Logo of jester cap with thought bubble.

Image source: The Motley Fool.

Enanta Pharmaceuticals Inc (NASDAQ:ENTA)
Q1 2020 Earnings Call
Feb 6, 2020, 4:30 p.m. ET

Contents:

  • Prepared Remarks
  • Questions and Answers
  • Call Participants

Prepared Remarks:

Operator

Ladies and gentlemen, thank you for standing by and welcome to the Enanta Pharmaceuticals First Quarter Financial Results Conference Call. At this time, all participants are in a listen-only mode. After the speakers' presentation, there will be a question-and-answer session. [Operator Instructions]

I would now like to hand the conference over to Ms. Carol Miceli, Director of Investor Relations. Please go ahead ma'am.

Carol Miceli -- Director, Investor Relations

Thank you, Erica, and thanks for joining us this afternoon. The news release with our fiscal first quarter financial results was issued today and it's available on our website. On the call today is Dr. Jay Luly, President and CEO; Paul Mellett, our Chief Financial Officer and other members of Enanta senior management team.

Before we begin with our formal remarks, we want to remind you that we will be making forward-looking statements, which may include our plans and expectations with respect to our research and development pipeline and financial projections, all of which involve certain assumptions and risks beyond our control that could cause our actual developments and results to differ materially from those statements. A description of these risks is in our most recent Form 10-Q 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 R. Luly -- President, Chief Executive Officer and Director

Thank you, Carol. Good afternoon, everyone. On today's call, I will discuss our recent clinical development progress on our lead RSV, NASH, and HBV compounds and upcoming milestones to look for in 2020.

I'll begin with EDP-938, the only N-inhibitor for RSV in clinical development today. RSV is a severe respiratory infection associated with significant morbidity and mortality in infants, the elderly, and immune-compromised adults and a condition for which there is currently no safe and effective therapy. At the end of 2019, we initiated our Phase 2b study named RSVP, which is a randomized double blind placebo controlled study of EDP-938 designed to enroll approximately 70 subjects, up to the age of 75 years randomized to receive either 800 milligrams of EDP-938 or placebo for five days. The primary objective of this study is to evaluate the effect of EDP-938 on the progression of RSV infection by assessment of clinical symptoms measured over the course of the 14 day study observation period. Antiviral efficacy will be evaluated as a key secondary endpoint. We're pleased to report that we've been able to identify many adult outpatients who have had cold-like symptoms that started within 48 hours of their visit to an RSVP study site. Identification of RSVP -- of RSV patients in this group has been aided by the prompt onsite confirmation of RSV infection, which we have been providing by PCR testing. Unfortunately it appears that the North American RSV season this winter peaked in December, which is approximately one month to two months earlier than in most years. As a result, we have seen fewer RSV cases unexpected and therefore we are planning to continue the study into the Southern hemisphere and have enrollment continue in all sites with the goal now to have data in the first half of 2021.

In addition to this study, we have also announced plans to initiate additional Phase 2 studies in pediatric patients and transplant patients by the end of this year, concurrent with the RSVP study. We continue to believe that our N-protein inhibitor approach represents the best chance for success against RSV because it attacks the virus' replication machinery. Building on our success with viral infections such as HCV and our ongoing program with RSV, last month we introduced our newest drug discovery program, which is seeking therapeutics for human metapneumovirus, also known as hMPV. hMPV is a pathogen identified in 2001, that causes upper and lower respiratory tract infections in young children and the elderly, as well as in COPD, asthma, and immunocompromised patients. During 2020, we will continue to perform optimization of our current nanomolar inhibitor leads against this virus.

Now let's shift to HBV. Our HBV program with EDP-514 is moving ahead nicely. And today we announced positive results from the SAD and MAD portion of our Phase 1 study in healthy volunteers. EDP-514 is our novel class II HBV core inhibitor sometimes referred to by others as a capsid assembly modulator or CAM. The aim of part one of this randomized, double-blind, placebo-controlled first-in-human study of EDP-514 was to evaluate the safety, tolerability, and pharmacokinetics of single ascending doses and multiple ascending doses in healthy subjects, while part 2 will assess the safety and antiviral activity of EDP-514 in nuc-suppressed patients with chronic HBV infection.

