Vaxart Announces Publication Demonstrating the Immunogenicity and Safety of its First-Generation Oral Pill Norovirus Vaccine Candidate in Elderly Adults
Vaxart (VXRT) has published complete data from its Phase 1b trial of its first-generation oral pill norovirus vaccine candidate in elderly adults aged 55-80 years. The study demonstrated strong and durable antibody responses in this population, which typically shows reduced immune responses to traditional injected vaccines.
Key findings include:
- Statistically significant increases in serum anti-VP1 IgA across all three dose cohorts
- Dose-dependent increases in vaccine-induced serum anti-VP1 IgG responses
- Strong IgA responses in saliva and nasal cavity
- Safety profile showing only mild to moderate side effects
The vaccine demonstrated effectiveness regardless of age group, with no significant differences between 55-65 and 66-80 year cohorts. Vaxart plans to initiate a Phase 1 trial comparing its second-generation oral norovirus vaccine constructs against first-generation versions in the first half of 2025.
Vaxart (VXRT) ha pubblicato dati completi dal suo studio di Fase 1b sul candidato vaccinale contro il norovirus di prima generazione, in forma di pillola orale, per adulti anziani di età compresa tra 55 e 80 anni. Lo studio ha dimostrato risposte anticorpali forti e durature in questa popolazione, che di solito mostra risposte immunitarie ridotte ai vaccini tradizionali somministrati per iniezione.
I risultati chiave includono:
- Aumenti statisticamente significativi degli anticorpi anti-VP1 IgA nel siero in tutti e tre i gruppi di dose
- Aumenti dipendenti dalla dose delle risposte anticorpali anti-VP1 IgG indotte dal vaccino
- Forti risposte IgA nella saliva e nella cavità nasale
- Profilo di sicurezza che mostra solo effetti collaterali lievi o moderati
Il vaccino ha dimostrato efficacia indipendentemente dal gruppo di età, senza differenze significative tra i gruppi di età 55-65 e 66-80 anni. Vaxart prevede di avviare un trial di Fase 1 per confrontare le sue costruzioni vaccinali orali di norovirus di seconda generazione con le versioni di prima generazione nella prima metà del 2025.
Vaxart (VXRT) ha publicado datos completos de su ensayo de Fase 1b sobre su candidato a vacuna contra el norovirus de primera generación en forma de píldora oral para adultos mayores de 55 a 80 años. El estudio demostró respuestas de anticuerpos fuertes y duraderas en esta población, que normalmente muestra respuestas inmunitarias reducidas a las vacunas tradicionales inyectadas.
Los hallazgos clave incluyen:
- Aumentos estadísticamente significativos en los anticuerpos anti-VP1 IgA en suero en los tres grupos de dosis
- Aumentos dependientes de la dosis en las respuestas de anticuerpos anti-VP1 IgG inducidas por la vacuna
- Fuertes respuestas de IgA en saliva y cavidad nasal
- Perfil de seguridad que muestra solo efectos secundarios leves a moderados
La vacuna demostró efectividad independientemente del grupo de edad, sin diferencias significativas entre los grupos de edad de 55-65 y 66-80 años. Vaxart planea iniciar un ensayo de Fase 1 que compare sus construcciones de vacuna oral contra el norovirus de segunda generación con las versiones de primera generación en la primera mitad de 2025.
Vaxart (VXRT)는 55세에서 80세 사이의 노인 성인을 대상으로 한 1b상 시험의 완전 데이터를 발표했습니다. 이 시험은 강력하고 지속적인 항체 반응을 이 집단에서 보여주었으며, 이 집단은 전통적인 주사 백신에 대한 면역 반응이 감소하는 경향이 있습니다.
주요 발견 사항은 다음과 같습니다:
- 세 가지 용량 집단 모두에서 혈청 내 항-VP1 IgA의 통계적으로 유의미한 증가
- 백신에 의해 유도된 혈청 내 항-VP1 IgG 반응의 용량 의존적 증가
- 타액 및 비강에서의 강한 IgA 반응
- 경미한 부작용만 나타나는 안전성 프로필
백신은 연령대에 관계없이 효과를 입증했으며, 55-65세와 66-80세 집단 간에 유의미한 차이는 없었습니다. Vaxart는 2025년 상반기 내에 두 번째 세대의 경구용 노로바이러스 백신 구조를 첫 번째 세대와 비교하는 1상 시험을 시작할 계획입니다.
