Enanta Pharmaceuticals - Q2 2024

Executive Summary

• Q2 2024 revenue was $17.1M, all from AbbVie MAVYRET/MAVIRET royalties; diluted EPS was a loss of $1.47. Net loss improved year over year to $(31.2)M from $(37.7)M in Q2 2023.
• Management raised full‑year expense guidance at the fiscal mid‑point: R&D to $125–$145M and G&A to $50–$60M, citing acceleration of RSV studies, new immunology programs, stock comp, and legal costs; prior guidance was R&D $100–$120M and G&A $45–$50M in Q1 2024.
• Balance sheet remains strong with $300.3M in cash and marketable securities; company expects liquidity plus retained royalties to fund operations through Q3 fiscal 2027.
• Near‑term catalysts: topline data from the Phase 2a RSV challenge study (EDP‑323) in Q3 2024 and Phase 2 pediatric RSV study (RSVPEDs; zelicapavir) in 2H 2024; RSVHR adult high‑risk enrollment progressing with guidance forthcoming as Southern Hemisphere season advances.
• Strategic expansion into immunology continues; target selection for an oral KIT inhibitor development candidate for CSU is on track for Q4 2024; management aims to announce a second immunology program in 2024.

What Went Well and What Went Wrong

What Went Well

• RSV pipeline momentum: multiple readouts expected this year; management reiterates commitment to “advancing the first antiviral treatment for RSV” and to delivering first‑in‑class replication inhibitors (N‑ and L‑protein).
• Year‑over‑year operating improvement: R&D fell to $35.6M from $43.5M, with net loss narrowing to $(31.2)M from $(37.7)M; CFO highlighted lower COVID‑19 program costs offset by RSV and immunology investments.
• Strong liquidity and runway: $300.3M in cash and marketable securities; expected runway through Q3 fiscal 2027 supported by retained royalty cash flows.

Management quotes:

• “We are committed to advancing the first antiviral treatment for RSV…pending positive data…we will be poised to deliver potential first‑in‑class antiviral replication inhibitors” — Jay R. Luly, Ph.D., CEO.
• “We expect…current cash…as well as our retained portion of ongoing royalties…to be sufficient…through the third quarter of fiscal 2027” — Paul Mellett, CFO.

What Went Wrong

• Modest top‑line declines: Q2 revenue declined to $17.1M from $17.8M YoY, reflecting lower MAVYRET/MAVIRET royalties at the 10% tier.
• Higher non‑operating drag: $2.6M interest expense from royalty monetization; ongoing 54.5% pass‑through of cash royalties to OMERS until the cap is reached.
• Elevated legal and G&A: G&A increased to $14.2M YoY, primarily from patent litigation costs; full‑year G&A guidance raised to $50–$60M.

Transcript

Operator (participant)

Good afternoon, and welcome to Enanta Pharmaceuticals' fiscal second quarter financial results conference call. At this time, all participants are on a listen-only mode. There will be a question-and-answer session at the end of the prepared remarks. Please be advised that this call is being recorded. I would now like to turn the call over to Jennifer Viera, Investor Relations. Please go ahead.

Jennifer Viera (Head of Investor Relations)

Thank you, Operator, and thanks to everyone for joining us this afternoon. The news release with our fiscal second quarter financial results was issued this afternoon and is available on our website. Making remarks on today's call are Dr. Jay Luly, President and Chief Executive Officer, and Paul Mellett, our Chief Financial Officer. Dr. Scott Rottinghaus, our Chief Medical Officer, and Dr. Tara Kieffer, our Chief Product Strategy Officer, will be available during the Q&A portion of the call. Before we begin with our formal remarks, we want to remind you that we will be making forward-looking statements. These statements may include our plans and expectations with respect to our research and development pipeline and financial projections. All of these statements involve certain assumptions and risks beyond our control that could cause our actual developments and results to differ materially from the statements.

A description of these risks is in our most recent Form 10-K and other periodic reports filed with the SEC. Enanta does not undertake any obligation to update any forward-looking statements made during this call. I'd now like to turn the call over to Dr. Jay Luly, President and CEO. Jay?

Jay Luly (President and CEO)

Thank you, Jennifer, and good afternoon, everyone. Throughout 2024, Enanta has remained squarely focused on advancing our virology and immunology pipeline to bring important oral therapeutics to market. Our commitment to developing treatments for areas of high unmet need is driven by our mission to transform patients' lives with curative therapies, and we are determined to achieve our milestones to drive near and long-term shareholder value to fulfill this mission. Our focus is critical as we approach meaningful inflection points with the potential to develop the first antiviral treatment for RSV. With that, today, I'll begin with an overview of our programs, beginning with our respiratory syncytial virus, or RSV, programs, and then discuss our immunology program for chronic spontaneous urticaria, or CSU.

