# Rezafungin as Primary Prophylaxis of Pneumocystis jirovecii Pneumonia in a Critically Ill Person Presenting with AIDS with Trimethoprim/Sulfamethoxazole Allergy: A Case Report

## TL;DR

A patient with AIDS and a TMP-SMX allergy successfully used rezafungin to prevent Pneumocystis jirovecii pneumonia, suggesting it could be a viable alternative when standard drugs are unavailable.

## Contribution

This is the first reported case of rezafungin used as PCP prophylaxis in a person with HIV.

## Key findings

- Rezafungin was used successfully as PCP prophylaxis in a PWH with a TMP-SMX allergy.
- No adverse events or fungal infections occurred during rezafungin use.
- The case highlights rezafungin as a potential alternative when standard prophylactic agents are contraindicated.

## Abstract

Primary prophylaxis of Pneumocystis jirovecii pneumonia (PCP) in people with HIV (PWH) and CD4+ counts <200 cells/µL using trimethoprim/sulfamethoxazole (TMP-SMX) is highly effective but often poorly tolerated. Alternative agents may have limited efficacy or availability. Although rezafungin demonstrated PCP protection comparable to TMP-SMX in animal models, human data are limited to the ongoing ReSPECT trial, and evidence in PWH is lacking. We report the first use of rezafungin as PCP prophylaxis in a PWH. A 43-year-old man presenting with AIDS (HIV-RNA 8.48 × 106 copies/mL; CD4+ 20 cells/µL) was admitted with disseminated tuberculosis and multiple bowel perforations requiring urgent surgery. The postoperative course was marked by infectious and surgical complications. Antitubercular therapy and TMP-SMX prophylaxis were initiated postoperatively, followed by antiretroviral therapy (ART). Later, TMP-SMX was discontinued due to hypersensitivity. Because drug–drug interactions precluded atovaquone or dapsone and pentamidine was unavailable, rezafungin was started. No adverse events or fungal breakthrough infections occurred despite abdominal complications. Further data are needed to determine whether rezafungin represents a viable prophylactic option when standard agents are contraindicated or unavailable.