Survey Shows Vancomycin Continues to Dominate MRSA Treatment

According to surveyed infectious disease specialists and internists as well as hospital patient-level medical data, Decision Resources and Arlington Medical Resources (AMR) find that vancomycinwhich has experienced increasing usage over the past five yearscontinues to dominate treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. Sixty to 76 percent of surveyed infectious disease specialists indicate that they use vancomycin as first-line treatment for bloodstream infections (BSIs), complicated skin and skin structure infections (cSSSIs) and hospital-acquired pneumonia (HAP) suspected to be or confirmed to involve MRSA.

Pfizers Zyvox (linezolid) and Cubists Cubicin (daptomycin) have been on the market for years and have steadily gained patient share and days of therapy with Zyvox having made notable gains in the treatment of HAP and Cubicin having gained usage for the treatment of bacteremia. However, despite increased usage, comparable efficacy to vancomycin in various indications and delivery advantages over vancomycin, neither Zyvox nor Cubicin have been able to supplant vancomycin as the preferred MRSA therapy in the hospital setting.

Study findings also reveal that surveyed infectious disease specialists consider sepsis and prosthetic joint infections to be the top most difficult-to-treat indications needing novel anti-MRSA therapies. Notably, 42 percent of surveyed infectious diseases specialists consider sepsis a top priority for novel agents to treat MRSA and 29 percent of surveyed internists agree. Additionally, patient level audit data of drug costs and usage reveal high antibiotic costs for sepsis and prosthetic joint infections owing to long treatment duration and use of premium-priced antibiotics.

"Sepsis is an indication for which there is little drug development and few treatment options and although drug development for this indication is a high risk, as evidenced by numerous unsuccessful development efforts to date, this indication is also one of significant commercial reward because of the high unmet need and limited competition," says Decision Resources analyst Charu Vepari, PhD. "Additionally, prosthetic joint infections due to MRSA are of equally high concern to infectious disease specialists and internists."

Analysis of the overall patient population in the hospital antibiotics market reveals that ten percent of inpatients receiving antibiotic treatment have a hospital-acquired bacterial infection. Infections of the lower respiratory tract, urinary tract, skin/skin structure, gastrointestinal/biliary tract, and bloodstream are the most commonly treated indications in the hospital, regardless of where a patient acquires the infection. Additionally, half of all antibiotic-treated inpatients receive empiric therapy while only one-quarter receive therapy for a confirmed or documented infection. The remaining one-fourth of patients receives antibiotic therapy for surgical prophylaxis.

Nearly two-thirds of confirmed gram-positive infections treated in the hospital setting are caused by MRSA, methicillin-sensitive Staphylococcus aureus (MSSA), or S. epidermidis. Study findings also reveal that three-quarters of confirmed gram-negative infections treated in the hospital setting are caused by either E. coli, P. aeruginosa, or K. pneumoniae. Increasing resistance among these pathogens and limited treatment options creates significant opportunity for the development of novel therapies.