As a reminder, RSV is a severe respiratory infection associated with significant morbidity and mortality that can cause serious disease in infants, children, and other high-risk populations, including the elderly and individuals with congestive heart failure, chronic obstructive pulmonary disease, asthma, or other high-risk conditions. Despite the availability of prophylactic options such as vaccines and monoclonal antibodies, there's a clear need for a safe and effective oral RSV antiviral treatment. Adoption of vaccines has been suboptimal, and breakthrough infections still occur. Additionally, pediatric monoclonal antibodies only provide passive immunity for a few months and not long-term protection against the infection. With this clear need, we have developed a broad clinical program that has the potential to enable multiple opportunities to treat RSV.

RSV pipeline includes the most advanced clinical replication inhibitors, zelicapavir, formerly known as EDP-938, an N protein inhibitor, as well as EDP-323, an L protein inhibitor. Zelicapavir is currently being studied in high-risk patient populations in two phase II studies, RSV Peds and RSV-HR. RSV Peds is a first-in-pediatrics, phase II randomized, double-blind, placebo-controlled study in hospitalized and non-hospitalized RSV patients aged 28 days to 36 months. The study, which will enroll approximately 90 patients, is being conducted in two parts. As this is the first-in-pediatrics study, the objective of the first part is to evaluate the safety and pharmacokinetics of zelicapavir in multiple ascending doses to select the optimal dose for each age group. The second part of the study will evaluate the antiviral activity of zelicapavir at the selected dose, and virology and symptom scores will be assessed throughout the treatment duration.

This study was designed as a small proof of concept in pediatric patients to show a trend toward improved virology metrics for zelicapavir compared to placebo and to give confidence to move forward efficiently into larger registrational studies. A key objective of this study is to show improvement in virology endpoints in patients on zelicapavir compared to placebo, sufficient to allow us to advance into phase III. Currently, we have virtually enrolled the last age cohort of 20 patients in part two of the study. As this cohort can only enroll patients 28 days to 6 months of age, the eligible population is narrower, and we will need to continue to recruit in the Southern Hemisphere. As we monitor the RSV season in the Southern Hemisphere, we anticipate reporting data from this study in the second half of 2024.

RSV-HR is a phase II randomized, double-blind, placebo-controlled study of approximately 180 adults with RSV infection who are at high risk of complications, including the elderly, those with congestive heart failure, chronic obstructive pulmonary disease, or asthma. The primary endpoint for RSV-HR is time to resolution of RSV lower respiratory tract disease symptoms, as assessed by the Respiratory Infection Intensity and Impact Questionnaire symptom scale. Secondary endpoints include additional clinical efficacy measures and any viral activity compared to placebo, pharmacokinetics, and safety of zelicapavir. The primary objective of this study is to show an improvement in time to symptom resolution. Given the study was designed to be a small phase II proof of concept study, it is powered based on a 50% reduction in symptom resolution.

However, as there are no data showing a statistically significant effect on symptoms in community-acquired RSV adult population with which to benchmark, this reduction likely represents a high bar. Therefore, directional efficacy data that is clinically meaningful would provide us with conviction to move directly into phase III. Enrollment is progressing, and we will provide additional guidance on the RSV-HR study as the Southern Hemisphere RSV season evolves. Also ongoing in our RSV portfolio is phase II-A challenge study of EDP-323, which is in development as a once-daily oral treatment for RSV.

In this randomized, double-blind, placebo-controlled study, up to 114 healthy adult subjects will be infected with RSV and then randomized one-to-one to one to receive once-daily dosing of either 600 mg of EDP-323, 200 mg of EDP-323, with a loading dose of 600 mg on the first day, or a placebo for five days. Primary and secondary outcome measures include safety, changes in viral load measurements, and changes in symptoms from baseline. The development of EDP-323 is supported by positive phase I results, in which the drug demonstrated favorable safety, tolerability, and pharmacokinetics in healthy volunteers. We anticipate reporting data from this challenge study in the third quarter of 2024. We believe either zelicapavir or EDP-323 would be effective as a monotherapy.

