A pilot study of high-dose short duration daptomycin for the treatment of patients with complicated skin and skin structure infections caused by gram-positive bacteria

Cost-effectiveness analysis of linezolid, daptomycin, and vancomycin in methicillin-resistant Staphylococcus aureus: complicated skin and skin structure infection using Bayesian methods for evidence synthesis

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) complicated skin and skin structure infection (cSSSI) is a prominent infection encountered in hospital and outpatient settings that is associated with high resource use for the health-care system.

OBJECTIVE

A decision analytic (DA) model was developed to evaluate the cost-effectiveness analysis (CEA) of linezolid, daptomycin, and vancomycin in MRSA cSSSI.

METHODS

Bayesian methods for evidence synthesis were used to generate efficacy and safety parameters for a DA model using published clinical trials. CEA was done from the US health-care perspective. Efficacy was defined as a successfully treated patient at the test of cure without any adverse reaction. Primary outcome was the incremental cost-effectiveness ratio between linezolid and vancomycin, daptomycin and vancomycin, and linezolid and daptomycin in MRSA cSSSI. Univariate and probabilistic sensitivity analyses were performed to test the robustness of the model.

RESULTS

The total direct costs of linezolid, daptomycin, and vancomycin were $18,057, $20,698, and $23,671, respectively. The cost-effectiveness ratios for linezolid, daptomycin, and vancomycin were $37,604, $44,086, and $52,663 per successfully treated patient, respectively. Linezolid and daptomycin were dominant strategies compared to vancomycin. However, linezolid was dominant when compared to daptomycin. The model was sensitive to the duration of daptomycin and linezolid treatment.

CONCLUSION

Linezolid and daptomycin are potentially cost-effective based on the assumptions of the DA model; however, linezolid appears to be more cost-effective compared to daptomycin and vancomycin for MRSA cSSSIs.

Safety and clinical outcomes among older adults receiving daptomycin therapy: Insights from a patient registry

BACKGROUND

Serious gram-positive bacterial infections are an important cause of morbidity and mortality among older adults and can present significant challenges to clinicians. Data evaluating the safety and effectiveness of newer agents in this population are limited.

OBJECTIVE

Daptomycin is a lipopeptide with activity against resistant gram-positive organisms. To better understand the overall safety and effectiveness of daptomycin in older adults (≥66 years of age), the authors reviewed the data that were collected as part of an ongoing registry maintained by Cubist Pharmaceuticals, Inc. (Lexington, Massachusetts), the manufacturer of daptomycin.

METHODS

The Cubicin Outcomes Registry and Experience (CORE) is a multicenter, retrospective registry designed to collect postmarketing clinical data on patients who received daptomycin. The CORE data collected from 58 institutions across the United States between January 1, 2005, and December 31, 2007, were analyzed to better understand the overall safety profile of daptomycin and the clinical outcomes of older adults who were treated with this agent. Patients were considered to be nonevaluable if the medical record did not contain sufficient information to determine response at the end of therapy. Nonevaluable patients were excluded from the clinical outcome analysis but included in the safety analysis.

RESULTS

The registry contained 1073 patients aged ≥66 years who received daptomycin; 23.8% (255/1073) were ≥81 years of age. Overall, 18.1% (194/1073) of patients experienced 324 adverse events, and 6.2% (67/1073) of patients experienced 97 adverse events that were considered possibly related to treatment with daptomycin. The most frequently reported adverse events that were considered possibly treatment related included creatine phosphokinase (CPK) elevations, gastrointestinal disorders, and skin rashes. Among the 67 patients who experienced ≥1 adverse event that was possibly related to daptomycin, 30 discontinued therapy due to the adverse event (13 due to CPK elevation). Overall, 78.7% (844/1073) of patients were considered evaluable for clinical outcomes. The clinical success rate for all evaluable patients was 90.2% (761/844). The success rate for evaluable patients ≥81 years of age (88.6% [171/193]) was comparable to that of the overall population.

CONCLUSION

Experience with daptomycin in this group of older adults suggests good tolerability and clinical outcomes that are consistent with the results of other studies published to date.

Complicated skin and soft tissue infections: literature review of evidence for and experience with daptomycin

Skin and soft tissue infections (SSTIs) are the second most common infection encountered in hospitals. Management decisions have become increasingly complex due to the prevalence of resistant pathogens, the wide array of licensed antimicrobials and the availability of potent oral agents and of out-patient parenteral antibiotic therapy. Daptomycin is one of the newer therapeutic agents licensed for complex SSTI management. Rapid cidality, good soft tissue penetration, once daily IV bolus administration and activity against resistant Gram-positive infections make daptomycin an attractive option both in hospitalized and community treated patients. A comprehensive review of the evidence for and experience with daptomycin and its use in SSTIs is presented.

