Conventional-dose Versus Half-dose Sulfamethoxazole-trimethoprim for the Prophylaxis of Pneumocystis Pneumonia in Patients with Systemic Rheumatic Disease: A Non-blind, Randomized Controlled Trial.

Pneumocystis pneumonia (PCP) due to Pneumocystis jirovecii infection is the leading cause of fatal opportunistic infections in immunocompromised patients. We will determine whether a daily sulfamethoxazole-trimethoprim (SMX/TMP) dose of 200/40 mg was non-inferior to 400/80 mg for PCP prevention in patients with systemic rheumatic disease under immunosuppressive therapy. This is a randomized, open-label, multicenter controlled trial. The primary outcome is the rate of PCP prevention at 52 weeks. The secondary outcome is the discontinuation rate of SMX/TMP. The trial will evaluate the optimal dose of SMX/TMP for PCP prevention in patients with systemic rheumatic disease under immunosuppressive therapy.