Efficacy of an alternative dosing strategy of meropenem in the treatment of high-risk febrile neutropenia in adult subjects

BACKGROUND: High-risk febrile neutropenia (FN), an oncologic emergency common in patients receiving myelosuppressive chemotherapy, requires prompt initiation of broad-spectrum antibacterials with current guidelines recommending meropenem 1 g intravenously (IV) every 8 hours as first-line treatment. However, an alternative dosage of meropenem, 500 mg IV every 6 hours, has been shown to attain a similar percentage of time above the minimum inhibitory concentration (%T > minimum inhibitory concentration) with a lower daily dose and associated drug cost in nonneutropenic subjects. METHODS: A retrospective study was conducted in adult subjects with FN who received the alternative dosage of meropenem during a 31-month period (February 2009 to August 2011). The primary end point was time to defervescence. Secondary end points included the need for additional gram-negative antibacterials, duration of meropenem treatment, and in-hospital mortality. RESULTS: A total of 449 subjects were screened with 74 meeting inclusion criteria. Median time to defervescence was 2 days. Additional gram-negative antibacterials were used in 6 subjects (8.1%), and in-hospital mortality occurred in 5 subjects (6.8%). Median duration of meropenem treatment was 5 days. There was a significant correlation toward a longer time to defervescence with longer durations of neutropenia (r = 0.272, P = 0.034). CONCLUSIONS: The alternative meropenem dosage regimen of 500 mg IV every 6 hours therefore yields similar outcomes as previously reported with conventional doses of 1 g IV every 8 hours in adults with FN, with potential cost savings due to a decreased daily meropenem dose.