Overall, EDP-514 in healthy subjects dosed for up to 14 days was well tolerated with a favorable safety profile; treatment emergent adverse events were infrequent and mild in intensity; no one discontinued EDP-514 due to adverse events; and there were no significant individual lab data findings or pattern of lab abnormalities. Additionally, the pharmacokinetic or blood level profile was fully supportive of once daily dosing. Following these results, which support further clinical evaluation of EDP-514 in HBV patients, Enanta has initiated a study in nuc-suppressed patients. These are patients with chronic HBV infection that is being suppressed with nucleoside-reverse-transcriptase treatment. We plan to enroll a total of 24 subjects among three escalating dose cohorts, with study drug dosed for 28 days. Our goal is to have data from this study in the first quarter of calendar 2021.

Next quarter, we plan to initiate a separate study in HBV patients who are not on therapy and who have high levels of virus in their blood, who are also referred to as viremic. EDP-514 was selected from our lead series of HBV compounds that are characterized by potent antiviral activity and promising preclinical data also support our excitement for EDP-514 and for this mechanism. An abstract of the healthy volunteer portion of the study has recently been accepted for presentation at the International Liver Congress, known as EASL, so stay tuned for additional data in April.

Switching to our NASH program. We are pleased to announce that the ARGON-1 Phase 2a proof of concept study of EDP-305, our lead FXR agonist candidate has been accepted as in oral presentation at EASL. We plan to further evaluate EDP-305 in ARGON-2, a Phase 2b study in which we expect to initiate dosing by early next quarter. ARGON-2 will be a randomized, double-blind, placebo-controlled 72-week study in approximately 340 subjects with biopsy-proven NASH. The primary endpoint of the study will be improvement in fibrosis without worsening of NASH and/or NASH resolution without worsening of fibrosis. We plan to use doses of 1.5 milligram and 2 milligram, with the aim of demonstrating stronger biomarker signals of efficacy than seen at one milligram in the ARGON-1 study and less pruritus than seen at the 2.5 milligram in that study. The study will include a 12-week interim analysis to generate dose information more quickly for potential combinations with other mechanisms and NASH.

Also in our NASH program, Enanta has identified EDP-297 as its follow-on FXR candidate. Preclinical data on EDP-297 reveal a differentiated profile that delivers high target tissue distribution along with potency greater than that published on any FXR agonist in clinical development today. Last month at the JP Morgan Conference we presented compelling data that demonstrate the high potency and tissue-targeting characteristics of EDP-297 compared to other FXR agonist in development. This tissue targeting data show that in preclinical models EDP-297 delivered the drug preferentially to tissues involved in FXR activity, namely liver and in intestine, while minimizing drug levels in plasma and skin. Two abstracts on EDP-297 have been accepted and will be presented at the EASL Conference in April. We believe that having a highly potent and highly targeted FXR agonist like EDP-297 will allow for lower doses and reduced drug levels at non-targeted tissues thereby potentially reducing pruritus, and less pruritus is FXR mediated by FXR receptors in the liver or intestine. We plan to initiate a Phase 1 study of EDP-297 in mid calendar 2020 and to have data in the first half of 2021.

Lastly, the INTREPID study of EDP-305 and PBC is completed dosing and we expect to announce top line data by early next quarter.

So keep your eye out for presentation of Phase 1 results of EDP-514 at EASL, the initiation of our Phase 1b study of EDP-514 in viremic HBV patients, Phase 2 results of EDP-305 and PBC and initiation of our Phase 1 study of EDP-297, all by mid-year.

I'd like to close by summarizing, a couple of key takeaways from today. First, despite the vagaries of the RSV season in North America, we are advancing the RSVP study and have plans for two additional studies of EDP-938 to start another RSV patient populations later this year. And second, we had good safety and PK results with our lead HBV core inhibitor in healthy volunteers, leading us to initiate the second part of the study in nuc-suppressed HBV patients. This is all good progress.

