bluuebunny/crossref_metadata_2025_split huggingface dataset:
1092. Population Pharmacokinetics of Cephalexin in Non-Obese and Obese Hospitalized Patients with Infectious Diseases
Authors: Jeong Kyeoul , Chung Eun Kyoung , Cheatham S Christian , Stock Andrea H , Utley Sara , Healy Daniel P , Campion Maureen G , Murrey Timothy , Gesenhues Alicia M , Jeffery Julia , Kays Michael B 
Published: December 2021

Abstract

Background
Obesity is a significant global health problem and has been associated with altered pharmacokinetics (PK) and pharmacodynamics (PD) of many drugs. Cephalexin is a commonly prescribed antibiotic as an oral drug for the treatment of mild to moderate infections; however, little is known regarding cephalexin pharmacokinetics in obese patients. The objective of this study was to investigate the population PK of cephalexin in non-obese and obese patients.

Methods
Hospitalized patients who were 18 years or older with a suspected or documented infection were studied. Patients weighing &lt; 120 kg were defined as non-obese patients whereas those weighing ≥ 120 kg as obese. All included patients received cephalexin 1000 mg every 6 hours orally. After ≥ 3 days of therapy, serial blood samples were collected. Ultrafiltration was used to separate the unbound drug from the protein-bound fractions, and both total and unbound serum concentrations were determined by HPLC. The concentration-time data for cephalexin were analyzed by a non-linear mixed effects modeling approach using NONMEM.

Results
Overall, 255 serum concentrations from 19 patients (10 males, 4 in an ICU) were included; ten patients were non-obese (total body weight [TBW] &lt; 120 kg) and nine were obese (TBW ≥ 120 kg). A 1-compartment model with first-order absorption, absorption lag-time, first-order elimination, and linear protein binding best fit the concentration-time data. Creatinine clearance (CrCl) was the only covariate significantly associated with cephalexin PK, specifically systemic clearance (CL): CL (L/h) = 12.3 + [0.0837*(CRCL – 81.8)]. No other covariates significantly affected the model-derived PK parameters including CL, volume of distribution (V), first-order absorption rate constant (Ka), unbound fraction (fu) with the fixed estimate of 0.776, and absorption lag-time (Tlag).

Conclusion
In conclusion, cephalexin PK is comparable between non-obese and obese patients. Dosing adjustments based solely on body size may not be necessary. Further analyses are warranted to suggest optimal cephalexin dosages in obesity through large-scale population PK-PD modeling and simulation.

Disclosures
All Authors: No reported disclosures
1093. Bypassing Penicillin Skin Testing in favor of Direct Oral Challenge: A Pharmacy-driven Inpatient Program
Authors: Ham YoungYoon , Joshi Shyam , Tucker Kendall J , Yu Diana , Lewis James , Sukerman Ellie 
Published: December 2021

Abstract

Background
Patient interview, penicillin skin testing (PST) and/or an oral challenge can be used to evaluate penicillin allergies. Programs favor PST prior to oral challenge, but there is interest in bypassing PST and directly oral challenging for logistical and financial reasons. Data on the safety and efficacy of a direct challenge in the inpatient setting when the index reaction is moderate to severe (e.g. swelling of throat, angioedema, anaphylaxis) is lacking.

Methods
Adult patients (≥18 years) admitted with a penicillin allergy were evaluated for eligibility between September 2019 and June 2021. Pregnant patients were excluded, while critically ill patients and those on anti-histamine medications were evaluated if clinical need was high. Institutional protocols allowing for patients to be challenged without PST if reaction was more than 10 years ago were used. Data collected included the number of patients challenged and delabeled, number of patients who had moderate to severe index reactions, number of patients who were relabeled without cause, and number of patients who declined further testing.

Results
Two hundred twenty-five patients were evaluated; 11 patients declined testing. Two hundred four patients were delabeled (95%) among those fully evaluated. One hundred twelve patients were delabeled by interview and chart review alone (52%), 99 by oral challenge (46%), and 2 by PST and oral challenge (1%). Twenty-nine patients with moderate to severe reactions were challenged and 27 were delabeled. Ten patients could not be delabeled due to mild or delayed reactions to challenge or subsequent treatment, including 2 patients with severe index reactions who had mild challenge reactions and required no rescue medications. No patients required epinephrine during challenge. Five patients were relabeled and then delabeled again as no new reaction had occurred.

