Vaxdyn: a Spanish candidate in the fight against antimicrobial resistance

On World Immunization Week 2025, which the World Health Organization framed under the theme Immunization for All is Humanly Possible, the European Innovation Council has highlighted Vaxdyn. The Seville based company is pursuing vaccines designed to prevent infections that no longer respond to antibiotics. The firm has attracted both public and private backing as it advances a lead candidate through early clinical testing.

What Vaxdyn is developing and why it matters

Vaxdyn is developing vaccines that target the outer shell proteins of Gram negative bacteria. The company says this can enable a multi pathogen strategy where a single vaccine formulation could protect against several species that share surface proteins linked to antibiotic resistance. Its lead product, known as K VAX, aims at Klebsiella pneumoniae which is one of the most worrisome contributors to antimicrobial resistance or AMR related deaths. A second candidate, P VAX, targets Pseudomonas aeruginosa and is intended for people with chronic respiratory illnesses who are at higher risk of difficult to treat infections.

Clinical status and trial funding

According to reporting and the EIC announcement, K VAX progressed into Phase 1A trials with early support from CARB X and private investors. The EIC Accelerator awarded Vaxdyn funding in January 2025. The specific EIC K VAX project received an EU contribution of €2,494,748.99 to support Phase 1B and Phase 2 studies. Those stages are described as crucial to determine the final vaccine formulation and to measure efficacy in larger groups.

Who is backing Vaxdyn and what that means

Vaxdyn has combined national and international support. Boston based CARB X, a public private initiative focused on alternatives to antibiotics, awarded funds and advisory resources that the company says helped advance K VAX to the first clinical phase. CARB X reported a broader award of 99 projects tackling bacterial resistance and has provided around $11 million in funding as part of that portfolio. The EIC contribution was awarded through the Accelerator scheme to underpin mid stage clinical development.

Scientific and commercial challenges that remain

The public narrative around vaccine development often focuses on potential impact. It is important to be clear about the uncertainties. Phase 1A primarily tests safety and is not evidence that a vaccine prevents infections. Demonstrating protection against AMR pathogens faces several hurdles. For Gram negative bacteria such as Klebsiella pneumoniae and Pseudomonas aeruginosa, antigenic diversity can limit the breadth of protection. Regulatory pathways for pathogen specific AMR vaccines are still maturing and there are limited market incentives for private companies to invest in large Phase 3 trials unless there are clear procurement commitments from health systems or advanced purchasing mechanisms.

Practical considerations for Vaxdyn include preparing for manufacturing at scale, navigating regulatory requirements in the EU and other jurisdictions, and securing commercial agreements that make large trials and distribution viable. Licensing plans are part of the company roadmap. Post trial licensing is a common route for small biotech firms that do not want to become large scale manufacturers. Licensing requires interest from larger vaccine producers which will depend on clinical results and market prospects.

Implications for EU innovation policy and AMR strategy

EIC support for companies such as Vaxdyn is aligned with broader EU efforts to stimulate innovation targeting public health threats. Small grants that bridge the funding gap between early human testing and later clinical stages are valuable. They reduce the technical and financial risk for projects hoping to attract larger industry partners or international funders. However public funders and health authorities will also need to think about incentives beyond grants. These include procurement guarantees, advance purchase agreements, and clearer regulatory guidance that de risk late stage investment.

What to watch next

Watch for announcements on Phase 1B and Phase 2 trial designs and timelines. Key signals will be immunogenicity readouts, any preliminary efficacy or challenge data, identified target populations and manufacturing partnerships. Also watch for licensing discussions and whether public purchasers or multinational vaccine manufacturers show interest. Each of these will materially affect the viability of a vaccine aimed at preventing antibiotic resistant infections.

Conclusion

Vaxdyn represents an example of an EU backed deep tech health start up pursuing a high impact but high risk approach to a growing global problem. The combination of CARB X mentorship and EIC funding is an important enabler for moving through early clinical stages. Success is far from assured and meaningful impact will require robust clinical results, clear regulatory pathways and commercial or public procurement commitments that support late stage trials and deployment. The company and its backers will need to demonstrate those elements for the promise to translate into public health benefit.

This article is based on an EIC community profile and reporting from regional press. The information is provided for knowledge sharing and does not represent the official view of the European Commission.