Interactions between meropenem and renal drug transporters

Preferential meropenem absorption activated by 1α,25-dihydroxyvitamin D3 and shared with foscarnet, a phosphate transporter substrate, in the rat ileum

Meropenem (MEPM) is used for the treatment of serious infectious diseases solely as. INJECTABLE: Therefore, the development of an oral formulation would expand its clinical utility. To this end, an exact understanding of the absorption characteristics of MEPM is essential. In this study, MEPM absorption in the rat small intestine was investigated using an in situ loop technique and an in vitro diffusion chamber method. The disappearance ratios of MEPM (0.1 mM) were in the order of ileum > duodenum > jejunum. The extensive MEPM disappearance in the ileum was significantly reduced in the presence of foscarnet, a Na+-dependent phosphate transporter (NaPi-T) substrate, whereas glycylsarcosine, thiamine, taurocholic acid, and biapenem had no effects. The mucosal-to-serosal (M-to-S) permeation of MEPM across the rat ileal segments was very small under normal experimental conditions. However, on addition of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) to the experimental medium, the M-to-S permeation of MEPM markedly increased, showing a more than 7-fold greater apparent permeation coefficient. The present results suggest that MEPM is preferentially absorbed in the rat ileum, sharing with foscarnet, and that 1,25(OH)2D3 potentially activates the absorption of MEPM there. A likely candidate for involvement in MEPM absorption was NaPi-T or a related transporter.

Maximum likelihood estimation of renal transporter ontogeny profiles for pediatric PBPK modeling

Optimal treatment of infants with many renally cleared drugs must account for maturational differences in renal transporter (RT) activity. Pediatric physiologically-based pharmacokinetic (PBPK) models may incorporate RT activity, but this requires ontogeny profiles for RT activity in children, especially neonates, to predict drug disposition. Therefore, RT expression measurements from human kidney postmortem cortical tissue samples were normalized to represent a fraction of mature RT activity. Using these data, maximum likelihood estimated the distributions of RT activity across the pediatric age spectrum, including preterm and term neonates. PBPK models of four RT substrates (acyclovir, ciprofloxacin, furosemide, and meropenem) were evaluated with and without ontogeny profiles using average fold error (AFE), absolute average fold error (AAFE), and proportion of observations within the 5-95% prediction interval. Novel maximum likelihood profiles estimated ontogeny distributions for the following RT: OAT1, OAT3, OCT2, P-gp, URAT1, BCRP, MATE1, MRP2, MRP4, and MATE-2 K. Profiles for OAT3, P-gp, and MATE1 improved infant furosemide and neonate meropenem PBPK model AFE from 0.08 to 0.70 and 0.53 to 1.34 and model AAFE from 12.08 to 1.44 and 2.09 to 1.36, respectively, and improved the percent of data within the 5-95% prediction interval from 48% to 98% for neonatal ciprofloxacin simulations, respectively. Even after accounting for other critical population-specific maturational differences, novel RT ontogeny profiles substantially improved neonatal PBPK model performance, providing validated estimates of maturational differences in RT activity for optimal dosing in children.

In Vitro Evaluation of Drug-Drug Interaction Potential of Epetraborole, a Novel Bacterial Leucyl-tRNA Synthetase Inhibitor

Epetraborole (EBO) is a boron-containing inhibitor of bacterial leucyl-tRNA synthetase, with potent activity against nontuberculous mycobacteria (NTM) and Gram-negative bacteria, including Burkholderia pseudomallei. EBO is being developed for the treatment of NTM lung disease and melioidosis, administered in combination with other therapeutic agents in both diseases. Therefore, EBO and its major circulating metabolite M3 were evaluated in comprehensive drug-drug interaction (DDI) in vitro studies. The CYP inhibitory and substrate potential of EBO and M3 were assessed using hepatic microsomes. Stably transfected cells that expressed individual efflux or uptake transporters were used to determine whether EBO or M3 were substrates or inhibitors for these receptors. Stability studies indicated that EBO is a poor substrate for major CYP enzymes. Neither EBO nor M3 was a potent reversible or time-dependent inhibitor of major CYP enzymes. EBO was not an inducer of CYP1A2 mRNA, while it was a weak inducer of CYP2B6 and CYP3A4. EBO was a substrate only for OCT2. At clinically relevant concentrations, neither EBO nor M3 inhibited major human efflux or uptake transporters. Based on these data, at clinically relevant concentrations of EBO and M3, there is a low risk of victim or perpetrator DDI.

