An adverse event (AE) was any untoward medical occurrence in a clinical trial Participant whether or not it appeared to have a causal relationship with the treatment administered. Treatment-emergent AEs were defined as AEs with onset at the time of or following the first exposure to open-label DX-2930 in this study, or medical conditions present prior to the start of treatment but increasing in severity or relationship at the time of or following the start of treatment.

HAE attack was defined as a discrete episode during which the participant progressed from no angioedema to symptoms of angioedema. Rate of investigator confirmed HAE attacks was analyzed using a generalized linear model (GLM) for count data assuming a poisson distribution with a log link function and Pearson chi-square scaling of standard errors to account for potential overdispersion. The logarithm of time in days each subject was observed during the treatment period was used as an offset variable in the model.

A SAE was any adverse experience occurring at any dose that resulted in any of the following outcomes: Death, Life-threatening experience, required inpatient hospitalization or prolongation of existing hospitalization. Resulted in persistent or significant disability or incapacity. Was a congenital anomaly or birth defect. Was considered to be an important medical event. An AE was considered treatment-emergent if the onset time was after administration of study drug through the Day 120 post-dose final follow-up visit or, in the event that onset time preceded study drug administration, the AE increased in severity during the 120-day post-dose follow-up period.