Chinese healthy male subjects.

Background: This study aimed to investigate the pharmacokinetics, safety, and immunogenicity of recombinant humanized anti-human IL-6R monoclonal antibody injection, LZM008, and evaluate the pharmacokinetic similarity between LZM008 and tocilizumab (ACTEMRA®) in Chinese healthy male subjects. Research design and methods: In this randomized, double-blinded, paralleled, two-center Phase I clinical trial, 96 subjects were randomized with a 1:1 ratio to receive 4mg/kg intravenous dose of LZM008 or ACTEMRA® and evaluated for 28days. The pharmacokinetic bioequivalence was assessed by the maximum serum concentration (Cmax), the area under the serum concentration-time curve (AUC) from time 0 to the last detectable drug concentration (AUC0-t), and AUC0-∞. The statistical analysis was conducted using SAS Enterprise Guide statistical software. Safety was assessed by physical examinations, vital signs, laboratory tests, and electrocardiograms. Anti-drug antibodies (ADAs) were measured by a bridged electrochemiluminescence immunoassay. Results: LZM008 (N = 49) and ACTEMRA® (N = 47) groups showed similar pharmacokinetic properties. After a single intravenous infusion of 4mg/kg LZM008, the Cmax and AUC0-∞ values of LZM008 reached 87.99μg/mL and 11,526.70h*μg/mL, respectively, with Tmax 1.98h, and the half-life (t1/2) was 83.45h. The 90% confidence intervals of ratios for Cmax, AUC0-t, and AUC0-∞ were within the range of 80.00%-125.00%. After infusion, one (2.0%) subject in the LZM008 group and three (6.4%) subjects in the ACTEMRA® group showed positive ADA test results. The incidence of treatment emergent adverse events (TEAEs) was comparable in LZM008 and ACTEMRA® groups (98.0% versus 100%), with the decrease in blood fibrinogen and neutrophil counts being the most common TEAEs. Conclusion: The pharmacokinetic characteristics and immunogenicity exhibited by LZM008 were similar to those of the reference product, ACTEMRA®. The safety profiles of LZM008 were similar in the two groups with mild-moderate adverse effects. Trial Registration: The trial is registered at www.chinadrugtrials.org.cn (CTR20190889).

Pharmacokinetic comparison of sitagliptin and metformin HCl extended-release tablets versus JANUMET® XR in healthy volunteers under fasting and fed conditions.

Background and Objectives: Janumet® XR is the combination of sitagliptin and extended metformin hydrochloride produced by Merck Sharp & Dohme. It is specially designed for diabetes mellitus patients taking both drugs already. Janumet® XR exhibited clinically significant blood glucose lowering efficacy and long-term use safety. However, no generic form of Janumet® XR has been approved in western countries. The relatively high cost made the medication less prescribed. A more affordable form of this drug may benefit an immense diabetes mellitus population. The current study compared the bioequivalence (BE) of sitagliptin 100mg and metformin 1000mg produced by Nanjing Chia-Tai Tianqing Pharmaceutical Company to Janumet® XR in healthy Chinese subjects. Methods: Twenty-eight healthy Chinese subjects were enrolled in Study 1 and 2, respectively. Both studies were conducted with an open, randomized, two-period crossover design using the test (T) or the reference (R) drug. Study 1 is conducted under the fasting state, and Study 2 is under the fed state. Subjects received an oral dose of sitagliptin 100mg and metformin 1000mg, and plasma concentrations of sitagliptin and metformin were determined up to 72h post-dose. Pharmacokinetic (PK) parameters, including maximum serum concentration (Cmax) and area under the concentration-time curve up to the last quantifiable concentration (AUC0-t) of both sitagliptin and metformin, were calculated and compared between the T and R treatments. Results: In the fasting study, the geometric mean ratios of Cmax, AUC0-t, and AUC0-∞ for sitagliptin were 109.42%, 101.93%, and 101.95%, respectively; the corresponding ratios for metformin were 98.69%, 94.12%, and 93.42%, respectively. In the fed study, the geometric mean ratios of Cmax, AUC0-t, and AUC0-∞ for sitagliptin were 98.41%, 100.30%, and 100.24%, respectively; the corresponding ratios for metformin were 97.79%, 99.28%, and 100.69%, respectively. The 90% CIs of Cmax, AUC0-t, and AUC0-∞ in both studies were all within acceptance limits (80.00%-125.00%). Conclusion: The results demonstrated for the first time that sitagliptin 100mg and metformin 1000mg produced by Nanjing Chia-Tai Tianqing Pharmaceutical Company was bioequivalent to the branded Janumet® XR, and both drugs were well tolerated.

