Population pharmacokinetics of daptomycin in critically ill patients receiving extracorporeal membrane oxygenation.

BACKGROUND: Daptomycin is widely used in critically ill patients for Gram-positive bacterial infections. Extracorporeal membrane oxygenation (ECMO) is increasingly used in this population and can potentially alter the pharmacokinetic (PK) behaviour of antibiotics. However, the effect of ECMO has not been evaluated in daptomycin. Our study aims to explore the effect of ECMO on daptomycin in critically ill patients through population pharmacokinetic (PopPK) analysis and to determine optimal dosage regimens based on both efficacy and safety considerations. METHODS: A prospective, open-label PK study was carried out in critically ill patients with or without ECMO. The total concentration of daptomycin was determined by UPLC-MS/MS. NONMEM was used for PopPK analysis and Monte Carlo simulations. RESULTS: Two hundred and ninety-three plasma samples were collected from 36 critically ill patients, 24 of whom received ECMO support. A two-compartment model with first-order elimination can best describe the PK of daptomycin. Creatinine clearance (CLCR) significantly affects the clearance of daptomycin while ECMO has no significant effect on the PK parameters. Monte Carlo simulations showed that, when the MICs for bacteria are  ≥1 mg/L, the currently recommended dosage regimen is insufficient for critically ill patients with CLCR > 30 mL/min. Our simulations suggest 10 mg/kg for patients with CLCR between 30 and 90 mL/min, and 12 mg/kg for patients with CLCR higher than 90 mL/min. CONCLUSIONS: This is the first PopPK model of daptomycin in ECMO patients. Optimal dosage regimens considering efficacy, safety, and pathogens were provided for critical patients based on pharmacokinetic-pharmacodynamic analysis.

Daptomycin Dose Optimization in Pediatric Staphylococcus aureus Bacteremia: A Pharmacokinetic/Pharmacodynamic Investigation.

Daptomycin is an antibiotic with Gram-positive activity, including methicillin-resistant Staphylococcus aureus, for which optimal pediatric dosing is unknown. This study aimed to evaluate daptomycin exposures achieved with package label dosing and to identify dosing regimens necessary to enhance efficacy and minimize toxicity in children with S. aureus bacteremia. Monte Carlo simulations were performed to determine probability of target attainment (PTA) for six pediatric age cohorts. Area under the curve to minimum inhibitory concentration ratio (AUC0-24:MIC) ≥666 was used to determine the PTA for efficacy (PTAE). Minimum concentration (Cmin) ≥24.3 mg/L determined the PTA for toxicity (PTAT). Acceptable dosing regimens were those which achieved the combined target of ≥90% PTAE and ≤5% PTAT. Package label dosing of daptomycin yielded insufficient efficacy with only 26.3% PTAE in children 13-24 months, 39.5% PTAE in children 2-6 years, 30.1% PTAE in children 7-11 years, and 50.1% PTAE in adolescents ≥12 years. To achieve the combined efficacy and safety target, doses of 18-24 mg/kg in children 3-12 months, 20-24 mg/kg in children 13-24 months, 19-24 mg/kg in children 2-6 years, 17-19 mg/kg in children 7-11 years, and 10-14 mg/kg in adolescents ≥12 years are necessary. Package label dosing resulted in suboptimal exposure for the majority of pediatric patients in all age groups evaluated. If targeting validated efficacy and safety endpoints, daily daptomycin doses of at least 20 mg/kg in children ≤6 years, 17 mg/kg in children 7-11 years, and 10 mg/kg in adolescents ≥12 years are necessary. Clinical studies evaluating these higher doses are needed.

Optimization of dosing regimens of vancomycin, teicoplanin, linezolid and daptomycin against methicillin-resistant Staphylococcus aureus in neutropenic patients with cancer by Monte Carlo simulations.

The objective of this study was to evaluate the efficacy of various dosing regimens of vancomycin, teicoplanin, linezolid and daptomycin against methicillin-resistant Staphylococcus aureus (MRSA) in neutropenic patients with cancer. Monte Carlo simulations were conducted using pharmacokinetic parameters and pharmacodynamic data to determine cumulative fraction of response (CFRs) in terms of area under the concentration-time curve/minimum inhibition concentration target. Currently clinical standard dosing regimens of vancomycin, teicoplanin, linezolid and daptomycin were insufficient to provide expected CFRs against MRSA for neutropenic patients with cancer. The high dosing regimens of vancomycin (3500 mg/d), teicoplanin (800 mg/d) and daptomycin (8 mg/kg/d) could provide CFRs of ≥ 80%, showing a higher treatment success. However, the majority of CFRs with linezolid simulated dosing regimens reached < 80% against MRSA. Therefore, a strategy of high dosages of vancomycin, teicoplanin and daptomycin may be needed to attain optimal therapeutic efficacy against MRSA in neutropenic patients with cancer.

