Good afternoon, everyone, and welcome to the Atea Pharmaceuticals 4th Quarter 2025 Financial Results and Business Update Conference Call. At this time, all participants are in a listen-only mode. Following the formal remarks, we will open up the call for your questions. I would now like to turn the call over to Janae Barnes, Senior Vice President of Investor Relations and Corporate Communications at Atea Pharmaceuticals. Ms. Barnes, please proceed. first.

Great. Thank you, Operator. Good afternoon, everyone, and welcome to Atea Pharmaceuticals fourth quarter and full year 2025 financial results and business update conference call. Earlier today, we issued a press release which outlines the topics 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 investor section of our website at ir.ateaopharma.com. With me today from Atea, are our Chief Executive Officer and Founder, Dr. John-Pierre Somajosi, Chief Development Officer, Dr. Janet Hammond, Chief Commercial Officer, John Vavrica, Chief Medical Officer, Dr. Arantzahorga, and Chief Financial Officer and Executive Vice President of Legal, Andrea Portgrin, who will be available for the Q&A portion of today's call. Before we begin the call, and as outlined on slide two, I would like to remind you that today's discussion will contain forward-looking statements that involves risk and uncertainty. These risk 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, Janaye. Good afternoon, everyone, and thank you for joining us. I will begin on slide I am pleased to report that we have made substantial clinical progress in the last year advancing our global Phase III program evaluating the regimen of benifazivir and resazivir for the treatment of HCV infections. Due to the rigorous execution of our two pivotal Phase III trials, C-Forward and CBR, we expect top-line redout this year for both trials. We also presented several data sets, reinforcing the potential best-in-class profile of our regiment at the ESO Congress in 2025 and the LIVER meeting in 2025, the annual meeting of ASLD. Janet will discuss highlights from these presentations. We convened two panel discussions with key opinion leaders that underscore the need for a new optimized HCV regimen to address treatment paradigm shifts, including the test and treat model of care and how our regimen is uniquely positioned to address the current needs of patients and prescribers and expand the market in the U.S. In November, we announced the expansion of our antiviral hepatitis pipeline to address a major and met medical need for immunocompromised patients living with chronic hepatitis E infection, a liver disease for which there is currently no approved therapy available. If left untreated, it can rapidly progress to cirrhosis within three to five years. In vitro and in vivo results, presented last month at Quarri 2026 and at the JPMorgan Health Care Conference in January, support our lead product candidate, AT587, as a potential first in class inhibitor against HEV infection. I will review this exciting program later in the presentation. Moving to slide four, I'm pleased to report that our global Phase III HCV program is on In December, we completed enrollment for our North American trial, CBR, with over 880 patients, and we expect to complete enrollment see-forward our trial outside of North America by mid-year. We anticipate top-line results for CBR mid-year and for C4 by year end. Following our selection of AT587 as the lead product candidate in our HEV program, we initiated IND and CTA-enabling studies and anticipated initiating a first in human study mid-year. Importantly, with $301.8 million of cash, cash equivalent, and marketable securities as of December 31st, 2025, we are in the strong financial position to execute and complete our Phase 3 HCV program and advance our new HEV development program. We anticipate our cash runway will extend through 2027. With that, I will now turn the call over to Janet to review the profile of our regimen.

