Bill Sheridan
Analyst · Jessica Fye with JPMorgan. Your line is open
Thanks, Jon, and good morning everybody. First, I would like to review the plan for completion of APeX-1. This trial in HAE patients is designed to estimate the efficacy effect that daily oral capsule 7353 in preventing angioedema attacks, evaluate safety tolerability and drug exposure, and measure the effects of the drug on a target enzyme. To achieve those objectives we're testing a range of doses, from 62.5 milligrams daily to 359 milligrams daily in a three-part design, as indicated on Slide 4. The total planned sample size is 70 subjects, 22 on placebo and 48 on various doses of active drug, 18 at 350 milligrams, 12 each at 250 milligrams, and 125 milligrams, and six at 62.5 milligrams. An update on trial progress is shown on Slide 5. As Jon noted, Parts 1 and 2 of APeX-1 are now fully enrolled, and we are on target to record the second interim analysis in the second quarter. This will include all subjects enrolled in Parts 1 and 2, and further protocol and the statistical analysis plan. Placebo subjects will be pooled from both parts for analysis. I'm pleased to report that in the final segment of the trial, Part 3, we have already randomized six subjects, with another seven subjects currently in screening. We expect to report the complete trial results, with the indicated planned total sample sizes in the third quarter. As indicated on Slide 6, the scope for the second interim analysis will be similar to that of the first, with reports on efficacy, safety, drug exposure, and PD effects on plasma kallikrein. The planned number of placebo subjects in this analysis is 20, 18 from Part 1 and two from Part 2. The planned number of subjects treated with 125, 250, and 350 milligram daily oral 7353 is six, six, and 18, with a total of 30 subjects treated with active drug. The comparisons of interest are also indicated in the panel at the bottom of Slide 6. These include comparisons of placebo to elective dose of combined, and each active dose level separately, and in addition, comparisons across the active dose levels. These analyses should help us further understand the potential of 7353 in this indication, and in framing preliminary thinking about dose selections of Phase 3 efficacy studies. Final petition on doses of Phase 3 will depend on the full study results expected in Q3 this year. Wrapping up the APeX-1 trial remains the number one priority for me and my team, and we very much look forward to then completing the regulatory interactions, and starting the registration Phase 3 program for 7353 as an oral prophylactic treatment in HAE. I'd now like to switch gears and provide some color on our acute treatment trial of oral liquid formulation of 7353 that we announced recently. In our interactions with the disease experts and patient advocates, we have been strongly encouraged to also consider developing 7353 as an acute oral therapy for treatment of angioedema attacks. There will always be a need for safe, effective, and convenient acute treatments, and obviously an oral acute therapy would be very accessible and highly attractive for patients. By developing 7353 oral capsules for prevention and oral liquid for acute treatment, BioCryst will be positioned to provide additional choice to the HAE community. The PK profile of single doses of 100, 250, 500, and 1000 milligrams of 7353 observed in the Phase 1 trial is shown for selected time points in the left-hand set of bar charts, on Slide 7. Single doses in the range of 250 to 1000 milligrams reached the target range of four to eight times the EC50 within one hour. And these levels are measure exceeded for many hours depending on the dose. Within background, we designed ZENITH-1 to explore the potential utility of 7353 as an acute therapy. A broad outline of this trial is shown on Slide 8. Previous trials of intravenous and subcutaneous drugs required the subjects to attend a clinic or a hospital when they had an attack, necessitating sometimes long delays before treatment. These days, patients with HAE most often treat their angioedema attacks at home with IV infusions or subcutaneous injections [indiscernible] taking advantage of that pattern of care and the oral route of our drug to evaluate liquid formulation 7353 administered as soon as possible after onset of symptoms. Patients will not be required to come to a clinic or a hospital to do that. Each subject will participate for a total of thee angioedema attacks with blinded trial therapy delivered in a randomized sequence. The trial is designed to estimate treatment effect of up to three dose levels in different cohorts of subjects. The primary efficacy endpoint is proportion of subjects with improved or stable composite visual analogue scale score at four hours post dose. We look forward to reporting additional details about the ZENITH-1 trial once enrollment has begun, which we expect in the summer. That concludes my update, and Tom will now cover the financial results.