Because they do not have cross resistance, we could also potentially use them in combination to broaden the treatment window or expand the eligible patient population to harder-to-treat patients. Also, in respiratory virology, data from SPRINT, our phase II study of EDP-235, a 3CL protease inhibitor, was presented in April at the ESCMID Conference, formerly known as ECCMID. We are pleased to present this comprehensive data package in a scientific forum for the first time. As a reminder, we will conduct any future COVID-19 work in the context of a collaboration. I'll now turn to our work in immunology, where we are concentrating on indications with a high unmet medical need and a clear clinical development path, including well-defined populations and biomarkers available for early signs of efficacy. Our first immunology indication is CSU, a severely debilitating chronic inflammatory skin disease, which can continue for years before remission.

Clinical manifestations include urticaria, commonly called hives, as well as angioedema, which is characterized by pronounced deep tissue swelling. The disease can be severely disabling, significantly impair quality of life, and affect performance at work or school, as patients with CSU can experience symptoms beyond the skin manifestations, including sleep disturbances, fatigue, irritability, anxiety, and depression. CSU is estimated to affect 0.5%-1% of the global population at any given time. The standard of care for CSU is antihistamines, but in approximately half the patients, symptoms are not alleviated, and a minority of patients are treated with one indicated biologic. Consequently, there is a substantial unmet need for a new efficacious drug that can be conveniently dosed as an oral agent. Mast cells are the primary driver for disease in CSU, as well as being involved in multiple other allergic diseases.

In our first immunology program, we are seeking to develop a best-in-disease oral KIT inhibitor treatment that reduces the number of mast cells available to drive pathology in patients suffering from CSU. We are also encouraged by the potential to study KIT inhibition in additional indications. Currently, our prototype KIT inhibitors in preclinical development demonstrate potent inhibition and are highly selective for KIT. We continue to optimize these leads around potency, selectivity, and DMPK properties, and we are on track to select a development candidate in the fourth quarter of 2024, and plan to move into the clinic shortly thereafter. We are excited about our pipeline growth into immunology and are confident in the team's ability to translate the learnings from our previous success with small molecule drugs to enable our development of a best-in-disease therapeutic for CSU.

We are also pursuing additional immunology targets and look forward to introducing a second program this year. Beyond our pipeline, I would also like to take a moment to welcome Matthew Kowalsky as our Chief Legal Officer, who joined last week. Matt is a strong addition to our team as he brings more than 20 years of experience in the life sciences industry, handling corporate governance, public company reporting, intellectual property, financing, business development, and M&A activities. At Enanta, he will lead all legal and compliance activities for the company and provide strategic guidance and corporate governance oversight. With that, I'd like to conclude by highlighting our upcoming milestones. We anticipate reporting data from the phase II A challenge study of EDP-323 in the third quarter and reporting data from the phase II pediatric study of zelicapavir in the second half of this year.

Further, we plan to identify a clinical candidate for our CSU program in the fourth quarter. And finally, we also plan to announce a second immunology program this year. Now I'll turn the call over to Paul to discuss our financials. Paul?

Paul Mellett (CFO)

Thank you, Jay. I would like to remind everyone that Enanta reports on a September 30th fiscal year schedule. Today, we are reporting results for our fiscal second quarter, ended March 31st, 2024. For the quarter, total revenue was $17.1 million and consisted of royalty revenue earned on AbbVie's global Mavyret net product sales. This compares to total revenue of $17.8 million for the same period in 2023. As a reminder, our royalties are calculated on a calendar year basis. Therefore, royalties for our fiscal first quarter, ending December 31, were calculated at 12%, the highest royalty rate for the year, and royalties for our fiscal quarter, ending March 31st, are calculated at 10%, our lowest royalty tier.

Of note, 54.5% of Enanta's ongoing royalties from AbbVie's net sales of Mavyret that are included in our revenue are being paid to OMERS, the royalty buyer in our April 2023 royalty sale transaction. For financial reporting purposes, the sale transaction was treated as debt, with the upfront purchase payment to us of $200 million recorded as a liability. As such, we continue to record 100% of the royalties earned as revenue and will then amortize the debt liability at 54.5% of the cash royalty payments are paid to OMERS through June 30, 2032, subject to a cap of 1.42x the purchase payment, after which point 100% of the cash royalty payments will be retained by Enanta.

