Good afternoon, ladies and gentlemen. Welcome to Atea Pharmaceuticals Second Quarter 2021 Financial Results Conference Call. At this time, all participants are in a listen-only mode. Following the formal remarks, we will open up for your questions. I would now like to turn the call over to Jonae Barnes, Senior Vice President of Investor Relations and Corporate Communications at Atea Pharmaceuticals. Please proceed.

Thank you, Operator. Good afternoon, everyone and welcome to Atea Pharmaceuticals second quarter 2021 financial results conference call. This afternoon, we issued a press release which outlines the topics that we plan to discuss. You can access the press release as well as the slides that we’ll be reviewing today by going to the Investors Relations section of our website at ir.ateapharma.com. With me today from Atea, our Founder, Chairman and Chief Executive Officer, Dr. Jean-Pierre Sommadossi; Chief Development Officer, Dr. Janet Hammond; Chief Financial Officer, Executive Vice President of Legal, Andrea Corcoran; and our Chief Commercial Officer, John Vavricka. They will all be available for the Q&A portion of today’s call. On the call today, we’ve a lot of important content to review. Jean-Pierre will provide an overview on the current COVID-19 environment and AT-527s potential to address these key challenges. Janet will review our clinical progress and results for AT-527 for the treatment of COVID and discuss AT-752 for the treatment of dengue fever. John will then provide an overview of the U.S commercial opportunities for AT-527; Andrea will provide a financial update and Jean-Pierre will provide closing remarks. Before we begin the call, I’d like to remind you that today’s discussion will contain forward-looking statements that involve risks and uncertainties. These risks and uncertainties are outlined in today’s press release and in the company’s recent filings with the Securities and Exchange Commission, which we encourage you to read. Our actual results may differ materially from what is discussed on today’s call. With that, I’ll now turn the call over to Jean-Pierre.

Thank you, Jonae. Good afternoon, everyone, and thank you for joining us today. I will begin on Slide 3 of the presentation. Since Atea founding, we’ve remained steadfast in our mission to discover and develop antiviral drugs for the treatment, cure and prophylaxis of severe viral diseases where there is a significant unmet medical need where we can make a meaningful impact for patients. Earlier last year, our antiviral platform put us at the forefront in the fight against COVID-19, and we believe a multipronged approach including therapeutics and vaccine will be essential solutions in this pandemic which is now becoming endemic. It has become abundantly clear the most countries and regions like Southeast Asia, South America and India where we’re seeing a devastating impact from COVID-19 of lower vaccination rates, which have become a source for variant and create new challenges for treatment and prevention. It is projected that the Delta variant currently account for 93% of all new cases in the United States and we are now back to 100,000 new infection per day. Obviously, this is a particular concern, given recent publication demonstrating lower efficacy rates for vaccine against the new strain. For example, the Delta variant has also been reported to be highly contagious, almost as contagious as chickenpox, and it has more rapid replication than earlier strains. And for this, we are seeing a significant number of breakthrough cases in vaccinated, fully vaccinated patients, accounting for as much as 15% in all hospitalized patients, and even 15% of the new cases now are in children, which further expand the infected population. In addition to the Delta variant, the lambda variant, first identified in Peru and now spreading in South America is highly infectious as well, and particularly concerning and I'm sure that in 6 months…

