Greetings and welcome to the Vaxart Business Update and Fourth Quarter and Full Year 2024 Financial Results Conference call. A question-and-answer session will follow management's opening remarks. Individual investors may submit written questions to [email protected]. As a reminder, this conference is being recorded. I would now like to turn the webcast over to your host, Ed Berg, Senior Vice President and General Counsel.

Good afternoon, and welcome to today's call. Joining us from Vaxart are Steven Lo, Chief Executive Officer; Dr. Sean Tucker, Founder and Chief Scientific Officer; Dr. James Cummings, Chief Medical Officer; and Phillip Lee, Chief Financial Officer. Before we begin, I would like to remind everyone that during this conference call, Vaxart may make forward-looking statements, including statements about the company's financial results, financial guidance, its future business strategies and operations, and its product development and regulatory progress, including statements about its ongoing or planned clinical trials. Actual results could materially differ from those discussed in these forward-looking statements due to a number of important factors, including uncertainty inherent in the clinical development and regulatory process and other risks described in the risk factors section of Vaxart's most recently filed annual report on Form 10-K and also on other periodic reports filed with the SEC. Vaxart undertakes no obligation to update any forward-looking statements after the date of this call. I'll now turn the call over to Steven Lo. Steve?

Thanks, Ed, and thanks to all of you for joining us this afternoon. On today's call, I will highlight our business progress. I'll then have James and Sean share updates on our clinical and preclinical programs. Then, Phil will discuss our financial results before we open the call for your questions. At Vaxart, our mission is to transform global public health by developing next generation oral pill vaccines to support pandemic preparedness and provide Americans and people around the world with a revolutionary new option to how they receive vaccines. Vaxart built a robust body of data across multiple clinical studies and we believe that our approach may provide important safety and immune response benefits compared to approved injectables. We have multiple programs in clinical development built on the strength of our oral vaccine platform. It is this platform that has generated promising data to date, harnessed in a pill formulation that can address many of the shortcomings of injectable vaccines. Our candidates have demonstrated broad immune and cross-reactivity responses, reduction in viral transmission and shedding, long duration of protection and immune responses, and importantly, a benign safety and tolerability profile. Across 19 clinical trials against seven different viruses, evaluating more than 800 participants, our vaccine candidates have shown favorable safety data. Starting with our COVID-19 program, as we stated previously, we received an award of approximately $460 million to conduct an approximately 10,000 participant head-to-head study against an available mRNA comparator. In November 2024, we completed enrollment of the initial sentinel cohort of this study comprised of 400 participants, with 200 receiving Vaxart's XBB strain COVID-19 vaccine candidate and 200 receiving an approved XBB mRNA vaccine comparator. In January, an independent data safety monitoring board recommended the study to proceed without modifications based on initial safety assessment of the 30-day data. On February 21st, we received a stop work order related to this BARDA funded Project NextGen award from the US Department of Health and Human Services, or HHS. We were not provided a reason for the stop work order. It halted all activities related to the planned 10,000 participant portion of the study and is in effect for a period of up to 90 days. Within these 90 days, the stop work order will either be canceled, extended, or work on this project will be terminated. To be clear, this does not apply to efforts associated with the 400-person Sentinel cohort of the study, and activities to monitor and further assess this cohort continue. Vaxart is aligned with HHS and BARDA's vision of improving efficiencies while protecting Americans from known and emerging disease threats, underscored by the progress we achieve with our oral vaccine pill candidates. We recognize and appreciate the importance of oversight, transparency, and fiscal responsibility in government-funded biomedical research, and we are committed to working collaboratively with Secretary Kennedy, HHS, BARDA, and other members of President Trump's administration as they evaluate their priorities as well as the data supporting the 10,000-participant portion of the Phase 2b study and determine whether and how the study should move forward. We maintain ongoing communications with our contacts at BARDA, primarily as it relates to the sentinel group follow-up work. At this time, we do not have any new updates to provide on the 10,000-participant portion of the trial. We will provide an update when we have additional information. The company continues to work through the impact of the stop work order, including making necessary expense adjustments in order to extend our cash runway. Turning to our norovirus program, we are making meaningful progress on our key milestones, and we are pleased to have initiated a Phase 1 trial earlier this month evaluating our second-generation oral norovirus vaccine constructs head-to-head against our first-generation constructs. We believe this was a prudent and responsible path that aligns with the recommendations of FDA based on constructive conversations that we previously held with the agency. If the Phase 1 trial is successful, the next step, pending a partnership or other funding, would be to conduct a Phase 2 safety and immunogenicity study that could potentially begin as early as the second half of 2025. This Phase 2 trial would be followed by an end of Phase 2 meeting with the FDA. A Phase 3 trial could then begin as early as 2026, pending a successful end of Phase 2 meeting and funding. Currently, there are no approved vaccines against norovirus. This winter was particularly challenging with numerous reports of norovirus spreading across the United States and around the globe. Norovirus is not just a cruise ship virus, but one that is highly contagious and is the leading cause of acute gastroenteritis symptoms such as vomiting and diarrhea. This $10 billion annual US economic burden can affect up to approximately 20 million Americans, further illustrating the unmet need that we are determined to meet. Finally, we continue to carefully review our preclinical programs before determining if further investment is needed to advance other indications. Two such indications that we are evaluating are our avian influenza and HPV vaccine programs. Sean will provide an update on these programs shortly. I'll now turn the call over to James to provide a further review of the recent progress for our norovirus program.