Pharmacokinetic similarity study comparing the biosimilar candidate, LY05008, with its reference product dulaglutide in healthy Chinese male subjects

ABSTRACT Background Dulaglutide, a glucagon-like peptide-1 (GLP-1) receptor agonist, has been approved for improving glycemic control and reducing the risk of cardiovascular (CV) adverse events. This study compared the pharmacokinetic (PK) profiles, safety, and immunogenicity of LY05008, a biosimilar candidate, to a licensed product dulaglutide in healthy Chinese male subjects. Research design and methods In this double-blind, open-label, parallel-group study, healthy Chinese male subjects were randomized 1:1 to receive either LY05008 or dulaglutide subcutaneously. Primary study endpoints were PK parameters such as the area under the concentration-time curve (AUC) from time zero to infinity (AUC0 – ∞), AUC from time zero to the last quantifiable concentration (AUC0–t), and maximum serum concentration (Cmax). Safety and immunogenicity profiles were also included for data analysis. Results 82 subjects were randomized to receive LY05008 (n = 41) or dulaglutide (n = 41). The 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) of AUC0 – ∞, AUC0–t and Cmax of LY05008 to dulaglutide were all within the bioequivalence limits of 80%-125%. Other PK parameters, safety, and immunogenicity profiles were comparable across the two treatment groups. Conclusion This study demonstrated PK similarity of LY05008, a dulaglutide biosimilar, to dulaglutide in healthy Chinese male subjects, with comparable safety and immunogenicity data. Trial registration The trial is registered at the Chinese Clinical Trial Registry (Identifier No. ChiCTR2200066519).

Darren P. Baker, PhD A Pioneer in the Development of Pegylated Interferon-β for Clinical Use

Darren P. Baker, PhD A Pioneer in the Development of Pegylated Interferon-β for Clinical Use

Glycyrrhetinic acid ameliorates diosbulbin B-induced hepatotoxicity in mice by modulating metabolic activation of diosbulbin B.

Exposure to diosbulbin B (DBB), the primary component of the herbal medicine Dioscorea bulbifera L. (DB), can cause liver injury in humans and experimental animals. A previous study found DBB-induced hepatotoxicity was initiated by CYP3A4-mediated metabolic activation and subsequent formation of adducts with cellular proteins. The herbal medicine licorice (Glycyrrhiza glabra L.) is frequently combined with DB used in numerous Chinese medicinal formulas in an effort to protect against DB-elicited hepatotoxicity. Importantly, glycyrrhetinic acid (GA), the major bioactive ingredient in licorice, inhibits CYP3A4 activity. The study aimed to investigate the protection of GA against DBB-induced hepatotoxicity and the underlying mechanism. Biochemical and histopathological analysis showed GA alleviated DBB-induced liver injury in a dose-dependent manner. In vitro metabolism assay with mouse liver microsomes (MLMs) indicated that GA decreased the generation of metabolic activation-derived pyrrole-glutathione (GSH) conjugates from DBB. Toxicokinetic studies demonstrated that GA increased maximal serum concentration (Cmax ) and area under the serum-time curve (AUC) of DBB in mice. In addition, GA attenuated hepatic GSH depletion caused by DBB. Further mechanistic studies showed that GA reduced the production of DBB-derived pyrroline-protein adducts in a dose-dependent manner. In conclusion, our findings demonstrated that GA exerted protective effect against DBB-induced hepatotoxicity, mainly correlated with suppressing the metabolic activation of DBB. Therefore, the development of a standardized combination of DBB with GA may protect patients from DBB-induced hepatotoxicity.

Pharmacokinetics and safety of CT-P17 (40mg/0.4ml) versus reference adalimumab: randomized study in healthy Japanese adults.