Conclusion
Penicillin allergies can be removed with a pharmacy-driven algorithm that prioritizes direct challenges when appropriate even when the index reaction was moderate to severe. Risks of a reaction are low, and reactions tend to be mild. Given well-documented benefits of delabeling patients for the patient and the institution, more hospitals should consider starting such services.

Disclosures
All Authors: No reported disclosures
129. Antimicrobial Resistance Genes Were Reduced Following Administration of Investigational Microbiota-Based Live Biotherapeutic RBX2660 to Individuals with Recurrent Clostridioides difficile Infection
Authors: Hau Heidi , Walsh Dana M , Gonzalez Carlos , Shannon Bill , Blount Ken 
Published: December 2021

Abstract

Background
Intestinal colonization by antimicrobial resistant (AMR) pathogens is a known health and infection risk, and is common among individuals with recurrent Clostridioides difficile infections (rCDI). Accordingly, therapeutic approaches that decolonize the gut of AMR pathogens could be valuable to patients to reduce risk of associated illnesses. Herein, we assessed gut colonization with AMR bacteria before and after treatment with RBX2660—a microbiota-based investigational live biotherapeutic—in the PUNCH CD3 Phase 3 trial for reducing CDI recurrence.

Methods
rCDI participants enrolled in PUNCH CD3 received a blinded single dose of RBX2660 or placebo within 24 to 72 hours after completing antibiotic treatment for the most recent rCDI episode. Clinical response was the absence of CDI recurrence at eight weeks after treatment, and participants were asked to submit stool samples prior to RBX2660 or placebo treatment (baseline) and 1, 4 and 8 weeks, 3 and 6 months after study treatment. Samples were extracted and sequenced using a shallow shotgun method. The presence and number of AMR genes was determined for 175 participant samples and 116 RBX2660 samples using 90% K-mer sequence coverage based on the MEGARes database. AMR gene count data were collapsed into count columns to adjust for sparseness in the matrices and were analyzed using a Generalized Linear Mixed Model.

Results
Clinically, RBX2660 demonstrated superior efficacy versus placebo (70.4% and 58.1%, respectively), and the total AMR genes per participant decreased significantly from before to after treatment in RBX2660-treated responders (p&lt; .05, Figure 1) and remained low to at least 6 months. Among genes that decreased in RBX2660 responders were clinically important extended-spectrum beta-lactamase (blaTEM, blaSHV, blaCTX-M), vancomycin resistance (vanA, vanB), and fluoroquinolone resistance genes (gyrA, parC).

Total AMR genes per PUNCH CD3 participant among RBX2660-treated responders at the indicated time points and in the RBX2660 investigational product. The red lines indicate timepoint group medians.

Conclusion
In the PUNCH CD3 Phase 3 trial of RBX2660 for rCDI, AMR gene content decreased after RBX2660 treatment and remained low to at least 6 months, consistent with prior RBX2660 trials. This underscores the potential of microbiota-based biotherapeutics for decolonizing AMR bacteria from gut microbiota and thereby reducing AMR infection risks.

Disclosures
Heidi Hau, PhD, Rebiotix Inc. (Employee) Dana M. Walsh, PhD, Rebiotix (Employee) Ken Blount, PhD, Rebiotix Inc., a Ferring Company (Employee)
1096. Evaluation of Vancomycin Pharmacokinetics in Intravenous Drug Users
Authors: Weihs Sayo , Quick Gadison , Bogdanich Ivana 
Published: December 2021

Abstract

Background
People who inject illicit drugs (PWID) are 16 times more likely to develop methicillin-resistant Staphylococcus aureus (MRSA) infections including severe infections like bacteremia and endocarditis. Vancomycin is recommended as the drug of choice for empiric and targeted coverage in both severe and non-severe MRSA infections. Pharmacokinetic literature has suggested up to 31% higher renal clearance in intravenous drug users (IVDU) compared to non-IVDUs. This increased clearance may theoretically lead to more frequent sub-therapeutic troughs in otherwise standard dosing schemes. There is a paucity of data examining vancomycin pharmacokinetics following typical dosing schemes in IVDU population.