New Antibiotics for the Treatment of Nosocomial Central Nervous System Infections

Nosocomial central nervous system (CNS) infections with carbapenem- and colistin-resistant Gram-negative and vancomycin-resistant Gram-positive bacteria are an increasing therapeutic challenge. Here, we review pharmacokinetic and pharmacodynamic data and clinical experiences with new antibiotics administered intravenously for the treatment of CNS infections by multi-resistant bacteria. Cefiderocol, a new siderophore extended-spectrum cephalosporin, pharmacokinetically behaves similar to established cephalosporins and at high doses will probably be a valuable addition in our therapeutic armamentarium for CNS infections. The new glycopeptides dalbavancin, telavancin, and oritavancin are highly bound to plasma proteins. Although effective in animal models of meningitis, it is unlikely that they reach effective cerebrospinal fluid (CSF) concentrations after intravenous administration alone. The β-lactam/β-lactamase inhibitor combinations have the principal problem that both compounds must achieve adequate CSF concentrations. In the commercially available combinations, the dose of the β-lactamase inhibitor tends to be too low to achieve adequate CSF concentrations. The oxazolidinone tedizolid has a broader spectrum but a less suitable pharmacokinetic profile than linezolid. The halogenated tetracycline eravacycline does not reach CSF concentrations sufficient to treat colistin-resistant Gram-negative bacteria with usual intravenous dosing. Generally, treatment of CNS infections should be intravenous, whenever possible, to avoid adverse effects of intraventricular therapy (IVT). An additional IVT can overcome the limited penetration of many new antibiotics into CSF. It should be considered for patients in which the CNS infection responds poorly to systemic antimicrobial therapy alone.

Does Cytokine-Release Syndrome Induced by CAR T-Cell Treatment Have an Impact on the Pharmacokinetics of Meropenem and Piperacillin/Tazobactam in Patients with Hematological Malignancies? Findings from an Observational Case-Control Study

Chimeric antigen receptor (CAR) T-cell therapy is a promising approach for some relapse/refractory hematological B-cell malignancies; however, in most patients, cytokine release syndrome (CRS) may occur. CRS is associated with acute kidney injury (AKI) that may affect the pharmacokinetics of some beta-lactams. The aim of this study was to assess whether the pharmacokinetics of meropenem and piperacillin may be affected by CAR T-cell treatment. The study included CAR T-cell treated patients (cases) and oncohematological patients (controls), who were administered 24-h continuous infusion (CI) meropenem or piperacillin/tazobactam, optimized by therapeutic drug monitoring, over a 2-year period. Patient data were retrospectively retrieved and matched on a 1:2 ratio. Beta-lactam clearance (CL) was calculated as CL = daily dose/infusion rate. A total of 38 cases (of whom 14 and 24 were treated with meropenem and piperacillin/tazobactam, respectively) was matched with 76 controls. CRS occurred in 85.7% (12/14) and 95.8% (23/24) of patients treated with meropenem and piperacillin/tazobactam, respectively. CRS-induced AKI was observed in only 1 patient. CL did not differ between cases and controls for both meropenem (11.1 vs. 11.7 L/h, p = 0.835) and piperacillin (14.0 vs. 10.4 L/h, p = 0.074). Our findings suggest that 24-h CI meropenem and piperacillin dosages should not be reduced a priori in CAR T-cell patients experiencing CRS.

