TMP-SMX Prophylaxis Reduces Pneumonia in Patients Treated With Rituximab

microscopic pneumonia in lungs
microscopic pneumonia in lungs
Does the benefit of using prophylactic trimethoprim-sulfamethoxazole to prevent pneumonia in patients receiving rituximab outweigh any potential risks?

Patients taking rituximab who were also treated prophylactically with trimethoprim-sulfamethoxazole (TMP-SMX) had a lower incidence of Pneumocystis jirovecii pneumonia, according to the results of a recent study published in the journal CHEST.

This retrospective study, conducted at a tertiary referral center in South Korea, compared the 1-year incidence rate of pneumocystis jirovecii pneumonia (PJP) between patients taking rituximab only and those taking rituximab and prophylactic TMP-SMX during the first 28 days of rituximab treatment.

Among the 3524 patients, 2523 patients were in the control group (receiving only rituximab), and 1001 patients were in the prophylactic group (receiving both rituximab and prophylactic treatment). Over a total of 2759.9 person years, a total of 92 infections of PJP occurred, with the prophylaxis group showing a significantly lower incidence of PJP (adjusted sub-distribution hazard ratio [aSHR], 0.20; 95% CI, 0.10–0.42) than the control group. The overall mortality rate for these infections was 27.2%. The incidence of adverse drug reactions related to TMP-SMX was 18.1 (14.6–22.2)/100 person-years, with most reactions of mild-to-moderate severity.

The study authors wrote, “We showed that TMP-SMX was associated with a significantly reduced 1-year incidence of PJP in patients receiving rituximab with a favorable safety profile.” They added, “Although this result should be confirmed in future randomized studies, it may affect practice regarding the use of PJP prophylaxis concomitant with rituximab treatment.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Park JW, Curtis JR, Jun KI, et al. Primary prophylaxis for Pneumocystis jirovecii pneumonia in patients receiving rituximab. Chest. Published online November 14, 2021. doi:10.1016/j.chest.2021.11.007