Thank you, Jean-Pierre. I'll begin with Slide 6. As the COVID-19 pandemic evolves, and we generate more data from AT-527 program, we are acting nimbly to optimize the design and conduct of our technical development program. As you can see here, we have six studies of AT-527 currently running in parallel, and we're leveraging lessons learned from each study to better serve our patients and improve our probability of success. Slide 7 outlines our global Phase 2 study of AT-527 in the hospitalized setting. Before we review the interim results, as a reminder, this is a randomized, double-blind, placebo controlled, multicenter study to evaluate AT-527 in patients with moderate COVID-19. Study objectives are to assess safety, tolerability, clinical and antiviral efficacy. But apparently amending the protocol to reflect the evolving COVID environment by changing the primary endpoint virology from its former progression to respiratory insufficiency. Going to the limited number of cases that now progress due to changes in the standard of care. We will also be exploring alternative doses and adding a Part B cohort comprised of up to 110 patients. Moving to Slide 8. In June, we were delighted to announce positive interim results from our global Phase 2 study of AT-527, indicating rapid and sustained antiviral activity against SARS-CoV-2 in patients with COVID-19 in the hospitalized setting. The interim analysis of the Phase 2 study included data from 70 hospitalized high-risk patients with COVID-19 from which 62 patients were valuable for virological analysis. These patients were infected with a broad array of virus lineages representing over 20 variants, and included the alpha and beta variants of concern. They were enrolled from seven countries in North America, Europe, Africa, and South America, representing a diverse geographic footprint. 46% of patients with SARS-CoV-2 seropositive by IgM measurement at baseline…

Thank you, Janet. Turning to Slide 17. We tend to view the target populations as four broad patient segments. There are symptomatic active disease and which patient were symptoms were present would be treated. There's asymptomatic active disease, and although they're asymptomatic, we believe the patients will be accessed through proactive testing from employers schools and travel. And the third area is prophylaxis, both pre and post exposure and finally at government purchase, which would include purchases both for active disease as well as for stockpile. And we see all of these segment as large -- the large market opportunity. We also consider it is important to look at vaccinated and unvaccinated people in each of these segments when considering different patient motivations, and communication. Compared to the last pandemic, with H1N1 in 2009. One of the biggest differences was that there were FDA approved antivirals readily available so that the government chose to stockpile during the pandemic. Current government efforts appear to target availability of new oral therapeutic treatments for COVID-19 and are meant for immediate utilization within the U.S distribution system, following an EUA or an NDA approval. There is currently a $3.2 billion government offering for oral therapeutic treatments or high risk outpatients, mild to moderate patients, and pre and post exposure prophylaxis treatment. And we remain in active discussions with the U.S government agencies recording this offering. We also believe that given the devastating global impact of COVID-19, it is highly likely that the U.S government will also stockpile treatment for future preparedness similar to what they stockpiled during H1N1. With that overview, I'll now turn the call back over to Janet.

Thanks, John. On Slide 19, I'm pleased to report that we are also making progress with AT-752, our program for Dengue. The Phase 1a single ascending dose study portion of the trial, evaluating multiple doses has been successfully completed, and the multiple ascending dose portion of the trial was initiated during this quarter. The objective of the study is to establish the safety and tolerability of AT-752 and also to support dose selection for future studies of AT-752 as a treatment and also for prophylaxis of Dengue fever. It is expected to roll up to 60 patients. With that I'll now turn the call over to Andrea for review of the financials.

Thank you, Janet. As Jonae mentioned in her introductory remarks, this afternoon, we issued a press release containing our financial results for the second quarter of 2021. Statement of operations and balance sheet are on Slides 21 and 22. For the second quarter 2021, the increase in research and development expenses in comparison to the second quarter of 2020 was principally driven by an increase in external clinical development and manufacturing expense, incurred primarily in conjunction with the advancement of AT-527 for the treatment of COVID-19 and to a lesser extent AT-752, which is being developed for Dengue fever. These expenses included our share of costs incurred by Roche and increases in internal spend, mostly due to an increase in personnel related expenses. The increase in general and administrative expenses was primarily due to the expansion of our organization and consists principally in an increase in payroll and personnel related expenses. I am pleased to report that we ended the second quarter with a strong balance sheet to support our clinical development programs. As of June 30, 2021, cash and cash equivalents were $816.5 million. Please note that this does not include the $50 million development milestone, the company achieved in June under our license agreement with Roche. That payment was received in July. I'll now turn the call back over to Jean-Pierre for closing remarks.

