Impact of a pharmacy resident on a transitions of care rotation for inpatients enrolled in an outpatient parenteral antimicrobial therapy (OPAT) program

A novel pharmacy residency rotation was created to meet the needs of patients enrolled in an outpatient parenteral antimicrobial therapy (OPAT) program but not yet discharged from the inpatient setting. This service resulted in a high number of antimicrobial stewardship interventions identified and accepted by the primary team(s).

A Case Report of May-Thurner Syndrome Identified on Abdominal Ultrasound

May-Thurner syndrome (MTS) is most commonly caused by the compression of the left iliac vein by the right iliac artery against the lumbar spine, which leads to the development of a partial or occlusive deep venous thrombosis (DVT).1 Diagnosis begins with a duplex ultrasound of the lower extremities to evaluate for a femoropopliteal thrombus, and in high-risk patients where a more proximal DVT is suspected and the DVT ultrasound is negative, a computed tomography venogram (CTV) or magnetic resonance venogram (MRV) is performed.1,3 In this case report, a patient presented to the emergency department (ED) with two days of left lower extremity pain and swelling. Initial lower extremity DVT ultrasound was negative, so a CTV was ordered and revealed a thrombus in the left common iliac vein with overlying compression by the right common iliac artery, suggesting the diagnosis of May-Thurner syndrome (Figure 1). Afterwards, a point-of-care ultrasound (POCUS) was performed at bedside to evaluate the caval and iliac arteries and the findings were consistent with the CTV (Figure 2, 3, 4). If the POCUS was performed prior to the CTV, the patient may have been spared the radiation exposure from CT, as well as the risks of intravenous (IV) contrast required for a venogram. Therefore, in high risk patients in whom a negative DVT ultrasound will prompt advanced imaging with CTV or MRV, I propose the addition of a lower abdominal ultrasound using a curvilinear probe to assess the caval and iliac arteries prior to obtaining a CTV or MRV.

Topics

May-Thurner Syndrome, leg swelling, POCUS, ultrasound, deep venous thrombosis.

1228. Outcomes Associated with Empiric Cefepime or Meropenem for Bloodstream Infections Caused by Ceftriaxone-Resistant, Cefepime-Susceptible Escherichia coli and Klebsiella pneumoniae

Background

Cefepime is a 4^th generation cephalosporin frequently used for empiric sepsis therapy. Dose- and MIC-dependent efficacy of cefepime is supported by the Clinical & Laboratory Standards Institute, however its use in infections due to extended-spectrum beta-lactamase-producing Enterobacterales is controversial. This study aims to compare outcomes in patients given empiric meropenem or cefepime for bloodstream infections (BSI) caused by ceftriaxone-resistant E. coli and K. pneumoniae.

Methods

This single-center retrospective cohort included adults hospitalized from 2010 - 2020 and received empiric cefepime or meropenem for BSI caused by ceftriaxone-resistant E. coli or K. pneumoniae. In the cefepime group, only organisms with MIC ≤ 2 mg/L were included. Patients who received the empiric agent for < 48 hours, or received an additional active agent within 48 hours were excluded. The primary outcome was 30-day mortality; secondary outcomes were recurrent infection, readmission, and time to clinical stability. Chi-squared or Fisher’s exact was used for categorical variables and Mann-Whitney-U for continuous variables. Inverse probability treatment weighing was used to determine the impact of empirical therapy on clinical stability at 48 hours.

Results

Fifty-four patients were included: 36 received empiric meropenem, 18 received cefepime. There were no significant differences in baseline severity of illness or comorbid conditions. Urinary source was less common in the meropenem group compared to cefepime (52.8 vs 83.8%, p=0.028) (Table 1). There was no difference in 30-day mortality between meropenem and cefepime (2.8 vs 11.1%, p = 0.255). More patients achieved clinical stability at 48 hours on empiric meropenem compared to cefepime (75 vs 44.4%, p = 0.027), and time to clinical stability was significantly shorter (median 21.3 vs 38.5 hours, p = 0.016). Most patients in the meropenem and cefepime groups completed definitive treatment with a carbapenem (88.9 vs 72.2%, p=0.142).

Table 1: Results

Summary of primary and secondary outcomes

Conclusion

There was no difference in mortality between patients receiving empiric cefepime for BSI due to ceftriaxone-resistant Enterobacterales, with cefepime MIC ≤ 2 mg/L, compared to meropenem; however, time to clinical stability was significantly delayed.

Disclosures

James Kirby, MD, D(ABMM), First Light Biosciences (Board Member)TECAN, Inc. (Research Grant or Support)

718. Posaconazole Versus Standard of Care for Treatment of Invasive Mold Infections

Background

Invasive mold infections (IMIs) including Aspergillus spp. are a significant cause of morbidity and mortality in immunocompromised patients. Voriconazole is recommended as first line treatment for primary IA. Liposomal amphotericin B and isavuconazole are also recommended alternative therapies. Posaconazole has activity against mold species including those not covered by voriconazole, is available as an IV and oral formulation with a distinct adverse effect profile making it a potential effective alternative for treatment. This study investigated the clinical outcomes of treatment of invasive mold infections (IMIs) with posaconazole compared to standard of care (voriconazole, isavuconazole, liposomal amphotericin B).

Methods

A retrospective, single center, cohort study was completed to evaluate patients with IMIs treated with posaconazole versus those treated with standard of care therapy. Medication orders for posaconazole or standard of care therapy between January 2012 and December 2020 were identified from a clinical data repository. Only patients with antifungal orders with a listed indication for “treatment of fungal infection” were included. Data collected for each group included baseline demographics, underlying conditions, site of infection, type of mold, therapeutic drug monitoring and classification of IMI.

Results

A total of 120 patients met inclusion criteria, with 35 patients in the posaconazole group and 85 patients in the SOC group. Baseline characteristics were similar except for increased severe neutropenia in the posaconazole group (p&lt; 0.0001), more probable IMIs in the SOC group (p=0.009) and more possible IMIs in the posaconazole group (p=0.043). In the posaconazole group 37.1% (13/35) of patients were treatment experienced vs. 29.4% (25/85) of patients in the SOC group. More patients achieved a complete/partial response in the SOC group compared to the posaconazole group (p=0.0001) and more patients experienced treatment failure in the posaconazole group (p=0.01). A higher proportion of patients experienced adverse effects in the SOC group compared to the posaconazole group (p=0.0001).

Conclusion

Posaconazole was not as effective as SOC in treating invasive mold infections but patients experienced comparatively fewer adverse events.

Disclosures

All Authors: No reported disclosures

Long Noncoding RNA NIHCOLE Promotes Ligation Efficiency of DNA Double-Strand Breaks in Hepatocellular Carcinoma

Long noncoding RNAs (lncRNA) are emerging as key players in cancer as parts of poorly understood molecular mechanisms. Here, we investigated lncRNAs that play a role in hepatocellular carcinoma (HCC) and identified NIHCOLE, a novel lncRNA induced in HCC with oncogenic potential and a role in the ligation efficiency of DNA double-stranded breaks (DSB). NIHCOLE expression was associated with poor prognosis and survival of HCC patients. Depletion of NIHCOLE from HCC cells led to impaired proliferation and increased apoptosis. NIHCOLE deficiency led to accumulation of DNA damage due to a specific decrease in the activity of the nonhomologous end-joining (NHEJ) pathway of DSB repair. DNA damage induction in NIHCOLE-depleted cells further decreased HCC cell growth. NIHCOLE was associated with DSB markers and recruited several molecules of the Ku70/Ku80 heterodimer. Further, NIHCOLE putative structural domains supported stable multimeric complexes formed by several NHEJ factors including Ku70/80, APLF, XRCC4, and DNA ligase IV. NHEJ reconstitution assays showed that NIHCOLE promoted the ligation efficiency of blunt-ended DSBs. Collectively, these data show that NIHCOLE serves as a scaffold and facilitator of NHEJ machinery and confers an advantage to HCC cells, which could be exploited as a targetable vulnerability. SIGNIFICANCE: This study characterizes the role of lncRNA NIHCOLE in DNA repair and cellular fitness in HCC, thus implicating it as a therapeutic target.See related commentary by Barcena-Varela and Lujambio, p. 4899.