Population Pharmacokinetic Analysis and Dosing Optimization Based on Unbound Daptomycin Concentration and Cystatin C in Nonobese Elderly Patients with Hypoalbuminemia and Chronic Kidney Disease.

PURPOSE: This study evaluated the population pharmacokinetics of daptomycin in nonobese elderly patients with hypoalbuminemia and chronic kidney disease (CKD) using the glomerular filtration rate estimated from cystatin C (eGFRcys) and estimated its optimal dose. METHODS: We performed population pharmacokinetic analysis of the unbound concentrations of daptomycin. The probability of target attainment of 90% for achieving an area under the concentration-time curve of unbound daptomycin at steady state/ minimum inhibitory concentration ratio of ≥66.6 was stochastically simulated. RESULTS: In the population pharmacokinetic analysis of 25 patients aged ≥65 years, the two-compartment model using eGFRcys and age as covariates of clearance in central compartment of unbound daptomycin were optimal. The unbound fraction rate (fu) was 0.05-0.14. According to the Monte Carlo simulation, the optimal doses for patients with eGFRcys of 20-60 mL/min and aged 65-95 years were calculated as 200-500 mg q24h. CONCLUSION: These results suggest that establishing the dose using total concentrations may result in under- or overestimation caused by alterations in fu. The optimal dose for nonobese elderly patients with hypoalbuminemia and CKD depends on eGFRcys and age, and a standard dose may be insufficient for some patients.

Assessment of invitrosynergy of daptomycin or vancomycin plus ceftaroline for daptomycin non-susceptible Staphylococcus aureus.

The combination of vancomycin or daptomycin plus ceftaroline has showed synergistic results in vitro. This study aimed to investigate in vitro synergy of vancomycin or daptomycin plus ceftaroline for seven patients with daptomycin non-susceptible Staphylococcus aureus (SA) bacteremia Thirteen isolates from seven patients were evaluated: two methicillin-susceptible and five methicillin-resistant SA infections. All patients were treated with daptomycin and became non-susceptible (minimum inhibitory concentration (MIC) >1 µg/mL) with therapy or had resistant strains initially. Time kill experiments were completed with 0.25 × MIC, 0.5 × MIC, and 0.75 × MIC concentrations. No synergy was seen at 0.25 × MIC. Synergy was observed for 4 isolates with vancomycin plus ceftaroline and with daptomycin plus ceftaroline for 2 isolates at 0.5 × MIC. These results are in accordance with literature that supports synergistic combinations of daptomycin or vancomycin with ceftaroline for SA bacteremia. Daptomycin non-susceptible SA bacteremia presents a treatment challenge.

Pharmacokinetic/Pharmacodynamic Analysis of Daptomycin Against Staphylococcus aureus and Enterococcus faecium in Pediatric Patients by Monte Carlo Simulation.

The objective of this study was to evaluate the efficacy of various daptomycin dosing regimens against Staphylococcus aureus and Enterococcus faecium in pediatric patients with proven/suspected gram-positive infection. Monte Carlo simulations (MCSs) were conducted using pharmacokinetic (PK) parameters and pharmacodynamic (PD) data to determine the probabilities of target attainment and cumulative fractions of response in terms of area under the concentration curve/minimum inhibition concentration (MIC) targets of daptomycin. According to the results of the MCSs, currently approved pediatric dosage regimens were sufficient against Staphylococcus aureus with MIC ≤ 0.5 µg/mL for all pediatric patients, but poor when MIC ≥ 1 µg/mL except for adolescents (12-17 years) who need a dosage of ≥10 mg/kg/day at MIC = 1 µg/mL. For Enterococcus faecium with MIC ≤ 4 µg/mL, the recommended dosage of 8-12 mg/kg/day in adults was enough for adolescents, but not subjected to younger pediatric patients. Furthermore, based on MIC distributions obtained from the European Committee on Antimicrobial Susceptibility Testing, the approved high-dose regimen should be recommended for infants aged 3-12 months, children (2-11 years), and adolescents to achieve better clinical efficacy against methicillin-resistant Staphylococcus aureus. In addition, the dosage of 8-12 mg/kg/day was powerful against Enterococcus faecium for adolescents; however, only the highest dosage of 12 mg/kg/day was effective for infants aged 3-12 months and children. All the simulated regimens were not optimal for infants aged 13-24 months. These PK/PD-based simulations rationalize and optimize the dosage regimens of daptomycin against Staphylococcus aureus and Enterococcus faecium in pediatric patients.

