Vaxart Highlights Oral Vaccine Platform, COVID Trial Progress at H.C. Wainwright Conference

Key Points

• Vaxart’s oral vaccine platform uses thermostable Ad5-based tablets designed to generate both systemic and mucosal immunity, potentially reducing reliance on injections and cold-chain storage.
• The company has completed enrollment of roughly 5,400 participants in its BARDA-funded Phase IIb COVID-19 trial; the 12-month relative efficacy results are expected in the first half of 2027. Early Sentinel-cohort data showed no vaccine-related serious safety concerns and fewer reported adverse events than the mRNA comparator arm.
• Vaxart is seeking funding or partnerships to advance its Phase II norovirus candidate and earlier-stage influenza programs, while saying its cash runway extends into the first half of 2027.

Vaxart OTCMKTS: VXRT Chief Executive Officer Steve Lo outlined the company’s oral vaccine platform, its government-funded COVID-19 study and development opportunities in norovirus and influenza during an H.C. Wainwright conference presentation.

Lo said Vaxart’s recombinant adenovirus type 5, or Ad5, delivery platform is designed to administer vaccines as thermostable oral pills rather than injections. The company is developing candidates for COVID-19, norovirus and influenza. According to Lo, the pill is intended to dissolve in the intestine and generate both systemic and mucosal immune responses, in contrast with injectable vaccines that primarily generate systemic immunity.

The company has dosed 3,880 subjects across its clinical studies to date and has manufacturing operations in South San Francisco, Lo said. He emphasized potential logistical benefits of an oral vaccine, including no cold-chain storage, no needles and the ability for patients to self-administer doses.

COVID-19 Study Enrollment Complete

Vaxart has fully enrolled approximately 5,400 participants in its BARDA-funded Phase IIb COVID-19 clinical trial, which compares the company’s oral vaccine candidate with an approved mRNA vaccine. The primary objectives include safety and tolerability, immunogenicity and relative vaccine efficacy.

The study consists of a 400-subject Sentinel safety cohort and a main cohort of approximately 5,000 participants. Lo said the main cohort’s 12-month relative efficacy endpoint is expected to read out in the first half of 2027.

In the Sentinel cohort, Vaxart reported no vaccine-related serious adverse events in either study arm and no sustained Grade 3 or higher adverse events related to vaccination. Participants receiving Vaxart’s oral vaccine and a placebo injection reported fewer adverse events than participants receiving a placebo pill and the mRNA comparator, according to Lo.

• Vaxart reported lower levels of injection-site pain, tenderness and swelling in its study arm, despite participants receiving a placebo injection to maintain trial blinding.
• The company also said the mRNA comparator arm showed higher rates of malaise, fatigue, headache and muscle pain.
• COVID-19 case counts, including symptomatic and asymptomatic cases, were similar between the two arms in the Sentinel cohort.

Lo noted that the Sentinel cohort was not designed or powered to establish a statistically significant efficacy comparison. He said the company viewed the similar case counts and lower reported reactogenicity as encouraging ahead of the larger study readout.

Vaxart’s COVID-19 program is partnered with Sanofi. Lo said Sanofi holds a worldwide license agreement and may choose to opt in following the Phase IIb results. Vaxart previously received a $25 million upfront payment and a $5 million equity investment under the collaboration, he said. If Sanofi opts in, Vaxart could be eligible for up to $670 million in milestone payments and tiered royalties in the low- to mid-teens, with a potential $50 million opt-in milestone.

Norovirus Candidate Awaiting Funding or Partnership

Lo also highlighted Vaxart’s second-generation bivalent norovirus vaccine candidate, which targets the GI.1 and GII.4 strains. He said the company estimates norovirus causes 22 million U.S. cases annually and creates more than $10 billion in annual domestic economic burden, while no approved vaccines currently exist.

Vaxart’s first-generation norovirus construct was evaluated in a GI.1 challenge study and showed a relative reduction in infection and norovirus acute gastroenteritis symptoms versus placebo, according to Lo. The company used findings from that work, including its norovirus-blocking antibody assay, or NBAA, as a correlate to guide development of the second-generation candidate.

Lo said the newer construct demonstrated improved geometric fold rises in the NBAA for both GI.1 and GII.4. The candidate is ready for a Phase II study, but Vaxart is seeking a partnership or investment to advance the program.

Influenza Programs Remain Earlier-Stage Opportunities

In influenza, Lo cited a prior BARDA-funded Phase II challenge study comparing Vaxart’s oral candidate with Fluzone. He said the company observed better protection versus Fluzone, along with mucosal and serum antibody responses, reduced shedding and a favorable safety profile.

Vaxart also previously evaluated an H5N1 pandemic influenza construct in ferrets. Lo said animals receiving the vaccine construct had 100% survival, while placebo-treated animals did not survive. He said the company is likewise seeking partnerships or investment to move its flu programs forward.

Lo said Vaxart’s cash runway extends into the first half of 2027 and that the company’s primary near-term focus is executing the COVID-19 Phase IIb study through its expected data readout. BARDA funding is expected to support the study through that milestone, he said, following a contract modification that enabled continued work and further study analysis.

About Vaxart (OTCMKTS:VXRT)

Vaxart, Inc is a clinical-stage biotechnology company pioneering the development of oral recombinant vaccines administered in tablet form. Leveraging a proprietary, room-temperature-stable platform, the company aims to simplify vaccine delivery while eliciting both systemic and mucosal immune responses. Its technology is based on the replication-defective adenovirus vector system, which encodes target antigens designed to protect against a range of infectious diseases without the need for injections or cold-chain logistics.

The company’s pipeline includes multiple vaccine candidates in various stages of development.

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