Interest expense for the debt will be recorded in Enanta's consolidated statement of operations based on an imputed interest rate. Interest expense was $2.6 million for the three months ended March 31, 2024. Moving on to other expenses. For the three months ended March 31, 2024, research and development expenses totaled $35.6 million, compared to $43.5 million for the same period in 2023. The decrease was primarily due to a decrease in costs associated with our COVID-19 program, as we previously announced that plans to pursue any future COVID-19 efforts would be in the context of a collaboration. This was partially offset by increased costs associated with our RSV program and our recently announced immunology programs. General and administrative expense for the quarter was $14.2 million, compared to $13.8 million for the same period in 2023.

This increase was primarily due to an increase in legal expenses related to a patent infringement lawsuit against Pfizer. Enanta recorded an income tax benefit of $0.4 million for the three months ended March 31, 2024, for interest earned on a pending $28 million federal income tax refund, compared to an income tax expense of less than $0.1 million for the three months ended March 31, 2023. Net loss for the three months ended March 31, 2024, was $31.2 million, or a loss of $1.47 per diluted common share, compared to a net loss of $37.7 million, or a loss of $1.79 per diluted common share for the corresponding period in 2023. At this fiscal year midpoint, we are updating our expense guidance.

We now expect our research and development expense to be between $125 million and $145 million, and our general and administrative expense to be between $50 million and $60 million. The research and development expense increase reflects the impact of our new immunology program, as well as additional efforts to accelerate our RSV clinical studies. The general and administrative expense increase is due to additional stock compensation expense and costs associated with pursuing our patent infringement lawsuit. Enanta ended the quarter with approximately $300 million cash and marketable securities. We expect that our current cash, cash equivalents, and short-term marketable securities, as well as our retained portion of ongoing royalties, will continue to be sufficient to meet the anticipated cash requirements of our existing business and development programs through the third quarter of fiscal 2027.

Further financial details are included in our press release and will be available in our report on Form 10-Q when filed. I'd now like to turn the call back to the operator and open up the lines for questions. Operator?

Operator (participant)

And thank you. As a reminder, to ask a question, please press star one one on your telephone and wait for your name to be announced. To withdraw your question, please press star one one again. Please stand by while we compile the Q&A roster. And one moment for our first question. And our first question comes from Akash Tewari from Jefferies. Your line is now open.

Speaker 13

Hi, this is Kathy on for Akash. So I had a question for RCPs. Since RCPs isn't explicitly powered to hit on viral loads or symptoms, what will you be looking at in terms of the data to inform your design for phase III? And as such, how should we think about gauging efficacy or safety? And then how much of a read-across do you believe the data will have for RCHR? And then are you expecting a symptom benefit of, like, one or two days? Thank you.

Jay Luly (President and CEO)

Thanks for the question. This is Jay. I think I'll hand it over to Tara Kieffer to talk about how we're gonna be viewing the data set coming out of Peds. Tara?

Tara Kieffer (Chief Product Strategy Officer)

Sure. Yeah, so the RCP study is our proof of concept phase II study in pediatrics. So we have to think about it a little bit differently than our adult study in phase II, because this is the first time that we're dosing children in this young age range of 28 days to three years. So we have to first confirm the safety profile and the dose. And so it's the study's been done in two parts. Part one, the primary endpoint is safety and PK, and done in a dose-escalating fashion, and we select the optimal dose from that part, which is then studied in part two. In that part, the primary objective is to look at the virology endpoint.

So, so we're primarily, again, looking for improvement in virology endpoints between the patients on EDP-938 or zelicapavir and placebo, with directional data that would give us the confidence to move into a phase III study. So we'll, we'll look at a number of different virology endpoints. We'll also look at the clinical endpoints as well. But primarily, we'll be looking at virology. You know, it's hard to give a specific threshold or a bar in terms of what we're looking at, because there's, there's not a lot of data out there in RSV for naturally acquired RSV in children. But there's one study that we can point to from a company called ArkBio, that did a phase III study in pediatrics in China.

And they did show a 0.6 log drop at day four, a statistically significant effect in virology. And they also, in that same study, demonstrated an improvement in symptoms. So we're, you know, not able to really give any kind of a bar that we're looking for, but we're really interested in the totality of the data and showing those trends and directional data that would give us the confidence to move into a larger, you know, more well-powered study to able, you know, tease out these effects.

Does that answer your question?

Operator (participant)

Thank you. One moment for our next question. Our next question comes from Eric Joseph from JP Morgan. Your line is now open.

Eric Joseph (Biotechnology Equity Research Analyst)

Great. Thank you. Just a couple of questions related to the immunology program, I guess, for this KIT development candidate. Can you talk a little bit about your strategic plans with respect to clinical development there? I guess, to the extent you might be seeking a strategic partner at some point along the way, are there-- is there a certain sort of hurdles kind of milestones you'd want to see cleared first? And then, secondly, just noting that you're looking to expand into or expand with a second immunology program. Can you give us a bit of a preview there, in terms of either target you might be pursuing? Are you perhaps doubling down on KIT? Thanks very much.

