Doripenem Versus Meropenem As the First-Line Empirical Therapy in High-Risk Febrile Neutropenic Patients with Hematological Malignancy: A Randomized, Controlled Trial

BACKGROUND: Febrile neutropenia (FN) is often observed in cases of hematological malignancy such as acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL) and myelodysplastic syndrome (MDS). Carbapenem antibiotics having a potent and broad antimicrobial activity against both gram-positive and gram-negative bacteria including Pseudomonas aeruginosa, are good candidates as the first-line therapy drug in high-risk FN patients. In the IDSA guideline 2010 on the use of antimicrobial agents in FN, mono-therapy with an anti-pseudomonal beta-lactam, such as piperacillin-tazobactam, cefepime or carbapenem [only meropenem (MEPM) and imipenem-cilastatin], is recommended as an empirical therapy for high-risk FN patients. Doripenem (DRPM) is a newer carbapenem with few data available as for the efficacy and safety in the setting of FN patients. Therefore, we conducted a randomized, cooperative group, open-label trial comparing DRPM (1.0 g every 8 hours) with MEPM (1.0 g every 8 hours) as the first-line empirical antibacterial therapy for high-risk FN patients with hematological malignancy including AML, ALL and high-risk MDS.

PATIENTS and METHODS: One hundred and forty-six hospitalized high-risk FN patients with hematological malignancy (AML 76, ALL 43, APL 13, MDS-AML 9, MDS-RAEB 5 cases) during or after chemotherapy were randomized to each drug group (DRPM: n=73, MEPM: n=73). The study drug was started to administer as a mono-therapy and continued at least for 5 days without drug toxicity, and the efficacy and safety were evaluated.

RESULTS: The overall response rate at 7 days in DRPM and MEPM group were not significantly different (DRPM: 67.6%, MEPM: 52.9%, respectively, P=0.098). Both the resolution of fever by mono-therapy at day 3 to 5 (DRPM: 56.9%, MEPM: 47.0%, respectively, p=0.26), and survival at day 30 (DRPM: 98.4%, MEPM: 98.5%, respectively, p=0.312) were not significantly different in the two groups. The frequency of cases needed for anti-MRSA agent and antifungal agent were a little less often in DRPM rather than in MEPM group [DRPM: 36.9%, MEPM: 50.0% (p=0.185), DRPM: 26.1%, MEPM: 32.3% (p=0.535), respectively]. Only grade 1-2 adverse events were observed in both groups (liver dysfunction, renal dysfunction, diarrhea and rash), and they were less often in DRPM group significantly (DRPM: 29.8%, MEPM: 40.8%, respectively, p=0.046). These adverse events were clinically acceptable in the two groups, and most of patients could continue the treatment by both study drugs.

CONCLUSIONS: Our clinical study suggested that DRPM had the non-inferiority of efficacy in comparison with MEPM as the first-line empirical therapy in high-risk FN patients with hematological malignancy, and both drugs could be generally well tolerated.