Methods
This was a single-center, retrospective chart review that examined therapeutic drug monitoring in patients treated with vancomycin between January 1st, 2015 through July 31st, 2020. Patients were identified as either IVDU or non-IVUD groups based on ICD-9/10 codes. The primary outcome was the difference between mean first vancomycin steady state troughs. Secondary outcomes were differences in time to first therapeutic trough, mean number of days on vancomycin based on infection, rate of acute kidney injury (AKI) after vancomycin, and rate of vancomycin failure.

Results
A total of 158 patients were included in the analysis (77 IVDU vs. 81 non-IVDU). Mean first vancomycin steady state trough were significantly less in IVDU group compared to non-IVDU group (11.85 vs. 13.98 mcg/mL P = 0.007). Mean time to first therapeutic trough and mean number of days treated were significantly higher in IVDU versus non-IVDR samples (65.9 vs. 50.2 hours P = 0.044 and 5.4 vs. 12.3 days P = 0.017, respectively). There was no detectable difference in rates of AKI and vancomycin failure.
Primary outcome graph for patients with IV drug use

Primary outcome graph for patients without IV drug use

Conclusion
Vancomycin use in patients with IVDU resulted in significantly lower steady state troughs compared to patients who were non-IVDU. These patients also had a longer time to first therapeutic trough. Patient populations who are IVDU may require additional consideration as a special population for future development of vancomycin pharmacokinetic models.

Disclosures
All Authors: No reported disclosures
1097. A Comparison of Area-Under Curve (AUC)-Guided vs Trough-Guided Monitoring of Vancomycin and Its Impact on Nephrotoxicity: A Systematic Review and Meta-analysis
Authors: Lim Ashley Shiyuan , Seng Jun Jie Benjamin , Ng Tao Tao Magdeline , Chng Hui Ting , Han Zhe 
Published: December 2021

Abstract

Background
Trough levels have been used for Vancomycin (VAN) therapeutic drug monitoring (TDM) historically due to its practicality. A paradigm shift towards the use of area under curve (AUC)-guided dosing TDM has been made due to availability of advanced pharmacokinetics software, variability between trough levels and AUC values and the potential for reducing toxicity. This review aims to evaluate the impact of AUC-guided vs trough-guided vancomycin TDM on nephrotoxicity-related outcomes.

Methods
A systematic review was conducted using PubMed®, Embase®, Web of Science®, CINAHL®, Google scholar and Cochrane library® up till 1st January 2021 and was reported according to the PRISMA checklist. Studies which evaluated AUC-guided or trough-guided VAN TDM and vancomycin-associated nephrotoxicity were included. Random effects models were used to compare differences in nephrotoxicity between trough level or AUC based vancomycin TDM due to expected heterogeneity in study designs.
PRISMA Flowchart

PRISMA flow chart depicting the selection process of studies included in the meta-analysis

Results
Of 1191 records retrieved, 57 studies were included. Majority of studies included adult and elderly patients (n=47, 82.5%). The pooled prevalence of nephrotoxicity was lower using the AUC-guided TDM [6.2%, 95% confidence interval (CI): 2.9 – 9.5%] compared to trough-guided TDM [17.0%; 95% CI: 14.7 – 19.2%]. The risk of nephrotoxicity was lower with the AUC-guided approach as compared with the trough-guided approach [OR: 0.53, 95% CI: 0.32–0.89]. AUC thresholds correlated with risk of nephrotoxicity only for the first 96 hours of therapy. A frequency analysis of significant multivariable factors showed that concomitant use of nephrotoxins, VAN trough levels and duration of VAN therapy were most commonly associated with nephrotoxicity.
Forest plot comparing the risk of nephrotoxicity of AUC-guided vs trough-guided

Forest plot comparing the risk of nephrotoxicity of AUC-guided vs trough-guided
Pooled nephrotoxicity rates from AUC-guided monitoring

Pooled nephrotoxicity rates from AUC-guided monitoring
Pooled nephrotoxicity rates from trough-guided monitoring

Pooled nephrotoxicity rates from trough-guided monitoring

Conclusion
The AUC-guided approach appeared to have lower risk of nephrotoxicity which supports the updated American Society of Health-System Pharmacists recommendations. More studies should be performed to evaluate the optimal derivation of AUC and clinical utility of repeated measurements of vancomycin AUC and trough levels.