Aim: Comparing pharmacokinetics and safety of CT-P17 and EU-approved reference adalimumab (EU-adalimumab) in Japan. Materials & methods: Double-blind, parallel-group phase I trial at three hospitals. Healthy Japanese adults were randomized (1:1) to CT-P17 or EU-adalimumab (single 40-mg subcutaneous dose). The primary end point was pharmacokinetic equivalence for area under the concentration-time curve from time zero to infinity and maximum serumconcentration. Results: Of the 205 randomized subjects (102 CT-P17, 103 EU-adalimumab), 204 received study drug. CT-P17 and EU-adalimumab were pharmacokinetically equivalent: 90% CIs for geometric least-squares mean ratios were within predefined 80-125% equivalence margins. Secondary pharmacokinetic end points, safety and immunogenicity were similar between the groups. Conclusion: CT-P17 had pharmacokinetics, safety and immunogenicity comparable to EU-adalimumab in healthy Japanese adults.

The Impact of Levetiracetam and Valproate on Platelet Functions-A Double-Blind, Placebo-Controlled Crossover Study.

It is known that valproate inhibits platelet functions; however, the exact mechanisms are not clearly identified. We studied 12 healthy adult volunteers (1 female, 11 male; age range 31.7 ± 7.8 years) before and after valproate 500 mg and compared the results to levetiracetam 1000 mg as a control substance and placebo. The study had a crossover and double-blind design. A blood sample was taken before and 90 min after medication intake, because the times to maximum serum concentration (Tmax) are 1.5 h for levetiracetam and 1 to 3 h for valproate. We analysed changes in platelet, erythrocyte, and leukocyte cell count and in platelet functions (CD62 expression (P selectin), thrombin binding, and fibrinogen binding). We found no significant differences in all cell counts before and after different study drugs. After valproate intake, but not after placebo or levetiracetam intake, the fibrinogen binding significantly decreased and the CD62 expression significantly increased resulting in decreased platelet aggregation. Our data suggest that the platelet dysfunctions reported for valproate result from decreased fibrinogen binding and from increased CD62 expression. This phenomenon might be one reason for the increased bleeding risk under valproate and cannot be observed for levetiracetam.

First-in-human study of JNJ-63709178, a CD123/CD3 targeting antibody, in relapsed/refractory acute myeloid leukemia.

This study aimed to identify a recommended phase II dose and evaluate the safety, tolerability, pharmacokinetics/pharmacodynamics, and preliminary clinical activity of JNJ-63709178, a CD123/CD3 dual-targeting antibody, in patients with relapsed or refractory acute myeloid leukemia. Intravenous (i.v.) and subcutaneous (s.c.) administration of JNJ-63709178 were evaluated. The i.v. infusions were administered once every 2 weeks (cohorts 1-5 [n=17]) or twice weekly (cohorts 6-11 [n=36]). A twice-weekly s.c. dosing regimen with step-up dosing was also studied (s.c. cohorts 1-2 [n=9]). Treatment-emergent adverse events (TEAEs) greater than or equal to grade 3 were observed in 11 (65%) patients in cohorts 1-5 and 33 (92%) patients in cohorts 6-11. At the highest i.v. dose (4.8μg/kg), 5 (71%) patients discontinued treatment due to TEAEs. For s.c. administration (n=9), eight (89%) patients experienced TEAEs greater than or equal to grade 3 and injection site reactions (≤ grade 3) emerged in all patients. At 4.8μg/kg (i.v. and s.c.), the mean maximum serum concentrations were 30.3 and 3.59 ng/ml, respectively. Increases in multiple cytokines were observed following i.v. and s.c. administrations, and step-up dosing strategies did not mitigate cytokine production or improve the safety profile and led to limited duration of treatment. Minimal clinical activity was observed across all cohorts. The i.v. and s.c. dosing of JNJ-63709178 was associated with suboptimal drug exposure, unfavorable safety profiles, limited clinical activity, and inability to identify a recommended phase II dose.

Pharmacokinetics of oral misoprostol for induction of labor in pregnancies complicated by obesity