I'll now turn the call over to Paul to discuss our financials for the quarter. Paul?

Paul J. Mellett -- Senior Vice President, Finance & Administration and Chief Financial Officer

Thank you, Jay. I'd like to remind everyone that Enanta reports on September 30 fiscal year schedule. Today we are reporting results for our first quarter ended December 31, 2019.

For the quarter, total revenue was $52.6 million and consisted entirely of royalty revenue earned on AbbVie's global HCV product sales. This compares to total revenue of $69.9 million for the same period in 2018. Royalty revenue was calculated on 50% of MAVYRET sales at a royalty rate for the quarter of 17% and on approximately 30% of VIEKIRA sales at a royalty rate of 10%, after adjustment for certain contractual discounts and rebates, which historically have been approximately 1.5% of AbbVie's total reported HCV product sales. AbbVie will be reporting their global HCV sales number on February 7. As a reminder, our royalties are calculated on a calendar year basis. Therefore royalties for our fiscal first quarter ending December 31 will be calculated at the highest royalty rate and royalties for our fiscal quarter ended March 31, will be calculated at 10%, our lowest royalty rate tier in our fiscal year. You can review our royalty tier schedule in our 2019 Form 10-K.

Moving on to expenses. For the three months ended December 31, 2019 research and development expenses totaled $32.8 million compared to $34.9 million for the same period in 2018. The decrease was primarily due to the timing of clinical trial costs associated with the progression of our wholly owned clinical programs in RSV, NASH, PBC and HBV. General and administrative expense for the quarter was $6.9 million, a slight decrease to the comparable quarter in 2018. Enanta recorded an income tax expense of $1.5 million for the three months ended December 31, 2019 compared to income tax expense of $3.7 million for the same period in 2018, reflecting the reduction in income tax -- in income before income taxes.

For the three months ended December 31, 2019 Enanta's effective tax rate was approximately 10% compared to approximately 12.5% for the corresponding period in 2018. The reduction in rate was driven by both research and development credits as well as a federal benefit from foreign derived royalty income.

Net income for the three months ended December 31, 2019 was $13.4 million, or $0.65 per diluted common share compared to a net income of $26 million or $1.25 per diluted common share for the corresponding period in 2018.

Enanta ended the quarter with approximately $415 million in cash and marketable securities, an increase of approximately $15 million from our 2019 fiscal year-end balance of $400 million. Further financial details are available in our press release and will be available in our quarterly 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?

Questions and Answers:

Operator

[Operator Instructions] Your first question is from Brian Abrahams with RBC.

Brian Abrahams -- RBC Capital Markets -- Analyst

Hey guys, thanks so much for taking my questions. First off on 938, the RSV program, I know you mentioned that you'll be getting the transplant and pediatric studies under way later this year. I was wondering if you could talk a little bit more about how you guys are thinking about the potential design there? And in particular, how -- what's going to be shaping elements like the dose -- dose selection, potential duration as you look to get those studies going later? Then I have a follow-up.

Jay R. Luly -- President, Chief Executive Officer and Director

So thanks for the question, Brian. The team is working right now on the fine details of both of those studies. So I'd say it's a little bit premature on this call to get into that. I'd say as the year progresses, we'll report more on RSVP and as the -- the exact design of these two new studies gels [Phonetic], we'll have -- we'll have a lot more to say about it then.

Brian Abrahams -- RBC Capital Markets -- Analyst

Okay, fair enough. And then it sounds like the Hep B program is moving along well with 514. Was wondering if you could maybe just elaborate a little bit more on what you guys observed in healthy volunteer Phase 1 study, with respect to PK and safety, your thoughts on the therapeutic window for that agent? And anything at least that you're able to glean from the Phase 1 study that might support your view of this being differentiated from others in the same class and development? Thanks.

