Study of PRA-216 in Healthy Participants and Participants With Mild-to-Moderate Asthma

Phase 1 Inclusion Criteria: * Age 18-65 * Must be in good health with no significant medical history * Willing and able to attend all study visits, comply with study requirements * Able and willing to provide written informed consent Exclusion Criteria: * Evidence of clinically significant condition or disease * Any physical or psychological condition that prohibits study completion * Known history of illicit drug use or drug abuse, harmful alcohol use (at the Investigator's discretion), alcoholism, and/or smoking or nicotine-containing product use within 3 months prior to the first dose of study agent * History of severe allergic reactions or hypersensitivity * Donation or loss of ≥ 1 unit of whole blood or plasma within 2 months prior to dosing Phase 2a Inclusion criteria: * Age 18-65 * Must be in good health with no significant medical history * Willing and able to attend all study visits, comply with study requirements. * Able and willing to provide written informed consent * Documented asthma diagnosis prior for at least 12 months prior to screening. * Symptomatic asthma * Currently receiving maintenance asthma medications Exclusion Criteria: * Evidence of clinically significant condition or disease * Known history of illicit drug use or drug abuse, harmful alcohol use (at the Investigator's discretion), alcoholism, and/or smoking or nicotine-containing product use within 3 months prior to the first dose of study agent * Donation or loss of ≥ 1 unit of whole blood or plasma within 2 months prior to dosing * History of severe allergic reactions or hypersensitivity * Current or former smoker with a smoking history of ≥10 pack-years * Receipt of immunosuppressant therapies or biologic therapy for asthma within 6 months of screening * Other investigational agent(s) within 30 days of dosing