The U.S. differentiated oral tablet recombinant vaccine platform is open to global collaboration, focusing on infectious diseases, with an emphasis on preclinical/proprietary antigen assets such as Clostridium difficile and Chlamydia for licensing-in and joint development.

1. Buyer information

A U.S. clinical-stage vaccine platform company deeply engaged in the infectious disease vaccine sector, with core strengths focused on the development of oral pill vaccine platforms. The company’s platform supports rapid access and modular development of different antigens, offering differentiated advantages such as tablet dosing.

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2. The assets you are looking for

Focus on identifying innovative infectious disease antigen assets that can be developed via its oral vaccine platform.

Focus areas include C. difficile, Chlamydia, and other infectious diseases with high unmet needs; The asset stage mainly consists of early antigens, preclinical antigen combinations, proprietary antigen designs, or licensable vaccine antigen assets.

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3. Financing and BD strength

The company has secured multiple rounds of public market financing, government project funding, and foundation support, providing a financial foundation for continuously advancing vaccine clinical development and platform-based project transformation.

4. Buyer strength and BD experience

The company has established a mature oral vaccine technology platform and has clinical experience in developing infectious disease vaccines. Has previously collaborated and licensed deals with major vaccine/biopharmaceutical companies, and recently completed a global licensing deal for a multi-million dollar upfront/equity investment structure.

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5. BD experience

Focusing on license-in/co-development, buyers use their own oral vaccine platform for subsequent development. Buyers are interested in antigens or early-stage candidate assets that can be integrated with their platforms to form differentiated oral vaccine projects.

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These needs are not isolated. In the global infectious disease vaccine sector, platform companies are increasingly focused on early-stage antigen assets.

Below, we analyze the industry logic behind this trend from four dimensions: track scale, scientific logic, R&D landscape, and asset screening criteria.

Infectious disease vaccine track—shifting from mature category competition to platform-based, differentiated antigen and mucosal immunological innovation

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(1) Track Overview: Infectious disease vaccines remain the core direction of global vaccine research and development

Infectious disease vaccines have long been a core segment of the global vaccine industry. The traditional vaccine market is mainly driven by mature categories such as influenza, HPV, pneumococcus, shingles, hepatitis, and childly immunization program vaccines, with competition focusing on protection rate, immunity durability, price coverage, production costs, and commercialization channels.

After COVID-19, the logic of global vaccine development has further changed:

On one hand, vaccine platform technologies have been rapidly validated, with significant improvements in industrialization capabilities for mRNA, recombinant proteins, viral vectors, VLP, OMV/GMMA, and other routes;

On the other hand, the R&D focus is gradually expanding from a single mature category to more specialized and higher-level unmet infectious disease categories, including respiratory infections, gastrointestinal infections, hospital-acquired infections, sexually transmitted infections, antibiotic-resistant infections, and multi-pathogen combination vaccines.

From the perspective of global R&D pipelines, infectious disease vaccines remain highly active. A 2025 study on the global infectious disease vaccine R&D landscape showed that as of March 2025, a total of 919 candidate projects had been identified in the global infectious disease vaccine pipeline, mainly covering COVID-19, influenza, HIV, HPV, pneumococcus, RSV, and other directions; Nucleic acid vaccines account for about 25%, while recombinant protein vaccines and viral vector vaccines are also important technical routes. The study also points out that more than half of the candidate projects are still in the pre-Phase II stage, indicating that many infectious disease vaccine projects are still in the early validation and platform screening stages. This pattern has direct implications for asset trading.

For large vaccine companies, the competitive barriers for mature vaccine categories come from clinical development, production scale, access payments, and global commercialization systems;

For platform vaccine companies, what is truly scarce are antigen assets that can be integrated into their platforms and form differentiated product hypotheses.

In other words, the BD logic for infectious disease vaccines is shifting from “purchasing a complete vaccine product” to gradually shifting from “seeking verifiable, accessible, scalable antigens or early candidates.” This is also a key reason why oral vaccines, nasal spray vaccines, mRNA vaccines, recombinant protein platforms, VLP platforms, and bacterial outer membrane vesicle platforms continue to attract attention.

