Even though, the administration of functional ACE-2 based biologics has shown to have a good safety profile in a study comprising repeated doses of ACE2-Fc in mice, and soluble ACE2 in Phase I and Phase II clinical trials for human pulmonary arterial hypertension and acute respiratory distress syndrome (ARDS) (ClinicalTrials.gov identifier: NCT04335136 and NCT04583228). The gene discussed is ACE2; the disease is pulmonary arterial hypertension.