Low- vs Standard-Dose TMP-SMX for Prevention of Pneumocystis Pneumonia After Kidney Transplantation

Pneumocystis jirovecii pneumonia (PJP) remains a significant opportunistic infection in kidney transplant recipients and continues to pose a major clinical challenge. Although trimethoprim-sulfamethoxazole (TMP-SMX) is widely used for prophylaxis, its tolerability is often limited by adverse effects, which may compromise adherence during long-term use. Therefore, identifying an optimal dosing strategy that maintains efficacy while improving safety is of considerable clinical importance.

This multicenter, prospective, randomized controlled trial is designed to compare the efficacy and safety of low-dose versus standard-dose TMP-SMX for PJP prophylaxis after kidney transplantation. Adult kidney transplant recipients with stable renal function after transplantation will be enrolled and randomly assigned in a 1:1 ratio to receive either a low-dose or standard-dose TMP-SMX regimen for 12 months following transplantation.

The primary outcome is the incidence of PJP during the 12-month prophylaxis period. Secondary outcomes include treatment-related adverse events, rates of dose modification or discontinuation, and the occurrence and timing of PJP after cessation of prophylaxis, as well as other post-transplant clinical outcomes. All participants will be followed for a total of 24 months, including a 12-month treatment period and an additional follow-up period after discontinuation. The results of this study are expected to provide evidence to inform optimal prophylactic strategies for PJP in kidney transplant recipients, with the aim of improving both efficacy and safety in clinical practice.

Inclusion criteria

-Age: Between 18 and 70 years old. Transplant Status: Recipients of a first-time kidney transplant. Renal Function: Serum creatinine levels have stabilized with a creatinine -----clearance (CrCl) > 30 mL/min.

Consent & Compliance: Voluntarily agree to participate in this study, are capable of cooperating with the investigators, and have signed the informed consent form.

Exclusion criteria

-HIV Infection: Known HIV positive status. Drug Allergy: History of allergy or hypersensitivity to TMP-SMX (Trimethoprim-Sulfamethoxazole).

Prior PJP: History of Pneumocystis jirovecii pneumonia (PJP) before transplantation.

G6PD Deficiency: Glucose-6-phosphate dehydrogenase deficiency. Multi-organ Transplant: Recipients of multi-organ transplants. Active Infection: Presence of other severe concurrent infections. Immune System Disorders: Concomitant diseases affecting the immune system (e.g., malignancies/tumors, connective tissue diseases, hematological system diseases).

Pregnancy: Pregnant women. Anemia: Megaloblastic anemia. Non-compliance: Inability to adhere to regular follow-up schedules or poor compliance.