Thanks, Steve. Vaxart continues to make important advancements with our promising norovirus vaccine candidate in clinical development. Earlier this month, we initiated a Phase 1 clinical trial evaluating our second-generation oral norovirus vaccine constructs head-to-head against our first-generation constructs. Sean will discuss our new constructs in more detail shortly, but this is an exciting study that will measure safety and immune parameters that have been correlated to protection in the completed norovirus challenge study. I want to remind you of why we took this approach. By accumulating data from our first-generation constructs, we measured efficacy against a robust, controlled human infection model and identified important immune markers that track with norovirus protection. Importantly, our norovirus oral vaccine candidate has shown that it induces mucosal and systemic immune responses and has generated protection that associates with making a functional antibody response to norovirus in the serum and norovirus-specific fecal IgA antibodies. Last year, our Phase 2 challenge study demonstrated encouraging data on the potential of our oral pill vaccine to reduce rates of norovirus infection, illness, and viral shedding. Additionally, in our Phase 1 clinical trial that focused on lactating mothers, we demonstrated positive data that suggested our vaccine candidates can potentially help protect infants through passive antibody transfer. In addition to the robust immunogenicity and promising efficacy profile, our norovirus program has demonstrated a benign safety and tolerability profile, consistent with the safety of our platform in previous studies. As previously exhibited in our challenge study, there were no significant differences in adverse events between our vaccine candidate and placebo. Now, we have promising preclinical data for our norovirus GI.1 and GII.4 constructs that we believe may be more potent than the first-generation constructs being evaluated in clinical trials. We are testing this hypothesis to allow us to move forward with the right dose of the right construct. The combined preclinical and clinical data, along with the constructive feedback on the correlate protection data we submitted, gives us optimism that we will have the most effective and safe norovirus vaccine candidate in clinical development. We look forward to reviewing the top-line noro data that is expected as early as mid-2025. I'll now hand the call over to Dr. Sean Tucker, our Founder and Chief Science Officer, for a brief discussion of our norovirus second-generation constructs, recent publications, and preclinical programs.

