This real-world observational study aims to evaluate the effectiveness, safety, and therapeutic drug monitoring (TDM) of liposomal amphotericin B (L-AmB) in solid organ transplant recipients with invasive fungal disease (IFD). IFD is a major cause of morbidity and mortality in transplant recipients because of long-term immunosuppressive therapy and increased susceptibility to opportunistic fungal infections.

This is a single-center ambispective cohort study conducted at Sichuan Provincial People's Hospital. The study includes a prospective cohort of solid organ transplant recipients receiving L-AmB therapy and a historical control cohort treated with alternative systemic antifungal regimens. Clinical management and treatment decisions will be determined by treating physicians according to routine clinical practice, and no study-specific intervention will be introduced.

The study will collect information on demographic characteristics, transplant type, immunosuppressive regimens, fungal pathogens, infection sites, antifungal treatment strategies, laboratory findings, and clinical outcomes. Particular attention will be given to renal safety, electrolyte abnormalities, and therapeutic drug monitoring of liposomal amphotericin B. Plasma concentrations of L-AmB, treatment modifications, temporary treatment discontinuation, and concentration-related safety and effectiveness outcomes will be recorded during antifungal therapy.

The primary outcomes are the 28-day clinical response rate and 84-day all-cause mortality. Secondary outcomes include mycological clearance, acute kidney injury, electrolyte abnormalities, breakthrough fungal infection, treatment discontinuation due to adverse events, liposomal amphotericin B plasma concentrations, and the associations between L-AmB exposure and clinical outcomes or treatment-related toxicities.

The study is expected to provide real-world evidence regarding the effectiveness, safety, and pharmacokinetic characteristics of L-AmB in transplant recipients, support optimization of antifungal treatment strategies, and inform individualized dosing and monitoring approaches in this high-risk population.

Inclusion Criteria:

• Age 18 to 75 years.
• Recipient of a solid organ transplant.
• Diagnosis of invasive fungal disease (IFD) according to EORTC/MSGERC criteria.
• Receiving liposomal amphotericin B therapy as part of routine clinical care.
• Provision of informed consent for prospective participants.

Exclusion Criteria:

• Known hypersensitivity to amphotericin B formulations.
• Severe hepatic dysfunction (ALT or AST >5× upper limit of normal, or total bilirubin >2× upper limit of normal).
• Severe renal dysfunction requiring permanent discontinuation of antifungal therapy at baseline.
• Pregnancy or breastfeeding.
• Participation judged inappropriate by the investigator.

Adult solid organ transplant recipients diagnosed with proven, probable, or possible invasive fungal disease and treated with liposomal amphotericin B or alternative systemic antifungal therapy at Sichuan Provincial People's Hospital.

Individual participant data will not be shared due to patient confidentiality and institutional data protection requirements.