Pharmacokinetics of single-dose daptomycin in patients with suspected or confirmed neurological infections

There are currently few or no published data on the amount of cerebrospinal fluid (CSF) penetration of daptomycin in patients with suspected or documented neurosurgical infections. We conducted a prospective study, assessing the pharmacokinetics and CSF penetration of a single intravenous daptomycin dose administered at 10 mg/kg, based on total body weight (TBW), in six neurosurgical patients with indwelling external CSF shunts with suspected or documented meningitis or ventriculitis. Each patient had four blood and CSF samples drawn simultaneously at specific times after the end of infusion: 30 min, 6 h, 12 h, and 24 h. Pharmacokinetic parameters of daptomycin in serum were calculated using standard noncompartmental methods, and daptomycin was assayed using high-performance liquid chromatography (for serum) or liquid chromatography with mass spectrometry (for CSF). The mean (± standard deviation [SD]) maximum measured daptomycin concentrations were 93.7 ± 17.3 mg/liter in serum at 0.5 h postinfusion and 0.461 ± 0.51 mg/liter in CSF at 6 h postinfusion. The mean (± SD) daptomycin minimum concentrations were 13.8 ± 4.8 mg/liter in serum at 24 h postinfusion and 0.126 ± 0.12 mg/liter in CSF at 0.5 h postinfusion. The mean daptomycin penetration, determined by the area under the concentration-time curve in CSF (AUC(CSF))/(AUC(serum) ratio), was 0.8%. Corrected for protein binding, the overall CSF penetration was 11.5%. Additional pharmacokinetic studies evaluating multiple and/or higher dosages of daptomycin are necessary in human subjects to better characterize the CSF penetration of daptomycin in neurosurgical patients.

Case Report: Persistent Elevation in Creatine Phosphokinase Associated with High-Dose Daptomycin Therapy

Objective

To report a persistent elevation in creatine phosphokinase (CPK) associated with high-dose daptomycin therapy that did not resolve following discontinuation of daptomycin.

Summary

A 34-year-old male with HIV/AIDS and stage IV Burkitt lymphoma was admitted for pain management. The patient's initial hospital course was complicated by left brachial deep vein thrombosis (DVT), Clostridium difficile colitis, and pancytopenia. The patient later developed severe sepsis and septic shock secondary to methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE), Candida albicans, and Escherichia coli infection. High-dose daptomycin (12 mg/kg) was initiated to treat MRSA and VRE bacteremia. The patient's baseline CPK was 118 U/L, which increased to 327 U/L following 2 days of therapy. The patient's CPK continued to increase to 1648 U/L on day 10 of daptomycin, thereby necessitating a discontinuation of daptomycin and the initiation of linezolid. Six days after discontinuation of therapy, the patient's CPK remained elevated at 1940 U/L.

Discussion

A Naranjo scale score of 6 was calculated, indicating that daptomycin was the probable cause for the increase in CPK. Although daptomycin is known to cause elevations in CPK, there are limited published data describing this adverse event with high-dose daptomycin therapy.

Conclusion

High-dose daptomycin is becoming more frequently used in clinical practice, so clinicians should monitor for and report any adverse events associated with this dosing strategy.

Daptomycin: pharmacology and clinical use

IMPORTANCE OF THE FIELD

Infections caused by Gram-positive organisms have increased in frequency and severity. Daptomycin offers a therapeutic option in an era of increasing resistance.

AREAS COVERED IN THIS REVIEW

Literature from 1986 to present was reviewed for pharmacological, preclinical and clinical studies on daptomycin.

WHAT THE READER WILL GAIN

The pharmacological properties, resistance mechanisms and clinical applications of daptomycin are discussed. Recommendations are offered on the use of this agent for the treatment of resistant Gram-positive infections.

TAKE HOME MESSAGE

Daptomycin is a reliable agent for the treatment of Gram-positive infections. It has been shown to be effective in bacteremia and endocarditis, as well as in soft-tissue infections caused by Gram-positive organisms. Its role in the treatment of bone and joint infections is not well-defined. Resistance is currently uncommon in clinical isolates. However, emergence of resistance during therapy is a concern. This may be prevented by use of higher doses.

Daptomycin Versus Other Antimicrobial Agents for the Treatment of Skin and Soft Tissue Infections: A Meta-Analysis

BACKGROUND

Skin and soft tissue infections (SSTIs) are common in everyday clinical practice. Daptomycin has been shown to achieve very good concentrations in skin and soft tissues.

OBJECTIVE

To compare the effectiveness and toxicity of daptomycin with that of other antimicrobials for the treatment of SSTIs.

METHODS

PubMed, Scopus, and the Cochrane Central Register of Controlled Trials were searched for articles published up to March 2009. Comparative studies in which daptomycin was used in the intervention group were included in this meta-analysis. The primary outcome of interest was clinical success; secondary outcomes were microbiologic success, clinical success in subsets with complicated SSTIs (cSSTIs) or infections due to methicillin-resistant Staphylococcus aureus; (MRSA), clinical success of daptomycin-versus vancomycin-treated patients, time to clinical cure, treatment-related adverse events, withdrawal from treatment due to toxicity, all-cause mortality, and development of resistance.