Jay Luly (President and CEO)

Thanks, Eric. This is Jay. So we're working up a few different approaches in parallel to, you know, figure out which we might prioritize, you know, going forward. So it's a little early to be discussing that. I think you asked, were we doubling down on KIT? I mean, we have one major KIT program now. I think we're looking to broaden beyond that. And so we'll provide more detail as the year progresses and after we've generated more data in-house, made more molecules in-house, filed intellectual property, and so forth. So stay tuned on that front. With regards to... I wasn't quite sure on your, the first part of your question, you were talking about strategic partnering.

I mean, our plan, just in a nutshell, initially at least, is to, again, identify the candidate in the fourth quarter. We're gonna be aiming to get it into the clinic, hopefully rapidly thereafter. And then, you know, phase I, I think, should be fairly straightforward and healthy. The nice thing is, with this mechanism, you can get sort of surrogate readouts of target engagement by looking at tryptase changes. So that'll help a lot, you know, having the biomarker available to us. And then, you know, the clinical development in CSU, I think is actually, you know, pretty straightforward. So we would be thinking about progressing to a fairly straightforward proof of concept study. It's a defined, accessible, and large patient population.

So, you know, we hopefully won't have the, you know, the seasonal trends that we experience in RSV. And, you know, are looking very much forward to progressing that first program in immunology and then, you know, again, bringing on additional targets and mechanisms as time goes on.

Tara Kieffer (Chief Product Strategy Officer)

Can I just add one thing to that, Jay, is the biomarker that Jay mentioned we can monitor in phase I in healthy volunteers is tryptase, serum tryptase. You know, there's a lot of data, excuse me, out there generated from some of the monoclonal antibodies against KIT from Celldex that have nicely been able to show a tight correlation with impacts on that biomarker and ultimate clinical outcomes. So I think, you know, it's something that really can de-risk the program early on in those phase I studies.

Eric Joseph (Biotechnology Equity Research Analyst)

That's great. Thanks for taking the questions.

Jay Luly (President and CEO)

You're welcome.

Operator (participant)

Thank you. One moment for our next question. Our next question comes from Ed Arce from H.C. Wainwright. Your line is now open.

Thomas Yip (Equity Research Associate)

Hi, good afternoon, everyone. This is Thomas Yip asking a couple of questions for Ed. Thank you for taking our questions. So first, can you outline what's your estimate of the patient population breakdown between the Northern and Southern Hemisphere to date, both for the RSV peds study and also for the HR study as well?

Jay Luly (President and CEO)

Are you making reference to numbers of sites? You say patient population, but are you talking about markets, or are you talking about clinical trial conduct?

Thomas Yip (Equity Research Associate)

More on the clinical trial conduct, so perhaps the number of sites. So both the number of sites or the number of patients enrolled, just a ballpark vantage.

Jay Luly (President and CEO)

Yeah, I don't have the exact figures in front of me. We have... I mean, maybe Scott, maybe I'll just let you amplify on that.

Scott Rottinghaus (Chief Medical Officer)

Yeah, sure. Thanks, Jay. So we've enrolled patients in both Northern and Southern Hemispheres in both the pediatric and the high-risk studies, including in, you know, the current season ongoing in the South. So I don't have the exact numbers in front of me either, but we are continuing to enroll actively in both of those studies. And as Jay mentioned on the call, in the pediatric study, in particular, we're down to the last cohort and enrolling in the South.

Jay Luly (President and CEO)

Yeah, but I think directionally, maybe your question, the Northern Hemisphere, beyond question, is more highly represented in terms of clinical trial sites than the Southern Hemisphere. I mean, we're in many different European countries, many different North American countries. We're in Asia. In the Southern Hemisphere, we're in South Africa, we're in Brazil, we're in Argentina, New Zealand, Australia. Not as large a footprint in the Southern Hemisphere, but you know, but nonetheless, we're hoping to make good progress on enrollment in that and wrap this up as soon as possible.

Thomas Yip (Equity Research Associate)

Understood. And as a follow-up on that, can you remind us how much overlap are there between the Southern Hemisphere RSV season and flu season? And also, do you expect, to that point, for the HR study, do you expect the study to complete enrollment kind of in line with the conclusion of the Southern Hemisphere RSV season?