Thank you, Andrea. In closing, we cannot underestimate the importance of the AT-527 clinical development program and the progress we are making. The COVID-19 endemic remained very much with us. And all data points to another search this fall due to the Delta variants and low vaccination rates around the world. It is our goal to advance this important program, and to provide rapidly a solution that can play an important role in helping to reduce the global burden of this disease. The Atea team, along with our partners at Roche are doing everything in our power to make this happen. Our success will be everyone success. As reviewed today, we continue to make substantial progress with AT-527. And now we have demonstrated that AT-527 as rapid and sustained antiviral activity against SARS-CoV-2, which is target drug label in the lungs, which as you know, is the primary site of infection. Unique dual mechanism targeting the RNA polymerase, which we believe will be important for high barrier to resistance, and hopefully also for addressing the problem that we are seeing with the variants, demonstrated that it is not a mutagen, very likely not leading to new variants in the future and no dose adjustment necessary for co-administration of drugs that are CYP3A substrate as you know, and Janet has indicated the largest majority of drugs being metabolized by these enzymes. As we continue to advance multiple, global clinical studies in parallel with our partner Roche, we look forward to the upcoming results from the Phase 2 MOONSONG and the Phase 3 mornings case studies. In addition to the substantial progress with AT-527, we continue to make progress with the other drug candidates, antiviral pipeline for the treatment of Dengue, hepatitis C and and we expect to provide an update on this programs later this year. With that, operator, we will now open the call to your questions.

And your first question comes from the line of one of Eric Joseph with J.P. Morgan.

Hi, good evening. Thanks for taking the question. A couple from, I guess, first with as it relates to the space to inpatient data. I'm curious to know whether at this stage where the field kind of has a sense of how the normal decay of viral load mirrors on to symptom improvement or symptom resolution. I guess if we're trying to relate the compare -- the comparative viral load data in the Phase 2 study. Is there a sort of an absolute threshold of viral load that might predict for symptom resolution, or is kind of a goal trying to get to viral clearance as many as a greater proportion of patients as possible. And then secondly, JP you highlighted the unmet need in the pediatric population. I would be curious to know whether there are any plans to kind of begin safety testing in pediatrics -- pediatric population to kind of expand access to that opportunity. Thank you.

Two great question. So thank you. Janet, can you maybe address both questions?

Thank you, Jean-Pierre. Yes, happy to. So firstly, in regard to your question around the symptoms, in comparison to what happens to the viral load decay, in our overall cohort of patients, and it's a very small cohort of patients, we didn't see much of it much of a correlation between symptom decline and viral load decline. However, we looked at the patient group who had viral loads in excess of the median. So greater than 5.26 logs of viral load, we actually saw -- actually, surprisingly, good correlation between declining viral load and declining symptoms. And so what that would translate to then was really that the viral load decline in patients who were treated was associated with a very much more rapid improvement in symptoms, and approximately a 2-day earlier, overall, came to resolution of symptoms. So I think that answers that question. And then in regards to the pediatric population. Yes, we are already in talks with both the EMA and the FDA in regard to our pediatric plan, and both agencies have seen the plan and have provided comments to that. And actually, I think, as I mentioned, in our MORNINGSKY study, we do have plans to start enrolling adolescents into that study, because obviously, it's going to be a really important patient population for that new treatment, particularly as it's taking longer for the vaccines to roll off. So thank you.

Great. Thanks for taking the questions.

The next question comes from the line of Jonathan Miller with Evercore.

Thanks for taking my question. First one on the big Phase 3s, what percentage of the patients do you expect to be zero-negative at baseline? Since as we've seen another direct acting antiviral trials, those have been responsible for driving the majority of the benefit. And secondly, as we've seen some recent positive results in post exposure prophylaxis trials done with monoclonal antibodies. And we've been wondering how you think that reads through to oral small molecule approach? Can you do even better or worse? And remind me what your timeline is for initiating some sort of prophy trial, whether pre or post exposure?

Janet?