228. Fluoroquinolone Prescribing for Diabetic Foot Infections following an FDA Drug Safety Communication for Aortic Aneurysm Risk

Background

Fluoroquinolones were commonly prescribed for hospitalized patients with diabetic foot infection (DFI) at our institution, included in 69% of empiric antibiotic regimens from 2011–2014. On December 20, 2018, the U.S. Food and Drug Administration (FDA) issued a Drug Safety Communication regarding the risk of aortic aneurysm with fluoroquinolones. The objective of this study was to assess the impact of the FDA Communication on antibiotic prescribing for DFI.

Methods

This was a single-center quasi-experimental study of hospitalized patients initiated on antibiotics for DFI before (February-December 2018) and after (February-December 2019) the 2018 FDA Communication. Patients with concomitant infections or documented beta-lactam or fluoroquinolone allergies were excluded. The primary outcome was inpatient days of fluoroquinolone therapy. Secondary outcomes included days of beta-lactam therapy and Outpatient Parenteral Antibiotic Therapy (OPAT) enrollment. Variables were compared using the Pearson’s chi square, Fisher’s exact, and Mann Whitney U tests, as appropriate. A logistic regression was performed to identify predictors for inpatient receipt of fluoroquinolones.

Results

A total of 198 patients were included. Baseline characteristics were similar between groups (Table 1). After the FDA Communication, the median duration of inpatient fluoroquinolones decreased from 3 [0–5.5] to 0 [0–1] days (p< 0.001). The duration of antipseudomonal beta-lactams increased from 0 [0–2] to 2 [0–6] days (p< 0.001). OPAT enrollment increased from 16.5% to 29.7% (p=0.028), with a corresponding increase in peripherally inserted central catheter placement (15.5% to 25.7%, p=0.074). There was no difference in outpatient fluoroquinolone prescribing over time. Incidence of re-infection, readmission for DFI, and antibiotic adverse events were similar between groups (Table 2).

Table 1

Table 2

Conclusion

Inpatient fluoroquinolone prescribing for DFI decreased significantly following the 2018 FDA Communication, followed by an increase in antipseudomonal beta-lactam use and OPAT enrollment. FDA statements can influence institutional antibiotic prescribing and transitions of care decisions, representing an opportunity for education by Antimicrobial Stewardship programs.

Disclosures

All Authors: No reported disclosures

1329. Vancomycin Therapeutic Drug Monitoring: How to hit the Curve

Background

For the management of serious S. aureus infections, area-under-the curve to minimum inhibitory concentration (AUC/MIC) applied dosing is recommended as the preferred method to goal trough-based monitoring. This pharmacodynamic dosing demonstrates efficacy with optimized exposure and decreased nephrotoxicity. While two levels are ideal for estimating AUC/MIC mathematically, the logistics and costs may outweigh the benefits of this approach. This study will compare AUC/MIC estimates using two single-level pharmacokinetic calculators (C2 and C3) and a Bayesian dosing calculator (C1) versus steady-state troughs.

Methods

A retrospective cohort study using a data repository to identify patients from 2019 included patients on intravenous vancomycin for greater than 48 hours with a steady state trough. Patients on dialysis or with unstable renal function were excluded. Vancomycin AUC/MIC and peak levels were estimated using C1, C2, and C3. The objective was to assess correlation of trough levels of 10-20mcg/ml to an AUC/MIC of 400-600 mg∙h/L. Secondary outcomes included examining the difference in R-squared values of the three calculators, and the percentage of patients with dose adjustments.

Results

55 patients met inclusion criteria. Of 55 troughs, 78% were 10-20mcg/ml and 5% were >20mcg/ml. On average, the three calculators found 85% of all initial troughs and 93% of therapeutic troughs correlated to an AUC >400. However, less than half of therapeutic troughs corresponded to an AUC of 400-600 mg∙h/L. Nearly 70% of patients had one or more dose adjustments often for unclear reasons as the AUC/MIC target of 400-600 mg∙h/L was met in 29-63% of initial adjustments. The three different calculators showed noticeable variability in calculating AUC/MIC.

Figure 1

Figure 2

Figure 3

Conclusion

A weak relationship between AUC/MIC and steady state troughs was found. Excess vancomycin exposure was demonstrated in 39% of therapeutic troughs. Over 25% of dose adjustments were deemed unnecessary. Utilizing AUC/MIC estimates for vancomycin may limit excess exposure while reducing the overall number of drug levels. Selecting a single-level calculator is problematic with the high degree of variation between calculators.

Figure 4

Disclosures

All Authors: No reported disclosures

164. Avoiding Complacency: Assessing the Perceived Impact and Value of Antimicrobial Stewardship at a Academic Medical Center

Background

Multi-disciplinary engagement and education remain key measures for Antimicrobial Stewardship Programs (ASPs). Over 3 years, our ASP has undergone key changes to pre-authorization review, post-prescriptive activities, and core team members, coinciding with a 30% increase in stewardship interventions.

The objectives of this study were to evaluate the familiarity of Nursing, Pharmacy and Prescribers at our academic medical center regarding ASP activities and services, as well as perceived impact on patient care and value. Secondary objectives were to determine what resources are currently utilized and areas for improvement.

Methods

Distinct surveys were distributed to three participant groups: Nurses, Pharmacists, and Prescribers (Housestaff, Advanced Practice Providers, and staff physicians). Questions were developed to assess familiarity, perceived value, and overall satisfaction with the ASP. Additional items included questions on the current use of ASP resources and educational engagement. Survey results were compared to a similar survey conducted 3 years amongst the same participant groups.

Results

The survey was delivered electronically to 3367 Prescribers, Nurses and Pharmacists. 403 responders completed the survey (208 Nurses, 181 Prescribers, and 18 Pharmacists). Familiarity was lowest amongst Nurses, but almost doubled compared to 2016 (Figure). Prescribers cited “restricted antibiotic approval”, “de-escalation”, and “alternative therapies relative to allergies” as the three most common interaction types, similar to 2016. ASP interactions continued to be rated “moderate” or “high” value (88.4% vs 89.15% in 2016), however, face-to-face interactions were preferred by only 4% of responders (unchanged compared to 2016). Prescribers also responded uncommon use of ASP online resources (20%) and clinical decision support tools (34%). 78% of responders expressed desire for increased ASP-related education.

Conclusion

As ASPs evolve, it is important to constantly evaluate impact and value, and identify areas for growth. Despite ASP familiarity being high and interactions valued, we need to further optimize ASP provided resources, clinical support tools, and educational offerings.

Disclosures

All Authors: No reported disclosures

54. Microbiologic Characterization and Antibacterial Use in Hospitalized Adults with covid-19 Infection

Background

Coronavirus disease 2019 (CoVID-19) admissions, oft complicated by an uncertain trajectory, lent to treatment influenced by supposition. Respiratory bacterial co-infection frequently was invoked. The purpose of this study was to determine the respiratory pathogen distribution and antibiotic prescribing patterns in hospitalized patients with CoVID-19.

Methods

Patients with a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ICD-10 code and/or positive polymerase chain reaction (PCR) hospitalized between March 1 and May 31, 2020 were included. Antibiotic utilization (patient days of therapy-pDOT) was collected for the institution during this period and two years prior. Respiratory microbiologic cultures were reviewed to examine the frequency of co-infection on presentation, categorized as within 3 calendar days from admission or afterward. The relationship of antibiotic utilization to positive cultures was also categorized.