Population pharmacokinetics and dosing considerations for the use of daptomycin in adult patients with haematological malignancies.

Objectives: To assess the population pharmacokinetics (popPK) of daptomycin at the conventional dose of 6 mg/kg/day in a cohort of oncohaematological patients. Methods: Patients underwent serial blood sampling on day 3 of therapy (before dosing and at 0, 0.5, 1, 2, 3, 5, 7, 9 and 12 h after dosing) to assess the pharmacokinetic profile of daptomycin. PopPK and Monte Carlo simulation were performed to define the probability of target attainment (PTA) with 6, 8, 10 and 12 mg/kg/day of the pharmacokinetic/pharmacodynamic target of AUC 24 /MIC >1081. Results: Thirty patients were recruited. A two-compartment open model with first-order intravenous input and first-order elimination was developed. Estimated creatinine clearance (CL CR ), serum albumin concentration (Alb) and presence of AML were covariates included in the final model. Monte Carlo simulation showed that the conventional 6 mg/kg/day dose resulted in optimal PTAs (≥80%) in the presence of pathogens with an MIC up to 0.5 mg/L only in patients with CL CR 50-100 mL/min/1.73 m 2 , Alb 26-45 g/L and a haematological diagnosis other than AML. Conversely, higher dosages, up to 12 mg/kg/day, were needed to achieve this goal in the presence of pathogens with an MIC of 0.25-0.5 mg/L in all of the other tested scenarios. In patients with CL CR 101-150 mL/min/1.73 m 2 and Alb 15-25 g/L, suboptimal PTAs (<60%) were predicted even with 12 mg/kg/day dosing . Conclusions: Our study provides a strong rationale for considering daptomycin dosages of ≥ 8 mg/kg/day in several clinical scenarios for oncohaematological patients. In some of these scenarios therapeutic drug monitoring could be a useful adjunct for optimized care.

Implementing an intensified antibiotic stewardship programme targeting daptomycin use in orthopaedic surgery: a cost-benefit analysis from the hospital perspective.

BACKGROUND: Hospital antibiotic stewardship (ABS) programmes offer several evidence-based tools to control prescription rates of antibiotics in different settings, influence the incidence of nosocomial infections and to contain the development of multi-drug-resistant bacteria. In the context of endoprosthetic surgery, however, knowledge of core antibiotic stewardship strategies, comparisons of costs and benefits of hospital ABS programmes are still lacking. MATERIALS AND METHODS: We identified a high daptomycin use for the treatment of methicillin-sensitive staphylococcal infections as a potential target for our ABS intervention. In addition, we endorsed periprosthetic tissue cultures for the diagnosis of PJI. Monthly antibiotic use data were obtained from the hospital pharmacy and were expressed as WHO-ATC defined daily doses (DDD) and dose definitions adapted to local guidelines (recommended daily doses, RDD), normalized per 1000 patient days. The pre-intervention period was defined from February 2012 through January 2014 (24 months). The post-intervention period included monthly time points from February 2014 to April 2015 (15 months). For a basic cost-benefit analysis from the hospital perspective, three cost drivers were taken into account: (1) the cost savings due to changes in antimicrobial prescribing; (2) costs associated with the increase in the number of cultured tissue samples, and (3) the appointment of an infectious disease consultant. Interrupted time-series analysis (ITS) was applied. RESULTS: Descriptive analysis of the usage data showed a decline in overall use of anti-infective substances in the post-intervention period (334.9 vs. 221.4 RDDs/1000 patient days). The drug use density of daptomycin dropped by -75 % (51.7 vs. 12.9 RDD/1000 patient days), whereas the utilization of narrow-spectrum penicillins, in particular flucloxacillin, increased from 13.8 to 33.6 RDDs/1000 patient days. ITS analysis of the consumption dataset showed significant level changes for overall prescriptions, as well as for daptomycin (p < 0.001) and for narrow-spectrum penicillins (p = 0.001). The total costs of antibiotic consumption decreased by an estimated € 4563 per month (p < 0.001), and around 90 % of these savings were linked to a decrease in daptomycin consumption. Overall, the antibiotic stewardship programme was beneficial, as monthly cost savings of € 2575 (p = 0.005) were achieved. INTERPRETATION: In this example of large endoprosthetic surgery department in a community-based hospital, the applied hospital ABS programme targeting daptomycin use has shown to be feasible, effective and beneficial compared to no intervention.

