Clinical Research Directory

Inclusion Criteria 1. Immunocompromised adults (≥18 years old) in an emergency department or hospital with a proven or probable diagnosis of PCP. 2. Severe PCP, defined as proven or probable PCP with new or increased PCP-attributable hypoxemic respiratory failure meeting at least one of the following criteria: a requirement for ≥4 L/min supplemental oxygen by nasal cannula to maintain oxygenation \>94%; a requirement for FiO₂ ≥0.35 via a controlled oxygen-delivery device; or a requirement for advanced respiratory support, including invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO). For patients with chronic baseline oxygen use, the increased support must be attributable to PCP. 3. Currently receiving, or eligible to receive, systemic anti-PCP therapy for the current episode. Patients receiving empiric PCP treatment may be enrolled before microbiological or pathological results are available if results are expected within 1 week. 4. No later than 48 hours after screening for inclusion and before more than 3 days of PCP therapy have elapsed. 5. Provision of informed consent by the participant or substitute decision maker, as locally applicable. Clinical Exclusion Criteria 1. More than 3 days of effective anti-PCP therapy before enrolment in ECHINO-PCP. 2. Another infection or clinical indication that independently requires echinocandin therapy. 3. Known allergy or hypersensitivity to echinocandins. 4. Receipt of more than 24 hours of caspofungin, micafungin, or anidulafungin, or receipt of one dose of rezafungin, before enrolment. 5. PCP is no longer considered the most likely diagnosis at the time of randomization. 6. PCP therapy has already been escalated or changed for presumed treatment failure before enrolment. 7. Death is deemed imminent (\<48 hours), as determined by the treating team and site investigator. 8. Treatment with antifungals is inconsistent with the patient's advanced care directives. Administrative Exclusion Criteria 1. Inability to obtain informed consent, or refusal to consent by the patient or substitute decision maker. 2. Treating team declines participation. 3. Inability to ensure reliable follow-up (e.g., lack of means of communication or patient non-resident of the jurisdiction). 4. Prior enrolment in ECHINO-PCP.