Results

Of the 7,969 encounters, 829 were ICD-10 coded and/or confirmed SARS-CoV-2 PCR positive and 196 (23.6%) had positive respiratory cultures. 89.8% of patients had endotracheal samples, the rest were isolated from sputum or bronchoalveolar lavage (17.4% and 6.6%, respectively). Patients were more likely to isolate commensal respiratory flora (108 versus 78 patients within the first 3 days of presentation. Notable isolates such as Staphylococcus aureus and Pseudomonas aeruginosa, were more often isolated after 3 days of hospitalization. While the CoVID-19 average hospital census was only 14.7% of the total, antibiotic utilization, (pDOT/1000) was 2.3 times higher, 831.9 versus 368.3 across the institution. During similar periods in 2018 and 2019, days of therapy overall were lower. For CoVID-19 infected patients, the frequency of antibiotic initiation was 73.2%. The length of therapy was on average 8 days with a high rate of observed restarts.

Table 1: Patient characteristics for CoVID-19 infected patients admitted during March 1 to May 31, 2020

Figure 1: Positive respiratory pathogen culture results for CoVID-19 encounters (March 1-May 31, 2020)

Table 2: Prevalence and select types of antibiotics administered to CoVID-19 patients. (March 1-May 31, 2020)

Conclusion

Bacterial co-infection in an acute viral process is generally low. In this examination of CoVID-19 infected patients, the rate of any positive respiratory culture was 23.6%. A disproportionate effect on the volume of antibiotics and total days of therapy prompted an interest in early stewardship efforts and education.

Table 3: Antibiotic consumption (patient days of therapy) for CoVID-19 encounters (March 1-May 31, 2020) compared to total consumption during identical time periods in 2018, 2019, and 2020

Disclosures

All Authors: No reported disclosures

219. Characteristics Associated with Inappropriate Antibiotic Prescribing in Patients with Asymptomatic Bacteriuria (ASB)

Background

Antibiotic treatment of asymptomatic bacteriuria (ASB) is considered inappropriate, does not improve patient outcomes, and may lead to adverse events such as antibiotic resistance and Clostridioides difficile infection. Previous stewardship interventions have focused on reducing unnecessary urine culture collection in individuals without urinary symptoms; however, further interventions to reduce inappropriate prescribing in ASB are warranted. This study sought to identify characteristics associated with treatment of ASB in order to implement future stewardship interventions.

Methods

This two-center, retrospective cohort study included unique emergency department or inpatient adults with consecutive non-duplicate monomicrobial urine isolates of Enterobacterales or Pseudomonas aeruginosa collected between 8/2013 and 1/2014 from two academic hospitals in Boston, Massachusetts. Patients with ASB (without chart-documented urinary-specific symptoms) were identified through chart review and stratified into two groups: those treated with empiric urinary tract infection (UTI) antibiotics and those untreated. Logistic regression analyses were performed to identify variables independently associated with antibiotic treatment of ASB.

Results

During the study, 255 patients were determined to have ASB and a majority (80.8%) were treated with empiric UTI antibiotics. Most patients were female (71.4%) and elderly (mean age 70 years). The most common organisms isolated were Escherichia coli (59.2%), Klebsiella spp. (23.1%), and P. aeruginosa (9.8%). The presence of isolated fever (OR, 7.83 [95% confidence interval, 1.51, 144.20]); p = 0.05), urinalysis positive for pyuria (>10 white blood cells) (OR, 2.52 [95% CI, 1.15, 5.54]; p = 0.02), and Klebsiella spp. urine isolate (OR, 2.99 [95% CI, 1.19, 8.60]; p = 0.02) were independently associated with treatment.

Conclusion

A large proportion of ASB patients were treated with antibiotics despite clinical practice guidelines recommending against this practice. Isolated fever, pyuria, and Klebsiella spp. culture were all significantly associated with the treatment of ASB; targeted review of these patients by stewardship programs may help to reduce inappropriate ASB treatment within these institutions.

Disclosures

Elizabeth B. Hirsch, PharmD, Merck (Grant/Research Support) Nabriva Therapeutics (Advisor or Review Panel member)

Evaluation of Inpatient Antimicrobial Regimens for Readmitted Outpatient Parenteral Antimicrobial Therapy Patients Receiving Daptomycin or Ertapenem for Ease of Administration

Background

Outpatient parenteral antimicrobial therapy (OPAT) allows for long-course intravenous treatment of infections without lengthy hospital stays. Upon discharge, antimicrobial therapy may be broadened for “ease” of once-daily administration (EOA). Patients requiring subsequent readmission can be tailored to pre-OPAT regimens to minimize adverse effects. This study assessed continuation of EOA regimens upon hospital readmission during or immediately after OPAT.

Methods

This was a retrospective review of adults enrolled in OPAT and discharged on ertapenem or daptomycin for EOA, defined by the terms “convenience” or “EOA” in OPAT notes or by switching to ertapenem or daptomycin upon OPAT enrollment despite adequate therapy with narrower-spectrum agents. The primary outcome was the percentage of patients readmitted during or after their OPAT course and maintained on an EOA regimen. Secondary outcomes included inpatient therapy cost, rates of Clostridioides difficile infection, and adverse events.

Results

Of 188 patients receiving an OPAT EOA regimen, 71 were readmitted, representing 113 unique readmissions. Patients were mostly males (81%) aged 57 years. The EOA regimens were continued in 27% of hospital readmissions. The Infectious Diseases (ID) team was consulted in 48% of readmissions, and the Antimicrobial Stewardship Program (ASP) intervened in 26%. Combined, this resulted in de-escalation in 28% of cases. Clostridioides difficile infections and adverse events occurred in 7% and 12% of readmissions, respectively. The median acquisition cost of inpatient EOA regimens was $150 per readmission.

Conclusions

The OPAT EOA regimens were continued in 27% of hospital readmissions indicating a role for improved indication documentation and collaboration between ID services, ASPs, and OPAT teams.

1092. Impact of Relieving Infectious Diseases Fellows from Off-Hour/Weekend Antimicrobial Stewardship Coverage

Background

Antimicrobial stewardship programs (ASPs) often utilize Infectious Diseases fellows (IDFs) to cover pre-authorization processes during evening and weekend hours. IDFs often provide ASP coverage in addition to their inpatient consult roles. In response to increasing consult volume, we worked with our fellowship program to relieve IDFs of evening and weekend coverage (a decrease in fellow coverage by 26 hours per week) starting in October 2017. Members of the ASP assumed the majority of these evening and weekend hours. Additional post-prescriptive activities and a rotation in Infection Control and Antimicrobial Stewardship were implemented in response. We sought to analyze the impact of this intervention.

Methods

Intervention and medication data were extracted from the electronic medical record during 1 July 2017 through 30 September of 2017 (IDF Coverage) and the same 3 months of 2018 (ASP Coverage). Comparisons between the two periods were performed using descriptive statistics of the number of interventions, number of weekend interventions, types of interventions, and days of therapy (DOT; per 1000 patient-days).

Results

Comparing July-September of 2017 and 2018, total ASP interventions increased 16% (1192 to 1391); weekend ASP interventions increased 75% (139 to 243). The most common interventions were “Choice of Therapy” (41% in both years), “De-Escalation” (17% in 2017, 16% in 2018), and “Dose/Interval Optimization” (10% in both years). The most intervened agents were piperacillin–tazobactam, cefepime, vancomycin, meropenem, and ceftazidime.

