A Long-term Study of KT-621 Administered Orally to Participants With Asthma Previously Enrolled in a KT-621 Asthma Study

Inclusion Criteria: * Must have completed all visits of the parent study, per its protocol, up to the end of treatment (EoT) visit. * Must be willing and able to comply with scheduled visits, treatment plan, laboratory tests, other study-related procedures, and questionnaires, including completing the electronic diary (e-diary), for the duration of the study as required by the study protocol. * Must agree to contraceptive requirements in compliance with the clinical study and local requirements. Exclusion Criteria: * Must not have experienced any clinically significant change in health status during the parent study, which, in the opinion of the Investigator, would interfere with participant safety, study evaluations, or compliance with study procedures; or otherwise make the participant unsuitable for participation in this study. * Must not have developed an AE during the parent study, that in the opinion of the Investigator or of the Sponsor's Medical Monitor, could indicate that continued treatment may present an unreasonable risk for the participant. * Must not have met permanent discontinuation criteria and/or permanently discontinued study treatment for any reason during the parent study. * Must not be a member of the Sponsor or site's investigational team or their immediate family. * Must not be unsuitable to enter the study for any other reason, as judged by the Investigator, including potential risk of noncompliance to study procedures.