[Pneumocystis pneumonia prophylaxis with low-dose trimethoprim/sulfamethoxazole during rituximab-containing chemotherapy].

: Although Pneumocystis pneumonia (PCP), a life-threatening infection, has been reported in patients with non-Hodgkin B-cell lymphoma (BNHL) who were treated with rituximab-containing chemotherapies (R-CTX), the PCP prophylaxis regimen awaits establishment to date. This study reports a retrospective analysis of the efficacy and safety of a low-dose trimethoprim/sulfamethoxazole (TMP/SMX) in patients with BNHL receiving R-CTX. We retrospectively analyzed 156 patients newly diagnosed with BNHL who received R-CTX at our institute from 2010 to 2015. We collected patients' clinical and laboratory data, including lymphocytes count, IgG level, PCP prophylaxis regimens, and adverse events (AEs). Patients were categorized into the following two groups based on the TMP/SMX regimen: group A (33 patients; 80 mg/400 mg×3/week) or group B (65 patients; 160 mg/800 mg×2/week). Both lymphocytes count and IgG level declined during R-CTX. No patient developed PCP. Patients in group B exhibited a significantly higher incidence of AEs (18.2% vs. 63.1%; p<0.05) and increased AST (6.1% vs. 26.6%; p<0.05), compared with those in group A. Thus, TMP/SMX (80 mg/400 mg×3/week) effectively prevents PCP and is preferable because of the lower rates of AEs.