Birthing parents with obesity have increased risk of medical and obstetric complications during pregnancy, often leading to a recommendation for induction of labor (IOL). Misoprostol is commonly used for IOL, however there is limited data on whether it’s pharmacokinetics (PK) are altered by body size. The objective of this study is to evaluate PK parameters of oral misoprostol in pregnancies complicated by obesity. Pilot, single-center, observational study of non-fasting, term, singleton pregnancies with body mass index (BMI) > 30.0 kg/m2 at time of IOL with 50 mcg oral misoprostol. Plasma concentrations of active metabolite misoprostol acid (MPA) were measured at four time points using liquid chromatography mass spectrometry. Plasma MPA-time data analyzed using a non-compartmental PK model to derive the area under the curve from the first time point to the last measured concentration (AUC0-t) using the trapezoidal rule. Terminal slope (λz) used to extrapolate plasma concentration to infinity (AUC0-∞). Maximum serum concentration (Cmax) and time to maximum plasma concentration (Tmax) also described. 26 plasma observations from 7 subjects were included (Table 1). Observed plasma concentrations over time (Figure 1) demonstrate median(range) Cmax 26.63 (7.18-56.24) pg/mL, AUC0-t 10.93 (2.43-24.64) pg-h/mL, λz 2.68 (2.00-3.07) h-1, AUC0-∞ 22.67 (12.09-30.60) pg-h/mL. Tmax observed at 0.25 hours. Prior study evaluating 50 mcg oral misoprostol in 12 subjects with normal BMI (mean 28.6 kg/m2) reports mean±SD Cmax 53.97±23.79 pg/mL, AUC0-t 55.02±28.80 pg-h/mL, λz 1.05±0.86 h-1, AUC0-∞ 66.63±33.22 pg-h/mL, Tmax 0.23±0.14 hours. To our knowledge, this study is the first examination of 50 mcg oral misoprostol PK parameters among parturients with obesity undergoing term IOL. Data show decreases in PK parameters in this population, however some results are still within reported margin of error and there is marked variance between subjects. A future, powered, comparative trial is necessary to confirm these findings as well as further investigate clinically relevant outcomes.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

ARIA in patients treated with lecanemab (BAN2401) in a phase 2 study in early Alzheimer's disease.

Lecanemab is a humanized immunoglobulin G1 (IgG1) monoclonal antibody that preferentially targets soluble aggregated Aβ species (protofibrils) with activity at amyloid plaques. Amyloid-related imaging abnormalities (ARIA) profiles appear to differ for various anti-amyloid antibodies. Here, we present ARIA data from a large phase 2 lecanemab trial (Study 201) in early Alzheimer's disease. Study 201 trial was double-blind, placebo-controlled (core) with an open-label extension (OLE). Observed ARIA events were summarized and modeled via Kaplan-Meier graphs. An exposure response model was developed. In the phase 2 core and OLE, there was a low incidence of ARIA-E (<10%), with <3% symptomatic cases. ARIA-E was generally asymptomatic, mild-to-moderate in severity, and occurred early (<3 months). ARIA-E was correlated with maximum lecanemab serum concentration and incidence was higher in apolipoprotein E4 (ApoE4) homozygous carriers. ARIA-H and ARIA-E occurred with similar frequency in core and OLE. Lecanemab can be administered without titration with modest incidence of ARIA.

Bioavailability and systemic transport of oleanolic acid in humans, formulated as a functional olive oil.

Evidence of the pharmacological activity of oleanolic acid (OA) suggests its potential therapeutic application. However, its use in functional foods, dietary supplements, or nutraceuticals is hindered by limited human bioavailability studies. The BIO-OLTRAD trial is a double-blind, randomized controlled study with 22 participants that received a single dose of 30 mg OA formulated as a functional olive oil. The study revealed that the maximum serum concentration of OA ranged from 500 to 600 ng mL-1, with an AUC0-∞ value of 2862.50 ± 174.50 ng h mL-1. Furthermore, we discovered a physiological association of OA with serum albumin and triglyceride-rich lipoproteins (TRL). UV absorption spectra showed conformational changes in serum albumin due to the formation of an adduct with OA. Additionally, we demonstrated that TRL incorporate OA, reaching a maximum concentration of 140 ng mL-1 after 2-4 hours. We conjecture that both are efficient carriers to reach target tissues and to yield high bioavailability.

Penetration of Enrofloxacin in Aqueous Humour of Avian Eyes.

