Study design.
The full trial protocol is available in Supplementary information. While the trial was partially supported by a research agreement from AstraZeneca, the design and conduct of the study were performed entirely by the investigators. All study procedures were conducted at a single site — Johns Hopkins University School of Medicine — in accordance with international ethics guidelines and local ethical and legal requirements, including the Declaration of Helsinki. Study visits were completed in the Clinical Research Unit at the Johns Hopkins University Bayview Campus in Baltimore, Maryland after written informed consent was obtained. All study visits occurred between December 2021 and October 2022. Patients stopped all antihistamines and medications with antihistamine properties at least 1 week before study visits in preparation for skin puncture testing and OFC. At Visit 1, medical history, vital signs, height, and weight were collected, and an electrocardiogram was performed (