Comparing the same time periods, total antibiotic DOT decreased 4% (714.1 to 684.9). There was a 28% decrease in piperacillin–tazobactam (41.47 to 29.85), 19% decrease in meropenem (28.08 to 22.61), and 7% decrease in vancomycin (125.09 to 116.17) use. Ceftazidime was unchanged (18.13 to 18.08). Cefepime increased by 9% (56.78 to 61.97).

Conclusion

Relieving IDFs of evening and weekend ASP coverage during busy inpatient consult rotations may help decrease burnout. The assumption of these hours by dedicated members of ASP led to an increase in documented total and weekend ASP interventions. In addition, the change was associated with a relative decrease in piperacillin–tazobactam, meropenem, and vancomycin use.

Disclosures

All authors: No reported disclosures.

2113. Evaluation of Empiric Antifungal Therapy in Critically Ill Patients with Liver Disease, Sepsis, and No Evidence of Active Fungal Infection

Background

While candidemia is uncommon in the immunocompetent, critically ill population, it is associated with longer lengths of stay (LOS), higher cost, and higher mortality. In critically ill patients with liver disease and sepsis of unknown origin, antifungals (AF) are commonly used empirically. Recent studies suggest that this practice may not improve clinical outcomes but had little representation of patients with liver disease. This study aims to evaluate clinical outcomes of critically ill patients with liver disease, sepsis, and no evidence of active fungal infection who received empiric AF vs. those who did not.

Methods

This was a single-center, retrospective review of adults with liver disease and sepsis, identified by ICD-10 codes, who were discharged from the intensive care unit (ICU) between October 1, 2015 and December 31, 2018. Patients with neutropenia, marrow or organ transplant, HIV infection, systemic immunosuppressants, or fungal infection at sepsis onset were excluded. The primary outcome was inpatient mortality. Secondary outcomes included ICU LOS, total LOS, and development of fungal bloodstream infection (BSI) > 48 hours after sepsis onset. Fisher’s exact and Wilcoxon rank-sum tests were used to compare baseline characteristics. Multivariable logistic regression models were used to compare outcomes. Model covariates were variables with P-values < 0.2 in univariate analysis.

Results

A total of 119 patients were included with 92 receiving empiric AF (micafungin or fluconazole) and 27 receiving no AF. Patients receiving empiric AF were more likely to have hepatic disease upon admission and less likely to have a bacterial infection. Both groups were similar in intubation and vasopressor requirements, febrile episodes, and Candida score. Unadjusted inpatient mortality for empiric vs. no AF was 70.4% vs. 70.7%. Unadjusted ICU LOS, total LOS, and development of a fungal BSI were 10 vs. 11 days, 19 vs. 19 days, and 63.0% vs. 2.2% (P < 0.001). In multivariable models, there was no difference in inpatient mortality between groups (OR 1.20, 95% CI 0.77–1.63).

Conclusion

In critically ill patients with liver disease, sepsis, and no evidence of active fungal infection, receipt of empiric antifungal therapy did not improve inpatient mortality, ICU LOS, or total LOS but did reduce fungal BSI.

Disclosures

All authors: No reported disclosures.

Does the Beta-Lactam Matter? Nafcillin versus Cefazolin for Methicillin-Susceptible Staphylococcus aureus Bloodstream Infections

BACKGROUND

Antistaphylococcal penicillins have historically been regarded as the drugs of choice for methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections (BSI). However, recent outcomes data compared to cefazolin treatment are conflicting.

OBJECTIVE

This study compared treatment failure and adverse effects associated with nafcillin and cefazolin for MSSA BSI.

METHODS

Adult inpatients with MSSA BSI between January 1, 2009 and August 31, 2015 were included in this retrospective cohort study if they received ≥72 h of nafcillin or cefazolin as directed therapy after no more than 72 h of any empiric therapy. The primary composite endpoint was treatment failure defined by clinician documentation, 30-day recurrence of infection, all-cause 30-day in-hospital mortality, or loss to follow-up. Secondary outcomes included antibiotic-related acute kidney injury (AKI), acute interstitial nephritis (AIN), hepatotoxicity, and rash.

RESULTS

Among 157 patients, 116 (73.9%) received nafcillin and 41 (26.1%) received cefazolin. The baseline characteristics were similar except cefazolin-treated patients had higher APACHE II scores and more frequent renal dysfunction. No difference in the composite treatment failure outcome (28.4 vs. 31.7%; p = 0.69) was detected between the nafcillin and cefazolin groups, respectively. In a sensitivity analysis excluding patients without known follow-up, there was no significant difference of treatment failure. AKI, AIN, hepatotoxicity, and rash were all numerically more frequent among nafcillin-treated patients.

CONCLUSIONS

Among nafcillin- or cefazolin-treated patients with MSSA BSI, there was no significant difference in treatment failure. Observing more frequent presumptive adverse effects associated with nafcillin receipt, future prospective studies evaluating cefazolin appear warranted.

1891. Assessing the Needs for Antimicrobial Stewardship Education and Acceptance Across a Spectrum of Prescribers, Nurses and Pharmacists at a Large Academic Medical Center

Background

Regulatory bodies and quality groups have adopted the Centers for Disease Control and Prevention (CDC) Core Elements for Antimicrobial Stewardship Programs (ASP) as a measure for accreditation and scoring healthcare institutions across the United States. Multiple elements are driven by educating and integrating staff across the provider network. The ideal method of providing education and addressing gaps is unknown. The objectives of this study were to evaluate the familiarity of Nursing, Pharmacy, and Prescribers regarding local ASP activities and services, as well as perceptions regarding patient care and value. Secondary objectives were to determine what educational tools are currently utilized and the desired method for future education.

Methods

Three distinct surveys were written for each provider type for Nurses, Pharmacists and Prescribers across ambulatory and inpatient sites. Each contained basic demographic data such as years in practice and primary practice site. Questions were developed to assess familiarity, perceived value, and overall satisfaction with the ASP. Additional items included the use of online ASP resources and desire for more education. The survey was delivered electronically to 5,091 providers.

Results

In total, 443 completed the survey, 267 Nurses, 160 Prescribers, and 16 Pharmacists. A majority of Nurses (67%) and Pharmacists (56%) worked on inpatient units. Prescribers were 48% from Medicine and 16% Hospitalists. Familiarity with the ASP was lowest among Nursing staff, 53% unaware, and highest among prescribers (55% very familiar, 8% not familiar) and pharmacists (56% very familiar and none unfamiliar) as seen in Figures 1 through 3. ASP-assisted harm prevention was identified by 43% and therapy optimization by 44%. Of the highly familiar prescribers and pharmacists, 90% rated ASP as a moderate to high value service. More than 80% of all disciplines expressed the desire for more education, primarily as didactic lectures (65%), intranet portal training (37%), or emails (36%).

Conclusion

Nursing staff at our institution have the greatest need for orientation with the ASP. The ASP is highly valued across prescribers and pharmacists, but all disciplines desire further education. Resource allocation toward education is an important need.

Disclosures

C. McCoy, Merck Inc.: Scientific Advisor, Consulting fee. Allergan: Scientific Advisor, Consulting fee.

1923. OPAT or No-PAT? Evaluation of Outpatient Parenteral Antimicrobial Therapy (OPAT) Patients Receiving Daptomycin or Ertapenem for “Ease of Administration”

Background

Outpatient parenteral antimicrobial therapy (OPAT) allows for long-course intravenous treatment of infections without lengthy hospital stays. Upon discharge, antimicrobial therapy may be broadened to ertapenem or daptomycin for “ease” of once-daily administration. Patients requiring subsequent readmission should be properly tailored to pre-OPAT regimens to minimize collateral damage and reduce cost. This study assessed the continuation of “ease of administration (EOA) regimens” upon hospital readmission during or immediately following OPAT.