Disclosures
All Authors: No reported disclosures
1098. A Phase 1 Safety and Tolerability of Single Ascending Doses of a Novel Engineered Cationic Peptide, PLG0206, in Healthy Subjects
Authors: Huang David , Dobbins Despina , Ghahramani Parviz , Steckbeck Jonathan 
Published: December 2021

Abstract

Background
PLG0206 is a novel engineered cationic antimicrobial peptide being evaluated for treatment of prosthetic joint infections (PJI). This abstract presents the results from the first in human study to evaluate the safety, tolerability and pharmacokinetic (PK) profile of PLG0206 when administered as an intravenous (IV) infusion.

Methods
6 cohorts of 8 participants were planned to receive escalating single 1-hour IV infusions of PLG0206 at 0.05, 0.125, 0.25, 0.5, 1, 2 and 3 mg/kg dose or placebo. Participants were randomized to receive either PLG0206 (6 per cohort) or placebo (2 per cohort). At each dose level, there were 2 sentinel participants (1 active, 1 placebo) who were dosed at least 48 hours in advance of the other participants in their group. Serial pharmacokinetic samples were taken prior to infusion and up to 48 post infusion. Safety and tolerability was assessed throughout the study. There was at least a 7-day period after dosing at each of the dose levels before dose escalation.

Results
PLG0206 was safe and well tolerated when administered to healthy volunteers at doses ranging from 0.05 and 1 mg/kg. Therapeutic exposures were achieved at 1 mg/kg. The 2 and 3 mg/kg cohorts were not studied. The incidence of treatment emergent adverse events related to study drug administration was low and most events mild (Grade 1) in severity and was similar between the PLG0206 treatment and placebo groups. There were no SAEs, life-threatening events or deaths throughout the study. IV PLG0206 exhibited linear PK over the dose range of 0.05 to 1.0 mg/kg. The median terminal half-life (t½) ranged from 7.37 to 19.97 hours. AUC0-∞ increased with increasing PLG0206 dose ranging between 1581.41 and 21141.52 ng.hr/mL. Cmax ranged between 256 and 2653 ng/mL. The mean apparent volume of distribution (Vz) increased was between 25.49 and 94.2 L, mean clearance (CL) were similar across all and ranged from 2.42 to 4.18 L/hour.

Conclusion
Following single IV infusion to healthy volunteers, PLG0206 was safe and well tolerated at doses ranging from 0.05 to 1 mg/kg. IV PLG0206 exhibits linear PK over the dose range. These findings support the ongoing development of IV PLG0206 and will inform dosing regimens in future studies to investigate its utility as an antimicrobial agent.

Disclosures
David Huang, MD, PhD, Peptilogics (Employee) Despina Dobbins, BS, Peptilogics (Employee) Parviz Ghahramani, PhD, PharmD, MSc, MBA, Peptilogics (Consultant) Jonathan Steckbeck, PhD, Peptilogics (Employee)
1099. Evaluation of the Safety and Pharmacokinetics (PK) following Administration of Single and Multiple Doses of Anti-Staphylococcal Lysin, LSVT-1701, in Healthy Adult Subjects
Authors: Wire Mary Beth , Jun Soo youn , Jany In-Jin , Hwang Jun Gi , Huang David 
Published: December 2021

Abstract

Background
LSVT-1701 is an anti-staphylococcal phage lysin being developed for treatment of MRSA infections in combination with SoC antibiotics. The safety and PK of single ascending doses of LSVT-1701 0.1 to 10 mg/kg in healthy adult volunteers were previously described (Jun, et.al, AAC 2017;61:e02629-16). We further evaluated the safety and PK of multiple ascending doses of LSVT-1701 in healthy adult subjects.

Methods
Study ITB-101-1b was a Phase 1, randomized, double-blind, placebo-controlled, multiple ascending dose study. 8 subjects were randomized 3:1 to active:placebo in each cohort. LSVT-1701 was administered as a 6 mg/kg single dose and twice daily (BID) doses of 1.5, 3.0, and 4.5 mg/kg for 4 days (24h between Doses 1-2, 12h between Doses 2-6). Study drugs were administered as a 1-hour IV infusion. Serial serum samples were collected over 24 hours following the first and last doses for measurement of LSVT-1701 concentrations by a validated ELISA method. PK analysis of LSVT-1701 concentration-time data was done using noncompartmental methods. Safety was assessed by AEs, clinical labs, vital signs, and ECG.

