Treatment With Reduced-Dose Trimethoprim-Sulfamethoxazole Is Effective in Mild to Moderate Pneumocystis jirovecii Pneumonia in Patients With Hematologic Malignancies

In a cohort of 113 patients with hematologic malignancies and Pneumocystis jirovecii pneumonia, treatment with reduced-dose trimethoprim-sulfamethoxazole was as effective as standard-dose treatment in patients with mild to moderate pneumonia. Background Recent studies have reported that reduced-dose trimethoprim-sulfamethoxazole (TMP-SMX) may be effective in the treatment of Pneumocystis jirovecii pneumonia (PJP), but data are lacking for patients with hematologic malignancies. Methods This retrospective study included all adult hematologic patients with PJP between 2013 and 2017 at 6 Swedish university hospitals. Treatment with 7.5-15 mg TMP/kg/day (reduced dose) was compared with >15-20 mg TMP/kg/day (standard dose), after correction for renal function. The primary outcome was the change in respiratory function (Delta partial pressure of oxygen [PaO2]/fraction of inspired oxygen [FiO(2)]) between baseline and day 8. Secondary outcomes were clinical failure and/or death at day 8 and death at day 30. Results Of a total of 113 included patients, 80 patients received reduced dose and 33 patients received standard dose. The overall 30-day mortality in the whole cohort was 14%. There were no clinically relevant differences in Delta PaO2/FiO(2) at day 8 between the treatment groups, either before or after controlling for potential confounders in an adjusted regression model (-13.6 mm Hg [95% confidence interval {CI}, -56.7 to 29.5 mm Hg] and -9.4 mm Hg [95% CI, -50.5 to 31.7 mm Hg], respectively). Clinical failure and/or death at day 8 and 30-day mortality did not differ significantly between the groups (18% vs 21% and 14% vs 15%, respectively). Among patients with mild to moderate pneumonia, defined as PaO2/FiO(2) >200 mm Hg, all 44 patients receiving the reduced dose were alive at day 30. Conclusions In this cohort of 113 patients with hematologic malignancies, reduced-dose TMP-SMX was effective and safe for treating mild to moderate PJP.