Thanks, John-Pierre. Moving to slide 6, hepatitis C remains a significant global healthcare crisis with an increasing incidence of infections despite the availability of direct action antiviral for the past decade. Currently in the United States, out of the reported 160,000 new chronic infections, only 85,000 patients are treated annually. In 2015, there were approximately 2.5 million people infected in the United States. Today, that number has nearly doubled to approximately 4 million. The unrelenting high rate of new chronic hepatitis C infections, which continues to outpace the number of patients being treated, underscores the need for a new, differentiated, and optimized therapy. In the map shown on the right, you can see that most countries worldwide, including the United States, are not on track to achieve the World Health Organization's goal of the elimination of hepatitis C by 2030. In fact, current estimates suggests we may not even achieve this goal by 2050. Let's not forget that hepatitis C is the primary cause of liver cancer in the United States, the incidence of which is projected to increase by over 50% within the next five years, from approximately 850,000 cases in 2025 to 1.4 million people. On slide seven, we're conducting the first global head-to-head active controlled phase trials in our program for hepatitis C, comparing our regimen against the current standard of care to Fosfavir and Velpatavir, which are marketed as Eptusa. Results support our regimen as a potential best-in-class treatment option for patients infected with HCV with a differentiated profile featuring a highly potent combination with a short treatment duration, low risk for drug-drug interactions and convenience with no food effect. We continue to build out our data set, and recent results demonstrated a low risk for drug-drug interactions with proton pump inhibitors, which are taken by an estimated 35% of hepatitis C infected patients. Moving to slide eight, we've presented several data sets supporting the potential best-in-class profile of the regimen of benifosavir and roosavir last year at the EASOL Congress, and then at the liver meeting results from the phase two study in 275 patients demonstrated the eight-week regimen of benbrudivir achieved 98 sdr12 in the protocol treatment adherent population and a 95 sdr12 in the efficacy evaluable population additional results demonstrated that the regimen has a high barrier to resistance the regimen has a low risk for drug drug interactions, including with proton pump inhibitors, H2 blockers, and also standard HIV therapy. There is no need for dose adjustment of benifosfivir in patients with hepatic or renal impairment. The regimen can be taken with or without food. In addition, recently generated data show that in addition to inhibiting HCV RNA replication through chain termination, Benifosbuver also inhibits assembly and secretion of new hepatitis C virions, further explaining its high antiviral potency. With that, I'll now turn the call over to Arantra to provide an update on our Phase 3 program for hepatitis C. Arantra?

Thank you, Janet. On slide 10, C-Beyond enrolled patients in the U.S. and Canada, and C-Forward is enrolling patients in 17 countries outside of North America. Combined, we expect to enroll more than 1,760 patients in our Phase III program. Both trials are open-labeled, randomized one-to-one against the active comparator, and stratified by cirrhosis status, genotype, and including patients co-infected with HIV. In patients without cirrhosis, treatment duration is 8 weeks with venifoscovirusevir and 12 weeks with the standard of care. Patients with compensated cirrhosis receive 12 weeks of treatment with either regimen. The primary endpoint for both studies is sustained viral response or cure 24 weeks after treatment initiation. Slide 11 shows the geographic footprint of our Global Phase III program with approximately 120 clinical sites in the U.S. and Canada for Sea Beyond and another 120 clinical sites in 17 countries outside of North America for Seaforward. As JP mentioned earlier, Sea Beyond patient enrollment was completed in December with more than 880 patients, and we anticipate top-line results mid-year. C-Forward has a broader global geographic and genotypic footprint, and we expect to complete enrollment mid-year and to report top-line results by year-end. On slide 12, let's review the Phase III endpoints, patient population, and data analysis for our global Phase III program. In C-Beyond, the primary endpoint will be analyzed in a modified intent-to-treat population as preferred by the US FDA. The analysis will include patients that have been randomized and dosed regardless of drug adherence or lost to follow-up. The statistical analysis will be based on an imputation model with success or failure depending on PCR value, whether negative or not, prior to patient treatment discontinuation. A key secondary endpoint will include the SBR rate of the per-protocol population. In C-forward, the per-protocol population will be analyzed as the primary endpoint, as preferred by the EMA. And the SDR rate will only include patients who are at least 80% adherent, as measured by pill count, and have an SDR assessment at week 24. A key secondary endpoint will include the SDR rate for a modified intent-to-treat population. The same methods for assessing non-inferiority will be conducted in both phase 3 studies and both patient populations. The Phase III studies are powered 90% with 5% non-inferiority margin with expected rates approximating 95% in an MITT population. Using these two approaches in a post hoc analysis of the Phase II results, the SBR rate was 95% in an MITT population and 98% in the per-protocol population. I will now hand the call over to John Babrica, our Chief Commercial Officer. John.

