Treatment comparisons between each berotralstat dose and placebo in the rate of investigator-confirmed HAE attacks during the Part 1 dosing period were analyzed using a negative binomial model. The number of investigator-confirmed attacks was included as the dependent variable, the treatment was included as a fixed effect, the stratification variable (baseline attack rate) was included as a covariate, and the logarithm of duration on treatment was included as an offset variable. The estimated attack rate for each treatment group, the treatment differences expressed as the attack rate ratio (berotralstat over placebo rate ratio), and the associated 95% confidence intervals (CIs) were provided from the negative binomial model.

The safety data was assessed for the safety population, for subjects who entered Part 2 and Part 3, and includes TEAEs that began in Part 2 or 3, respectively, for these subjects. Safety data for Part 2 and Part 3 is combined to clearly show TEAEs occurring in subjects as the proceeded through the 2 study parts. TEAEs are defined as AEs that occurred on or after first dose of study treatment, whether in Part 1 or 2, and were assigned to the relevant treatment depending on when the TEAE began (Part 2 or Part 3 treatment). No statistical analysis was performed on this safety data.

The number and percentage of subjects with treatment-emergent adverse events.