Publications by authors named "Crass R"

Objective: To develop a population pharmacokinetic (PK) model to characterize serum pegcetacoplan concentration-time data after intravitreal administration in patients with geographic atrophy (GA) or neovascular age-related macular degeneration (nAMD).

Design: Pharmacokinetic modeling.

Participants: Two hundred sixty-one patients with GA or nAMD enrolled in 4 clinical studies of pegcetacoplan.

View Article and Find Full Text PDF
Article Synopsis
  • Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disorder that can cause severe hemolysis and blood clots, and the new therapy pegcetacoplan aims to improve patient outcomes by targeting both types of hemolysis.
  • The analysis of data from clinical studies showed that administering pegcetacoplan at a dose of 1080 mg twice weekly resulted in effective and stable levels in the body, along with significant improvements in blood biomarkers related to hemolysis within four weeks.
  • Factors such as body weight and previous treatments influenced drug exposure and responses, but these effects were not significant enough to alter treatment effectiveness, supporting the approved dosage for optimal patient care.
View Article and Find Full Text PDF

Pegcetacoplan is a complement C3/C3b inhibitor indicated for the treatment of geographic atrophy (GA). A population pharmacokinetic (PK)/pharmacodynamic (PD) analysis of pegcetacoplan used GA lesion area measurements from three clinical studies to determine the effect of pegcetacoplan exposure on GA progression. A base disease progression model was developed using data from sham-treated eyes and untreated fellow eyes, followed by treatment effect assessment in dose-response and PK/PD models.

View Article and Find Full Text PDF

Valbenazine is a highly potent and selective inhibitor of synaptic vesicular monoamine transporter 2. The current therapeutic doses of valbenazine for tardive dyskinesia (TD) are 40, 60, or 80 mg capsules, given orally, once daily (QD). While 40 and 80 mg were investigated in phase 3 KINECT 3 trial and initially approved, the approval of valbenazine 60 mg was based on the analysis utilizing the Model-informed drug development (MIDD) approach, facilitated through the US Food and Drug Administration's MIDD Pilot Program.

View Article and Find Full Text PDF

Population pharmacokinetics (popPK) of bempedoic acid and the popPK/pharmacodynamic (popPK/PD) relationship between bempedoic acid concentrations and serum low-density lipoprotein cholesterol (LDL-C) from baseline were characterized. A two-compartment disposition model with a transit absorption compartment and linear elimination best described bempedoic acid oral pharmacokinetics (PK). Multiple covariates, including renal function, sex, and weight, had statistically significant effects on the predicted steady-state area under the curve.

View Article and Find Full Text PDF

Objectives: Colistimethate sodium and tobramycin are important systemic antibiotics for treatment of cystic fibrosis (CF) pulmonary exacerbations but can induce acute kidney injury (AKI). We characterize the rate of AKI in CF patients treated with systemic colistimethate sodium compared with tobramycin.

Methods: This single-centre, retrospective cohort study included hospitalized CF patients treated with IV colistimethate sodium or tobramycin.

View Article and Find Full Text PDF

Tocilizumab is one of few treatments that have been shown to improve mortality in patients with coronavirus disease 2019 (COVID-19), but increased demand has led to relative global shortages. Recently, it has been suggested that lower doses, or fixed doses, of tocilizumab could be a potential solution to conserve the limited global supply while conferring equivalent therapeutic benefit to the dosing regimens studied in major trials. The relationship between tocilizumab dose, exposure, and response in COVID-19 has not been adequately characterized.

View Article and Find Full Text PDF

Antibiotic efficacy determination in clinical trials often relies on non-inferiority designs because they afford smaller study sample sizes. These efficacy studies tend to exclude patients within specific populations or include too few patients to discern potential differences in their clinical outcomes. As a result, dosing guidance in patients with abnormal liver and kidney function, age across the lifespan, and other specific populations relies on drug exposure-matching.

View Article and Find Full Text PDF

Aims: Many patients are unable to achieve guideline-recommended LDL cholesterol (LDL-C) targets, despite taking maximally tolerated lipid-lowering therapy. Bempedoic acid, a competitive inhibitor of ATP citrate lyase, significantly lowers LDL-C with or without background statin therapy in diverse populations. Because pharmacodynamic interaction between statins and bempedoic acid is complex, a dose-response model was developed to predict LDL-C pharmacodynamics following administration of statins combined with bempedoic acid.

View Article and Find Full Text PDF

The optimal polymyxin B dosage needed to achieve an efficacy target of 50 to 100 mg · h/liter when treating multidrug-resistant bacterial infections in adult cystic fibrosis (CF) patients is unclear. The pharmacokinetics of intravenous polymyxin B were evaluated to better inform dosing. This was a prospective, observational pharmacokinetic (PK) study of nine CF adults receiving intravenous polymyxin B as part of usual clinical care.

View Article and Find Full Text PDF

Apomorphine is an on-demand treatment of "OFF" episodes in patients with Parkinson's disease (PD). A joint parent-metabolite population pharmacokinetic (PK) model characterized apomorphine and apomorphine-sulfate following administration of apomorphine sublingual film (APL) and two formulations of subcutaneous apomorphine. Overall, 2485 samples from 87 healthy subjects and 71 patients with PD and "OFF" episodes were analyzed using nonlinear mixed-effects modeling.