Measuring Creatinine Clearance Is the Most Accurate Way for Calculating the Proper Continuous Infusion Meropenem Dose for Empirical Treatment of Severe Gram-Negative Infections among Critically Ill Patients

Assessment of glomerular filtration rate (GFR) is necessary for dose adjustments of beta-lactam that are excreted by the kidneys, such as meropenem. The aim of this study was to compare the daily dose of 24 h-continuous infusion (CI) meropenem when GFR was calculated by means of measured creatinine clearance (mCL_CR) or estimated by the CKDEPI (eGFR_CKDEPI), Cockcroft-Gault (eGFR_CG), and MDRD (eGFR_MDRD) equations. Adult critically ill patients who underwent therapeutic drug monitoring (TDM) for the assessment of 24 h-CI meropenem steady state concentration (Css) and for whom a 24 h-urine collection was performed were retrospectively enrolled. Meropenem clearance (CL_M) was regressed against mCL_CR, and meropenem daily dose was calculated based on the equation infusion rate = daily dose/CL_M. eGFR_CKDEPI, eGFR_CG, and eGFR_CKDEPI were regressed against mCL_CR in order to estimate CL_M. Forty-six patients who provided 133 meropenem Css were included. eGFR_CKDEPI overestimated mCL_CR up to 90 mL/min, then mCL_CR was underestimated. eGFR_CG and eGFR_MDRD overestimated mCL_CR across the entire range of GFR. In critically ill patients, dose adjustments of 24 h-CI meropenem should be based on mCL_CR. Equations for estimation of GFR may lead to gross under/overestimates of meropenem dosages. TDM may be highly beneficial, especially for critically ill patients with augmented renal clearance.

Association of vancomycin plus piperacillin-tazobactam with early changes in creatinine versus cystatin C in critically ill adults: a prospective cohort study

PURPOSE

Although dozens of studies have associated vancomycin + piperacillin-tazobactam with increased acute kidney injury (AKI) risk, it is unclear whether the association represents true injury or a pseudotoxicity characterized by isolated effects on creatinine secretion. We tested this hypothesis by contrasting changes in creatinine concentration after antibiotic initiation with changes in cystatin C concentration, a kidney biomarker unaffected by tubular secretion.

METHODS

We included patients enrolled in the Molecular Epidemiology of SepsiS in the ICU (MESSI) prospective cohort who were treated for ≥ 48 h with vancomycin + piperacillin-tazobactam or vancomycin + cefepime. Kidney function biomarkers [creatinine, cystatin C, and blood urea nitrogen (BUN)] were measured before antibiotic treatment and at day two after initiation. Creatinine-defined AKI and dialysis were examined through day-14, and mortality through day-30. Inverse probability of treatment weighting was used to adjust for confounding. Multiple imputation was used to impute missing baseline covariates.

RESULTS

The study included 739 patients (vancomycin + piperacillin-tazobactam n = 297, vancomycin + cefepime n = 442), of whom 192 had cystatin C measurements. Vancomycin + piperacillin-tazobactam was associated with a higher percentage increase of creatinine at day-two 8.04% (95% CI 1.21, 15.34) and higher incidence of creatinine-defined AKI: rate ratio (RR) 1.34 (95% CI 1.01, 1.78). In contrast, vancomycin + piperacillin-tazobactam was not associated with change in alternative biomarkers: cystatin C: - 5.63% (95% CI - 18.19, 8.86); BUN: - 4.51% (95% CI - 12.83, 4.59); or clinical outcomes: dialysis: RR 0.63 (95% CI 0.31, 1.29); mortality: RR 1.05 (95%CI 0.79, 1.41).

CONCLUSIONS

Vancomycin + piperacillin-tazobactam was associated with creatinine-defined AKI, but not changes in alternative kidney biomarkers, dialysis, or mortality, supporting the hypothesis that vancomycin + piperacillin-tazobactam effects on creatinine represent pseudotoxicity.