Vaxart (VXRT) a publié des données complètes de son essai de Phase 1b sur son candidat vaccin contre le norovirus de première génération sous forme de pilule orale pour les adultes âgés de 55 à 80 ans. L'étude a démontré des réponses anticorpales fortes et durables dans cette population, qui montre généralement des réponses immunitaires réduites aux vaccins traditionnels injectés.
Les résultats clés incluent:
- Augmentations statistiquement significatives des anticorps anti-VP1 IgA dans le sérum dans les trois groupes de dose
- Augmentations dépendantes de la dose des réponses d'anticorps anti-VP1 IgG induites par le vaccin
- Réponses IgA fortes dans la salive et la cavité nasale
- Profil de sécurité montrant uniquement des effets secondaires légers à modérés
Le vaccin a démontré son efficacité, quel que soit le groupe d'âge, sans différences significatives entre les groupes d'âge de 55 à 65 ans et de 66 à 80 ans. Vaxart prévoit de lancer un essai de Phase 1 comparant ses constructions de vaccin oral contre le norovirus de deuxième génération avec celles de première génération au cours de la première moitié de 2025.
Vaxart (VXRT) hat vollständige Daten aus seiner Phase 1b-Studie zu seinem oralen Impfstoffkandidaten gegen Norovirus der ersten Generation bei älteren Erwachsenen im Alter von 55 bis 80 Jahren veröffentlicht. Die Studie zeigte starke und langlebige Antikörperreaktionen in dieser Population, die typischerweise reduzierte Immunreaktionen auf traditionelle injizierte Impfstoffe zeigt.
Wichtige Ergebnisse umfassen:
- Statistisch signifikante Erhöhungen von Serum-Anti-VP1-IgA in allen drei Dosierungsgruppen
- Dosisabhängige Erhöhungen der durch den Impfstoff induzierten Serum-Anti-VP1-IgG-Reaktionen
- Starke IgA-Reaktionen im Speichel und in der Nasenhöhle
- Sicherheitsprofil, das nur leichte bis moderate Nebenwirkungen zeigt
Der Impfstoff zeigte unabhängig von der Altersgruppe Wirksamkeit, ohne signifikante Unterschiede zwischen den Altersgruppen 55-65 und 66-80 Jahren. Vaxart plant, in der ersten Hälfte des Jahres 2025 eine Phase-1-Studie zu starten, die seine Impfstoffkonstrukte gegen Norovirus der zweiten Generation mit denen der ersten Generation vergleicht.
- Strong and durable antibody responses across all dose levels
- Successful immune response in elderly population despite age-related challenges
- Demonstrated safety profile with only mild to moderate side effects
- Previous Phase 2 challenge study showed significant reduction in infection rate
- Still in early clinical development stages
- Previous Phase 2 showed non-statistically significant reduction in gastroenteritis
Insights
Vaxart's publication of its Phase 1b trial results for their oral norovirus vaccine represents meaningful clinical progress for their lead program and validates their proprietary oral vaccine platform technology. The study's demonstration of robust antibody responses in elderly adults is particularly significant, as this population traditionally shows diminished immune responses to vaccines yet faces higher risks from norovirus infections.
From a pipeline development perspective, these results provide scientific validation in a respected peer-reviewed journal (Science Translational Medicine) and support advancement to their planned comparative Phase 1 trial of first and second-generation constructs in H1 2025. The company's platform technology showing effectiveness beyond the gastrointestinal tract expands potential applications beyond norovirus.
While promising, investors should recognize these remain early-stage clinical results. The path to commercialization will require successful completion of later-stage trials demonstrating not just immunogenicity but prevention of actual norovirus illness. The study adds credibility to Vaxart's approach in the competitive vaccine landscape where oral delivery could provide distinct advantages over traditional injection-based alternatives, particularly for populations with vaccination challenges.
For a micro-cap biotech with a
The immunological data from Vaxart's Phase 1b trial is scientifically noteworthy for several reasons. First, the vaccine stimulated robust mucosal immunity in elderly subjects—traditionally challenging due to immunosenescence—with antibody responses that were age-independent, addressing a key concern for vaccines targeting older populations.
The observation of strong IgA responses in saliva and nasal cavity following oral administration represents an important immunological finding. This demonstrates the vaccine's ability to generate immune responses at mucosal surfaces distant from the administration site, suggesting broader mucosal protection potential than typical site-specific mucosal vaccines.
The induction of VP1-specific IgA mucosal-homing antibody-secreting B cells and mucosal-homing T cells at the high dose provides a mechanistic basis for the observed responses. These cellular responses are critical for establishing durable mucosal protection, especially against pathogens like norovirus where mucosal immunity at the site of infection is essential.