Thanks, Jean-Pierre. So with regard to the proportion of patients who are going to be seronegative, I think to some extent, my interpretation of the literature to date has been that, actually patients who are more immuno-compromised, and who have far higher viral loads tend to be seronegative. And patients who have zero risk factors and are generally in better shape tend to have low viral loads and also to be seropositive. So I think that for our Phase 3 studies, where we're planning to enroll both high and low risk patients, and ready to roll both populations into a similar -- into a single study. I think it's likely that we will see more patients who tend to be seropositive and seronegative, because of the fact that we will have the patients who are already very risk and likely to be seropositive, and then the patients who are high risk. I think, as you saw in our hospitalized study, approximately 50% of patients were surprised seropositive or seronegative. So, I'm guessing that, that will translate into a higher proportion of patients being seropositive. But you're right, it's a good question, because I think one tends to see a better bar or response, or it's more easy to see that correlation in patients who start with seronegative, just because they have a higher viral load initially to start with. With regard to your question around post exposure prophylaxis, I think that there are differences and similarities between what we anticipate seeing. I think we anticipate that pre-exposure prophylaxis ought to deliver similar levels of benefits to what you see with the antibodies. I think there are both pros and cons to both approaches. And the beauty of the approach of a small molecule in that type of setting, obviously, is that access is relatively considerably easier and that you don't need to go and get an injection, and you can initiate therapy much more conveniently. I think the disadvantage to some extent will be that the monitoring of antibodies have a longer duration of effect after a single dose, whereas the prophylaxis with a direct acting antiviral will be dependent on taking the drug. But of course, that means that there is more room for tailoring it. And potentially I suppose also ultimately less likelihood for genesis of resistance. So, I think we'll have to see how it all evolves and how -- and what we learn. But I think that in general, there are advantages and disadvantages to both approaches, but we believe that the antiviral efficacy for both approaches ought to be very similar.

And your plans to initiate the trial?

I'm sorry. Yes, we've had to initiate the trial in this second half of the year.

Thanks very much.

Your next question comes from the line of Tim Lugo with William Blair.

Hey, guys. This is on for Tim. Thanks for taking the questions. First of all, just wanted to clarify when you said that MORNINGSKY is rolling globally, does that included the U.S? Because I know that the FDA is kind of the way out a bit in the past. So just wanted to check that’s up and running. And second, you've said that you're looking at higher doses? Can you share any details on what that higher dose is? When we might see the first data from that? Is that going to be with the MORNINGSKY might be wave Q3 . And how much incremental efficacy you might expect to see from that, especially given the Bronchoalveolar lavage that you, the database shared from healthy patients?

I'm going to address the second one, and Janet will go over the first one. Look, first, we anticipate that we should saw proportional increase in those concentrations. And until we don't have the data, obviously, we cannot make some extrapolation, but from the data that we see and that from the Phase 1 that are going at higher doses, we believe that there is going to be substantial drug exposure increase and hopefully this should translate in antiviral efficacy and ultimately clinical benefit. So, we are encouraged by the fact that we continue to see the same tolerance and safety. And obviously, we have to expand in larger cohorts. And now week study will show the results. As Janet has indicated, we have six studies in parallel. And as soon as the cohort will be completed, we will share with the street. Janet, you want to address the first question?

So the first question, I think was in regard to MORNINGSKY, was it currently running in the U.S? And the answer to that is no. It is not. We're in discussions with the FDA, but it is currently not running in the U.S.

Okay. Thanks. And just to follow-up on that, do you have given any guidance as to how much data or how many patients worth of data they need to see to allow that to enroll. Do you have a sense of when that might be able to get up and running?

Janet?

So I can't -- we don’t generally comment on those types of specifics, unfortunately. So I’m not able to answer your question.

Got it. Thanks.

And your next question comes -- and I'm showing no more questions at this time.

So thank you everybody for your interest and support, and appreciate. And so thank you for, again for joining us and continued support to Atea. Thank you.

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