The prevalence of Staphylococcus aureus causing prosthetic joint infection (PJI) supports investigation of higher doses of daptomycin in the management of PJI. This was a prospective, randomized controlled trial studying safety and efficacy of daptomycin (6 and 8 mg/kg of body weight) compared with standard-of-care therapy for PJI. This open-label study randomized 75 patients undergoing 2-stage revision arthroplasty to daptomycin at 6 or 8 mg/kg or a comparator (vancomycin, teicoplanin, or semisynthetic penicillin). After prosthesis removal, patients received 6 weeks of antibiotic treatment and a 2-to 6-week antibiotic-free period before implantation of a new prosthesis. Test of cure (TOC) was within 1 to 2 weeks after reimplantation. The primary objective was evaluation of creatine phosphokinase (CPK) levels. Secondary objectives were clinical efficacy and microbiological assessments. Of 73 CPK safety population patients, CPK elevation of >500 U/liter occurred in 4 of 25 (16.0%) (daptomycin, 6 mg/kg) and 5 of 23 (21.7%) (daptomycin, 8 mg/kg) daptomycin-treated patients and 2 of 25 (8.0%) comparator patients. Adverse-event rates were similar among daptomycin and comparator groups. Among modified intent-to-treat patients at TOC, clinical success rates were 14 of 24 (58.3%) for 6 mg/kg daptomycin, 14 of 23 (60.9%) for 8 mg/kg daptomycin, and 8 of 21 (38.1%) for the comparator. Overall microbiological success at TOC was 12 of 24 (50.0%) for 6 mg/kg daptomycin, 12 of 23 (52.2%) for 8 mg/kg daptomycin, and 8 of 21 (38.1%) for comparator patients. In conclusion, daptomycin at 6 and 8 mg/kg given for up to 6 weeks was safe and appeared to be effective in managing staphylococcal PJI using a 2-stage revision arthroplasty technique in a total of 49 patients.
Prosthetic joint infection (PJI) occurs in 0.5% to 1.0% and 0.5% to 2% of hip and knee replacements, respectively (5,20,24,25). PJI is predominantly caused by Staphylococcus aureus (28%) and coagulase-negative staphylococci (CoNS) (25%) (23). PJI is associated with mortality (up to 2.5%) and significant morbidity, and outcomes are poor (8). There are no prospective, randomized controlled trials to guide treatment in this area (16,21). Conducting trials is challenging due to the difficulty of identifying patients and confounding outcomes by prior use of antibiotics.The ideal antimicrobial agent should be bactericidal, with activity against biofilm-producing microorganisms (26). Daptomycin exhibits rapid, concentration-dependent bactericidal activity in vitro against Gram-positive organisms, including S. aureus (regardless of methicillin susceptibility), Staphylococcus haemolyticus, and Staphylococcus epidermidis (4). Clinical outcomes in osteomyelitis from a retrospective, noncomparative registry showed that daptomycin doses of Ͼ4 mg/kg of body weight were more effective than doses of Յ4 mg/kg (88% versus 65%; P ϭ 0.013) (15).This study assessed the safety and efficacy of 6 and 8 mg/kg daptomycin compared with standard-of-care therapy in patients with hip or knee PJI c...