Enrofloxacin has been shown to be appropriate to treat bacterial eye infections in mammals. However, the anatomy and physiology of the avian eye substantially differ from those in mammals, and pharmacokinetic data substantiating the clinical efficacy of enrofloxacin in birds are still lacking. In total, 40 chickens (Gallus gallus, Lohman Selected Leghorn) received single intramuscular administration of enrofloxacin at a dosage of 25 mg/kg body weight (BW). Serial blood and aqueous humour samples were taken at 12 different time points after administration (0-60 min and 2-32 h) and were analysed for their fluoroquinolone concentrations using a competitive enzyme immunoassay. The metabolization of enrofloxacin to ciprofloxacin was determined using liquid chromatography-mass spectrometry. The maximum serum concentrations of fluoroquinolones were observed at the time point of 2.82 ± 0.1 h and amounted to 10.67 ± 0.5 µg/mL. Fluoroquinolones redistributed to a minor extent into the aqueous humour reaching maximum concentrations of 4.52 ± 1.2 µg/mL after 7.54 ± 1.0 h of drug administration. The mean residence time (MRT), volume of distribution (Vd), and terminal half-life (t1/2 ß) were 1.68-, 2.84-, and 2.01-fold higher in aqueous humour than in serum, indicating that fluoroquinolones were trapped in aqueous humour. Enrofloxacin was only marginally metabolized into ciprofloxacin. A single intramuscular injection of a therapeutical dose of enrofloxacin (25 mg/kg BW) thus generated sustained and therapeutically active levels of enrofloxacin in the aqueous humour of chicken eyes.

Tixagevimab Plus Cilgavimab Does Not Affect the Interpretation of Electrophoretic and Free Light Chain Assays.

There is concern that the anti-severe acute respiratory syndrome coronavirus 2 therapeutic monoclonal antibodies, used as preexposure prophylaxis in patients with multiple myeloma, may appear as a detectable monoclonal protein by electrophoretic methods, resulting in misinterpretation or inability to measure therapeutic responses in some patients. In this pilot study, we characterize the effect of tixagevimab plus cilgavimab (Evusheld; T + C) on interpretation of serum protein electrophoresis (SPE), immunofixation electrophoresis (IFE), and serum free light chain (sFLC) assays. We performed spiking experiments with T + C at serum maximum concentration following a 300-mg dose (1× Cmax) and at 10 times the concentration of Cmax (10× Cmax) with pooled serum samples. SPE and IFE technical procedures were performed on the SPIFE 3000, and sFLC and immunoglobulin G1 (IgG1) subtype quantitation was performed on the Optilite. T + C-associated interference was not visible as an M-spike in normogammaglobulinemic pooled samples. Hypogammaglobulemic pooled samples at 10× Cmax demonstrated an M-spike in SPE and immunoglobulin Gκ pattern in IFE. No increases were noted in the results of sFLC or IgG1 levels. This study indicates that T + C at pharmacologic Cmax is unlikely to interfere with SPE, IFE, sFLC, or IgG1 analyses when spiked into patient serum samples, but further evaluation of recently injected patients may be warranted.

The impact of enteral feeding and therapeutic monitoring of rifampicin with dose escalation in critically ill patients with tuberculosis

ObjectivesCritically ill patients with tuberculosis (TB) face a high mortality risk and require effective treatment. There is a paucity of data on rifampicin pharmacokinetics, the impact of continuous enteral feeding on drug absorption, and the potential of therapeutic drug monitoring (TDM) to optimize drug exposure in these patients. MethodsWe performed a sequential pharmacokinetic study to determine the impact of feeding and TDM with rifampicin dose escalation in critically ill patients with TB. Noncompartmental pharmacokinetic analysis was performed. ResultsAmong 20 critically ill patients (40% were HIV-infected), median rifampicin Cmax (maximum serum concentration) in the fasted and fed states were 5.1 µg/ml versus 3.3 µg/ml, respectively (P <0.0001; geometric mean ratio 1.95; 90% confidence interval 1.46-2.60). The proportion of patients with low rifampicin concentrations in the fasted and fed states was 80% vs 100% (P-value = 0.1336). Optimized dosing led to a per-patient median rifampicin dosing of 24.6 mg/kg and a median Cmax increase from 2.4 µg/ml to 17.8 µg/ml (P-value = 0.0005; geometric mean ratio 8.29; 90% confidence interval 3.88-17.74). TDM-guided dose escalation increased the proportion of patients achieving the suggested target rifampicin concentration compared with standard dosing (83% vs 0%, P-value = 0.004). ConclusionWe found low rifampicin concentrations in all patients receiving continuous enteral feeding. TDM-guided dose escalation provided an effective strategy to achieve target drug exposure in these critically ill patients with TB.