Jay Luly (President and CEO)

Was the first question about overlap with the flu season?

Thomas Yip (Equity Research Associate)

Yes. How much overlap are there between the RSV season and the flu season?

Jay Luly (President and CEO)

I mean, generally, they're somewhat correlated, but, you know, even in any given year, they can deviate a little bit one way or the other. Flu could come on a little earlier or a little later, come on twice. RSV has been, and flu, but especially RSV, have been substantially impacted by the pandemic years in terms of just, you know, only more recently starting to settle down into what we would call more normal seasonality. So I think, again, we follow, we track the RSV season much more closely than flu. As it relates to HR, my guess is we'll need to come back to the Northern Hemisphere, given that we, again, have just much stronger footprint there. We made excellent strides in the Northern Hemisphere this year.

That's why, especially in the United States, it was, it was a very nice season for us. So, we may need, we, we may need some of that as well. We'll, again, we'll be tracking this, and reporting progress, later this summer, you know, when we're well into the Southern Hemisphere season, and we'll be able to forecast a little bit better based on, you know, more current data. But that's, that's my expectation.

Thomas Yip (Equity Research Associate)

Okay, understood. Thank you again for taking our questions, and we look forward to the progress in the second half of this year.

Jay Luly (President and CEO)

Thank you. You're welcome.

Operator (participant)

Thank you. One moment for our next question. Our next question comes from Roy Buchanan from Citizens JMP. Your line is now open.

Roy Buchanan (Equity Research Analyst)

Hey, thanks for taking my question. Just a couple on RSV. Jay, for the RSV-HR, I think I heard you say that it was powered for a 50% reduction in symptoms, and it's probably a high bar. Just wondering where that, I guess, conclusion about it being a high bar comes from. I think the challenge trial, you had a 75% reduction in symptoms. And are you just interpolating between that and RSV-P, or is there something you're seeing in the trial?

Jay Luly (President and CEO)

Yeah, so to be clear, we're talking about time to resolution of symptoms, so it's different than in the challenge. We're looking at the, you know, the number of days improvement in time to resolution of symptoms versus placebo. I mean, I can give a little color on that. I think, for example, with flu, in a placebo study, and Tara can correct me if I'm wrong, there's about a four-day time period for time to resolution, and Tamiflu will shorten that by a day. So it's a three-day time resolution. So it's a one-day shortening out of four days. That's a 25% improvement in time to resolution.

You know, the way this was powered with HR and in order to keep it a relatively small study of only just under 200 patients, it was powered on a 50% effect. Had we powered it on a 25% effect, the, the study would be even much larger. So it's that fine balance of running a phase II study that is enabling of a pivotal trial, keeping it at a manageable size. We felt with a couple hundred patients, even though it's a high bar to to reach stat signal on the way it was powered, we should be able to make good decisions based on clinical- clinically meaningful improvements.

Again, shortening time to resolution of symptoms by one or more days, you know, would be clinically meaningful.

Roy Buchanan (Equity Research Analyst)

Yeah. Okay. Makes sense. And then the, for the EDP-323 challenge, just what are you hoping to, to see there? You know, we've said many times the zelicapavir data is probably best in class. Are you expecting to see something similar? Do you need to see something similar? Just help us think about that. Thanks.

Jay Luly (President and CEO)

Yeah, you know, zelicapavir does set a high bar. You know, the mechanism is an N protein inhibitor. It is about the best challenge study data in any book companies ever put on the boards. So it does represent a high bar. That said, EDP-323 is another mechanism. It's a polymerase inhibitor. It's a picomolar polymerase inhibitor, so it's super potent. You know, can we replicate the same best-in-class data that we saw with zelicapavir? You know, we'll see. Hopefully, yes. It's hard to do much better. I think we wanna be in the same range to declare it as a, as a strong, you know, player in the field.

But, you know, based on, every bit of data that we have pre-clinically in our phase I data, which showed good safety, tolerability, wonderful exposures after QD dosing, and again, very, very strong virology. You know, we've set it up about as best as we can. We're running it, at the same clinical site as we ran the zelicapavir trial. So, you know, we'll see. So we should have, data for that, in, Q3. Next, next quarter.

Roy Buchanan (Equity Research Analyst)

Okay. Thank you.

Jay Luly (President and CEO)

You're welcome.

Operator (participant)

Thank you. One moment for our next question. Our next question comes from Roanna Ruiz from Leerink Partners. Your line is now open.