Thank you, James. First, I'll highlight the research into our second-generation vaccine constructs and discuss in greater detail the results of our recent publications in Science Translational Medicine. Through the power of machine learning, we created new second-generation norovirus GI.1 and GII.4 constructs. In preclinical testing, our data show our new constructs are more potent than the first-generation norovirus constructs we previously evaluated in clinical trials. The second-generation constructs are designed to express the antigenic protein at higher levels in the intestinal space, the site of delivery of our vaccine after release from the tablet. We were able to improve the expression by small changes in the DNA sequence. In preclinical models, this higher-level expression has led to substantially improved immune responses compared to our first-generation constructs. Further, these new constructs take advantage of recent changes in the backbone designed to improve RNA stability. Our expectation is that the improvements will translate to better performance in humans, either by eliciting more robust immune responses or by creating a similar response at a lower dose, also known as dose sparing, or both. As James mentioned, we look forward to showcasing the potency of our new constructs against our first-generation constructs in a Phase 1 study that we initiated earlier this month. On March 5th, Science Translational Medicine published two articles on our norovirus studies that underscored the efficiency of our platform in generating mucosal antibody responses. I'll start with our Phase 1b trial that evaluated the safety and immunogenicity of our first-generation oral norovirus vaccine candidate in two groups of healthy older adults, aged 55 to 65 and 66 to 80 years old. We announced the data in a press release, but I would like to highlight a few key findings from the study. First, the vaccine candidate generated robust and durable systemic antibody responses, induced VP1-specific mucosal homing antibody-secreting B cells and mucosal homing T-cells. These data support the immunogenicity of the vaccine candidate in a patient population that often has age-related reductions in immune responses to injected vaccines. Second, oral administration of the vaccine stimulated strong and durable IgA responses in the saliva and the nasal cavity, which could have important implications for the use of our vaccine platform for norovirus and other indications as well. And third, the vaccine was safe and well tolerated in older adults. All solicited events were mild to moderate, no Grade 3 events related to the vaccine. Based on these results, our oral pill norovirus vaccine program may be uniquely positioned to protect elderly individuals from adverse norovirus infection outcomes and prove to safely provide the benefits of the mucosal vaccine to patients at higher risk of adverse norovirus outcomes. The second publication in Science Translational Medicine focused on identifying broadly neutralizing antibodies targeting the human norovirus and to determine the biochemical and structural basis of broad humoral protective immunity. The majority of this work was performed by two academic groups, one at UT Austin and one at the University of North Carolina. Two donors were selected for detailed studies. Both candidates received a single dose of our oral candidate vaccine to GII.4 and were selected based on their post-vaccine immune responses to norovirus. In participant A, vaccination substantially boosted ligand-binding blockade serum titers to all tested GII.4 variants circulating from a 3.5 to a 68-fold increase on day 29 compared with pre-vaccination serum collected on day one. Serum for participant B had exceptional cross-genotype blocking serum breadth across seven GII and two GI genotypes on day one before vaccination and were modestly boosted from 2.0 to 3.6-fold at day 29 after vaccination. Data suggests that immune imprinting likely affects the response to mucosal norovirus vaccination in adults, creating a highly cross-reactive response rather than a simple strain-specific response due to prior norovirus exposure. The oral vaccine likely enhanced those cross-strain responses. Indeed, several monoclonal antibodies were isolated from oral vaccinated subjects, and many of those antibodies were found to bind to conserved epitopes of norovirus and led to that cross-reactivity. We believe these data published are highly compelling from both efficacy and safety standpoints and support the continued advancement of our promising norovirus vaccine candidate. I would like to take this time to thank our incredible R&D team and our collaborators for supporting conducting these studies and making these publications possible. As Steve mentioned earlier, we are reviewing our preclinical programs in terms of the next steps of bringing future candidates into the clinic. On avian influenza, we published data demonstrating protection in preclinical models after oral immunization and recently created a new vaccine candidate to cover the latest clade 2.3.4.4b strain. We're in the process of conducting several preclinical studies to evaluate the new construct and preparing to manufacture it for clinical use. On our HPV vaccine, we have additional preclinical studies planned to further characterize the immune-stimulating antitumor activity of this candidate. Previously published data suggests that our mucosal vaccine platform represents a possible non-invasive approach to prevent the progression to cervical cancer. We will publish the results for preclinical studies when complete. I'll now hand the call over to Phil Lee, our CFO, for a brief discussion of our financials.

Thank you, Sean. The details of our full year 2024 financial results are summarized in today's press release. Revenue for 2024 was $28.7 million, compared to $7.4 million in 2023. Revenue in 2024 was primarily from government contracts related to BARDA and non-cash royalty revenue from sales of Inavir in Japan. Revenue in 2023 was primarily from revenue recognized for work performed under Vaxart's grant from the Bill and Melinda Gates Foundation and non-cash royalty revenue from sales of Inavir in Japan. Vaxart ended 2024 with cash, cash equivalents, and investments of $51.7 million. In the first quarter of 2025, the company implemented measures to reduce expenses, including a reduction in its workforce following the BARDA stop work order. Based on our current plan, Vaxart anticipates cash runway into the fourth quarter of 2025. Vaxart continues to explore various strategies to extend its cash runway through strategic partnerships, non-dilutive funding, and other cost reduction initiatives. I will now turn the call back to Steve for closing remarks.

Thank you, Phil. The team here at Vaxart is dedicated to reimagining the way global public health is approached. Advancing vaccine development is a time and capital-intensive process that we are pursuing to ensure our vaccines are not just highly effective, but safe. Our unique strategy centered on mucosal immunity is a cornerstone of our vision for success. And we believe that our benign safety and tolerability profile reinforces our confidence in our science. As trailblazers in oral vaccines, we take pride in bringing groundbreaking innovations to the field. The desire to shield people from infectious diseases and promote longer, healthier lives fuels our team's passion every day. We look forward to sharing our progress with you in 2025 and beyond. Before we open the call for questions, we request that listeners do not ask questions related to the HHS stop work order directive. As we stated earlier, we do not have any additional information to provide at this time and so cannot comment further on this matter. We appreciate your understanding. Thanks, everyone, for your time today. We will now open the call for your questions.