The dose-dependent response profile and durable antibody presence through day 390 further support the vaccine's immunological effectiveness. While these results don't yet demonstrate clinical protection against norovirus infection, the immunological correlates observed—particularly the mucosal IgA responses—align with what would theoretically be needed for protective immunity against this gastrointestinal pathogen.
These findings have potential implications beyond norovirus, suggesting Vaxart's platform might effectively generate mucosal immunity for other pathogens requiring similar protection mechanisms.
Robust, antigen-specific responses in the nasal cavity following oral administration underscore the efficiency of Vaxart’s oral vaccine platform in generating mucosal antibody responses beyond the site of administration
SOUTH SAN FRANCISCO, Calif., March 05, 2025 (GLOBE NEWSWIRE) -- Vaxart, Inc. (Nasdaq: VXRT) today announced that complete data from the Phase 1b trial of its first-generation oral pill norovirus vaccine candidate in elderly adults (55-80 years) (NCT04854746) have been published in Science Translational Medicine. The data, which show strong and durable antibody responses and induction of norovirus-specific antibody and T cell responses, support immunogenicity of the vaccine candidate in a patient population that often has age-related reductions in immune responses to injected vaccines.1,2 Norovirus is a highly contagious virus that causes acute gastroenteritis (AGE) and can lead to substantial morbidity in older adults.3
“A key finding of this study evaluating our first-generation oral pill norovirus vaccine candidate in elderly individuals was that the antibody and serum responses observed in these participants were robust and durable, and a cross-study analysis suggested that the observed antibody and cellular responses were independent of age. These findings are encouraging given that older adults have an increased risk of norovirus-related morbidity and may have less robust immune responses following vaccination compared with younger individuals,” said James F. Cummings, MD, Chief Medical Officer at Vaxart. “Another key result was that an orally-administered vaccine can generate potent antibody responses in mucosal tissues outside the gastrointestinal tract, which could have important implications for use of our vaccine platform for norovirus and other indications as well.”
The Phase 1b study evaluated the safety and immunogenicity of Vaxart’s oral norovirus vaccine candidate in two groups of healthy older adults aged 55-65 and 66-80 years old. The vaccine was administered orally at three dose levels by prime and boost, 28 days apart. Participants were randomized to receive vaccine or placebo at a 2:1 ratio, and 63 volunteers completed the study, which included safety and immunogenicity assessments through day 390.
Key findings from the study include:
- The vaccine candidate generated robust and durable serum antibody responses, with all three dose cohorts demonstrating statistically significant increases in serum anti-VP1 IgA compared to the placebo cohort on day 29 and day 57. No statistically significant differences were found between the two age groups within each dosing cohort.
- Dose-dependent increases in vaccine-induced responses were also observed for serum anti-VP1 IgG in all vaccinated cohorts on day 29 and day 57 compared to pre-vaccination levels.
- The vaccine induced VP1-specific IgA mucosal-homing antibody-secreting B cells and this response was independent of age.
- The high-dose vaccine induced mucosal-homing T cells, which may contribute to protection against persistent infections.
- Oral administration of the vaccine stimulated strong and durable IgA responses in saliva and the nasal cavity.
- Overall, the vaccine was safe and well tolerated in older adults. All solicited events were mild to moderate, with no grade 3 events related to the vaccine. Headache (
14% ) and malaise/fatigue (16% ) were the most common solicited symptoms reported in the week following vaccine administration; headache (14% ) and malaise/fatigue (14% ) were reported at similar rates in the placebo group.
“The results of this clinical trial suggest that our oral pill norovirus vaccine program may be uniquely positioned to protect elderly individuals from adverse norovirus infection outcomes,” said Steven Lo, Chief Executive Officer at Vaxart. “These patients are at higher risk of severe AGE but also respond less effectively to injected vaccines. Additionally, most approved mucosal vaccines are not recommended for older individuals due to safety concerns. While early stage, the data reported today suggest that our candidate may prove to safely provide the benefits of a mucosal vaccine to patients at higher risk of adverse norovirus outcomes.”
Vaxart previously reported that a Phase 2 challenge study of an oral pill norovirus vaccine candidate produced a statistically significant reduction in infection rate, a non-statistically significant reduction in norovirus AGE and a substantial reduction in viral shedding. A Phase 1 study in lactating mothers showed that the Company’s vaccine candidate resulted in a 4-6-fold increase in norovirus antibodies in breast milk, which may help to protect infants through passive antibody transfer. In January 2025, Vaxart announced that the next step in its norovirus program will be a Phase 1, open label, dose ranging clinical trial evaluating its second-generation oral norovirus vaccine constructs head-to-head against its first-generation constructs. This trial is expected to initiate in the first half of 2025.