Jay R. Luly -- President, Chief Executive Officer and Director

Well, certainly -- I'll just start with a little bit of a pre-clinical background on 514 too first. So 514, we worked a long time to identify this candidate and picked we believe it's has a great pre-clinical profile not only in terms of virology, but in vitro and in vivo where it certainly looks better than first generation capsid -- core capsid inhibitors. You know everything about that pre-clinical profile including the pharmacokinetic profile across multiple different species suggested that it had a pretty good chance of having a strong profile clinically too. So we'll have lot of details around this data set presented formally at EASL, but suffice it to say it was generally safe and well tolerated. Again nothing remarkable in terms of any findings and importantly and as you know the PK is really all important when you're looking at viral. And so we think we've got good exposures and good troughs and so forth that would give us a good amount of pressure on the virus. So this is a 14 day study and it's in healthy -- we'll lay it out very clearly with all the details at EASL, but the results are definitely strong.

Brian Abrahams -- RBC Capital Markets -- Analyst

Great. Thanks very much, Jay.

Jay R. Luly -- President, Chief Executive Officer and Director

You're welcome.

Operator

Your next question is from Eric Joseph with J.P. Morgan.

Eric Joseph -- J.P. Morgan -- Analyst

Hi. Thanks for taking the questions. A couple from me, first on 514, I'm guess I'm thinking about the Phase 1b study portion in nuc-suppressed patients. If I heard correctly this would be a MAD study assessing 514 over a 28-day treatment period. Can you talk a little about sort of the study objectives in that trial portion. Are you -- how are you looking at antiviral activity against walk us through sort of the surrogates for efficacy? Are you looking at zero conversion or pgRNA?

Jay R. Luly -- President, Chief Executive Officer and Director

Again I'll remind you that this is a Phase 1b 28-day study. So it's -- it's a short-term study where we'll be looking principally at safety as primary endpoint, but I'll let Nathalie comment on some of the other aspects related to other things of each study.

Nathalie Adda -- Senior Vice President and Chief Medical Officer

Hi, thank you for your questions. So I think just to echo what Jay said, this is the second part of first in man study to do 1b we'll be looking obviously at nuc-suppressed subjects, safety, PK are the key primary and secondary objectives. We will be also looking at exploratory endpoint that you know all the other company I would say in that in that field are looking. Just to remind you that so for all those endpoint in [00:20:10] on nuc-suppressed are still consider exploratory in essence. So we would be looking at something such as HBV DNA and HBV RNA and other. And we will -- that as we are obviously finalizing the study.

Eric Joseph -- J.P. Morgan -- Analyst

Great. And maybe just a separate question on the RSVP study, I just wanted to revisit the trial design and powering assumptions there, can you just kind talk about what the power -- what the trial is powered to detect in terms of total symptom, reduction versus no treatment? And I'm also curious to know whether looking at some of the flu antiviral programs are useful comps in terms of thinking about longer term study design and whether if that's appropriate, looking at time to symptom -- whether or not you're looking at time to symptom resolution? Thanks.

Nathalie Adda -- Senior Vice President and Chief Medical Officer

So I think again I heard very clearly your first question about the core of the RSVP study. I'm not sure I completely understood the second part that maybe you can repeat once I address the first part.

So I think we had that question a few times, look regarding the core or RSVP study. We have as you know run a challenge study and there was what we used as far as understanding our drug in context of the patients who received the placebo in the challenge study to really identify and analyze, clearly the dynamic of symptoms was evolving over time. I'm not yet ready to disclose completely, how we powered the study as I think it's more relevant when you present the data, but obviously we will be looking at seeing a difference of the progression of the symptoms from time to answer it over 14 days course of study conduct.

I know it's an indirect way of responding, but that's what can I say today. Would you remind me the second part of your question, please.

Eric Joseph -- J.P. Morgan -- Analyst

Sure. I would -- I'm curious to know whether you're looking at time to symptom resolution specifically in the RSVP study? And the reason for asking the question is that that is an endpoint used in the influenza anti-viral studies that I'm wondering whether that is a useful comparators sort of studies to look than thinking about longer term development of the pivotal development potentially of the of EDP 938. Thanks.

