Q2 2024 Enanta Pharmaceuticals Inc Earnings Call

Participants

Jennifer Viera; IR; Enanta Pharmaceuticals, Inc.

Jay Luly; President, Chief Executive Officer, Director; Enanta Pharmaceuticals Inc

Paul Mellett; Chief Financial and Administrative Officer; Enanta Pharmaceuticals Inc

Tara Kieffer; Chief Product Strategy Officer; Enanta Pharmaceuticals Inc

Scott Rottinghaus; Chief Medical Officer; Enanta Pharmaceuticals Inc

Eric Joseph; Analyst; JPMorgan Chase & Co.

Roy Buchanan; Analyst; Citizens JMP Group, LLC

Nick Asic; Analyst; Leerink Partners

Jay Olson; Analyst; Oppenheimer & Co.

Presentation

Operator

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

Thank you, operator, and thanks to everyone for joining us this afternoon. The news release with our fiscal second quarter financial results. It 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 these statements involve certain assumptions and risks beyond our control that could cause our actual developments and results to differ materially from these 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 CYOJ.

Jay Luly

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 treatments.
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 our RCC, but for SV. pipeline and most advanced clinicals replication inhibitors selling capability or formerly known as EDP. nine, three, eight and protein inhibitor as well as EDP. three, two three and L. protein inhibitor filling capability is currently being studied in high-risk patient populations in two Phase two studies, RSVP. and RSVHR. RCPs as a first in pediatrics, Phase two randomized double-blind placebo-controlled study in hospitalized, a 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 a first pediatric study. The objective of the first part is to evaluate the safety and pharmacokinetics of selling cap of beer and multiple ascending doses to select the optimal dose for each age group.
The second part of this study will evaluate the antiviral activity of selling half of the year at the selected dose and virology on 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, facility capability 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 and virology endpoints in patients on silicon heavier compared to placebo sufficient to allow us to advance into Phase three. Currently, we are fully enrolled the last age cohort, 20 patients in Part two of the study. As this cohort can only enroll patients 28 days to six 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. Our SVHR. is a Phase two 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 our CHR 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 antiviral activity compared to placebo, pharmacokinetics and safety of Zilli catheter. 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 two 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 and community acquired RS., the 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 three.
Enrollment is progressing, and we will provide additional guidance on the RSVHR. study is the southern hemisphere RSV season evolves. Also ongoing in our RSV. portfolio is the Phase IIa challenge study of EDP-323, which is in development as a once daily oral treatment for RSV. And 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 milligrams of EDP-323, 200 milligrams of EDP-323 with a loading dose of 600 milligrams on the first day or placebo for five days.
Primary and Secondary outcome measures include safety changes in viral load measurements and changes in symptoms from baseline to development of EDP-323 is supported by positive Phase one 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 Z cap of your or EDP. three, two three 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 two study of EDP-235, a three CL. protease inhibitor was presented in April at the ESK mid conference, formerly known as estimates. We are pleased to present this comprehensive data package and at scientific forum for the first time as a reminder, we will conduct any future COVID-19 work in the context of the collaboration.
I'll now turn to our work in immunology, where we are concentrating on indications with 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 CSBU, a severely debilitating chronic inflammatory skin disease, which can continue for years for 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 in effect, 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% to 1% of the global population at any given time.
Standard of care for CFC2 as any system means. But in approximately half 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 and CSU as well as being involved in multiple other allergic disease. And 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 and additional indications currently are a prototype KIT inhibitors in preclinical development demonstrate potent inhibition and are highly selective for kids.
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 Koraleski 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. It announced that 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 IIa challenge study of EDP-323 in the third quarter and reporting data from the Phase two pediatric study of Zeltiq half of the year 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

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 by as these global Maverick net product sales. This compares to total revenue of $17.8 million for the same period of 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 Maverick that are included in our revenue are being paid to homeowners. 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 we'll then AmeriChoice amortize the debt liability at 54.5% of the cash royalty payments are paid to owners through June 30th, 2032, subject to a cap of 1.42 times the purchase statement, after which point 100% of the cash royalty payments will be retained by Enanta.
Interest expense from the debt will be recorded in and Antas consolidated statement of operations based on an imputed interest rate. Interest expense was $2.6 million for the three months ended March 31st, 2024.
Moving on to other expenses for the three months ended March 31st, 2020, for 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, the 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 financial recorded an income tax benefit of $0.4 million for the three months ended March 31st, 2024.
For interest earned and attending $28 million of federal income tax refunds 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. And at the end of the quarter with approximately $300 million of 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 I'll open up the lines for questions, operator, and thank you.

