Dr. Bill Sheridan
Analyst · Jessica Fye with JP Morgan. Your line is now open
Thank you, Jon. As related to data readout from ApeX-2 this quarter, we thought it would be helpful to review with you how we will approach the doctor [ph] analysis around the primary endpoints and the secondary endpoints in this trial. APeX-2 is a randomized, double-blind, placebo-controlled, three-arm trial testing two dose levels of orally administered once daily BCX7353, 110 milligrams and 150 milligram for prevention of angioedema attacks. 121 patients with Type I and Type II HAE were randomized from centers in the United States, Canada and Europe. As a reminder, the trial enrolled very quickly. In fact, it over-enrolled and with 121 subjects is powered at 99% to detect 50% reduction in attack rate versus placebo. To qualify for the trial, patients were required to have two investigator-confirmed HAE attacks during the running period of between 14 and 56 days from screening visit by a minimum rate of 1 per 28 days. In previous trials, the mean baseline attack rate was always much higher than the minimum requirement. We expect this will also be case in APeX-2 and that the mean baseline attack rate should be in the range of two to four per 28 days. The primary efficacy endpoint of APeX-2 is the rate of investigator-confirmed angioedema attacks over 24 weeks of study drug administration. So, the analysis will compare the on-study attack rates patients receiving 7353 at each dose level to the on-study attack rates of patients receiving placebo. As specified in the protocol and agreed with the regulators, the analysis will use a well established statistical approach called the Hochberg's step-up procedure. This controls familywise Type I error associated with multiplicity study arms and does not require specification of order of testing of the doses. In this procedure, each of the two dose levels of 7353 is tested against placebo for the primary endpoint. Statistical significance is met for both arms is both p values of less than 0.05. If the largest p value is more than 0.05, then in the other arm, statistical significance is declared if its p value is less than 0.025. In addition, hierarchical testing is used to control the Type I error rate for multiple endpoints. Testing may only proceed to the secondary endpoints if statistical significance is met for at least one dose for the primary endpoint. The secondary endpoints for the 24-week analysis of APeX-2 are in hierarchical order of testing, changed from baseline in the angioedema quality of life, score at week 24; the portion of days with angioedema symptoms through 24 weeks; rate of investigator-confirmed HAE attacks during dosing in the effective treatment period, beginning on day eight through 24 weeks. The secondary endpoints reached those levels that meet the primary endpoint tested in the order I just mentioned. Statistical significance of each test allows testing as the next secondary endpoint. If the single dose proceeds to the next level in the hierarchy, statistical significance at the next level in the hierarchy declared is p less than 0.025. In the absence of statistical significance, subsequent endpoints to that dose level are not tested. Following completion of the 24-week blinded placebo-controlled study period in APeX-2, subjects continue in an ongoing extension phase through 48 weeks. Patients initially randomized with placebos are re-randomized to receive one of the two 7353 doses in the extension phase, and patients initially randomized with 7353 continue on the same dose. Subjects in APeX-2 who complete 48 weeks with 7353 will contribute to the NDA long-term safety database of 100 patients. Our APeX-S long-term safety study also contributes to this total. Both of these studies continue to progress well. And we are on target for NDA filing by the end of the year and an MAA filing in the first quarter of 2020. As Jon mentioned, we are also on schedule to begin a Phase 3 study with our acute program in summer. And I would note that data from our Phase 2 ZENITH-1 trial will be presented at the upcoming C1-inhibitor workshop in Budapest in May and also at the EAACI Congress in Lisbon in June. Now, I’d like to turn the call over to Tom.