The role of trimethoprim/sulfamethoxazole in preventing opportunistic infections in systemic lupus erythematosus patients receiving low-level immunosuppressive treatment: an open-label, randomized, controlled trial.

OBJECTIVE

Systemic lupus erythematosus (SLE) patients receiving immunosuppressive therapy are at risk for opportunistic infections (OIs), particularly Pneumocystis pneumonia (PCP). This study aimed to evaluate the effectiveness of trimethoprim/sulfamethoxazole (TMP/SMX) as primary prophylaxis against OIs and its adverse effects in SLE patients receiving low-level immunosuppressive treatment in a real-world setting.

METHODS

This open-label randomized controlled trial enrolled SLE patients receiving low-level immunosuppressive treatment at Ramathibodi Hospital between May 2021 and December 2022. Patient demographics and relevant clinical data were collected. Participants were randomized 1:1 to receive TMP/SMX or no prophylaxis, with dose adjustments according to renal function. The incidences of TMP/SMX-sensitive OIs and adverse events were monitored for 12 months post-enrollment.

RESULTS

The trial was terminated early due to a high rate of adverse drug reactions (ADRs) associated with TMP/SMX. In total, 138 SLE patients receiving low-level immunosuppressive treatment were enrolled. Most patients (98.4%) were in disease remission. No TMP/SMX-sensitive OIs were observed in either group during the 12-month follow-up period. Among individuals receiving TMP/SMX, 10/70 (14.3%) developed ADRs. Of these 10 patients, eight experienced grade 1 ADRs, and two had grade 3 ADRs; all declined to resume prophylaxis. There were no deaths in the study.

CONCLUSIONS

During the 12-month follow-up period, no TMP/SMX-sensitive OIs occurred in SLE patients receiving low-level immunosuppressive therapy, suggesting that primary prophylaxis with TMP/SMX may not significantly benefit this population. The high rate of ADRs observed underscores the need for clinicians to carefully consider the risks and benefits of TMP/SMX prophylaxis in these patients.