CHICAGO – Daptomycin works as well at clearing diabetic skin and soft tissue infections in real-world clinical practice as it does in clinical trials, according to a retrospective analysis of data from a large European registry.
The rate of clinical success, meaning cure or improvement of the infection, was 86% among nearly 300 patients with diabetic ulcers or foot infections.
By comparison, in a newly completed phase III study of daptomycin, success rates were in the upper 80% range, said Uwe Trostmann, Ph.D., an employee of Novartis Pharma AG in Basel, Switzerland, who presented the registry analysis results at the annual meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy.
In everyday clinical settings, the rate of adverse events possibly related to daptomycin was 1.4%. Only a single patient experienced an increase in levels of creatine phosphokinase (CPK), a known possible adverse effect of the antibiotic.
These are "real-world data. This is not a clinical trial," he stressed. "This is very important information for the clinicians," because it helps them understand what outcomes they can anticipate in their own inpatient and outpatient settings.
Daptomycin has some advantages over vancomycin, which is the current mainstay antibiotic for such infections but also increases the risk of renal complications, Dr. Trostmann said.
The investigators analyzed data from the European Cubicin Outcomes Registry and Experience (EU-CORE), an ongoing, retrospective, noninterventional registry that captures information on patients treated with daptomycin (Cubicin) in routine clinical practice. For the registry, clinicians fill out case report forms after a patient’s treatment has been completed, to avoid any bias.
Of 3,621 patients enrolled between 2006 and 2010, the investigators specifically assessed outcomes among the 277 with diabetic ulcer or foot infections.
On average, these patients were 66 years old. The majority were male (70%) and white (94%). Nearly all (97%) had additional comorbidities, most commonly cardiovascular disease. By setting, the largest share came from the community (43%) followed by the hospital (40%).
Overall, 81% of the patients had a diabetic foot infection, while 19% had a diabetic ulcer infection, Dr. Trostmann reported at the conference, which was sponsored by the American Society for Microbiology. Some had secondary infections as well, such as osteomyelitis (4%) and bacteremia (3%).
Among patients with culture results, the most common pathogen was Staphylococcus aureus (seen in 54%), which was methicillin resistant in more than two-thirds of cases. Thirty-nine percent of patients had received previous antibiotic therapy, usually a fluoroquinolone or penicillin.
Sixty percent received daptomycin in combination with another antibiotic, most often a fluoroquinolone or carbapenem. In addition, 61% of patients had tissue debridement and 15% had bone debridement as part of their treatment.
Daptomycin was started at 4 mg/kg in 55% of patients and at 6 mg/kg in 17%. The median duration of daptomycin therapy was 6 days for outpatients, 12 days for general inpatients, and 2 days for intensive care unit patients.
The overall success rate was 86% (the infection was cured in 31% of patients and improved in 55%). The rate was similar among patients who also had secondary skin and soft-tissue infections (85%), osteomyelitis (91%), and bacteremia (89%). It was lower among patients who also had a urinary tract infection or pyelonephritis (50%); only two patients were in this group.
Overall, 1.4% of patients had adverse events possibly related to the drug. A single patient (0.4% of those studied) had an increase in CPK level.
Daptomycin is manufactured/marketed by Cubist Pharmaceuticals in the United States and by Novartis in Europe.