Nik Gasic (Equity Research Associate)

Hey, this is Nik Gasic on for Roanna. Thanks for taking our questions. Maybe first on RSV, could you give us a sense of how close you are to completing enrollment of the younger age cohort of RSVP? Maybe how long, you know, do you think it could take to analyze and ultimately share the data afterward?

Jay Luly (President and CEO)

Yeah. Again, so there are two parts to the study. Part one is completed in all age cohorts. Part two of this study is done in the older age cohorts, and we're down to the final cohort of 20 patients. It's the youngest children from age 28 days to six months, and we've been actively recruiting that cohort. So, you know, we're in the home stretch, and we just unfortunately, you know, we can- our pool of patients is now only 1/6 of what it was based on age groups, so it's a narrower pool, and they, you know, any older children, you know, we really have to, we can't enroll in the study anymore. So we're just really zeroed in, focused on getting the remaining young children to fill out this cohort.

Nik Gasic (Equity Research Associate)

Got it. Thanks, Jay. And then maybe on CSU, curious, you know, what are you hoping to see in a future phase I, for your oral KIT inhibitor in terms of safety? Maybe how should we think about, frequency of administration for this asset? Is it a once daily, twice daily, how should we think about that?

Jay Luly (President and CEO)

Well, we're still, you know, finalizing the candidate. Again, we're targeting to have the finalist in Q4. But suffice it to say, we're very much zeroed in on QD dosing. You know, we've made molecules that are very potent, they're very selective. We're optimizing DMPK profiles, tissue distribution, a number of other sorts of parameters like that, to make it the kind of candidate that we typically bring forward. So, we've already shown data on a strong prototype, and we continue to, the chemists are very busy. Well, not just chemists, but, you know, the chemists and all the, the biology people who are doing the characterization and our DMPK and safety team are working very, very diligently on this.

So we would be aiming for a QD candidate that would have, you know, the best safety profile we can provide, as well as has good potency and selectivity.

Nik Gasic (Equity Research Associate)

That's helpful. Thank you.

Jay Luly (President and CEO)

You're welcome.

Operator (participant)

Thank you. One moment for our next question. Our next question comes from Brian Skorney from Baird. Your line is now open.

Speaker 12

Hi, this is Luke. I'm for Brian. For EDP-323, can you remind us of your current thoughts on potentially entering phase II-B in otherwise healthy adults, as opposed to starting with the higher risk in pediatric populations like you've done with zelicapavir? Would you wait for RSVPs or RSVHR data to make this decision?

Jay Luly (President and CEO)

Yeah, that's a good question. I mean, the short answer is we won't do another RSV study in otherwise healthy adults. They just. We found out from our RSVP trial that they're otherwise healthy folks just resolve the self-resolve the infection so quickly on their own. So they're really not in need of a therapy. We would only focus on high-risk patient populations. And, you know, we're hoping to have an abundance of data here, you know, in the second half. You know, we'll have EDP-323 data, we'll have Peds data. We'll be able to look at the totality of the information and figure out how best to position, you know, EDP-323. So, for us, it's been about bringing another strong mechanism forward.

We've been working on this, you know, from the beginning, I guess. We've been working on it for a few years now, to bring forward another differentiated asset in RSV, and that could, you know, give us the potential for, doing combination therapy down the road in particularly hard to treat patient populations. Potentially, it could help, widen the treatment window, were we to, go after a patient with two drugs rather than one. So it's just, just part of our strategy overall to try to build a leadership position in RSV as a therapeutics company. And the more, the more sort of cards we have to play, I think we, we can come up with ways to, you know, to, to leverage, another asset over time.

The key is getting it up to a strong threshold on the challenge study data first.

Speaker 12

Great. Thank you.

Operator (participant)

Thank you.

Jay Luly (President and CEO)

You're welcome.

Operator (participant)

One moment for our next question. Our next question comes from Liisa Bayko, from EVR. Your line is now open.

Seema Sheoran (Senior Biotechnology Equity Research Associate)

Hi, this is Sima on for Liisa. I have a question on the EDP-323 program. What doses of EDP-323 are you testing in phase II, a human challenge study?

Jay Luly (President and CEO)

... Yeah, so, we're looking at a couple of different dose regimens. So the first is 600 mg straight across for 5 days. The other is 600 mg loading dose on day one, followed by 200 mg on each subsequent day. It's kind of like, in antibiotics, they do that sometimes. They give you a loading dose on day one and then a lower maintenance dose for a few days thereafter. So we just put both of them in. And, I think in theory, either at least based on, you know, calculations and modeling, either has a good chance of demonstrating the activity we want. One obviously is a lower dose and has different cost of goods ramifications, et cetera, et cetera.