Nathalie Adda -- Senior Vice President and Chief Medical Officer

Yes, thank you. I appreciate your question. So obviously we have looked at many of the flu studies to understand and point on symptoms in relationship to that patient population. There is a series of key secondary endpoint that we'll be looking at more details, time to resolution, time to progression, there will obviously more details analysis of all the symptoms.

Eric Joseph -- J.P. Morgan -- Analyst

Great, thanks for taking my question.

Nathalie Adda -- Senior Vice President and Chief Medical Officer

You're welcome.

Operator

Our next question is from Yasmeen Rahimi with ROTH Capital.

Paul -- Roth Capital Partners -- Analyst

Hi Jim. Paul on for Yasmeen. Thanks for taking my questions. So first, I just wanted to ask about -- again about RSVP. Can you talk more about the confirmation of RSV diagnosis and the optimal window for the study and can PCR be used to determine quantitatively, if patients viral loads fall in the optimal range for intervention?

Nathalie Adda -- Senior Vice President and Chief Medical Officer

So we are using [Indecipherable] and it's a PCR when the patient show up at the clinic within the 48 hours of the window. So it's confirmed at the site and there will be a centralized also PCR that we do afterward.

Paul -- Roth Capital Partners -- Analyst

Okay. Okay, and just one more question, can you give some more color on what the profile for a viremic patient would look like in the next portion of the EDP-514 study?

Nathalie Adda -- Senior Vice President and Chief Medical Officer

Say it one more time please.

Paul -- Roth Capital Partners -- Analyst

I was wondering what the profile for viremic patient in the next portion of the EDP-514 study would look like?

Nathalie Adda -- Senior Vice President and Chief Medical Officer

[Speech Overlap] for 514 for the HBV. Okay, sorry I didn't -- switched to HBV. So there will be patient while dynamic obviously you have a higher level of HBV DNA than the nuc-suppressed. They could be either naive of treatment or they could have received treatment, but having working window where they don't receive any treatment, but they have to show an elevated level of HBV DNA at entry.

Paul -- Roth Capital Partners -- Analyst

Got you. Okay, thanks so much.

Nathalie Adda -- Senior Vice President and Chief Medical Officer

You are welcome.

Operator

Your next question is from Akash Tewari with Wolfe Research.

Akash Tewari -- Wolfe Research -- Analyst

Hey, guys. So maybe on the RSV trial, maybe a little bit of color on why you chose AUC symptom benefit as your Phase 2b primary endpoint versus maybe like baseline viral load or something that used in Phase 1 or some of the flu trials? Would love to get some detail on that. Additionally, in your protocol you say that patients will have to present within 48 hours of symptom onset. Are there any tricks that you're using for the trial to kind of ensure that patients are actually presenting within that treatment video, I mean that treatment timeline?

And finally, it seems like you're -- I think you had previously mentioned that the powering was going to be similar to Phase 1. So I think that was around 80% powered, is there a chance that you could increase your enrollment. Now that the trial is getting pushed to first half '21? Thanks so much.

Jay R. Luly -- President, Chief Executive Officer and Director

So there -- I don't think there are any special tricks. I think we are taking people as they present and we have to rely on the reliability of what they say in terms of symptoms. Obviously, they are only people who can know. But the good news is, we're seeing lots of people coming in within that time window with symptoms. Could you repeat your first question? The first part of your first again.

Akash Tewari -- Wolfe Research -- Analyst

Yeah, absolutely. So I think we're looking at like J&J's outpatient RSV Phase 2, their pilot trial and they are looking at a lot of primary and secondary endpoints, viral kinetics, clinical symptoms. So why specifically -- it's an interesting endpoint, AUC symptom benefit as your primary endpoint, does it somehow, give you a bit more wiggle room than some of these other exploratory endpoints that other companies are looking at?