Question and Answer Session

Operator

(Operator Instructions) Akash Tewari, Jefferies.

Hi, this is Kathy on for Akash. So I had a question for our CPs since our CP. is an 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 three? 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 our CHR.? And then are you expecting a symptom benefit of like one or two days.

Jay Luly

Thank you and thanks for the question. This is Jay. I think I'll hand it over to Tara Keefer to talk about how we were going to be viewing the data set coming out of Pete's.

Tara Kieffer

To show our A.M. Castle RCT study, as is our proof of concept Phase two study in pediatrics, which think about it a little bit differently than our adult study in Phase two because it's the first time that we're dosing children in this young age range of 28 days to three years. And so we have to first confirm the safety profile and the dose. And so the study has been done in two parts. Part one.
The primary endpoint is safety and PK and done in a dose and dose ascending fashion. And we select the optimal dose from that part, which has been studied in, say, in part two. And that part, the primary objective is to look at the virology endpoints. So we're primarily, again looking for improvements in virology endpoints between the patients on nine three, eight or zero cap Revere and the CFO. And with directional data that would give us the confidence to move into a Phase three study. And so we'll look at a number of different virology endpoints.
We'll also look at the clinical endpoints as well but primarily what we're looking at virology, um, you know, it's hard to give a specific threshold or bar in terms of what we're looking at because there's there's not a lot of data out there in RSV core naturally acquired from RSV in children. But there's one study that we can point to from a company called Arc Bio that did a Phase three 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 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 so showing those trends and directional data that would give us the confidence to move into a larger, more well-powered study to be able to tease out these effects.

Operator

Eric Joseph, JP Morgan.

Eric Joseph

Great. Thank you. And just a couple of questions related to the immunology program, I guess, for the kits development candidate, and 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 out a strategic partner at some point along the way, either, is there a certain sort of thing hurdles kind of milestones you'd want to see clear 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 may be pursuing perhaps doubling down on KIT? Thanks very much.

Jay Luly

Thanks, Eric. This is Jay. So we're we're working up a few different approaches in parallel come to, you know, figure out which we might prioritize going forward. So it's a little early to be to be discussing that. I think you asked where are we doubling down on a kid. I mean, we have one major kit program now. I think we're looking to broaden beyond that, Tom, and so we'll provide more details as the year progresses and after we've generated more data in house, made more molecules and 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 two, again identify the candidate in the fourth quarter. We're going to be aiming to get it into the clinic, hopefully rapidly thereafter. And then some in our Phase one, I think should be fairly straightforward and healthies. 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 having the biomarker available to us and then from the clinical development in MCSU.
I think is actually pretty straightforward. So we would be thinking about progressing to a fairly straightforward proof of concept study on a defined accessible in large patient populations. So here we hopefully won't have the seasonal trends that we experienced in our SVM. and I'm looking very much forward to progressing that first program in immunology and then on again bringing on additional our targets and mechanisms says as time goes on.

Tara Kieffer

Can I just add one thing to that? Jay is and the biomarker that Jay mentioned, we can monitor and Phase one in healthy volunteers is tryptase serum tryptase. There's a lot of data could be out there generated from some of the monoclonal antibodies against KIT from Celldex that have we have nicely been able to show a tight correlation with impacts on that biomarker and ultimate clinical outcomes. So I think it's something that really can derisk PROGRAM early on in those Phase one studies.

Eric Joseph

Patrick, thanks for taking the questions.

Operator

Ed Arce, H.C. Wainwright.

Go afternoon, everyone. This is Thomas Yip asking a couple of questions for Ed. Thank you for taking our questions. And so first from can you outline what's your estimate of the patient population break down between the northern and southern hemisphere to date, both for the RCPs study and also for the HR study as well.

Jay Luly

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

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?

Jay Luly

Certainly yes, 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

Yes, sure. Thanks, Jay. On so we've enrolled patients in both northern and southern hemispheres in both the pediatric and the high-risk studies, including in 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

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

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

Jay Luly

It was the first question about overlap with the flu season.

Yes. How much overlap are there opportunity RSV season and flu season.