So we're just, the challenge study is just such a wonderful way to tease all those kinds of questions out, because you don't have to wait for the season. You can just infect human volunteers, line cohorts up every few weeks and dose them. So, does that, does that answer your question?

Seema Sheoran (Senior Biotechnology Equity Research Associate)

Yeah, that's helpful. Thank you. I had second question on the patent case against Pfizer, because last year, Pfizer said that Paxlovid doesn't infringe the patent because Paxlovid has trifluoro group, which is not described in your patent. So if you can comment on that.

Jay Luly (President and CEO)

Yeah, I really can't get into the discussion on our ongoing patent litigation. The only thing I can say is that, you know, assuming it were to go to trial, we would expect a trial around the end of the year.

Seema Sheoran (Senior Biotechnology Equity Research Associate)

Okay. Thank you. That's helpful.

Jay Luly (President and CEO)

You're welcome.

Operator (participant)

Thank you. If you would like to ask a question, that is star one one. Again, if you would like to ask a question, that is star one one. One moment for our next question. Our next question comes from Jay Olson from Oppenheimer. Your line is now open.

Jay Olson (Biotechnology Equity Research Analyst)

Well, hi, Jay. Thanks for providing the update and taking the questions. On the immunology program, what are the most important differentiators you're looking for with your oral KIT inhibitor candidate versus other oral KIT inhibitors in development? And how are you thinking about positioning oral KIT inhibitors versus other oral therapies for CSUs, such as BTK inhibitors?

Jay Luly (President and CEO)

Thanks, thanks for the question, Jay. I'll let Tara speak to that.

Tara Kieffer (Chief Product Strategy Officer)

Sure. Hi, Jay. So I think, you know, some of the data that's been generated from the monoclonal antibodies against KIT, that would be from, from Celldex, and then an earlier program with Jasper, have indicated that, you know, this target, inhibiting this target has some of the best-in-disease efficacy, at least from the phase II trials that have been, have been run. So, you know, it gives us confidence in the target, and what we're really hoping for our program is to match, or even exceed potentially that efficacy with a good safety profile, just with an oral route of administration. So that's the goal of our program. You know, as you mentioned, there's other companies working on this as well. They're all early, they're all preclinical, at the moment.

There's really only preclinical data at the moment, so it's hard to sort of say what would be differentiated, but I can tell you what our program is looking to achieve, and that would be, you know, something that is able to be dosed QD orally, something that is very potent against KIT, but selective, and so, you know, leading to a good safety profile and just balancing that, that potency and selectivity so that the efficacy and safety profile could potentially be something that you would have as best in class. Then I would just say that the oral inhibitors, you know, may be more tunable.

I think this is something that remains to be proven in the clinic, but, you know, whether they're able to be dosed and tuned more finely than a monoclonal antibody, you can certainly, you know, have a little bit more flexibility over that. So I think remains to be determined, but one potential strategy as well.

Jay Olson (Biotechnology Equity Research Analyst)

Okay, great. Thank you. And then can you just talk about how you're thinking about additional indications in your development plan beyond CSU?

Tara Kieffer (Chief Product Strategy Officer)

Sure. You mean for the KIT inhibitor?

Jay Olson (Biotechnology Equity Research Analyst)

Yes.

Tara Kieffer (Chief Product Strategy Officer)

Yeah. So, you know, the reason that we're interested in KIT is it obviously is a key driver for mast cells, and we know that mast cells have been implicated in a number of different indications. So certainly chronic inducible urticaria or CIndU is something that's also been studied with this target, and there's some good data from the monoclonal antibodies here. EoE or eosinophilic esophagitis is also another indication we'd be interested in. PN as well, and even potentially asthma is something that, you know, one could think about with these types of inhibitors.

Jay Olson (Biotechnology Equity Research Analyst)

Okay, great. That's super helpful. Thanks for taking the questions.

Tara Kieffer (Chief Product Strategy Officer)

Mm-hmm.

Operator (participant)

Thank you. I'm showing no further questions. I would now like to turn the call back over to Jennifer Viera for closing remarks.

Jennifer Viera (Head of Investor Relations)

Thank you, operator, and thanks to everyone for joining us today. If you have additional questions, please feel free to contact us by email or call the office. Have a great night.

Operator (participant)

This concludes today's conference call. Thank you for participating. You may now disconnect.