Nathalie Adda -- Senior Vice President and Chief Medical Officer

I think the choice of the AUC as far as the primary endpoint to look into the total symptom score was mainly driven also to the understanding and the very thorough analysis of our challenge study. As we work with our statistician, we thought that AUC for symptom score will be better end point for what we are looking for in the context of that study.

Akash Tewari -- Wolfe Research -- Analyst

Got it.

Jay R. Luly -- President, Chief Executive Officer and Director

It's also easier on an outpatient basis to get -- to get more data points, because people will be reporting symptoms in diaries, etc. so just as from practical basis on an outpatient study, you can -- you can get more data sampling that way.

Nathalie Adda -- Senior Vice President and Chief Medical Officer

Just want to compliment to what Jay said about the trick. I mean there is obviously -- there's obviously a lot of work that went into educating the site and site is educating patients that come to see them. We are using family practice, emergency care center with patients with allergy, asthma, COPD. So we have launched a large campaign that try to attract patient with clear understanding of the eligibility criteria for our study. So we were able to be successful in that sense to attract patients with symptom within our window.

Akash Tewari -- Wolfe Research -- Analyst

Got it. And just -- just a quick question, given the trial delay on the RSV side, is there any chance that you'd be looking at increasing the enrollment so suddenly you might have more of a flu like total number of patients in your trial versus something more in line with other RSV Phase 2b studies?

Nathalie Adda -- Senior Vice President and Chief Medical Officer

There is no plan to increase the enrollment number.

Akash Tewari -- Wolfe Research -- Analyst

Got it. Thank you. Really appreciate it.

Jay R. Luly -- President, Chief Executive Officer and Director

Welcome.

Operator

Your next question is from Liisa Bayko with JMP Securities.

Liisa Bayko -- JMP Securities -- Analyst

Hi, there. Just wondering if you're going to be doing any interim cuts of the RSVP study I thought you that needed some data in adult patients before moving into pediatric. So just wondering how that's all going to work? And if you're still on time to start at the end of this year?

Jay R. Luly -- President, Chief Executive Officer and Director

They're not -- they're not really interrelated. And there won't be an interim cut, so we'll take the wealth of all the information we have and all the adults who have received study drug and partly that into our thinking about how we dose speeds ultimately. But our expectation is that these studies would be run concurrently.

Liisa Bayko -- JMP Securities -- Analyst

Okay. So FDA doesn't need to see the data in the adult population before starting the pediatric study?

Jay R. Luly -- President, Chief Executive Officer and Director

No.

Liisa Bayko -- JMP Securities -- Analyst

Okay, OK, got it. And then could you maybe talk a little bit more about the differentiated profile of 297, as you mentioned it was differentiated. I'd just be curious and I think a little bit more about that? Thank you.

Jay R. Luly -- President, Chief Executive Officer and Director

Sure. So shifting gears to FXR now. So 297 are follow-on FXR agonist. We spent a lot of time trying to optimize whatever characteristics of the molecule we could. Obviously looking at potency and selectivity and other kinds of things. What surprised us as you know with 305 in the ARGON study was that the doses that we used, we saw more pruritus than we would have expected from all the information we saw in Phase 1. And so for us thinking about how to use 305 in a way that gives better tolerability going forward is the path that we're thinking about for 305, but 297 then it became clear that pruritus perhaps more so than lipids is the thing we needed to really try to figure out how to improve upon. The confounding part of that is that nobody -- nobody really understands what's causing pruritus with these various FXRs that have seen it, is it on target, is it off target, is it on target in certain tissues, but not others and so absent having the sort of confirmed mechanistic understanding of how to reduce pruritus, what we did was took other approaches that we could do sort of independent of knowing the mechanism. So number one is drill down the potency to as good a potency is you could possibly do. So we worked and worked and worked on that you've -- we put the data out at JP Morgan initially, we'll have more at EASL, but it's a very, very potent FXR. It is the most potent one based on the data that we've generated side by side versus any other FXR agonist that's in development today. So number one, that's good because you will reduce the amount of drug that it takes to deliver the punch. So we know that FXR receptors are in the intestine and also in the liver in terms of the sites of efficacy for a compound that we would be looking for in NASH. And so in addition to making these exquisitely potent for FXR and hopefully less potent for something else that we might not know, we aimed it directly at liver and intestine and not had plasma and skin, because obviously if you have high plasma levels you are going be circulating the drug around to all kinds of other tissues in the body and we specifically thought it would be interesting to minimize the skin exposure of the drug as well.