Methods

This was a single-center, retrospective review of adult patients enrolled in OPAT and discharged between January 1, 2014 and September 30, 2017 on ertapenem or daptomycin for “EOA.” This was defined by the presence of the terms “convenience” or “EOA” in OPAT notes or by broadening of coverage to ertapenem or daptomycin upon OPAT enrollment despite adequate therapy with more narrow-spectrum agents. Patients receiving directed carbapenem or daptomycin therapy prior to OPAT enrollment were excluded. The primary outcome was the percentage of patients readmitted during or within 90 days of their OPAT course and maintained on an “EOA regimen” of antibiotics. Secondary outcomes included inpatient therapy cost, rates of Clostridium difficile infection, and adverse drug reactions. Demographics and outcomes were summarized using descriptive statistics.

Results

Of the 188 patients receiving an OPAT “EOA regimen,” 71 were readmitted, representing 113 unique readmissions. Patients were mostly male (81%) with a median age of 57 years. “EOA regimens” were continued in 27% of hospital readmissions. The Infectious Diseases team was consulted in 48% of cases, and the Antimicrobial Stewardship Team intervened in 26%, prompting de-escalation in a total of 28% of cases. C. difficile infections and adverse events occurred in 7% and 12% of readmissions respectively. The median drug acquisition cost of inpatient “EOA regimens” was $121 per readmission.

Conclusion

At our institution, OPAT “EOA regimens” were continued in 27% of hospital readmissions indicating a role for improved indication documentation and antimicrobial stewardship involvement.

Disclosures

C. McCoy, Merck Inc.: Scientific Advisor, Consulting fee. Allergan: Scientific Advisor, Consulting fee. M. V. Mahoney, Melinta Therapeutics: Consultant, Consulting fee. Cutis Pharma: Consultant, Consulting fee. Tetraphase Pharmaceuticals, Inc.: Consultant, Consulting fee. Roche Diagnostics USA: Consultant, Consulting fee.

212. Impact of a Prospective Audit and Feedback Antimicrobial Stewardship Initiative on Pneumonia Treatment at an Academic Teaching Hospital

Background

Antimicrobial stewardship programs (ASPs) may improve patient outcomes by reducing antimicrobial adverse effects and resistance. Pneumonia is the most common infectious reason for hospitalization and is a key target for improvement in antimicrobial use. The purpose of this study was to measure the impact of a prospective audit and feedback program for patients with pneumonia in addition to an already robust pre-authorization program at an academic teaching hospital.

Methods

We analyzed the impact of a prospective audit and feedback initiative among inpatients with pneumonia treated with antimicrobials for at least 72 hours. The primary outcome was the percent of optimal antimicrobial days of therapy received based on hospital-approved pneumonia guidelines, compared pre- and postintervention. This outcome was defined as the number of optimal days of therapy compared with the total days of therapy over the entire study period from the hospital’s perspective. Secondary outcomes included the incidence rate of optimal antimicrobial days of therapy on a patient-specific level, overall antimicrobial days of therapy, length of hospital stay, rates of Clostridium difficile infection (CDI), and in-hospital mortality.

Results

The study included 248 patients, 125 pre- and 123 postintervention. Forty interventions were made post-implementation, with duration (47.5%) and de-escalation (35%) recommendations most commonly suggested. 50.8% of patients were male, the median [interquartile range (IQR)] age was 71 (60–83) years old, 45.6% of patients had community-acquired pneumonia, and patients had a median (IQR) Elixhauser comorbidity score of 5 (3–6). The overall rate of guideline concordance was 65.8% pre- and 77.5% postintervention (P = 0.041). On an individual level, patients were 17% more likely to have optimal antimicrobials postintervention [Incidence rate ratio 1.17 (95% confidence interval 1.03–1.32, P = 0.013)]. Length of stay, days of therapy, CDI, and in-hospital mortality rates did not differ significantly between groups.

Conclusion

Initiating a prospective audit and feedback program in addition to pre-authorization led to a significant increase in concordance with hospital pneumonia guidelines, but no difference in secondary outcomes in our patient population.

Disclosures

M. V. Mahoney, Melinta Therapeutics: Consultant, Consulting fee. Cutis Pharma: Consultant, Consulting fee. Tetraphase Pharmaceuticals, Inc.: Consultant, Consulting fee. Roche Diagnostics USA: Consultant, Consulting fee. C. McCoy, Merck Inc: Scientific Advisor, Consulting fee. Allergan: Scientific Advisor, Consulting fee.

Clinical characteristics and treatment outcomes among respiratory syncytial virus (RSV)-infected hematologic malignancy and hematopoietic stem cell transplant recipients receiving palivizumab

Palivizumab has been used to treat respiratory syncytial virus (RSV)-infected hematologic malignancy patients at our institution based on limited published data. We conducted this retrospective study to evaluate clinical outcomes and mortality rates of RSV-infected hematologic malignancy patients from 2007 to 2016. A total of 67 patients (19 received palivizumab and 47 received supportive care) were identified. Palivizumab-treated patients had a significantly higher proportion of underlying ischemic heart disease, graft-versus-host-disease, hypogammaglobulinemia, and concomitant pulmonary infections. There were no significant differences in mortality rates or readmission rates between the two groups. The estimated odds ratio for death in patients receiving palivizumab after adjusting for propensity scores and covariates were 0.12 ([0.01, 1.32], p = .08) and 0.09 ([0.01, 1.03], p = .05) respectively. After adjustment for factors associated with severity of illness, there was no difference in mortality among patients treated with palivizumab.

Strength in Amalgamation: Newer Combination Agents for HIV and Implications for Practice

Antiretroviral (ART) therapy for the treatment of human immunodeficiency virus (HIV) infection has undergone significant changes over the past 30 years. Many single-tablet regimens (STRs), including newer fixed-dose combination (FDC) tablets, are available, offering patients several options for choosing a treatment regimen that works best for them. Given these changes, patients are more likely to adhere to treatment, achieve better clinical outcomes, and experience both fewer side effects and drug-drug interactions. Newer STRs include dolutegravir (DTG)/lamivudine (3TC)/abacavir (ABC) (Triumeq; Viiv Healthcare, Research Triangle Park, NC), rilpivirine (RPV)/emtricitabine (FTC)/tenofovir alafenamide (TAF) (Odefsey; Gilead, Foster City, CA), RPV/FTC/tenofovir disoproxil fumarate (TDF) (Complera; Gilead), elvitegravir (EVG)/cobicistat (COBI)/FTC/TDF (Stribild; Gilead), and EVG/COBI/FTC/TAF (Genvoya; Gilead). Recently approved FDCs, such as atazanavir (ATV)/COBI (Evotaz; Bristol-Myers Squibb, Princeton, NJ), darunavir (DRV)/COBI (Prezcobix; Janssen Products, Titusville NJ), and FTC/TAF (Descovy; Gilead), are also now available. The Department of Health and Human Services treatment guidelines for HIV recommend many of these integrase strand transfer inhibitor (INSTI) STRs as a preferred choice for initiation of treatment in both ART-naive and -experienced patients because they offer comparably faster rates of virologic suppression, reduced rates of resistance development (especially with DTG), and overall better adherence than protease inhibitors or NNRTIs. Numerous phase 3 clinical trials support these recommendations including several switch or simplification clinical trials. Notably, the novel pharmacokinetic booster COBI, with its water soluble properties, has enabled the development and coformulation of a few of these STRs and FDCs. Also, a newer tenofovir salt formulation, TAF, has an advantageous pharmacokinetic profile, contributing to better overall renal and bone tolerability compared with TDF. Further simplification regimens comprising dual ART therapies are currently being explored. This review provides an overview of the clinical efficacy and safety data for these coformulated agents, highlighting the relative impact on comparative adverse events, assessing the potential for experiencing fewer drug-drug interactions, and discussing the clinical implications regarding adherence to treatment.