Thank you, Arantxa. Moving on to slide 14. As discussed earlier in the call, the rate of newly reported HCV infections in the U.S. is outpacing treatment. Out of approximately 160,000 new HCV infections, only 85,000 patients are treated annually for a total of approximately $1.3 billion in net sales in the U.S. We have consistently heard from healthcare providers that the test and treat model of care, which allows for HCV testing, diagnosis, and treatment at the point of care, can reduce the barriers to prompt initiation of therapy that exists today. The test and treat model of care has gained broad support, including by the CDC, and continues to gain momentum through recent bipartisan efforts to advance HCV elimination in the U.S. Key opinion leaders also assert it can play a critical role in HCV elimination efforts and agree that a treatment optimized to work seamlessly with this model is still needed. Slide 15. While we are advancing our global phase three trials, we are also preparing for a commercial product launch. Our commercial package will include a blister card for convenience and adherence with a simple four-week dosing package. The drug product has a low cost of goods relative to net price, and based on our current projections, we anticipate achieving profitability relatively shortly post-launch. From a commercial standpoint, the USHCV prescriber base is highly concentrated, with approximately 6,000 prescribers writing 80% of the DAA prescriptions. making it optimal for efficient commercialization using a focused specialty sales force. We anticipate a commercial sales force of around 75 people, which includes the sales team and medical science liaisons. Let's move on to slide 16. Using our phase two results, IQVIA conducted an independent quantitative market research study with 153 U.S. high prescribers. These physicians indicated that they would likely prescribe the BEM RZR regimen to approximately half of their patients, and the results were similar for all patients, regardless of their cirrhosis status. Our market research also showed that U.S. payers responded favorably about the potential to include BEM RZR in the formulary based on the regimen's profile. I'll now hand the call back to Jean-Pierre to review the HEV program.

Dr. Thank you, John. Let's now move to slide 18. Hepatitis E virus, or HEV, is an acute and chronic liver disease. In developing countries, genotype 1 and 2 are most prevalent, and the virus is transmitted primarily through contaminated water and mostly cause epidemics of of acute, self-limiting viral hepatitis. In developed countries, genotype three is predominantly transmitted primarily to contaminated food, such as undercooked meat. This can cause chronic hepatitis in immunocompromised patients and can progress to cirrhosis within three to five years, which is much far more aggressive than what is seen with hepatitis C or hepatitis B. With no approved therapies for HEV, there is a significant admin need for a treatment option. Moving to slide 19, in recent years, with the increasing number of patients who are immunocompromised, which include solid organ transplant recipients, hematopoietic stem cell transplant recipients, patients with hematologic malignancies such as multiple myeloma, there have been a growing incidence of chronic HCV infection in U.S. and In the absence of any approved therapies for HIV, the standard of care includes reducing immunosuppression and or ribavirin administration, which both presents challenges. On slide 20, each year in the U.S. and Europe, about 3% of approximately 450,000 patients where these underlying medical conditions are at risk to develop chronic HIV. We estimate that the unmet need for this patient population represents a market opportunity between 750 million to one billion per year, and obviously this will follow an orphan designation. Section 21, let's now review data supporting the selection of AT587, our lead chronic candidate, a potential first-in-class direct-acting antiviral treatment option for chronic HEV. As you see on this slide, in vitro and in vivo activity of benefazvivir was shown against hepatitis E. However, the more potent in vitro activity of AT587 combined with the positive PK data, which we'll discuss next, led us to select AT587 as the lead product candidate. The in vitro data on this slide shows the potent nanomore antibody activity of AT587 against HEV genotype 3, anti-remain, also active against clinical rebarin-resistant associated substitutions of RAS. As noted earlier, ribavirin is used off-label for the treatment of HEB. On slide 22, we observed that the in vivo single-dose PK studies in rats and monkeys AT587 achieved high plasma concentration of the active triphosphate metabolite sorghum, which were comparable to those obtained with benifosbivir. On slide 23, of particular importance, we also demonstrated that AT87 efficiently converted to its active tri-phosphate intolerant in human hepatocytes, which is the site of viral replication in H-EV infection. To date, AT587 has a clean preclinical safety profile, positioning this product candidate as a first-in-class direct active antiviral for chronic H-EV. I will now turn the call over to Andrea to discuss at their financials.