So it's really the twofold combination of having very, very good potency. So that we'll be dosing just very small amounts of drug and then having that drug go directly to the sites where we need the drug and hopefully not at the sites where we don't need the drug were only -- were only -- were only other things could happen. So that's our thesis and there is a scenario where it might not play out as we hoped, but that sort of narrow scenario of bad luck would be, if it is FXR mediated, the pruritus and if it's FXR mediated by FXR receptors inside the liver or intestine, then we may only have achieved a super, super potent version of 305 or some of the other FXRs that are out there today. But if it's any other scenario, we have the chance to come up with benefit and that's what we'll be exploring. We think we can learn actually, a fair amount in Phase 1 and we're on track to start that Phase 1 study in the middle of this year with -- with the -- with the data coming in the first half of next year. So it's a pretty straightforward plan, it looks like an excellent molecule chemical profile more at EASL, but it's a -- it's a polished entrant into the field.

Liisa Bayko -- JMP Securities -- Analyst

Thank you.

Jay R. Luly -- President, Chief Executive Officer and Director

Welcome.

Operator

Your next question is from Brian Skorney with Baird.

Brian P. Skorney -- Robert W. Baird & Co. -- Analyst

Good afternoon everyone. Thanks for taking my questions. I guess first just on EDP-514. Can you just walk us through how to think about the dosing here and where you want to target to maximize antiviral activity? If I look at the results you have in the chimeric liver mouse model, it seems like dose escalation isn't really topping out despite going to pretty high mg per kg doses? Any thought on how to think about translating that date into a target dose in patients?

Jay R. Luly -- President, Chief Executive Officer and Director

Yeah, I wouldn't -- I wouldn't translate the rodent model numbers into -- to humans. What I wouldn't look at in that -- in that experiment is a very strong dose response and a very robust antiviral effect. In fact, it's the most robust anti-viral effect that anybody has reported in that model. So, but in terms of comparing the doses and milligrams per kilogram to a rodent to the actual doses we'll use in humans. I wouldn't -- I wouldn't get spend too much time thinking about that translation and again we'll get into the whole dose escalation work that we did at EASL when we lay whole data set out and you will be able to take a good look at it -- a good look at it then.

Brian P. Skorney -- Robert W. Baird & Co. -- Analyst

And then if I could just ask a question on the patient flow in the RSVP study, can you just remind us how screening works here? Are you just first primarily screening for patients with respiratory symptoms and then screening them in for RSV in the study? And do you have any data on how many patients coming in with respiratory symptoms screening for RSV versus screening out with influenza?

Jay R. Luly -- President, Chief Executive Officer and Director

Yeah, so we take people again within 48 hours of symptoms. There's an in-office PCR that's done. We look for RSV versus flu A or flu B and if you're positive for RSV and negative for flu A and negative for flu B, then you are a potential candidate. You know there is more flu out there than there is RSV. So you're going to see more of that in these screens, but generally speaking, it's a straightforward test worth a straightforward presentation of people coming in within 48 hours, which again, we've seen many people coming in, in that window.

Brian P. Skorney -- Robert W. Baird & Co. -- Analyst

I guess what I'm trying to get at is if eventually this moves into sort of a seasonal RSV treatment. I'm trying to see if in the real world setting, what sort of as a reasonable number to assume as a percent of flu and we could obviously kind of comp it to what like Tamiflu does, get a feel for the commercial offers?