Discordance of SHEA/IDSA Clostridium difficile Disease Severity Scale in Solid Organ Transplant Patients

Background

Solid organ transplant (SOT) patients are at high risk for Clostridium difficile infections (CDI) due to chronic immunosuppression and a propensity to receive antimicrobials. Management of CDI in SOT patients poses unique challenges as this population has disease-altered clinical and laboratory parameters. The objective of this study was to assess concordance between various CDI severity scales and the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America (SHEA/IDSA) guidelines.

Methods

This retrospective study included all SOT recipients with a first CDI episode following transplant and time-matched (2:1) to non-SOT patients experiencing first CDI episodes between 2008 and 2016. The primary endpoint was concordance rates of CDI episodes considered mild-moderate or severe/severe-complicated in published CDI scales compared with the SHEA/IDSA guidelines. We also sought to compare the distribution of CDI severity across all scales between SOT and non-SOT patients.

Results

Overall, 32 SOT patients and 64 non-SOT patients were included. The SOT group had significantly higher leukopenia rates at CDI diagnosis; however, the magnitude of serum creatinine change did not differ between groups. According to the SHEA/IDSA scale, CDI episodes in SOT recipients were categorized as mild-moderate and severe/severe-complicated in 23 (72%) and 9 (28%) patients, respectively. Overall concordance rates among SHEA/IDSA guidelines and other scales ranged from 28% to 72%. Concordance rates were highest for mild-moderate CDI with Belmares and for severe/severe-complicated CDI with ESCMID (Table 1). No scale evenly categorized SOT and non-SOT patients across all severities (Figure 1).

Conclusion

Severity scales with heavy emphasis on white blood cell counts may not adequately categorize SOT patients. Immunocompromised status may need to be considered on its own when categorizing CDI severity and prescribing therapy.

Disclosures

C. D. Alonso, Merck: Grant Investigator and Scientific Advisor, Research grant sanofi pasteur: Investigator and Scientific Advisor, Research support GSK: Investigator, Research support; E. B. Hirsch, Merck: Grant Investigator, Grant recipient The Medicines Company: Speaker’s Bureau, Speaker honorarium

Validation of an Empiric Candidemia Treatment Algorithm

Background

Judicious use of echinocandins may limit the development of resistance in Candida species. Guidelines endorse the use of echinocandins as initial therapy in candidemia, with fluconazole as an alternate choice in select patients. We compared the ability of providers to predict the need for echinocandin therapy in Candida bloodstream infections to that of a proposed institutional treatment algorithm designed to optimize empiric antifungal use.

Methods

In this retrospective study (10/2015–10/2016), patients were included with Candida isolated in ≥1 blood culture, without candidemia in the prior 14 days. Empiric treatment (the first antifungal prescribed for ≥24 hours after index blood culture draw) was considered “overly broad” if an echinocandin was administered to a fluconazole-susceptible isolate and “inappropriate” if fluconazole was administered to a fluconazole-non-susceptible isolate. An institutional algorithm was created recommending empiric echinocandin use based on the presence of ≥1 risk factors (Table 1). Provider choice and the recommended agent according to the algorithm were compared with the final fluconazole susceptibility of the organism.

Results

Among 65 episodes of candidemia, the majority of isolates were C. glabrata (Figure 1). Ninety-one percent of patients received non-azole therapy, primarily micafungin. Fluconazole was recommended by the algorithm in 25% of cases but initially prescribed in only 9% (Figure 2). Providers prescribed both overly broad and inappropriate treatment at a higher rate than algorithm recommendations (Figure 3).

Conclusion

An algorithm using risk factors for fluconazole-non-susceptible Candida was able to predict appropriate empiric antifungal therapy better than provider decision making in cases of candidemia. Implementation of this algorithm into local treatment guidelines may improve empiric antifungal prescribing.

Disclosures

All authors: No reported disclosures.

Incidental Pulmonary Nodules Reported on CT Abdominal Imaging: Frequency and Factors Affecting Inclusion in the Hospital Discharge Summary

Incidental imaging findings require an assessment of risk and clinical relevance, as well as consideration of further evaluation. Incidental findings are common on imaging obtained in the hospital, with pulmonary nodules being among the most frequent findings that may require additional evaluation. We conducted a retrospective study to determine the factors associated with documentation of incidental findings in the hospital discharge summary, using pulmonary nodules reported on abdominal computed tomography (CT) as an example of incidental findings with well-defined follow-up guidelines. Between January 1, 2012 and December 31, 2014, 7173 patients underwent in-patient abdominal CT without concurrent chest CT; of these patients, 62.2% were ≥60 years old, 50.6% were men, and 45.5% were current or former smokers. Incidental pulmonary nodules were reported in 402 patients (5.6%; 95% confidence interval [CI], 5.1%-6.2%). Based on nodule size, reported size stability, and patients' smoking status, 208 patients (2.9%; 95% CI, 2.5%-3.3%) required follow-up surveillance, per the 2005 Fleischner Society guidelines. Of these 208 patients, 48 (23%) received discharge summaries that included documentation of the incidental findings, with 34 summaries including a recommendation for nodule follow-up and 19 summaries including a time frame for repeat CT. Three factors were positively associated with the inclusion of the pulmonary nodule in the discharge summary: mention of the pulmonary nodule in the summary headings of the radiology report (P ≤ 0.001), radiologist recommendations for further surveillance (P ≤ 0.001), and medical discharging service (P = 0.016). These findings highlight the need for a multidisciplinary systems-based approach to incidental pulmonary nodule documentation and surveillance. Journal of Hospital Medicine 2017;12:454-457.

Bezlotoxumab: Could This be the Answer for Clostridium difficile Recurrence?

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, safety, and place in therapy of bezlotoxumab (BEZ), a novel monoclonal antibody against Clostridium difficile toxin B.

DATA SOURCES

A PubMed search was conducted for data between 1946 and April 2017 using MeSH terms bezlotoxumab, MK-6072, or MDX-1388 alone and the terms Clostridium difficile combined with monoclonal antibody or antitoxin.

STUDY SELECTION AND DATA EXTRACTION

The literature search was limited to English-language studies that described clinical efficacy, safety, and pharmacokinetics in humans and animals. Abstracts featuring prepublished data were also evaluated for inclusion.

DATA SYNTHESIS

BEZ is indicated for adult patients receiving standard-of-care (SoC) antibiotics for C difficile infection (CDI) to prevent future recurrence. Two phase III trials-MODIFY I (n = 1452) and MODIFY II (n = 1203)-demonstrated a 40% relative reduction in recurrent CDI (rCDI) with BEZ compared with placebo (16.5% vs 26.6%, P < 0.0001). The most common adverse drug events associated with BEZ were mild to moderate infusion-related reactions (10.3%).

CONCLUSIONS

In patients treated with SoC antibiotics, BEZ is effective in decreasing rCDI. BEZ has no apparent effect on treatment of an initial CDI episode. In light of increasing rates of CDI, BEZ is a promising option for preventing recurrent episodes. The greatest benefit has been demonstrated in high-risk patients, though the targeted patient population is yet to be defined.

Invitro Apramycin Activity against multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa

The in vitro activity of apramycin was compared to that of amikacin, gentamicin, and tobramycin against multidrug-resistant, extensively drug-resistant, and pandrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa. Apramycin demonstrated an MIC₅₀/MIC₉₀ of 8/32μg/ml for A. baumannii and 16/32μg/ml for P. aeruginosa. Only 2% of A. baumannii and P. aeruginosa had an MIC greater than an epidemiological cutoff value of 64μg/ml. In contrast, the MIC₅₀/MIC₉₀ for amikacin, gentamicin, and tobramycin were ≥64/>256μg/ml for A. baumannii with 57%, 95%, and 74% of isolates demonstrating resistance, respectively, and the MIC₅₀/MIC₉₀ were ≥8/256μg/ml for P. aeruginosa with 27%, 50%, and 57% of strains demonstrating resistance, respectively. Apramycin appears to offer promising in vitro activity against highly resistant pathogens. It therefore may warrant further pre-clinical study to assess potential for repurposing as a human therapeutic and relevance as a scaffold for further medicinal chemistry exploration.