Safety and Tolerability of AZD0466 As Monotherapy for Patients with Advanced Hematological Malignancies. Preliminary Results from an Ongoing Phase I/II Trial

Background: Anti-apoptotic proteins of the BcL-2 family such as Bcl-2 and Bcl-xL are critical to tumor survival and are associated with resistance to anticancer therapy. Specific Bcl-2 inhibition using venetoclax is beneficial in patients with acute myeloid leukemia (AML), but resistance often develops due to upregulation of anti-apoptotic proteins such as Bcl-xL and Mcl-1. Dual inhibition of Bcl-2 and Bcl-xL therefore has potential for broader activity than is observed with Bcl-2-specific inhibitors such as venetoclax. AZD0466 is a drug-dendrimer conjugate in which the Bcl-2/xL dual inhibitor AZD4320 is covalently conjugated to a pegylated poly-L-lysine dendrimer and gradually released by hydrolysis. Release of AZD4320 results in lower peak plasma levels compared to direct infusion of AZD4320 at similar concentrations, reducing the potential for the on-target toxicity associated with Bcl-xL inhibition (Balachander et al. Clin Cancer Res 2020; Patterson et al. Commun Biol 2021). AZD0466 has shown preclinical efficacy in solid (Arulananda et al. Cell Death Discov 2021) and hematological malignancies (Balachander et al. Clin Cancer Res 2020; Patterson et al. Commun Biol 2021). Preliminary results from the first-in-human study (NCT04214093) in advanced solid malignancies indicated that AZD0466 is well tolerated; no dose-limiting toxicities (DLTs) were reported. Here, we present preliminary data from an ongoing phase I trial of AZD0466 in patients with advanced hematological malignancies (NCT04865419). Methods: NIMBLE (drug deNdrIMer targeting BCL2/xL in acute LEukemias) is a modular, non-randomized phase I/II trial. Module 1 is evaluating the safety, tolerability, pharmacokinetics (PK), and preliminary efficacy of AZD0466 as monotherapy in adults with relapsed/refractory AML, acute lymphocytic leukemia (ALL), or higher risk myelodysplastic syndrome who have received ≥1 prior line of therapy, have no standard-of-care treatment available, and have no active CNS involvement. No minimum platelet count at study entry was specified and transfusions were permitted as part of supportive care. Module 1, Part A is a dose escalation study evaluating the safety and tolerability of AZD0466 monotherapy. The selected starting dose is AZD0466 300 mg IV; decisions on escalation and de-escalation are based on a mTPI-2 design (Guo et al. Contemp Clin Trials 2017;58:23-33). AZD0466 administration starts with a dose ramp-up with administration on days 1, 4, and 8 of cycle 1, followed by weekly IV administration at the target dose. The duration of Cycle 1 is 35 days, while subsequent cycles of 28 days. All patients are treated until progressive disease, unacceptable toxicity, or withdrawal of consent. The primary objectives of Module 1A are DLT (according to predefined criteria and occurring during cycle 1), maximum tolerated dose (MTD), and recommended phase 2 dose (RP2D). Secondary objectives include assessment of PK parameters for total and released plasma AZD4320. Results: As of May 31, 2022, 9 patients had been treated (55% male; median age, 70 years). Patients received AZD0466 at target doses of 300 mg (n=4), 600 mg (n=4), or 1200 mg (n=1). The safety analysis set consists of 9 patients and the DLT-evaluable set of 7 patients. No DLTs have been observed. All patients experienced at least one adverse event (AE). Five patients experienced AEs possibly related to treatment (grade 3 febrile neutropenia event, n=1; grade 3 gamma-glutamyltransferase increase, n=1; grade 2 sinus tachycardia, n=1; grade 1 aspartate aminotransferase increase, n=3; grade 1 alanine aminotransferase increase, n=2; grade 1 abnormal coagulation test, lactate dehydrogenase increase and alkaline phosphatase increase, all n=1). Four serious AEs occurred, none of which was treatment related. No AZD0466 discontinuations due to AEs have been observed. There were no thrombocytopenia events considered related to AZD0466 at the doses given. Following IV infusion, released AZD4320 exhibited a dose-proportional increase in area under the concentration time curve (AUC) and maximum serum concentration (Cmax), moderate PK variability (≈50% coefficient of variation), and a half-life of ≈18 hours. Conclusions: AZD0466 has been well tolerated, with no DLTs to date and no discontinuations due to treatment-related AEs. The trial continues to enroll, further dose escalation is planned, and updated data will be presented.