Jay Luly

I mean, generally there they're somewhat correlated, but you know, even in any given year they can 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 as far as fee has been and flu, but especially RC have been substantially on impacted by the pandemic. Some years in terms of just to get not only more recently starting to settle down into what we would call more normal seasonality, Tom?
So I think again, we follow We track this RCC's and much more closely than than flu.
Um, as it relates to HR and 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 and it was a it was a very nice season for us. So we may need we may need some of that as well. Will again, we'll be tracking this and reporting progress later this summer when we're well into the southern hemisphere season, and we'll be able to forecast a little bit better based on more current data. But that's that's my expectation.

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

Jay Luly

You're welcome.

Operator

Roy Buchanan, Citizens GMP.

Roy Buchanan

Just a couple on Ares V on Jay, for the RZHR. and I think I heard you say that you've powered for a 50% and reduction in symptoms and there's probably a high bar. Just wondering where that I guess conclusion about it being a high bar come from, I think the challenge trial, you had a 75% reduction in symptoms. And are you just interpolating between that and RSVP. is there something you're seeing in the trial?

Jay Luly

Yes. So to be clear, we're talking about time to resolution of symptoms. So it's different than any challenge. We're looking at the number of days improvement in time to resolution of symptoms versus placebo.
On MI, I can I can give a little color on that. Think, for example, with flu on a placebo study, enteric and correct me if I'm wrong, there's about a four day time period for time to resolution and Tamiflu, we'll shorten that by day. So it's a three day time resolution. So it's a one-day shortening and out of four days, that's a 25% improvement in time to resolution.
And so even though 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% effective rate, the study would be even much larger. So it's that fine balance of running a Phase two study that is enabling of a pivotal trial and keeping it at a manageable size. And we felt with a couple of hundred patients, even though it's a high bar to reach stat sig on the way it was powered, we should be able to make good decisions based on clinical, clinically meaningful improvements. And again, on shortening and shortening the time to resolution of sometimes by one or more days, it would be clinically meaningful.

Roy Buchanan

Okay. Makes sense. And then that for the three to three challenge was what are you hoping to see there?
We've said many times is the only covered data is probably best in class, are you expecting to see something similar or do you need to see something similar? Just help us think about that? Thanks.

Jay Luly

Yes, selling cap of your does set a high bar, um, you know, the mechanism is an N protein inhibitor and it is about the best challenge study data and any But companies that are put on the boards. So it does represent a high bar that said, three to three as another mechanism. It's a polymerase inhibitor. It's a picomolar polymerase inhibitor. So it's super potent. Tom, you know, can we replicate the same best-in-class data that we saw was only half of the year. Com, we'll see.
Hopefully, yes, Tom, it's hard to do much better. I think we want to be in the same range to declare it as a as a strong, um, you know, player in the field. But based on every bit of data that we have preclinically in our Phase one data, which showed good safety, tolerability, wonderful exposures after QD dosing. And again, very, very strong virology in how we've set it up about as best as we can. We're running at at the same clinical site as we ran a facility cap of your trial. So we'll see. So we should have data for that in Q three next next quarter.

Operator

Roanna Ruiz, Leerink Partners.

Nick Asic

This is [Nick Asic] on Toronto. Thanks for taking your questions. Maybe first on RC, could you give us a sense of how close you are to completing enrollment at a younger age cohort of our SVPs. Maybe how long do you think it could take to analyze and ultimately share the data accurate?

Jay Luly

Yes, again. So there are two parts to this study from part one is completed in all age cohorts. And 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 of 28 days to 6 months, and we've been actively recruiting that cohort. So we're in the homestretch and we just the and unfortunately, we can with our pool of patients is now only one, six of what it was based on age groups.
So it's a narrower pool than they are any older children. We really have to we can't enroll on the study anymore. So we're just really zeroed in and focused on getting the remaining young children to fill about this cohort.

Nick Asic

Got it. Thanks, Jay. And then maybe on CSU. Com, curious, what are you hoping to see in a future Phase one for your oral KIT inhibitor in terms of safety, maybe how should we think about frequency administration for this asset has been a once daily twice daily? How should we think about that?

Jay Luly

And while we're still on finalizing the candidate, again, we are targeting to have the finalists in Q4. But suffice it to say, we're very much zeroed in on QD dosing. And we've made molecules that are very potent or very selective and 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 on a strong prototype, and we continue to the chemists are very busy well, not just chemist chemist and all the of 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 Acuity candidate that would be and the best safety profile we can provide as well as has some good potency and selectivity.