WHO currently continuously tracks vaccine pipelines for HIV, malaria, tuberculosis, RSV, ETEC, Shigella, and Norovirus, and regularly updates progress on candidate vaccines, indicating that these areas remain key global public health research and development priorities. According to Vaccines Europe’s 2025 pipeline data from the European vaccine industry organization, as of the end of August 2025, its member companies have 91 vaccine candidate projects, most of which focus on viral infectious diseases, with nearly half targeting disease areas for which no vaccines have yet to be registered. This indicates that new opportunities in the vaccine sector are not limited to mature major product upgrades, but are more concentrated in niche pathogens that have yet to form sufficient product supply.

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(2) Scientific logic: Mucosal immunology, antigen design, and platform-based delivery have become key differentiators

The core scientific challenge of infectious disease vaccines is how to establish effective immune protection before pathogens invade or in the early stages of infection. Traditional intramuscular vaccines are generally better at inducing systemic IgG antibodies and circulating immune responses, but many infectious pathogens first enter the body through the mucosa of the respiratory, gastrointestinal, or genitourinary tract. For these pathogens, relying solely on serum antibodies may not be sufficient to establish a sufficient defense at the infection entrance. Therefore, vaccine pathways that can induce local mucosal immunity are becoming an important direction in the development of vaccines for respiratory infections, gastrointestinal infections, and some sexually transmitted infections.

The theoretical advantage of mucosal vaccines lies in their potential to induce secretory IgA, tissue-resident memory T cells, local B cell responses, and systemic immune responses at the first barrier of infection, thereby achieving multi-layered interception of infection, transmission, and disease progression. Related reviews point out that mucosal vaccines can induce both local and systemic immunity, but their development challenges are more pronounced, including antigen degradation, mucosal barrier limitations, oral tolerance, delivery efficiency, adjuvant selection, and immune response stability.

From a technical implementation perspective, non-injectable delivery pathways such as oral, nasal, and sublingual administration are not simply changes in the delivery method, but involve systematic design of antigens, vectors, adjuvants, dosage forms, and immune activation mechanisms. For example, in oral vaccines, antigens or delivery vectors need to cross gastric acid, digestive enzymes, and intestinal barriers, and be effectively recognized in gut-related lymphoid tissue; At the same time, it is necessary to avoid inducing oral tolerance and maintain sufficient immunogenicity. For nasal spray vaccines, local residence time, mucosal penetration ability, upper respiratory tract immune activation, and safety are also critical issues.

Therefore, the value of platform-based delivery is not just “making vaccines into more convenient dosage forms,” but also solving the problem of stable delivery and effective immune activation of different pathogenic antigens in mucosal environments through delivery systems, antigen engineering, and immune regulation design. If the platform can support modular access for different antigens, there is an opportunity to form replicable development pathways across multiple infectious disease directions. For external antigen investors, this means early antigen design, proprietary epitope design, animal protection data, and clear IP boundaries may be amplified by integrating with mature platforms.

Antigen design itself is also shifting from empirical screening to structural guidance and mechanism-oriented approaches. For pathogens such as RSV, hMPV, Norovirus, Chlamydia, C. difficile, ETEC, and Shigella, vaccine development failures are often not due to insufficient disease burden, but because protective antigens are difficult to define, pathogen subtypes are complex, immune protection correlation is unclear, or clinical endpoints are hard to verify. Therefore, early assets that demonstrate antigen conservation, structural stability, functional neutralizing ability, mucosal immune induction ability, or animal protection effects have higher value in BD.

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(3) R&D landscape: Platform companies, large pharmaceutical firms, and niche pathogen companies are ramping up investments simultaneously

From the perspective of global company layouts, infectious disease vaccines are forming three types of competitive entities.

Sanofi is one of the typical representatives. In March 2025, Sanofi announced that its mRNA vaccine candidate for preventing Chlamydia infection had received Fast Track designation from the U.S. FDA. Chlamydia currently has no approved human vaccine, and the infection site is closely related to mucosal immunity, placing high demands on antigen design, local immunity, and protective immunity mechanisms. Sanofi also announced the acquisition of Vicebio in 2025, incorporating its early RSV+hMPV combination vaccine candidate and Molecular Clamp technology into its own respiratory vaccine portfolio, indicating that major pharmaceutical companies are strengthening their respiratory combination vaccine direction through external technology platforms.