View Article and Find Full Text PDF

The risk of vancomycin (VAN)-associated acute kidney injury (AKI) may be altered with combination regimens. The specific AKI risk when VAN is combined with imipenem-cilastatin/relebactam (IMP-C/REL) or piperacillin/tazobactam (TZP) has not been clearly defined. We sought to quantify the dose-AKI relationships of VAN alone and in combination with TZP or IMP-C/REL.

View Article and Find Full Text PDF

In patients with renal impairment ( = 22 of 39), the median serum concentrations of linezolid, PNU-142300, and PNU-142586 were 1.6-, 3.3-, 2.

View Article and Find Full Text PDF

To address the background and rationale for the recent introduction of the Modification of Diet in Renal Disease (MDRD) equation for renal dose adjustment of antimicrobials and to provide recommendations for pharmacists dosing new antimicrobial agents. Comprehensive MEDLINE and EMBASE literature searches (from August 2018 to October 2019) were performed. Search terms included , and and a subsequent search included the preceding terms AND OR .

View Article and Find Full Text PDF

Linezolid (LZD) is a widely used antimicrobial that is active against a broad range of disease-causing bacteria. Myelosuppression is major treatment-limiting toxicity of LZD that occurs more frequently in patients with renal insufficiency. Quantification of LZD and its two primary metabolites (PNU-142300 and PNU-142586), which undergo significant renal elimination, may support design of improved dosing strategies to mitigate the risk of myelosuppression.

View Article and Find Full Text PDF

Purpose: To compare methods of estimating vancomycin volume of distribution (V) in adults with class III obesity.

Methods: A retrospective, multicenter pharmacokinetic analysis of adults treated with vancomycin and monitored through measurement of peak and trough concentrations was performed. Individual pharmacokinetic parameter estimates were obtained via maximum a posteriori Bayesian analysis.

View Article and Find Full Text PDF

Linezolid is administered as a fixed dose to all patients despite evidence of increased exposure and myelosuppression in renal impairment. The objectives of these studies were to assess the risk of thrombocytopenia with standard-dose linezolid in renal impairment and to identify an alternate dosing strategy. In study 1, data from adult patients receiving linezolid for ≥10 days were retrospectively reviewed to determine the frequency of thrombocytopenia in patients with and without renal impairment.

View Article and Find Full Text PDF

Background: The estimated glomerular filtration rate (eGFR) is often used to model drug clearance (CL) and scale doses across age and body size. Over their lifetime, patients with cystic fibrosis (CF) receive repeated courses of tobramycin, an antibiotic with eGFR-dependent CL, for the treatment of pulmonary exacerbations. Tobramycin population pharmacokinetic (PK) modeling can be used to decipher the best approach to define eGFR for pediatric bridging studies.

View Article and Find Full Text PDF

Novel β-lactamase inhibitors have extended the reach of new and existing β-lactams against multidrug-resistant bacteria expressing β-lactamases. The efficacy of these combination therapeutics relies on a complex two-component pharmacodynamic (PD) system where the β-lactamase inhibitor inactivates the bacterial β-lactamase enzyme and frees the companion β-lactam to act against its penicillin-binding protein target. Despite considerable investigation into the pharmacokinetics (PK) and pharmacodynamics of β-lactams, the pharmacology of their companion β-lactamase inhibitors has only recently been rigorously explored.

View Article and Find Full Text PDF

Abraham Flexner's 1910 report on medical education in the United States (US) and Canada propelled medical training forward into a contemporary renaissance. The report heralded many seismic changes that still resonate within medical and health professions education throughout the US. Today several factors are accelerating curricular reform within pharmacy education, including but not limited to accreditation standards, technologic advances, and student diversity.

View Article and Find Full Text PDF

The management of Staphylococcus aureus bacteremia is limited by high rates of methicillin resistance and the paucity of antibiotic agents with proven efficacy in complicated infectious syndromes, such as endocarditis. Vancomycin is the mainstay of therapy; however, salvage therapy is frequently required due to persistence of infection or drug toxicity. Daptomycin is FDA-approved for S.

View Article and Find Full Text PDF

Background: Empirical models to predict β-lactam pharmacokinetics (PK) using information from routine aminoglycoside therapeutic drug monitoring (TDM) have been proposed for critically ill patients; however, no such models exist for patients with cystic fibrosis (CF).

Objectives: To investigate whether PK parameters of tobramycin could be used to predict those of piperacillin.

Methods: A non-interventional, open-label PK study was conducted in hospitalized adults treated with piperacillin/tazobactam and tobramycin for acute pulmonary exacerbations of CF.

View Article and Find Full Text PDF

Antibiotic renal dose adjustments are determined in patients with stable chronic kidney disease and may not translate to patients in late-phase trials and practice. Ceftolozane/tazobactam, ceftazidime/avibactam, and telavancin all carry precautionary statements for reduced clinical response in patients with baseline creatinine clearance of 30-50 mL/min, potentially due to unnecessary dose reduction in the setting of acute kidney injury (AKI). In this review, we discuss the regulatory landscape for antibiotics eliminated by the kidney and highlight the importance of the first 48 hours of therapy.

View Article and Find Full Text PDF

Background: Vancomycin remains the mainstay of empirical therapy directed against MRSA. National guidelines recommend empirical dosing based on total body weight with trough-level therapeutic drug monitoring (TDM), which may not be optimal in obese and super obese patients. Furthermore, nomograms for empirical vancomycin dosing by estimated kidney function pre-date standardization of creatinine assays.

View Article and Find Full Text PDF