Our first question comes from Cheng Li with Oppenheimer. Please go ahead with your question.

Hi, thanks for taking the question and congrats on the progress as well as the publications from Science Translational Medicine. Just a couple of questions from us regarding the new Phase 1 study for norovirus. I'm wondering if you can talk about whether the new or second-generation product is bivalent or it's a monovalent vaccine. And then for the Phase 1 study, whether you are planning to enroll both young adults and older adults in the trial? Thank you.

Yeah, hi, Cheng, thanks for the question. I'll let James and Sean answer that. James, if you want to go first.

Sure, thanks, Steve. So, Cheng, for the Phase 1 study, we are enrolling folks 18 to 49 into the study population. In terms of the second-generation product, we are looking at a GI.1 and a GII.4, and I'll bounce it off to Sean for a little more definition in terms of what the second-generation product might be.

Sure. Yeah, we made some small changes to the DNA backbone as well as this antigen sequence, and we found that those changes led to, and they were very minor changes, to enhanced expression in intestinal epithelial cells. And once we put those constructs into preclinical models, we found that the animals made much greater immune responses to the antigen of choice than our first generation. Obviously, they were very bullish and have moved this forward into the clinic.

Got it. Thank you. And just maybe a quick follow-up. Can you maybe provide some color on the scope of the top-line data we should expect in media? Thank you.

I will take that, Sean. In terms of the top-line data we should be looking for, it's related to preliminary safety and immunogenicity.

Thank you. Our next question comes from the line of Mayank Mamtani with B. Riley Securities. Please proceed with your question.

Hey guys, Madison on from Mayank and thank you for taking our questions. Curious regarding the second-generation version, the animal data that you've referenced when you see this greater immune response, just wondering how this could translate to top-line efficacy relative to what we've seen from the prior first gen? And then also wondering, will the data generated from the first gen still contribute to FDA discussions? Thanks.

Yeah, thanks for the question. I'll was going to let James and Sean go and take that. From our standpoint, right, even the first construct, first version, we had pretty good results. But please go ahead, James.

Actually, I'll have Sean go first and I'll back clean up. Sean?

Yeah. So, yeah, the new constructs, we know that they make better immune responses in animals. And again, and our expectation is that even like a small change in humans because of the exponential amplification of the signal will make a big difference from the standpoint of protective efficacy. Again, this is through mathematical modeling. We think we know what antibodies are needed in the intestinal space, as well as, when we measure it with serum. And we think that just the small increases would be phenomenally better from the standpoint of efficacy. I'll let James answer the regulatory question.

Thanks, Sean. And from a regulatory standpoint, finding the right construct, the right dose moving forward is the key for us. I think that it will be part of the overall discussion as we want to pick the best vaccine to bring to people to protect them.

Got it. Understood And congrats on initiating the trial and publication. Thanks, guys.

Thank you.

Thank you. Our next question comes from the line of Liang Cheng with Jefferies. Please proceed with your question.

Hey, good afternoon. Thank you for taking our questions. This is Liang Cheng for Roger Song. I guess my first question is about the norovirus program, so congrats on your progress in initiating the Phase 1 study. So, understanding that's going to be head-to-head study versus your first-gen construct. So, I guess for the top-line readout, so what unicity measurement should we focus on? And how would you expect that translate into the protection efficacy?

Yeah, I would say the two things that we're going to measure initially from that study are we're going to measure the serum, what we call NBAA response norovirus blocking antibody assay titers. We know that in our clinical study or the challenge study, we know that that correlated with protection pretty well. And the other thing we're going to measure is going to be the fecal IgA. And again, that also was part of the top-line data that was most important from the standpoint of showing efficacy in that challenge model.

Thanks, Sean. Maybe a follow-up question. So, regarding the second-generation construct, so you mentioned that stronger potency, so how should we think about that regarding the dose that is going to be used in a clinical study compared to a first-generation?

Sure. I'll take that, Sean. So, we're enrolling a total of 60 patients in the Phase 1 trial in three separate cohorts of 20. So, in taking a look at the new construct, it would be considered low dose and high dose. And then the traditional or the original construct would be considered the high dose, looking at both GI.1 and GII.4. Our enrolling takes into account the best practices for safety, dose, and for clinical development. And I'm happy to say it's progressing smoothly.

Thanks, James. Maybe a final question regarding the COVID-19 program. So, understanding that the DSMB has seen the data and recommended to go ahead without any change. So, has FDA ever seen the data for the sentinel cohort?

Yes, this is James. The data was sent to the FDA. At the same time, it was sent to the DSMB.