Thanks, Jean-Pierre. As Jornay mentioned in her introductory remarks, earlier today we issued a press release containing our financial results for the fourth quarter and full year 2025. The Statement of Operations and Balance Sheet are on Slides 25 and 26. We are pleased to report that our cash and investments were $301.8 million at December 31, 2025. The funds expended in 2025 were principally directed to the advancement of our HCP Phase III program, evaluating the combination regimen of benifosavir and rucosavir, and to discovery efforts leading to the nomination in January 2026 of AT587 as the lead product candidate for the treatment of HEP. In 2025, we also returned $25 million to our stockholders through a share repurchase program. Each of these investments and use of funds reflects our steadfast commitment to drive value for our stockholders. For R&D expenses, quarter over quarter and year over year, there was an increase in 2025 compared to 2024. The net increase in 2025 was principally driven by an increase in external spend for HCV Phase III clinical development, offset by a decrease in 2025 in external spend for our COVID-19 clinical development, and lower internal expenses, primarily related to a decrease in stock-based compensation expense and lower payroll and payroll-related expenses. For G&A expenses, quarter-over-quarter and year-over-year, expenses decreased. The net decrease was primarily related to lower stock-based compensation expense, partially offset by increased professional fees. For 2026, we intend to maintain our rigorous financial discipline while remaining laser focused on execution and value-creating advancement of our HCV and HEV product candidates. As we complete our Phase III clinical trials, prepare to submit our regulatory filings, and engage in pre-launch activities, including the manufacturing of commercial launch supply, The substantial majority of our spending in 2026 will be focused on the advancement of our HCV program. With the resources in hand as of the end of the year, we expect to realize value-creating milestones for both programs and project our cash runway to extend through 2027. I'll now hand the call back to Jean-Pierre for closing remarks.

Thank you, Andrea. Okay, on slide 27, in closing, 2026 will be a pivotal year for AT&T. We are on track to deliver top-line Phase III results from CBR mid-year. These results will be followed by the top-line results from C4 by the end of this year. We believe that the target profile of our regimen featuring high efficacy, short treatment duration, low risk of drug-drug interaction, convenience with no food effect, will uniquely position us to address the need of today's patients and seamlessly fit in the test and treat model care, which has the potential to bring us closer to the ultimate goal of HCV eradication. Our HEV program will present a strategic expansion of our antiviral pipeline and address a major unmet need in the highly vulnerable patient population for which there is no approved treatment available. We anticipate initiating a first-in-human study mid-year with the proof-of-concept by the end of the year and possible to advance to a phase 2-3 trial in the second half of 2027. With that, I will turn the call back over to the operator.

Thank you. We will now begin the question and answer session. To ask a question, you may press star and then one on your touchtone phone. If you are using a speakerphone, please pick up your handset before pressing the keys. If at any time your question has been addressed and you would like to withdraw your question, please press star and then two. The first question will come from Maxwell Score with Morgan Stanley. Please go ahead.

Hello, this is Selena on for Max. Having achieved your enrollment target for the cirrhotic population for C-Beyond, does that increase your confidence in hitting your target in C-Forward?

Aretha?

We are going to achieve our target overall for the program, both in C-Beyond and C-Forward. The cirrhotic involvement has not been an issue.

Thank you.

The next question will come from Jonathan Miller with Evercore ISI. Please go ahead.

Hi, guys. Thanks so much for taking my question. As we look forward to a commercial launch in HCV, I guess I'll focus there. Can you talk a little bit about how the commercial landscape is currently organized in terms of contracting? Are there centralized groups that you're going to have to convince to switch over from legacy systems? How is pricing in the commercial universe currently going to evolve as we've seen the legacy regimens get put under significant pricing pressure? So can you talk a little bit about how the commercial landscape has evolved over the past six, nine months and how well you're positioned to deal with those changes?

