Daptomycin for the Treatment of Severe Necrotizing Soft-Tissue Infections

Study Summary

Daptomycin is a new antimicrobial agent which has activity against resistant Gram positive cocci including MRSA. The phase 3 clinical trials for skin and soft tissue infections (SSTI) with Staphylococci and Streptococci have already demonstrated that daptomycin was noninferior to the comparator agent (vancomycin or beta-lactams) (10). Although this clinical trial did not include any patients with clostridial infection, there is in vitro data to support the activity of daptomycin against a variety of clostridial species(11) ( Clostridium perfringens) Therefore, for this trial we will include patients with clostridial infections with this species. Additionally, the patients in the SSTI study were not as ill as the proposed study population. Therefore for treatment of such severe infections, we would like to use a higher dose of daptomycin (6mg/kg/dose). The reasons for using a higher dose of daptomycin in this subgroup are as follows: 1. Patients who are severely ill have an increased volume of distribution; and therefore have a lower serum concentration of daptomycin. These patients might require a higher dose of daptomycin to achieve the desired serum concentration. 2. One of the organisms involved in necrotizing fasciitis is enterococcus (both-fecalis and faecium). E.faecium has higher MICs to daptomycin and would require a higher dose of the drug to achieve adequate free (unbound) serum concentration of the drug. 3. Both necrotizing fasciitis and endocarditis are serious deep seated infections. The clinical trials for endocarditis are using 6mg/kg/dose of daptomycin. Therefore for optimal treatment of necrotizing fasciitis, it is justifiable that we should use the higher dose of daptomycin. Objective: To evaluate the clinical and microbiological efficacy and safety of higher dose daptomycin therapy in the treatment of patients with severe necrotizing skin and soft tissue infections. Type of Study: Open label, single center study.

Primary Outcome

Clinical response was assessed by measuring impact of therapy on certain wound parameters. Specifically Erythema, Induration/Swelling, Suppuration, were recorded visually and WBC Counts were considered improved if \<12,000/cu mm. The clinical response was documented as: 1. CURE (resolution of clinical signs and symptoms and no additional need for gram-positive antibiotic therapy. 2. IMPROVED (partial resolution of clinical signs and symptoms (although patient's clinical status had not complete

Interventions

• DRUG Daptomycin 6mg/kg/day