References
1. A. Ciabattini, C. Nardini, F. Santoro, P. Garagnani, C. Franceschi, D. Medaglini, Vaccination in the elderly: The challenge of immune changes with aging. Semin Immunol 40, 83-94 (2018).
2. A. Pera, C. Campos, N. López, F. Hassouneh, C. Alonso, R. Tarazona, R. Solana, Immunosenescence: Implications for response to infection and vaccination in older people. Maturitas 82, 50-55 (2015).
3. A. J. Hall, R. I. Glass, U. D. Parashar, New insights into the global burden of noroviruses and opportunities for prevention. Expert Rev Vaccines 15, 949-951 (2016).
About Vaxart
Vaxart is a clinical-stage biotechnology company developing a range of oral recombinant vaccines based on its proprietary delivery platform. Vaxart vaccines are designed to be administered using pills that can be stored and shipped without refrigeration and eliminate the risk of needle-stick injury. Vaxart believes that its proprietary pill vaccine delivery platform is suitable to deliver recombinant vaccines, positioning the company to develop oral versions of currently marketed vaccines and to design recombinant vaccines for new indications. Vaxart’s development programs currently include pill vaccines designed to protect against coronavirus, norovirus and influenza, as well as a therapeutic vaccine for human papillomavirus (HPV), Vaxart’s first immune-oncology indication. Vaxart has filed broad domestic and international patent applications covering its proprietary technology and creations for oral vaccination using adenovirus and TLR3 agonists.
Note Regarding Forward-Looking Statements
This press release contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, included in this press release regarding Vaxart's strategy, prospects, plans and objectives, results from preclinical and clinical trials and the timing of such results, commercialization agreements and licenses, and beliefs and expectations of management are forward-looking statements. These forward-looking statements may be accompanied by such words as "should," "believe," "could," "potential," "will," "expected," “anticipate,” "plan," and other words and terms of similar meaning. Examples of such statements include, but are not limited to, statements relating to Vaxart's ability to develop and commercialize its product candidates, Vaxart's expectations regarding clinical results and trial data, and the timing of receiving and reporting such clinical results and trial data; and Vaxart's expectations with respect to the effectiveness of its product candidates. Vaxart may not actually achieve the plans, carry out the intentions, or meet the expectations or projections disclosed in the forward-looking statements, and you should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions, expectations, and projections disclosed in the forward-looking statements. Various important factors could cause actual results or events to differ materially from the forward-looking statements that Vaxart makes, including uncertainties inherent in research and development, including the ability to meet anticipated clinical endpoints, commencement, and/or completion dates for clinical trials, regulatory submission dates, regulatory approval dates, and/or launch dates, as well as the possibility of unfavorable new clinical data and further analyses of existing clinical data; the risk that clinical trial data are subject to differing interpretations and assessments by regulatory authorities; whether regulatory authorities will be satisfied with the design of and results from the clinical studies; decisions by regulatory authorities impacting labeling, manufacturing processes, and safety that could affect the availability or commercial potential of any product candidate, including the possibility that Vaxart's product candidates may not be approved by the FDA or non-U.S. regulatory authorities; that, even if approved by the FDA or non-U.S. regulatory authorities, Vaxart's product candidates may not achieve broad market acceptance; that a Vaxart collaborator may not attain development and commercial milestones; that Vaxart or its partners may experience manufacturing issues and delays due to events within, or outside of, Vaxart's or its partners' control; difficulties in production, particularly in scaling up initial production, including difficulties with production costs and yields, quality control, including stability of the product candidate and quality assurance testing, shortages of qualified personnel or key raw materials, and compliance with strictly enforced federal, state, and foreign regulations; that Vaxart may not be able to obtain, maintain, and enforce necessary patent and other intellectual property protection; that Vaxart's capital resources may be inadequate; Vaxart's ability to resolve pending legal matters; Vaxart's ability to obtain sufficient capital to fund its operations on terms acceptable to Vaxart, if at all; the impact of government healthcare proposals and policies; competitive factors; and other risks described in the "Risk Factors" sections of Vaxart's Quarterly and Annual Reports filed with the SEC. Vaxart does not assume any obligation to update any forward-looking statements, except as required by law.
Contact
Vaxart Media and Investor Relations:
Matt Steinberg
FINN Partners
IR@vaxart.com
(646) 871-8481
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