The second category consists of platform vaccine companies centered on technologies such as mRNA, recombinant proteins, VLP, and OMV/GMMA. Such companies typically do not rely on a single vaccine category, but instead aim to quickly integrate different antigens through platform technology, forming multiple candidate projects. After COVID-19, mRNA vaccine companies further expanded into influenza, RSV, CMV, EBV, Norovirus, and combination vaccines. For example, Moderna’s public pipeline shows that as of May 2026, its mRNA pipeline covers multiple infectious disease projects, and the Norovirus vaccine mRNA-1403 has entered Phase III clinical trials. The advantage of mRNA platforms lies in their fast antigen encoding and iteration speed, making them suitable for multivalent combination design and pathogen mutation response; However, its delivery method, cold chain, tolerability, and long-term commercial competition still need to be validated separately across different disease scenarios.

The third category is specialized companies or niche platform companies focused on pathogens with high unmet demand. These companies often build differentiated barriers around specific pathogens or technological pathways, with R&D targets including C. difficile, ETEC, Shigella, Staphylococcus aureus, Chlamydia, Gonorrhea, Norovirus, and others. Although such projects are more challenging in clinical development, once successfully validated, they often possess strong scarcity and trading value.

ETEC and Shigella are representative directions in gastrointestinal infection vaccines. EDEC is a major cause of travelers’ diarrhea and diarrhea in children in developing countries, and there is still a lack of widely approved human vaccines. Scandinavian Biopharma’s ETVAX is a relatively advanced oral ETEC vaccine candidate. The company announced its Phase IIb data published in The Lancet Infectious Diseases in 2026 and confirmed that the project is ready for Phase III. For Shigella, GSK will license its Shigella candidate vaccine altSonflex1-2-3 to Bharat Biotech for continued development and potential distribution in 2025, with a primary focus on preventing diarrheal diseases among children in low- and middle-income countries. Such cases indicate that the commercialization path for gastrointestinal infection vaccines may not rely entirely on traditional out-of-pocket markets, but is closely tied to global public health, foundation support, government procurement, and regional access.

C. difficile represents typical challenges related to hospital-acquired infections and antibiotic-related infections. C. Difficile infection is closely related to antibiotic use, hospital and long-term care settings, and risk in the elderly; currently, no approved vaccine exists. Novavax’s public information shows that it is exploring multivalent C. difficile vaccine candidate to prevent primary C. difficile infection. Pfizer previously promoted C. The difficile vaccine PF-06425090 did not meet its primary endpoint in the Phase III CLOVER study, but the company disclosed that the study showed potential effects in reducing secondary endpoints such as disease duration and severity. This case also highlights the core challenges in developing infectious disease vaccines: even with clear disease burden and targeted populations, clinical protection endpoints and real-world benefits may still be difficult to fully demonstrate.

Lilly’s redeployment of infectious disease vaccines in 2026 is also worth noting. In May 2026, Lilly announced plans to acquire three vaccine companies—Curevo, LimmaTech Biologics, and Vaccine Company—to build a portfolio of infectious disease vaccines covering areas such as shingles, bacterial pathogens, and EBV. Among them, LimmaTech focuses on bacterial pathogen vaccines, with pipelines including Staphylococcus aureus, Neisseria gonorrhoeae, and Chlamydia trachomatis. Such deals demonstrate that even non-traditional vaccine giants are reassessing the strategic value of infectious disease prevention assets, especially in areas such as antibiotic resistance, chronic viral infections, and pathogens related to tumors or neurological disorders.

Chinese companies are also building more expertise in innovative vaccines for infectious diseases. InnoRNA’s bivalent RSV mRNA vaccine IN006 will complete Phase II enrollment and vaccination in 2025. This project targets RSV-A and RSV-B, based on its pre-fusion F protein design, mRNA, and LNP platform. Clover Biotech will initiate Phase II clinical trials of RSV+hMPV and RSV+hMPV+PIV3 respiratory combination vaccine candidates in 2026, targeting elderly patients aged 60 to 85, evaluating safety, reactivity, and immunogenicity. This indicates that China’s innovative vaccine companies are gradually extending from traditional vaccines and single-pathogen vaccines to mRNA, recombinant proteins, respiratory combination vaccines, and international clinical pathways.

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(4) Business logic: Early antigen assets are becoming an important entry point for platform-based buyers

The commercial value of infectious disease vaccines is not determined solely by disease burden but also depends on the definitivity of target populations, clinical endpoint verifiability, payment pathways, vaccination scenarios, and competitive landscape. Mature vaccine categories usually have large market sizes, but fierce competition, high development costs, and strong commercialization barriers; Conversely, many niche pathogen markets without approved vaccines, although risky, often offer significant differentiation if clinical protection can be demonstrated.