Nick Asic

That's helpful. Thank you.

Operator

Brian Skorney, Baird.

Hi, this is Luke on for Brian. On for EDP. three to three, can you remind us of your current thoughts on potentially entering a Phase 2b in otherwise healthy adults as opposed to starting with the higher risk and pediatric populations like you've done with solid cap of here and would you wait for our SEP.s or RSVHR. data to make this decision?

Jay Luly

Yes, 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 SPP. trial from that. They're otherwise healthy folks just resolve the self resolve the infection. So quickly on their own. And so they're really not in need of kind of other therapy on. We would only focus on high-risk patient populations, and we're hoping to have an abundance of data here, um, you know, in the second half, some we'll have three to three data. We'll have Peet's data. We'll be able to look at the totality of the information and figure out how best to position and three to three.
So on price, it's been about bringing another strong mechanism forward. We've been working on this from the beginning, and I guess we've been working on it for a few years now to bring forward another differentiated asset in RSV. And that could give us the potential for doing combination therapy down the road and particularly hard to treat patient populations from potentially could help widen the treatment window where we to go after a patient with two drugs rather than one. So it's just become just part of our strategy overall to trying to build a leadership position and RSV. as a therapeutics company, the more the more sort of cards we have to play, I think we can come up with ways to to leverage another asset over time. So the key is getting it up to a strong threshold on the challenge study data first.

Great. Thank you.

Operator

Liisa Bayko, EVR.

Hi, this is Tina on for Lisa. And I have a question on the 323 program. What doses of two three are you testing in Phase IIa human challenge study?

Jay Luly

Yes, so we're looking at a couple of different dose regimens. So the first it's 600 milligrams straight across for five days. And the other is 600 milligram loading dose on day one, followed by 200 milligrams on each subsequent day. It's kind of like a in antibiotics. They do that sometimes to give you a loading dose on day one and then a lower maintenance dose for a few days and thereafter.
So we just put both of them in Tom and I think in theory, either at least based on 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 disease and you can just in fact, human volunteers, nine cohorts up every few weeks and dose and so on to that and does that answer your question?

Yes, that's helpful. Thank you. I had second question on the patent against the case against Pfizer because loss created by this setback exclusive, it doesn't infringe the patent because it has high floral growth, which is not described in York PATTY. So if you can comment on that?

Jay Luly

Yes. I really can't get into the discussion on our ongoing patent litigation. And the only about the only thing I can say is that I'm assuming it were to go to trial and we would expect to trial around the end of the year.

Okay. Thank you. That's helpful.

Operator

(Operator Instructions) Jay Olson, Oppenheimer.

Jay Olson

Your line is now open for RJ fixed 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 CF use such as TK. inhibitors?

Jay Luly

Thanks for the question, Jay. I'll let Tara speak to the chair, Jay could be.

Tara Kieffer

And so I think 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 had indicated that this target inhibiting this target has some of the best-in-disease efficacy, at least from the Phase two trials that have been have been run. So that 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 on just with an oral route of administration.
So Mexico, our program, you mentioned there's other companies working on this as well. They're all early. They're all preclinical on 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 something that is able to be dosed QD orally. It is something that is very potent against KIT, but selective and so and you know, leading to a good safety profile and just balancing that on that potency and selectivity so that the efficacy and safety profile could potentially be something that you would have as best-in-class.
And then I would just say that the oral inhibitors may be more tunable. I think this is something that remains to be proven in the clinic. But whether they're able to be dosed and tune more finely than a monoclonal antibody, you can certainly you have a little bit more some flexibility over that. So I think remains to be determined, but one potential strategy as well.

Jay Olson

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

Tara Kieffer

Sure. You mean for the KIT inhibitor?

Jay Olson

Yes.

Tara Kieffer

Yes. So 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 Simandou is something that's also been studied with this target and there's some good data from the monoclonal antibody here and Y o Y or is it a fillet esophagitis is also another indication we'd be interested in and PN as well. And even potentially asthma is something that one could think about with these types of inhibitors.

Jay Olson

Okay. Helpful.

Operator

Thanks for taking the questions, and thank you. And I'm showing no further questions. I would now like to turn the call back over to Jennifer Viera for closing remarks.

Jennifer Viera

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

Operator

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