Under the agreement, Instituto Butantan will conduct registrational clinical trials of Replicate's novel srRNA rabies vaccine for post-exposure and pre-exposure prophylaxis
Replicate to provide GMP material for clinical trials and transfer manufacturing process to Butantan mRNA vaccine production facility
Replicate retains rights for development in markets outside of Latin America
SAN DIEGO and SAO PAULO, Dec. 4, 2025 /PRNewswire/ -- Replicate Bioscience, a clinical-stage company pioneering novel self-replicating RNA (srRNA) technology for applications across infectious disease, immunology, and other therapeutic areas, and Instituto Butantan, Sao Paulo, Brazil, a leading non-profit producer of immunobiologic products for Brazil and other markets, today announced a collaboration agreement under which Instituto Butantan will obtain exclusive rights to develop and commercialize Replicate's novel srRNA rabies vaccine RBI-4000 in Brazil and other Latin American countries.
In a Phase 1 clinical study conducted by Replicate, RBI-4000 demonstrated a high therapeutic index showing durable bioactivity at low doses accompanied by mild/moderate reactogenicity, in contrast with other RNA-based vaccine technologies. 1,2
Under the terms of the newly announced agreement, Instituto Butantan will fund the development of RBI-4000 for post-exposure and pre-exposure prophylaxis. In addition, Replicate is eligible to receive tiered royalties on future product sales in Latin America and will retain rights for RBI-4000 in other markets and to all data generated under the agreement.
The collaboration will also accelerate improvement of cold chain storage and thermostability, which may bolster adoption of srRNA technology and support a cost advantage versus conventional vaccine technologies.
"We are very enthusiastic about the partnership with Replicate, which brings cutting-edge technology, innovation, and science to the fight against rabies," said the director of Instituto Butantan, Esper Kallás. "It is a partnership that can bring great benefits to public health and that reinforces the strategic role of Instituto Butantan as a hub for innovation and science."
"We are honored to collaborate with Instituto Butantan, a global leader in the fight against deadly infectious diseases," said Replicate CEO Nathaniel Wang, Ph.D. "We view this as an exciting opportunity to clinically advance Replicate's srRNA rabies vaccine with Butantan and expand our scientific, operational, and manufacturing frameworks that can be applied to other diseases."
About Rabies
Endemic in over 150 countries, rabies is a deadly disease with a 99% mortality rate if left untreated, causing 59,000 deaths annually. Deaths due to rabies are fully preventable if exposed individuals receive an effective vaccine before the virus spreads to the central nervous system and clinical symptoms appear. Rabies is most frequently addressed through post-exposure prophylaxis including a course of human rabies vaccine. Although effective, current rabies vaccines require 3 to 5 doses and are subject to supply shortages due to complicated manufacturing processes, limiting accessibility and increasing complexity of administration in resource-limited settings. Rabies is included in WHO's 2021-2030 Roadmap for the global control of neglected tropical disease. And as part of the 21st Century Cures Act, the U.S. Food and Drug Administration (FDA) included rabies in its Tropical Disease Priority Review Voucher Program List.
About Replicate Bioscience
Replicate Bioscience is a clinical-stage company amplifying the power of RNA therapeutics by pioneering its novel self-replicating RNA (srRNA) technology to overcome the shortcomings of existing mRNA approaches, with potential improvements in bioactivity, induction of more potent immune responses, and improved therapeutic index. RBI-4000, the company's clinical-stage srRNA rabies vaccine, has demonstrated protective levels of immunity at doses lower than any other reported mRNA or srRNA vaccine in Phase I trials. Funded by Apple Tree Partners, Replicate is advancing a robust pipeline of srRNA vaccines and therapeutics, fueled by its proprietary library of customizable viral vectors. With deep expertise in srRNA and end-to-end development capabilities, Replicate is uniquely positioned to expand the reach of RNA treatments toward widespread use in infectious disease, immunology, immuno-oncology and more. To learn more, visit replicatebioscience.com.
About Instituto Butantan
Instituto Butantan is the main producer of immunobiological products and vaccines in Brazil. Instituto Butantan carries out scientific missions domestically and abroad through the Pan American Health Organization, the World Health Organization, UNICEF and the United Nations. The Institute collaborates with other agencies of the São Paulo State Secretariat of Health and the Brazilian Ministry of Health for the improvement of overall health in Brazil. It acts in partnership with various universities and entities such as the Bill & Melinda Gates Foundation for the achievement of its institutional objectives. For more information, please visit the Institute website at www.butantan.gov.br or contact the press office at (+55 11) 2627-9606 / 9428 or email to imprensa@butantan.gov.br.
Replicate Contacts
Investors and Partners: Nathaniel Wang nwang@replicatebioscience.com
Media: Tyler Hubin tyler.hubin@deerfieldgroup.com
References:
- Maine CJ, Miyake-Stoner SJ, Spasova DS, et al. Safety and immunogenicity of an optimized self-replicating RNA platform for low dose or single dose vaccine applications: a randomized, open label Phase I study in healthy volunteers. Nat Commun. 2025a;16(1):456. Published 2025 Jan 7. doi:10.1038/s41467-025-55843-9.
- Maine CJ, Picarda G, Miyake-Stoner SJ, et al. Durability of next-generation self-replicating RNA vaccine RBI-4000: a phase 1, randomized open label clinical trial. Commun Med (Lond). 2025b;5(1):392. Published 2025 Sep 24. doi:10.1038/s43856-025-01147-4.
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SOURCE Replicate Bioscience
