Dr. Bill Sheridan
Analyst · JPMorgan. Your line is now open
Thank you, Jon. I'll start with the HAE program and the data we just reported last week from the ZENITH-1 trial at the AAAAI Meeting. You’ll recall that ZENITH-1was a Phase 2 dose ranging proof-of-concept trial designed to estimate treatment effect, evaluate safety and tolerability, select clinically meaningful endpoints for a Phase 3 registration trial, and to identify the distance to advance. We are thrilled that ZENITH-1 clearly achieved all its objectives. This trial also broke new ground as the first prospective randomized placebo-controlled trial of acute HAE treatment administered at-home by the patients early in the course of the attack, with a goal of stopping escalation and attack symptoms. This aligns with modern treatment guidelines and is an important element of treatment that has got a disease impact. We selected the three dose levels to test based on clinical PK profiles. As you can see on Slide 9, we had previously reported at all HAE subjects in a PK study dose considering 150 milligrams had drug levels more than 8 times EC50 within 30 minutes sustained through 24 hours post dose. This long duration of action is important given the recent evidence of the high rate of re-dosing with short half life acute HAE treatments. With ZENITH-1 completed, we now have real world controlled clinical trial results confirming its rapid onset of action and 24 duration of effect, with single oral doses of 7353 and to create dose response going from 250 milligrams to 750 milligrams. As Jon noted, in September, we reported results showing clinically meaningful and statistically significant treatment effects from our 750 milligram dose, together with a favorable safety and tolerability profile, strongly supporting advancing the 750 milligram dose to Phase 3. Most noteworthy additional data from the 250 milligram and 500 milligram cohorts reported last week at AAAAI was the clear dose response we observed across multiple endpoints. This is reflected on Slide 12 with the examples of improvements in visual analog scale scores and proportion of subjects who use rescue medicine. As detailed on the safety summary Slide 13, 7353 was generally safe and well tolerated with no notable differentiation from the adverse event profile from placebo. The next step for the acute program for 7353 is to meet with regulators to discuss the Phase 3 trial with goal of starting patient enrollment over the summer. The prophylactic program also continues to make excellent progress. As Jon noted, the 24-week safety and efficacy readout from APeX-2 is on schedule for the second quarter. As a reminder, the trial enrolled very quickly. In fact, over-enrolled, with 121 subjects and is now powered at 99% to detect a 50% reduction in attack rate versus placebo. We look forward to sharing the results with you in the second quarter. Both APeX-2 and our safety trial APeX-S continue to progress well. Patients have now started to enter an extension period beyond 48 weeks of dosing. That is continued daily oral treatment through 96 weeks. In parallel, the team has made an excellent start on our regulatory filings and we remain on schedule to file a New Drug Application with the FDA by the end of the year and a Marketing Authorization Application with the EMA in the first half of 2020. We recently enrolled our first patient in the APeX-J trial in Japan, which is being conducted to support the J-NDA. This trial is a 24-subject, randomized, placebo-controlled trial, similarly designed to APeX-2, using the same dosage of 7353. Because there are no prophylactic treatments for HEA approved in Japan, the unmet need there for HAE patients is high and clear. Now, I'm very excited to tell you more about 9930, our oral Factor D inhibitor for complement-mediated diseases, which is advancing into Phase 1 clinical development. Today, patients with complement-mediated diseases either have no specific treatment options or must be treated with lifelong IV infusions. The only approved therapies in this field work to inhibit a terminal component of the complement cascade C5. Factor D is critical enzyme in the alternative complement pathway that drives amplification of the entire complement system upstream to C5. With this mechanism of action of the Factor D inhibitor, we believe that 9930 is a potential treatment for a broader range of complement-mediated disorders. Potential indications for 9930 include many rare diseases of the kidney, blood, and nervous system. Treatment with oral 9930 could fundamentally transform patients' lives and improve on existing therapies. The preclinical profile of oral 9930 is extremely attractive, and after oral dosing in non-human primates, complement activity was immediately and dramatically suppressed. In preclinical studies, this compound was potent, specific and had a very wide safety margin. Let me now walk you through the data that has us so excited. On slide 18, the left hand table reports the consistent in-vitro potency of 9930 across multiple complement assays. These include measurement of Factor D enzymatic action, complement-mediated destruction of red blood cells of hemolysis and deposition of complement enzyme C3 fragment on the surface of red cells for patients with PNH. The specificity values in the right-hand table indicate a low likelihood of off-target effects on other serine proteases. An important preclinical proof-of-concept test for 9930 was to dose animals orally and measure its effects on the complement cascade. This experiment answers the fundamental question, does enough drug get absorbed to work on the target. We use standard assay in this field hemolysis of heterozygous red cells. On Slide 19, you can see that after dosing non-human primates, 9930 rapidly suppressed complement activity with near complete suppression of complement-mediated hemolysis by 24 hours despite the 50% lower potency of 9930 on non-human primate Factor D compared to human Factor D. Of note, the drug exposure needed was a fraction of the no observed adverse event level, or NOAEL exposure, in preclinical safety studies. The preclinical safety margin of 9930 that supports entry into clinical trials is also very encouraging. On slide 20, you can see first, that with still very high drug exposures proportional to dose and second that drug levels for the NOAELs of 9930 were more than 500 times greater than the estimated therapeutic target level with an associated human equivalent dose of more than 5,000 milligrams. This dose is so much higher than needed for target pharmacodynamic effects that it will never be necessary to study it in the clinic. The preclinical safety and pharmacology profile of 9930 should provide us with tremendous dosing flexibility. Based on its preclinical PK PD and safety profile, we expect that we'll be able to safely dose oral 9930 in people and achieve drug levels that block the complement cascade. The proof-of-concept can be very efficient in this field. Complement assays and many validated and highly predictive disease related biomarkers are already very well established. By using these tools in our clinical studies, we will be able to see proof-of-concept in a matter of days or weeks in most cases, with very small patient numbers. We look forward to seeing the results from our single ascending dose and multiple ascending dose Phase 1 trial when it reads out in the fourth quarter. In summary, the body of preclinical evidence for 9930 suggests that we have a great molecule here. We are driving hard to-proof-of concept in patients and we can do this very quickly because complement assays and disease biomarkers are so good, needing very few patients to generate convincing evidence. We believe oral 9930 could represent a pipeline and a product with the potential to address many different complement-mediated disorders. Now, I'd like to turn the call over to Lynne.