RESULTS

Four studies were included in the analysis (3 were randomized controlled trials [RCTs]). Vancomycin and semisynthetic penicillins were used in the comparator arm. Three studies reported on patients with cSSTIs. The intention-to-treat (ITT) population was 1557 patients. No statistically significant difference between daptomycin and comparators was found regarding clinical success in clinically evaluable (OR 0.89; 95% CI 0.63 to 1.25 in the 3 RCTs and OR 1.34; 95% CI 0.38 to 4.66 with all 4 studies included), ITT, MRSA-infected patients, and those with cSSTIs. Two studies reported that significantly fewer patients with cSSTIs required prolonged treatment in the daptomycin arm and that clinical cure was faster than with comparators. No difference between the compared regimens was found in other outcomes.

CONCLUSIONS

Daptomycin is effective and safe for the treatment of SSTIs. Studies evaluating the optimal duration of daptomycin therapy for cSSTIs, comparing daptomycin with new agents, and focusing on proven MRSA SSTIs will be helpful for the further evaluation of the drug.

Efficacy of high doses of daptomycin versus alternative therapies against experimental foreign-body infection by methicillin-resistant Staphylococcus aureus

Since the currently approved dose of daptomycin (6 mg/kg of body weight/day) has been associated with clinical failures and resistance development, higher doses for some difficult-to-treat infections are being proposed. We studied the efficacy of daptomycin at high doses (equivalent to 10 mg/kg/day in humans) and compared it to that of reference and alternative treatments in a model of foreign-body infection with methicillin (meticillin)-resistant Staphylococcus aureus. In vitro studies were conducted with bacteria in the log and stationary phases. For the in vivo model, therapy with daptomycin at 100 mg/kg/day, vancomycin at 50 mg/kg/12 h, rifampin (rifampicin) at 25 mg/kg/12 h, or linezolid at 35 mg/kg/12 h was administered for 7 days. Antibiotic efficacy was evaluated using either bacteria from tissue cage fluids or those attached to coverslips. We screened for the emergence of linezolid- and rifampin-resistant strains and analyzed the surviving population from the daptomycin-treated group. Only daptomycin was bactericidal in both the log- and stationary-phase studies. Daptomycin (decrease in the log number of CFU per milliliter of tissue cage fluid, 2.57) and rifampin (decrease, 2.6 log CFU/ml) were better (P < 0.05) than vancomycin (decrease, 1.1 log CFU/ml) and linezolid (decrease, 0.9 log CFU/ml) in the animal model. Rifampin-resistant strains appeared in 60% of cases, whereas no linezolid resistance emerged. No daptomycin-resistant subpopulations were detected at frequencies of 10(-7) or higher. In conclusion, daptomycin at high doses proved to be as effective as rifampin, and the two were the most active therapies for this experimental foreign-body infection. These high doses ensured a profile of safety from the development of resistance.

Safety and Clinical Outcomes when Utilizing High-Dose (≥8 mg/kg) Daptomycin Therapy

Background:

Daptomycin is approved for the treatment of skin and skin-structure infections (4 mg/kg) and Staphylococcus aureus bacteremia, including right-sided endocarditis (β mg/kg). In vitro and animal studies have reported increased activity with increased daptomycin doses. There are limited clinical data on use of daptomycin at doses greater than 6 mg/kg.

Objective:

To evaluate the safety and efficacy of higher doses (≥8 mg/kg) of daptomycin when administered for a variety of gram-positive infections.

Methods:

Data were collected retrospectively as part of an ongoing registry (the Cubicin Outcomes Registry and Experience database) for the 2005–2007 program years. For the purpose of this study, the safety and efficacy of daptomycin were evaluated in patients who received doses of 8 m/kg or higher.

Results:

Ninety-four (2.6%) of 3617 patients received daptomycin doses of 6 mg/kg or higher; 18 (19%) of those patients received doses of 10 mg/kg or higher. The most common infections were bacteremia (30/94), skin and skin-structure infections (22/94), and endocarditis (15/94). The most common pathogens were Enterococcus spp. (37/94; 57% vancomycin-resistant) and S. aureus (28/94; 68% methicllin-resistant). Fifty-one percent of the patients were male. 39% were aged 66 years or older, 27% had an initial creatinine clearance less than 30 mL/min, and 17% were on dialysis. The median duration of daptomycin therapy was 15 days (minimum 1, maximum 90). Six (6.4%) of the 94 patients experienced 1 or more adverse events or abnormal laboratory value changes possibly related to daptomycin; in 2 (2.1%) of the 94 patients, daptomycin was discontinued due to treatment-related adverse events. Seventy-four (79%) patients were considered evaluable for efficacy. The overall clinical success rate was 89% (bacteremia, 91 %; skm and skin-structure infections. 88%: endocarditis. 67%)

Conclusions:

Daptomycin was well tolerated and effective at doses of 8 mg/kg or higher in patients with gram-positive infections. Further prospective and comparative studies of daptomycin at doses greater than 6 mg/kg are warranted.