Statins and daptomycin: safety assessment of concurrent use and evaluation of drug interaction liability.

BACKGROUND: Acute muscle injury and potentially fatal rhabdomyolysis may occur with use of statins and certain interacting medications. This investigation assessed risk for myopathy in patients receiving treatment with a statin in combination with daptomycin, a medication also associated with muscle injury. METHODS: Patients hospitalized from July 1, 2005, through June 30, 2010, who received simvastatin or rosuvastatin concurrently with daptomycin were identified and their medical records were examined. Patients were judged to have treatment-related muscle injury if their records contained evidence of myalgia with or without weakness and secondarily impaired mobility together with elevated creatine kinase (CK) levels. These assessments were compared with similar data from hospitalized patients who received a statin alone. RESULTS: A total of 52 patients received 66 courses of concurrent treatment with simvastatin or rosuvastatin and daptomycin. Of these, no patient (0%) met evidentiary requirements for diagnosis of myopathy or related complications. No patient (0%) developed muscle pain or discomfort and none developed markedly elevated CK levels. The incidence of asymptomatic elevations of CK in these simvastatin or rosuvastatin plus daptomycin recipients (9%) was statistically indistinguishable from the incidence of CK elevations found in a cohort of 105 inpatients who received simvastatin or rosuvastatin alone (21%; p=0.135). CONCLUSIONS: In patients receiving treatment with simvastatin or rosuvastatin and daptomycin, no symptoms or objective evidence of muscle injury attributable to a drug interaction were identified. These findings are consistent with data indicating that the myopathic effects of statins and daptomycin are incited by disparate and perhaps unique pharmacological mechanisms. Risk of muscle injury therefore appears to be no greater when a statin is administered with daptomycin than when either medication is used alone.

Treatment of methicillin-resistant Staphylococcus aureus infections with a minimal inhibitory concentration of 2 µg/mL to vancomycin: old (trimethoprim/sulfamethoxazole) versus new (daptomycin or linezolid) agents.

BACKGROUND: Guidelines recommend that agents other than vancomycin be considered for some types of infection due to methicillin-resistant Staphylococcus aureus (MRSA) when the minimum inhibitory concentration (MIC) to vancomycin is 2 µg/mL or more. Alternative therapeutic options include daptomycin and linezolid, 2 relatively new and expensive drugs, and trimethoprim/sulfamethoxazole (TMP/SMX), an old and inexpensive agent. OBJECTIVE: To compare the clinical efficacy and potential cost savings associated with use of TMP/SMX compared to linezolid and daptomycin. METHODS: A retrospective study was conducted at Detroit Medical Center. For calendar year 2009, unique adults (age >18 years) with infections due to MRSA with an MIC to vancomycin of 2 µg/mL were included if they received 2 or more doses of TMP/SMX and/or daptomycin and/or linezolid. Data were abstracted from patient charts and pharmacy records. RESULTS: There were 328 patients included in the study cohort: 143 received TMP/SMX alone, 89 received daptomycin alone, 75 received linezolid alone, and 21 patients received a combination of 2 or more of these agents. In univariate analysis, patients who received TMP/SMX alone had significantly better outcomes, including in-hospital (p = 0.003) and 90-day mortality (p < 0.001) compared to patients treated with daptomycin or linezolid. Patients receiving TMP/SMX were also younger (p < 0.001), had fewer comorbid conditions (p < 0.001), had less severe acute severity of illness (p < 0.001), and received appropriate therapy more rapidly (p = 0.001). In multivariate models the association between TMP/SMX treatment and mortality was no longer significant. Antimicrobial cost savings associated with using TMP/SMX averaged $2067.40 per patient. CONCLUSIONS: TMP/SMX monotherapy compared favorably to linezolid and daptomycin in terms of treatment efficacy and mortality. Use of TMP/SMX instead of linezolid or daptomycin could potentially significantly reduce antibiotic costs. TMP/SMX should be considered for the treatment of MRSA infection with MIC of 2 µg/mL to vancomycin.