Got it, Thank you. That's it from us. Congrats again.

Thank you.

Thank you. And we have reached the end of the audio question-and-answer session. I'll now turn it back over to Ed Berg for the written questions.

Thank you. We have a number of questions that have been submitted by our shareholders. The first question, this one clearly is for Steve. Are you managing the company differently given the challenging and rapidly evolving regulatory and political environment?

Great, thanks for the question. We're a small company, so we always operate in a very lean fashion, and we also pride ourselves on being nimble and adaptable, and we'll continue to do so. The listeners know the science of vaccines represents a big achievement in modern medicine. So they're one of the most powerful tools in combating infectious diseases, safeguarding against public health, et cetera. And we all know vaccines have profoundly reduced illness and death rates around the world. We still consider Vaxart to be an innovator in this field, given our oral vaccine platform. It's demonstrated a clean safety profile to date that's similar to placebo. And it's that type of differentiator that we believe could assist with the acceptance of vaccines, allowing consumers and physicians to have more options. We're certainly appreciative of our working dialogue with FDA, BARDA, and HHS. Our plan in 2025 has always been to advance more than one vaccine program. And we're happy to report that we continue to do so.

Thanks. A couple of questions on the COVID-19 program. The first one is about the DSMB. Did they provide specific feedback? And then maybe, James, you can also cover sort of how we think about the FDA submission if anyone is unclear. But for James, both around sort of what has occurred with regard to the monitoring and the oversight of the program from the scientific bodies.

Thanks, Ed. The DSMB reviewed the 30-day safety data for 400 participants from our central cohort in the COVID-19 Phase 2B study. They clearly recommended that the study proceed without changes based on their assessment, which we believe highlights the strong safety profile of our vaccine candidate, similar to placebo. We submitted that data to the FDA at the same time, and they've completed their review. There's no hold on progressing our plans, and we are on track to continue the program.

Thanks, James. The next question, how does the stop work order impact manufacturing? Was the product already produced for the trial? If so, what's the shelf life? Can it be salvaged if the stop work order lasts the full 90 days or later? So a set of questions around manufacturing and the use of the product we've produced. And with that, I'll ask Ray Stapleton, who is our Chief Technical Officer, to answer for us. We have him here.

Thank you, Ed. We're fortunate that we maintain our own GMP manufacturing facilities, and they are all inside the United States. These capabilities have allowed us to pivot quickly in support of this trial. This was demonstrated when we initially manufactured product targeting the XBB strain of COVID and subsequently manufactured product targeting the KP2 strain of COVID. As part of our ongoing manufacturing plan, we routinely monitor product stability and based on our stability data across our platform to date, shelf life is expected to last for two years. As we obtain clarity on the stop work order, we remain confident that we can adjust to it.

Thanks, Ray. Next question is on our norovirus program. And this is about how do we think about the market opportunity given there is a competitor already in Phase 3? And, I'll ask Steve to answer that.

Sure, thanks for the question. I think any time a large company with lots of resources believes that there's a significant unmet need, we're encouraged by that because we see it the same way as well. So, yeah, there's a significant market opportunity for norovirus, which has a $10 billion impact to the US. And we certainly believe that consumers and physicians will appreciate having options for future vaccines. Obviously, we believe an oral option is going to be competitive in the marketplace. And as we've been talking about earlier, we're excited that we are on track to have some top line data in our Phase 1 as early as mid-year this year.

Thank you. Questions on our other programs for Sean. First, when can we expect updates with regard to your preclinical studies in influenza and HPV? And then follow another question separately, is there a way for Vaxart to expedite work on the bird flu vaccine?

Great. Thanks. Well, the company is in the process of conducting several preclinical studies to evaluate our second-generation construct, and is also preparing to manufacture those constructs for clinical use. Obviously, we will publish the results when the preclinical studies are complete.

Thanks. And we have a question on finance. What partnership or non-dilutive funding options are you considering? I'll ask Phil to answer that.

Thank you, Ed. We are continuously engaging with various parties and providing updates on our progress with our programs and platform. We also take part in both financial and scientific conferences, which allows us to connect with new third parties. Overall, we are pleased to see ongoing interest from multiple parties in our vaccine candidates and the potential of the oral pill vaccine platform. While we cannot share more details at this moment, we will make announcements when it is appropriate and when we have something to share.

Thank you, Phil. That concludes the questions that have been submitted. With that, I'll turn it back over to the operator to close our session.

Thank you. And ladies and gentlemen, this does conclude today's conference and you may disconnect your lines at this time. We thank you for your participation.