Pneumocystis jirovecii pneumonia is a significant concern in peaple with HIV/AIDS, often severe and potentially fatal. While trimethoprim/sulfamethoxazole remains the primary treatment, safety concerns exist with alternative options. Research on Pneumocystis jirovecii's beta-D glucan composition has prompted investigations into echinocandins like caspofungin, showing promise in murine models and some positive results in human studies. Evaluating caspofungin's efficacy through observational studies is crucial due to safety advantages over current treatments and limited documented data.

Pneumocystis jirovecii pneumonia (PCP) is a significant opportunistic disease in immunocompromised patients with HIV/AIDS, becoming increasingly prevalent. This condition can range in severity, at times being fatal and necessitating drastic measures. The standard first-line treatment, trimethoprim/sulfamethoxazole, has been unchanged for over three decades. While other drugs have been approved as second-line treatments, they come with safety concerns such as increased risk of hypersensitivity reactions and adverse effects.

Research on Pneumocystis jirovecii has faced challenges due to difficulties in cultivation, requiring in vivo models for study. Previous studies have found that the wall of Pneumocystis spp. contains beta-D glucans in one phase of its life cycle. This discovery has led to investigations into the effectiveness of echinocandins, specifically caspofungin, on Pneumocystis spp. Promising results have been observed in murine models; however, these studies were conducted on species that do not affect humans. Clinical observational studies in humans have shown positive response and safety, albeit using caspofungin in combination with other drugs rather than as monotherapy.

Considering the superior safety profile of echinocandins compared to first-line treatments for P. jirovecii, and the limited documented data in case reports or series, it is important to assess the efficacy of caspofungin in observational studies to address this gap.

Inclusion Criteria:

• Diagnosis of probable or proven PCP, according to its diagnostic classification (refer to classification at the end of this section).

• Have clinical laboratory and virological diagnostic laboratory studies at the time of admission.

  • Classification criteria for Pneumonia by P. jirovecii according to Robert-Gangneux et al.:

Proven: Confirmation by pathology or microbiology. Possible: Presence of three out of four clinical or radiological criteria. Probable: Presence of one clinical or radiological criterion without another identified microorganism.

Exclusion Criteria:

• With a treatment switch to caspofungin after day 7 of treatment initiation (applies only to group B).
• Patients who have developed an additional opportunistic lung infection during their hospitalization, other than cytomegalovirus pneumonitis or SARS-CoV-2 pneumonia.

The study will be conducted with data extracted from the clinical records of patients with human immunodeficiency virus (HIV), hospitalized for Pneumocystis jirovecii pneumonia (PCP) from January 2015 to December 2023.

It is planned to publish the database used for the statistical analysis, including only the variables utilized for the manuscript(s) submitted for publication. These databases will be shared according to the specifications of the journal to which they have been submitted.

These databases will be shared once the manuscript(s) have been accepted for publication in a journal and will remain open indefinitely.

The databases will be available in a public repository or as a downloadable file attached to the publication.