Great question, John. John?

Sure. So as you know, the distribution market for DAA is a specialty market, and there are three segments, pretty much commercial, Medicare, and Medicaid. All of those current distribution pathways are known and are fully utilized. And we're currently looking at all those relative to the three segments, as well as relative to the payers. So it's a known quantity where we will have to be. We actually have conducted preliminary research with the payers. And obviously seeing the profile, it is of interest to them. and it was stated that they would be eager to include it in a formulary. As far as where pricing goes, the pricing, you know, it's relatively stable. Year-over-year, moderate pricing went up a little bit, but inclusive pricing did, net pricing did go down. But overall, for the past, you know, at least two or three years, the overall net pricing has been relatively stable, and their market shares are getting pretty close to a 50-50 with the favoring EPCUSA.

Does that answer your question?

Yes, it does. Thank you very much. Yeah, I'll get back in a queue. Thanks.

The next question will come from Andy Shea with William Blair. Please go ahead.

Thanks for taking our question. So looking at the primary endpoint of C-Beyond based on the modified to intend to treat population, am I thinking about this correctly that based on this analysis plan, you can actually really expand the effect size because you can basically magnify a regimen that actually can have flexibility into, you know, missing doses and, you know, given the more potency profile compared to the standard of care. So that's part number one. And part number two is, you know, in a scenario where you can actually show material clinical benefit over the standard of care, say maybe with a statistical perspective, John, based on your market analysis, how would that change some of the physician response in terms of, you know, their excitement or potential market uptake? Thank you. Good question, Dendi.

Arisa, you want to to try the first one yeah um andy um so the the mitp as you know it's everybody that gets a dose you know so there will be a range there from people that uh will get one dose or maybe five days of dosing two people who will be you know almost uh done with the full picture so with all the doses. So I think it will be interesting to see how it pans out, you know, what's the minimum, I guess. But right now we're really aiming for an eight-week regimen. We can do some analysis in the future.

John?

Yeah, we're, you know, we're actually very excited because when we look at the market research that has been done just with the Phase 2 data, bearing in mind that these physicians had 10 years' experience with two DAAs and showing them a profile, which, as we talked about, the short duration, low likelihood of drug-drug interactions and the convenience of with or without food. You know, just seeing that profile the first time, they saw it being used in approximately 50% of their patients, regardless of their cirrhosis status. So the profile right now stands very, very well. So, your question about if there was some kind of a more favorable response in terms of Benmore's ER, obviously that would play into their likelihood to prescribe Benmore's ER, but we're also very conscious that we play in the specialty arena, and in that specialty arena, you know, obviously the distribution of market share tends to balance itself out to make sure that the market is preserved over time.

Just to add, Andy, it's clear from the QOL and the prescriber that number one key important feature is the treatment duration. So, treatment duration definitely will be in the shortest with Marivad, but then after So when you evaluate all the, I would say, complex aspects with patients, with polymedication, we feel that the prescriber will really highly favor our regimen. And then we'll see, we'll have to weigh the clinical data, you know, in terms of all the type of side effects with fatigue and nausea and headaches that have been reported. So let's not forget, this is the first head-to-head. There is a lot of world-type studies, but as a controlled, randomized, clinical study, this is the first one. And let's see what we are going to learn. Great.

And maybe a quick housekeeping item, just from an R&D perspective, it seems like there is a one-time work license agreement. Can you talk about that just so you have a better sense of kind of going forward?

Okay, sure. Andrea?

So, yes, Andy, we have in-licensed Rusasvir, which is the combination product with Benifasvir in the HCV product candidate. We are paying milestones and we will pay royalties to Merck on successful commercialization. The next milestone will be due when we submit the NDA and the NDA is approved. We believe that's in 2027.

I see. That's helpful. Thank you.

This concludes our question and answer session. I would like to turn the conference back over to Jean-Pierre Samadossi for any closing remarks.

Thank you all for joining our first quarter 2025 and for your early conference call and thank you for your continued support.

The conference has now concluded. Thank you for attending today's presentation. You may now disconnect.