Pharmacokinetics and pharmacodynamics of intravenous daptomycin during continuous ambulatory peritoneal dialysis.

BACKGROUND AND OBJECTIVES: This study sought to (1) characterize the pharmacokinetic (PK) profile of intravenous (i.v.) daptomycin among patients receiving continuous ambulatory peritoneal dialysis (CAPD); (2) identify optimal i.v. CAPD dosing schemes; and (3) determine extent of daptomycin penetration into the peritoneal space after i.v. administration. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A PK study was conducted among eight CAPD patients. Population PK modeling and Monte Carlo simulation (MCS) were used to identify CAPD dosing schemes providing efficacy and toxicity plasma profiles comparable with those obtained from MCS using the daptomycin population PK model derived from patients in the Staphylococcus aureus bacteremia-infective endocarditis (SAB-IE) study. The primary efficacy exposure target was the area under the curve (AUC). For toxicity, the goal was to identify CAPD dosing schemes that minimized plasma trough concentrations in excess of 24.3 mg/L. Finally, peritoneal cavity penetration was determined. RESULTS: Administration of i.v. daptomycin 4 or 6 mg/kg, depending on indication, every 48 h was identified as the optimal CAPD dosing scheme. This regimen provided cumulative (AUC(0-48)) and daily partitioned (AUC(0-24 h) and AUC(24-48 h)) plasma AUC values similar to the SAB-IE or "typical patient" simulations. In addition, the proportion of patients likely to experience an elevated trough concentration in excess of 24.3 mg/L was similar between every 48 h CAPD dosing and the referent group. Penetration into the peritoneal cavity was 6% of plasma. CONCLUSIONS: Daptomycin 4 or 6 mg/kg, on the basis of indication, i.v. every 48 h was found to be the optimal i.v. CAPD dosing scheme.

Use of pharmacokinetic and pharmacodynamic principles to determine optimal administration of daptomycin in patients receiving standardized thrice-weekly hemodialysis.

This study identified optimal daptomycin dosing for patients receiving thrice-weekly hemodialysis (HD). Twelve adult patients on HD received daptomycin at 6 mg/kg of body weight intravenously (i.v.) one time; plasma and dialysate samples were collected over 3 days. A 2-compartment model with separate HD and non-HD clearance terms was fit to the data. A series of 9,999-subject Monte Carlo simulations (MCS) was performed to identify HD dosing schemes providing efficacy and toxicity profiles comparable to those obtained for MCS employing the daptomycin population pharmacokinetic (PK) model derived from patients in the Staphylococcus aureus bacteremia-infective endocarditis (SAB-IE) study. For efficacy, we selected the HD dosing scheme which generated an area-under-the-curve (AUC) exposure profile comparable to that for the SAB-IE population model. For toxicity, we selected HD dosing schemes that minimized trough concentrations of ≥ 24.3 mg/liter. Separate HD dosing schemes were developed for each FDA-approved regimen and for two weekly interdialytic periods (48 and 72 h). Administration of the same parent daptomycin dose intra-HD and post-HD resulted in AUC, maximum concentration of drug in serum (C(max)), and C(min) values most comparable to those for SAB-IE simulations for the 48-hour interdialytic period. In contrast, all candidate HD dosing schemes provided AUC(48-72) values that were at least 50% lower than the SAB-IE AUC(48-72) values. Increasing the parent dose by 50% provided more comparable AUC(48-72) values while maintaining acceptable C(min) values. Administration of the daptomycin parent dose intra-HD or post-HD was optimal for the 48-h interdialytic period. For the 72-h interdialytic period, clinicians should consider increasing the dose by 50% to achieve more comparable AUC(48-72) values.

[Daptomycin in home hospitalization]. / Daptomicina en el paciente con hospitalización a domicilio.

Outpatient Parenteral Antimicrobial Therapy (OPAT) is widely used in the United States and has advantages for both patients and hospitals. In the last few years, several European countries such as the United Kingdom and Italy have begun to show interest in OPAT, developing this therapeutic modality through distinct healthcare structures. In Spain, the most widely used resources are hospital at home units. Daptomycin is an antibiotic that is administered in a single daily dose, which allows its rapid infusion, and does not require monitoring of plasma levels. These two factors greatly facilitate the ambulatory treatment of severe infections due to Gram-positive microorganisms. The results of clinical trials, case series and post-commercialization registries support the safety and efficacy of the use of daptomycin in OPAT.