For platform vaccine buyers, external antigen assets hold special value. The platform itself addresses issues of delivery, expression, immune activation, and dosage form development, while antigen assets determine which pathogens a product can enter, which subtypes it covers, and what kind of immune protection mechanisms it establishes. Especially in C. Difficile, Chlamydia, Norovirus, ETEC, Shigella, and other directions. Antigen selection and protective immune mechanisms are key to project success,

Therefore, early-stage assets with proprietary antigen design, structural biology foundations, animal protection data, or preclinical immunological evidence may become important sources for platform companies to rapidly expand their pipelines.

From the transaction structure perspective, such collaborations usually do not primarily involve acquiring mature products, but are more likely to adopt license-in, co-development, option-to-license, regional rights splits, joint filings, or platform adaptation verification. For antigen asset holders, if they lack comprehensive clinical development and global commercialization capabilities, cooperating with platform companies can lower the threshold for early translation; For buyers, introducing external antigens allows faster expansion of platform indication boundaries and the establishment of product portfolios across multiple pathogen directions.

Such deals also have practical significance for Chinese innovative vaccine companies. In recent years, domestic companies have made significant progress in recombinant proteins, mRNA, antigen engineering, LNP delivery, adjuvants, animal models, and industrialization, but many early-stage projects still face challenges such as global clinical development pathways, overseas regulatory filings, and insufficient commercialization resources. If the asset itself has a clear IP, early PoC data, and modular access potential, more efficient international cooperation can be achieved through overseas platform buyers.

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(5) Asset Screening Criteria: Which projects have greater cooperation value?

For such buyers, the most valuable collaboration is usually not the fully mature, soon-to-commercialize complete vaccine product, but the early antigen or candidate assets that can synergize with their platform. The main criteria for judgment include the following aspects.

First, whether the antigen has a clear protective immune logic. For C. For pathogens such as difficile, Chlamydia, Norovirus, ETEC, and Shigella, vaccine development failures are often not due to the disease being unimportant, but because of complex immune protection mechanisms, difficulty in antigen selection, unclear protective endpoints, or diverse pathogen subtypes. Therefore, if the asset party has completed conserved epitope screening, structural biological validation, animal toxin protection, toxin neutralization, mucosal IgA induction, or T cell response validation, the value of the collaboration will be significantly enhanced.

Second, whether the antigen is suitable for platform-based access. Different platforms have requirements for antigen expression, conformational stability, vector capacity, dosage, adjuvant compatibility, delivery stability, and immune activation methods. Antigens that are too complex, highly conformationally dependent, or difficult to express may not be suitable for direct platform-based development. Conversely, antigens with a foundation for recombinant expression, clear structure, well-defined immune dominance epitopes, and multivalent combination design are more likely to collaborate with platform-type buyers.

Third, whether the assets have a clear intellectual property foundation. For early-stage antigen assets, IP value often comes from antigen sequences, conformational stabilization designs, epitope combinations, detoxifying mutations, adjuvant combinations, delivery methods, or patent applications. When conducting license-in or co-development, buyers usually focus on whether the antigen has defensible patent boundaries, circumvents existing core patents, and can support development in major global markets.

Fourth, whether there is early-stage data that can be converted. Early assets do not necessarily need to enter clinical trials, but at minimum, PoC data supporting further development should be available, including in vitro expression and stability, animal immunogenicity, toxin protection, toxin neutralization, mucosal immune markers, systemic antibody responses, T cell responses, or preliminary safety data. If the asset remains only at the antigen sequence or conceptual stage, the value of cooperation is relatively limited; If a complete early evidence chain of “antigen design—animal immunity—protective efficacy—IP layout” has been established, it is easier to enter substantive BD discussions.

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(6) Opportunities and Challenges: Clear needs are not met, but clinical validation remains a core hurdle

From the opportunity side, infectious disease vaccines are entering a stage more suitable for platform companies and antigen asset holders to collaborate. Mature major categories are dominated by large vaccine companies, with high entry barriers and fierce commercialization competition; But C. Directions such as difficile, Chlamydia, Norovirus, ETEC, Shigella, hMPV, EBV, and Staphylococcus aureus still have many unmet needs and technical gaps. Some areas have not yet received approved vaccines, but large pharmaceutical companies, mRNA platform companies, bacterial vaccine companies, and non-injectable drug delivery platform companies have entered R&D or trading layouts, indicating that these areas have clear industry attention but have not yet formed a fully fixed competitive landscape.