Results
30/32 (94%) subjects completed the study. No subjects withdrew due to AEs, and there were no severe AEs, no serious AEs, and no deaths. AEs were of mild (97%) to moderate (3%) intensity and were reported by all subjects in the LSVT-1701 6 mg/kg single dose group and 1-3 (17-50%) of subjects receiving 1.5 to 4.5 mg/kg BID or placebo. The most common AEs of headache, chills, rigors, and fever generally lasted for ≤2 days with or without acetaminophen treatment, and no clinically significant changes in blood pressure, heart rate, ECG, or clinical labs (other than transient increases in CRP) were observed. Infusion site reactions (erythema, pain, induration, warmth) were observed with BID administration of LSVT-1701, but not with the single 6 mg/kg dose or placebo. LSVT-1701 exposure increased greater than in proportion to dose and t1/2 was concentration-dependent, increasing with higher doses. No accumulation in LSVT-1701 exposure was observed.
Summary of LSVT-1701 PK Parameters

Summary of LSVT-1701 PK Parameters

Conclusion
The safety and PK profile of LSVT-1701 is favorable for evaluation in patients with
S. aureus infections, including bacteremia and infective endocarditis, for which new treatments are needed.

Disclosures
Mary Beth Wire, Pharm#, Lysovant (Consultant) Soo youn Jun, PhD, iNtRON Biotechnology (Consultant) In-Jin Jany, PhD, iNtRON (Consultant) Jun Gi Hwang, PhD, Lysovant (Consultant) David Huang, MD, PhD, Lysovant (Consultant)
1101. Implementing a Beta-Lactam Therapeutic Drug Monitoring Program: Experience from a Large Academic Medical Center
Authors: Veena Venugopalan , Hamza Malva , Santevecchi Barbara A , DeSear Kathryn , Cherabuddi Kartikeya , Peloquin Charles A , Peloquin Charles A , Al-Shaer Mohammad H 
Published: December 2021

Abstract

Background
Beta-lactams (BL) are the cornerstone of antimicrobial treatment for infections. Beta-lactam therapeutic drug monitoring (BL-TDM) optimizes drug concentrations to ensure maximal efficacy and minimal toxicity. The goals of this study were to describe the implementation process of a BL-TDM program and to further describe our experience using BL-TDM in clinical practice.

Methods
This was a retrospective review of adult patients with available BL-TDM between January 2016 and November 2019 at the University of Florida (UF) Health Shands Hospital. Total serum concentrations of BL were measured in the Infectious Diseases Pharmacokinetics Lab (IDPL) at UF, using a validated ultrahigh pressure liquid chromatography assay with triple quadrupole mass spectroscopy (LC-MS-MS). At our institution, TDM is available for 11 BLs and in-house assays are performed from Mon-Fri for most BLs.

Results
A total of 3,030 BL concentrations were obtained. An analysis was performed on the first BL-TDM encounter in 1,438 patients. The median age was 57 years (IQR, 41-69) and the median BMI was 27.5 kg/m2 (IQR, 22.5-34.5). On the day of BL-TDM, the median serum creatinine was 0.83 (IQR, 0.59-1.30). Fifty-one percent of patients (n=735) were in an ICU at the time of BL-TDM with a median SOFA score of 6 (IQR, 3-9). BL-TDM was most frequently performed on cefepime (61%, n=882), piperacillin (15%, n=218), and meropenem (11%, n=151). The BL was administered as a continuous infusion in 211 (15%) patients. An interim analysis of 548 patients showed that BL-TDM was performed a median of 2 days (IQR, 1-4) from the start of BL therapy and resulted in a dosage adjustment in 26% (n=145).

Conclusion
BL-TDM was performed in older, non-obese patients with normal renal function. Over half of the evaluated patients were in an ICU at the time of TDM. This finding emphasizes the value of BL-TDM in the ICU setting because altered pharmacokinetics during critical illness has been linked to enhanced BL clearance. Interestingly, BL-TDM resulted in dosage adjustment in 1 in 4 patients who were receiving licensed BL dosing regimens, thus highlighting the role of TDM in dose individualization. BL-TDM was performed most commonly within the 72-hours of therapy initiation. Early BL-TDM has been shown to improve patient outcomes and should be promoted.

Disclosures
Venugopalan Veena, PharmD, Melinta (Other Financial or Material Support, Received a stipend for participation in a drug registry)Merck (Other Financial or Material Support, Received a stipend for participation in a drug registry) Charles A. Peloquin, Pharm.D., Nothing to disclose