Jay R. Luly -- President, Chief Executive Officer and Director

Yeah, it changes every it doesn't correlate perfectly every year. The seasonality is a little bit different and you know what might be a more robust RSV season could be lower flu season. There is just so overarching seasonality to it, the patient numbers are probably not as high as -- not as high as flu, but again I don't think people really fully know yet and part because this testing is not routinely -- routinely done on a broad scale basis and clinical practice. So and in part because it's not that the test don't exists it is the drugs don't exist. So people don't often order out the test.

Also different to be thinking about the patient demographic that's in the RSVP study, which is the adult outpatient study. We know adults in general are a fraction of what they are. At all RSV cases in general are a fraction of what they are in peds so ultimately the question will drive down to what are those peds numbers, but they are very significant in peds again every -- every, every peds gets typically an RSV infection by the time they are aged two or three. It's just a question of severity and it's a question of what happens once they get that infection.

Brian P. Skorney -- Robert W. Baird & Co. -- Analyst

Great, thanks Jay.

Jay R. Luly -- President, Chief Executive Officer and Director

You're welcome.

Operator

[Operator Instructions] Your next question is from Patrick Trucchio with Berenberg Capital Management.

Iris -- Berenberg Capital Markets -- Analyst

Hi, this is Iris on for Patrick. Thanks for taking my question. So regarding EDP-938, can you tell us if you expect to evaluate the drug in elderly patients? And if so, would you move directly into a pivotal trial or would you anticipate running maybe another two Phase 2 trials in this patient population? And then finally, would you anticipate having to run two pivotal trials for each patient population or is one pivotal trial sufficient? Thank you.

Nathalie Adda -- Senior Vice President and Chief Medical Officer

Thank you for your question, I can address that, and they are good questions. So I think for now we have informed that our next studies will be in the transplant and the peds. We know that those population are really unmet medical need. We are not excluding for the next future to be looking into the elderly, obviously. They are also population of good target for RSV. But the plan for now will be to focus on the transplant and the peds.

To your next question regarding pivotal study, I think that's a very good question. Today, if you look at the guidance issued FDA or EMA, I don't think there is a clear understanding of if we will need one or two pivotal study like we usually do, when we register a drug. I think it's going to be interesting to engage regulatory authorities as we are moving in progress of our program. So we will know more as we obviously progress further.

Iris -- Berenberg Capital Markets -- Analyst

Okay, got it. And then regarding RSVP, can you tell us what you would consider to be a highly successful top line data result? Thanks.

Nathalie Adda -- Senior Vice President and Chief Medical Officer

Well, I guess, simply to make the per million with a nice p-value, I'll be happy to see that. And I think RSVP is also an interesting study for us and maybe for the field, trying to understand the feasibility of how soon can you attract the patient with nasal symptoms that you can treat to present severity and progress to lower respiratory tract inflection. And I think this is what we need to understand and if we understand it, then we can put it in practice. I think there will be probably [Indecipherable] winning a cure for RSV if you have a good product.

Iris -- Berenberg Capital Markets -- Analyst

Got it. Thank you.

Nathalie Adda -- Senior Vice President and Chief Medical Officer

You're welcome.

Operator

And there are no further questions at this time. I will turn the call back over to Ms. Carol Miceli.

Carol Miceli -- Director, Investor Relations

Thank you everyone for joining us today. If you have any further questions feel free to give us a call in the office. Thank you.

Operator

[Operator Closing Remarks]

Duration: 45 minutes

Call participants:

Carol Miceli -- Director, Investor Relations

Jay R. Luly -- President, Chief Executive Officer and Director

Paul J. Mellett -- Senior Vice President, Finance & Administration and Chief Financial Officer

Nathalie Adda -- Senior Vice President and Chief Medical Officer

Brian Abrahams -- RBC Capital Markets -- Analyst

Eric Joseph -- J.P. Morgan -- Analyst

Paul -- Roth Capital Partners -- Analyst

Akash Tewari -- Wolfe Research -- Analyst

Liisa Bayko -- JMP Securities -- Analyst

Brian P. Skorney -- Robert W. Baird & Co. -- Analyst

Iris -- Berenberg Capital Markets -- Analyst

More ENTA analysis

All earnings call transcripts

AlphaStreet Logo