From the challenge side, clinical development of infectious disease vaccines is usually more complex than in the early stages. First, immunogenicity does not equate to protective efficacy, especially in pathogenic directions lacking clear immune protection replacement endpoints; mere elevation in antibody titers is insufficient to prove clinical protection. Second, pathogen diversity and antigen drift may affect vaccine coverage; for example, Norovirus, Shigella, ETEC, etc., all involve different genotypes, serotypes, or virulence factor combinations. Third, vaccine clinical trials usually require large sample sizes, clearly identify exposure risk groups, and long observation periods, demanding high funding and execution capabilities. Fourth, public health values and commercial payment logic do not always align. Some high-burden diseases in developing countries may have clear public health needs, but commercial returns may depend on global funds, government procurement, nonprofits, or regional cooperation models.

Therefore, for China’s innovative antigen investors, a more realistic path is not necessarily to independently complete global vaccine development, but to cooperate with overseas companies that have delivery platforms, clinical development experience, and international BD capabilities. Through license-in, co-development, option-to-license, regional rights splits, or joint application, early antigen assets can leverage platform delivery technologies and clinical development systems to quickly form more complete product hypotheses.

Overall, the infectious disease vaccine sector is shifting from mature categories to platform-based, differentiated antigens and high-demand pathogens competing comprehensively. For those with proprietary antigen design, a foundation in structural biology, preclinical immunogenicity or protection data, clear IP layout, and potential in C. Projects that create differentiated products among high-demand pathogens such as difficile, Chlamydia, Norovirus, ETEC, Shigella, and others all hold potential for further exploration of license-in, co-development, or global/regional rights collaborations.

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Cooperation and integration include high-quality assets such as C. difficile, Chlamydia, and other high-demand infectious diseases! We welcome founders, BD leaders, and project teams to connect and recommend at any time to efficiently advance deal negotiations and implementation.

Contact person: Tang Huadong

Cooperation Email: huadong.tang@meritsandtree.com;

yuhan.zhang@meritsandtree.com
zehao.yue@meritsandtree.com

Tang Huadong

Partner at Zhide

Lawyer Tang Huadong is a partner at Beijing Zhide Law Firm. Before joining Zhide, Lawyer Tang Huadong worked for many years at China Patent Agency (Hong Kong) Co., Ltd. and Beijing King & Wood Mallesons. He also worked for a long time in patent examination at the National Intellectual Property Administration and earned the title of Associate Researcher. Lawyer Tang Huadong has over ten years of practical experience in the field of technology and legal services, leading a team of key members graduated from renowned domestic and international universities with a combined technical and legal background, providing clients with professional and efficient technical and intellectual property legal support for high-value patent asset structuring, investment and financing transactions, IPOs and listings, dispute resolution, and government compliance.

Lawyer Tang Huadong specializes in providing practical intellectual property protection solutions based on clients’ commercial objectives, including but not limited to patent strategy planning, patent mining, drafting and examination of patent application documents, patent due diligence, patent stability analysis, FTO freedom implementation legal opinions, patent infringement analysis, patent invalidity challenges, patent infringement litigation, trade secret protection, and the construction of intellectual property protection systems.

Lawyer Tang Huadong graduated from Tsinghua University with a PhD in Biochemistry and Molecular Biology, and also earned a Master of Laws degree from China University of Political Science and Law. He is a visiting scholar at the University of Notre Dame, a member of the Pharmaceutical Professional Committee of the China Patent Protection Association, a member of the Patent Law Committee of the Beijing Lawyers Association, a council member of the Tsinghua Healthy Chinese Returned Scholars Association, a council member of the Intellectual Property Subcommittee of the World Federation of Chinese Medicine Societies, a member of the South-South Cooperation Promotion Association of the Ministry of Foreign Affairs, and has been awarded the title of Chambers by the internationally authoritative legal rating agency Recognized in the 2026 annual ranking of intellectual property businesses, recognized by internationally renowned legal media CBLJ as the “A-list Legal Elite Legal Elite” in 2023, Minglutang-Client Choice (an outstanding lawyer recommended by the Medical Health and Life Sciences Industry Law Association), invited to lecture at Yihong Business School, Tsinghua Institute of Technology, Beike University, Beijing Administration of Traditional Chinese Medicine, and keynote speeches at conferences held by Tongxieyi, Yaozhi.com, Yaorongquan, DIA, and others.

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