Assessment of Fosfomycin for Complicated or Multidrug-Resistant Urinary Tract Infections: Patient Characteristics and Outcomes

BACKGROUND

Bacterial resistance among uropathogens is on the rise and has led to a decreased effectiveness of oral therapies. Fosfomycin tromethamine (fosfomycin) is indicated for uncomplicated urinary tract infections (UTIs) and displays in vitro activity against multidrug-resistant (MDR) isolates; however, clinical data assessing fosfomycin for the treatment of complicated or MDR UTIs are limited.

METHODS

We conducted a retrospective evaluation of patients who received ≥1 dose of fosfomycin between January 2009 and September 2015 for treatment of a UTI. Patients were included if they had a positive urine culture and documented signs/symptoms of a UTI.

RESULTS

Fifty-seven patients were included; 44 (77.2%) had complicated UTIs, 36 (63.2%) had MDR UTIs, and a total of 23 (40.4%) patients had a UTI that was both complicated and MDR. The majority of patients were female (66.7%) and elderly (median age, 79 years). Overall, the most common pathogens isolated were Escherichia coli (n = 28), Enterococcus spp. (n = 22), and Pseudomonas aeruginosa (n = 8). Twenty-eight patients (49.1%) were clinically evaluable; the preponderance achieved clinical success (96.4%). Fifteen out of 20 (75%) patients with repeat urine cultures had a microbiological cure.

CONCLUSIONS

This retrospective study adds to the limited literature exploring alternative therapies for complicated and MDR UTIs with results providing additional evidence that fosfomycin may be an effective oral option.

Clinical pathway for moderate to severe acute bacterial skin and skin structure infections from a US perspective: a roundtable discussion

This article was written with the aim to establish a consensus clinical pathway for long-acting lipoglycopeptide antibiotics such as oritavancin (Orbactiv®) and dalbavancin (Dalvance®) for the treatment of acute bacterial skin and skin structure infections (ABSSSI). Seven infectious diseases pharmacy specialists from a variety of facilities across the United States (US) participated in a roundtable discussion to consider the use of newer single-dose long-acting lipoglycopeptides, and integrate them into clinical pathways for ABSSSI. They identified two ways of treating with these drugs: first, to facilitate discharge from the hospital by switching from initial therapy (e.g., with intravenous (IV) vancomycin) and second, to avoid hospital admission altogether, since the product can be administered in several outpatient settings of care including the emergency department (ED), observation unit (OU) or outpatient infusion center. The participants used existing literature on classification and treatment of ABSSSI and their experience in the clinical setting as bases for their discussion and came to a consensus on the considerations for patient inclusion and exclusion as well as a pathway for outpatient treatment with long-acting lipoglycopeptides. As a result of the discussion, we concluded that the current treatment paradigm for ABSSSI is ripe for re-evaluation and reconfiguration in order to more closely align with the changing healthcare landscape. Hospital stakeholders are constantly searching for new strategies that can improve quality of care while simultaneously reducing overall expenses. The availability of single-dose long-acting lipoglycopeptides is an opportunity to opt for lower-cost outpatient treatment of appropriate ABSSSI patients. This article proposes the inclusion and exclusion considerations, along with a consensus treatment pathway, that could provide a solid foundation for facilities to construct and adapt their own effective clinical pathways for ABSSSI.

Evaluation of mobilized peripheral blood CD34(+) cells from patients with severe coronary artery disease as a source of endothelial progenitor cells

BACKGROUND AIMS

The distinction between hematopoietic stem cells (HSC) and endothelial progenitor cells (EPC) is poorly defined. Co-expression of CD34 antigen with vascular endothelial growth factor (VEGF) receptor (VEGFR2) is currently used to define EPC ( 1 ).

METHODS

We evaluated the phenotypic and genomic characteristics of peripheral blood-derived CD34(+) cells in 22 granulocyte-colony-stimulating factor (G-CSF)-mobilized patients with severe coronary artery disease and assessed the influence of cell selection and storage on CD34(+) cell characteristics.

RESULTS

The median CD34(+) cell contents in the products before and after enrichment with the Isolex 300i Magnetic Cell Selection System were 0.2% and 82.5%, respectively. Cell-cycle analysis showed that 80% of CD34(+) cells were in G0 stage; 70% of the isolated CD34(+) cells co-expressed CD133, a marker for more immature progenitors. However, less than 5% of the isolated CD34(+) cells co-expressed the notch receptor Jagged-1 (CD339) and only 2% of the isolated CD34(+) population were positive for VEGFR2 (CD309). Molecular assessment of the isolated CD34(+) cells demonstrated extremely low expression of VEGFR2 and endothelial nitric oxide synthase (eNOS) and high expression of VEGF-A. Overnight storage at 4 degrees C did not significantly affect CD34(+) cell counts and viability. Storage in liquid nitrogen for 7 weeks did not affect the percentage of CD34(+) cells but was associated with a 26% drop in cell viability.

CONCLUSIONS

We have demonstrated that the majority of isolated CD34(+) cells consist of immature and quiescent cells that lack prototypic markers of EPC. High VEGF-A gene expression might be one of the mechanisms for CD34(+) cell-induced angiogenesis.

Clinically significant adverse events from a drug interaction between quetiapine and atazanavir-ritonavir in two patients

Clinicians caring for patients infected with the human immunodeficiency virus (HIV) and diagnosed with psychiatric comorbidities must be aware of potential drug-drug interactions, particularly with protease inhibitor-based antiretroviral therapy. Although possible interactions can be predicted based on a drug's pharmacokinetic parameters, the clinical significance is often unknown. We describe two patients who experienced serious quetiapine adverse effects potentially mediated through an interaction with ritonavir-boosted atazanavir. The first patient was a 57-year-old man with HIV and bipolar disease who developed rapid and severe weight gain when quetiapine was added to a stable atazanavir-ritonavir-based antiretroviral regimen. After the patient discontinued both quetiapine and ritonavir, his weight returned to its baseline value. The second patient was a 32-year-old woman with HIV, anxiety disorder, and a history of intravenous drug abuse who developed increased sedation and mental confusion when an atazanavir-ritonavir-based antiretroviral regimen was added to her stable antianxiety drug regimen, which included quetiapine. Her symptoms resolved promptly after discontinuation of the quetiapine. Use of the Naranjo adverse drug reaction probability scale indicated that the adverse effects experienced by the two patients were possibly related and probably related, respectively, to an interaction between quetiapine and atazanavir-ritonavir. Quetiapine is primarily metabolized by cytochrome P450 (CYP) 3A4, and ritonavir is a potent inhibitor of CYP3A4. Thus, it is reasonable to theorize that quetiapine concentrations will increase when these drugs are used concurrently, which would be the likely cause of the toxicities in these two patients. To our knowledge, these are the first published reports of a clinically significant interaction between atazanavir-ritonavir and quetiapine. Clinicians should be aware of the potential for this interaction, and extreme caution should be used when prescribing quetiapine and other atypical antipsychotic agents in HIV-positive patients who are receiving antiretroviral therapy.

