Adults with cSSSI

Adult patients with clinically documented complicated skin and skin structure infections (cSSSI) (Table 15) were enrolled in two randomized, multinational, multicenter, investigator-blinded trials comparing daptomycin for injection (4 mg/kg IV every 24h) with either vancomycin (1 g IV q12h) or an anti-staphylococcal semi-synthetic penicillin (i.e., nafcillin, oxacillin, cloxacillin, or flucloxacillin; 4 to 12 g IV per day). Patients could switch to oral therapy after a minimum of 4 days of IV treatment if clinical improvement was demonstrated. Patients known to have bacteremia at baseline were excluded. Patients with creatinine clearance (CLCR) between 30 and 70 mL/min were to receive a lower dose of daptomycin for injection as specified in the protocol; however, the majority of patients in this subpopulation did not have the dose of daptomycin for injection adjusted. 

One trial was conducted primarily in the United States and South Africa (study 9801), and the second was conducted at non-US sites only (study 9901). The two trials were similar in design but differed in patient characteristics, including history of diabetes and peripheral vascular disease. There were a total of 534 adult patients treated with daptomycin for injection and 558 treated with comparator in the two trials. The majority (89.7%) of patients received IV medication exclusively. 

The efficacy endpoints in both trials were the clinical success rates in the intent-to-treat (ITT) population and in the clinically evaluable (CE) population. In study 9801, clinical success rates in the ITT population were 62.5% (165/264) in patients treated with daptomycin for injection and 60.9% (162/266) in patients treated with comparator drugs. Clinical success rates in the CE population were 76.0% (158/208) in patients treated with daptomycin for injection and 76.7% (158/206) in patients treated with comparator drugs. In study 9901, clinical success rates in the ITT population were 80.4% (217/270) in patients treated with daptomycin for injection and 80.5% (235/292) in patients treated with comparator drugs. Clinical success rates in the CE population were 89.9% (214/238) in patients treated with daptomycin for injection and 90.4% (226/250) in patients treated with comparator drugs. 

The success rates by pathogen for microbiologically evaluable patients are presented in Table 16. 

Pediatric Patients (1 to 17 Years of Age) with cSSSI

The cSSSI pediatric trial was a single prospective multi-center, randomized, comparative trial. A total of 396 pediatric patients aged 1 to 17 years with cSSSI caused by Gram positive pathogens were enrolled into the study. Patients known to have bacteremia, osteomyelitis, endocarditis, and pneumonia at baseline were excluded. Patients were enrolled in a stepwise approach into four age groups and given age-dependent doses of daptomycin for injection once daily for up to 14 days. The different age groups and doses evaluated were as follows: Adolescents (12 to 17 years) treated with 5 mg/kg of daptomycin for injection (n=113), Children (7 to 11 years) treated with 7 mg/kg of daptomycin for injection (n=113), Children (2 to 6 years) treated with 9 mg/kg of daptomycin for injection (n=125) and Infants (1 to <2 years) treated with 10 mg/kg (n= 45). 

Patients were randomized 2:1 to receive daptomycin for injection or a standard of care (SOC) comparator, which included intravenous therapy with either vancomycin, clindamycin, or an anti-staphylococcal semi-synthetic penicillin (nafcillin, oxacillin, or cloxacillin). Patients could switch to oral therapy after clinical improvement was demonstrated (no minimum IV dosing was required). 

The primary objective of this study was to evaluate the safety of daptomycin for injection. The clinical outcome was determined by resolution or improvement of symptoms at the End-of-Treatment (EOT), 3 days after the last dose, and Test-of-Cure (TOC), 7-14 days after the last dose. Investigator observed outcomes were verified in a blinded fashion. Of the 396 subjects randomized in the study, 389 subjects were treated with daptomycin for injection or comparator and included in the ITT population. Of these, 257 subjects were randomized to the daptomycin for injection group and 132 subjects were randomized to the comparator group. Approximately 95% of subjects switched to oral therapy. The mean day of switch was day 4, and ranged from day 1 to day 14. The clinical success rates determined at 7–14 days after last dose of therapy (IV and oral) (TOC visit) were 88% (227/257) for daptomycin for injection and 86% (114/132) for comparator.