Oral antibiotic prophylaxis of early infection in multiple myeloma: a URCC/ECOG randomized phase III study.

Multiple myeloma (MM) is a malignancy of clonal plasma cells, resulting in an increased production of ineffective immunoglobulins with suppression of non-involved immunoglobulins. Patients with MM are at increased risk of infectious complications, particularly streptococcal and staphylococcal infections. This study evaluated the impact of prophylactic antibiotics on the incidence of serious bacterial infections (SBIs) during the first 2 months of treatment in patients with newly diagnosed MM. Patients with MM receiving initial chemotherapy were randomized on a 1:1:1 basis to daily ciprofloxacin (C; 500 mg twice daily), trimethoprim-sulfamethoxazole (T; DS twice daily) or observation (O) and evaluated for SBI (Eastern Cooperative Oncology Group ≥grade 3) for the first 2 months of treatment. From July 1998 to January 2008, 212 MM patients were randomized to C (n=69), T (n=76) or O (n=67). The incidence of SBI was comparable among groups: C=12.5%, T=6.8% and O=15.9%; P=0.218. Further, any infection during the first 2 months was also comparable (20% vs 23% vs 22%, respectively, P=0.954). We demonstrate that prophylactic antibiotics did not decrease the incidence of SBI (≥grade 3) within the first 2 months of treatment. We conclude that routine use of prophylactic antibiotics should not be mandated for patients receiving induction chemotherapy.