Flea blood feeding patterns in cats treated with oral nitenpyram and the topical insecticides imidacloprid, fipronil and selamectin

A series of studies was conducted to determine the effect of systemically and topically active insecticides on blood consumption by fleas (Ctenocephalides felis). Infestations were conducted by placing fleas into plexi-glass chambers attached to the lateral rib cage of domestic short-hair cats. After pre-defined periods, fleas and flea feces were extracted using vacuum aspiration and spectrophotometrically analyzed for hemoglobin using Drabkin's reagent. To determine how rapidly nitenpyram kills actively feeding fleas, a single oral treatment was administered 24h after infestation. To determine the effect of nitenpyram on blood consumption of newly acquired fleas, cats were infested with fleas 1h post-treatment and fleas and flea feces from both studies were extracted at 15, 30, 60, 120, 240 and 480min post-treatment or post-infestation. To compare the effects of topically versus systemically active insecticides, 20 cats each with 2 chambers attached, were randomly allocated among groups and were infested with fleas 1h after each of 4 nitenpyram treatments, or at 7, 14, 21 and 28 days after a single application of commercial spot-on formulations of fipronil, imidacloprid or selamectin. Infestations were also completed for untreated (control) cats. Twenty-four hours after infestation, fleas and flea feces were removed for host blood quantification. If at any time, flea blood consumption in a treated group did not significantly differ from that of fleas infesting controls, that treatment group was withdrawn from the study. Nitenpyram effects on actively feeding fleas were first observed at 60min post-dosing when 38% of fleas were dead or moribund, and at 240min 100% were dead or moribund. Nitenpyram produced a significant reduction in flea blood consumption (p<0.05), which appeared to cease 15min after infestation. For the treatment comparisons, significantly more (p<0.05) blood was consumed by fleas taken from imidacloprid and fipronil-treated cats than from the nitenpyram or selamectin groups. Only on nitenpyram- or selamectin-treated cats were there significant reductions (p<0.05) in flea blood consumption on days 21 and 28, with significant difference (p>0.05) between these two groups on day 28. In this study systemically acting insecticides such as nitenpyram, and the topically applied but systemically active insecticide selamectin, were more effective in interfering with flea blood feeding than were imidacloprid and fipronil.

Darunavir: a nonpeptidic antiretroviral protease inhibitor

BACKGROUND

Protease inhibitors were a major therapeutic breakthrough in the mid-1990s for the treatment of HIV infection, which resulted in improved life expectancy for patients who had failed previous therapies. With time and evolution of the virus, however, there is a new population of patients with treatment-resistant disease and few treatment options. Darunavir is a synthetic nonpeptidic analogue of amprenavir with enhanced activity against resistant virus that became available in 2006.

OBJECTIVES

The purpose of this review was to describe the clinical pharmacology, pharmacokinetic and pharmacodynamic properties, and clinical efficacy of darunavir. Also discussed are the published clinical experience with darunavir, its adverse events, drug interactions, pharmacoeconomics, and dosing and administration.

METHODS

A MEDLINE and EMBASE search (English-language only) was performed from January 1996 through April 2007 using the key words darunavir and TMC114. Abstracts from relevant scientific meetings were searched for the years 2000 through 2007. Additionally, the US Food and Drug Administration Web site was accessed to review the new drug application summary and data presented therein.

RESULTS

Darunavir was found to maintain antiretroviral activity against HIV with protease inhibitor mutations in 6 studies. Clinical efficacy and safety data are limited to 4 controlled and 2 uncontrolled trials. In 2 large Phase IIb clinical studies, viral suppression at 48 weeks to undetectable levels in heavily pretreated patients was achieved in 45% of patients compared with 10% of patients in the control group (P < 0.001). The addition of enfuvirtide enhanced this response rate to 58% compared with 11% of the patients who did not receive enfuvirtide (P < 0.001). Gastrointestinal symptoms, nausea, and headache were the most commonly reported events.

CONCLUSIONS

Darunavir has improved activity against resistant HIV isolates in patients with few treatment choices, particularly when enfuvirtide is added. The safety profile of darunavir is comparable to other protease inhibitors based on early data.

Phase I dose-escalation study of novel oral multi-target tumor growth inhibitor (MTGI) ZK 304709 administered daily for 7 days of a 21-day cycle to patients with advanced solid tumors

2073

Background: ZK304709 is a novel MTGI that selectively inhibits activity of Cyclin Dependent Kinases (CDKs) 1, 2, 4, 7, 9, and the tyrosine kinase activity of VEGF-R 1, 2, 3 and PDGF-βR. Methods: Adult patients (pts) with a good performance status (WHO PS ≤2) and a histologically or cytologically confirmed relapsed/refractory solid tumor were eligible. ZK304709 is administered, as a monotherapy, orally on days 1–7 of a 21-day cycle to fasting patients at a starting dose of 15 mg qd. Dose escalation has ranged from 33% - 100% of prior dose, depending on occurrence of drug-related toxicity ≥ grade (gr) 2 (CTC v2.0). Between 3 and 7 patients are to be enrolled per dose level, depending on DLTs that are observed. The primary objective is determination of the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT) of ZK304709. Secondary objectives include tolerability, pharmacokinetic (PK) profile, and preliminary efficacy. Results: Interim results are available for 22 pts (15 M/7 F, median age 60.5 yrs; range 37–71) treated with ZK304709 at 6 dose levels (15 - 180 mg qd). Patients completed a median of 2 cycles (range 0–8). Common AEs were nausea, vomiting, diarrhea, and lethargy. Two DLT were observed: supraventricular tachycardia and vomiting, but the MTD was not reached. The PK profile shows rapid absorption, with a Tmax of 2–4 hrs, and a dose-dependent increase in systemic exposure over the 15–90 mg dose range. Disease stabilization for ≥4 cycles has been observed. Conclusions: ZK304709 is rapidly absorbed and has been tolerated on this schedule at doses up to 180 mg qd. The MTD has not been reached, and enrolment is ongoing. These preliminary data demonstrate that oral delivery on this schedule of an agent that inhibits both cell cycle and angiogenesis is feasible.

[Table: see text]

Phase I dose-escalation study of ZK 304709, an oral multi-target tumor growth inhibitor (MTGI), administered for 14 days of a 28-day cycle

2076

Background: ZK 304709 is a novel oral MTGI that induces cell cycle arrest and inhibits tumour angiogenesis by selectively inhibiting Cyclin Dependent Kinases (CDKs) 1, 2, 4, 7 and 9,VEGF-R 1, 2 and 3, and PDGF-Rβ tyrosine kinases. Methods: Adult patients (pts) (WHO PS ≤2) with a histologically or cytologically confirmed solid tumor, resistant or refractory to conventional therapy, were eligible. ZK304709 was administered orally, once daily, at a 15 mg starting dose, on days 1–14 of a 28-day cycle, then escalated by 33–100% depending on incidence of drug-related toxicity ≥ grade (gr) 2 (CTC v2.0). At least 3 pts were treated at each dose level. The primary objective was to identify the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT). Secondary objectives were to determine the tolerability, pharmacokinetic (PK) profile, and preliminary efficacy. Results: Interim results were available for 24 pts (19 M/5 F; median age 56.5) at 5 dose levels (15–120 mg qd). Pts received a median of 2 cycles (range 0–10). Common drug related toxicities were nausea, vomiting, and fatigue. Two DLT were observed: dizziness and hypertension. However, the MTD has yet to be established. The PK profile for dose levels up to 90 mg demonstrated rapid absorption and a dose-dependent increase of exposure and Cmax. Disease stabilization for ≥4 cycles has been observed. Conclusions: ZK 304709 was rapidly absorbed and has been tolerated on this schedule at up to 120 mg qd. The MTD has not been reached and enrolment is ongoing. These preliminary data demonstrate that oral delivery on this schedule of an agent that inhibits both cell cycle and angiogenesis is feasible.

[Table: see text]