Preclinical data show that Sail’s eRNA vaccine candidates induce robust anti-malaria immune responses and protect against infection in a mouse challenge model
Sail Biomedicines, a Flagship Pioneering company and leader in RNA-based programmable medicines, today announced that it will present new preclinical data from its malaria vaccine program at the 2025 Grand Challenges Annual Meeting, taking place virtually June 1-4. The findings highlight the potential of Sail’s Endless RNA™ (eRNA) platform to enable durable antigen expression and drive potent immune responses for protection from malaria challenge.
At the meeting, Sail will present new preclinical results demonstrating that its AI-driven design of eRNA vaccine candidates encoding a R21-based malaria antigen successfully formed virus-like particles with durable expression in vitro. In mouse immunogenicity studies, two doses of eRNA R21 vaccines generated robust anti-PfCSP antibody responses, with titers equal to and exceeding those reported for three doses of licensed malaria vaccines in published studies. In a mouse malaria challenge model, two doses of Sail’s lead eRNA vaccine candidate substantially reduced liver parasite burden and achieved sterile protection in 53% of animals, suggesting a potential advantage over licensed malaria vaccines that are administered over three doses.
“These results demonstrate how Sail’s eRNA platform can address key challenges in vaccine development, particularly by supporting more potent immune responses with a reduced dosing regimen,” said Amy Espeseth, Ph.D., SVP, Head of Integrated Sciences at Sail Biomedicines, who will be delivering the presentation. “We believe that platforms like eRNA could play an important role in enabling more effective prevention of diseases like malaria.”
Sail’s malaria vaccine program, supported by funding from the Gates Foundation, focuses on optimizing the eRNA payload using AI to maximize antigen expression and durability of immune response. The vaccine candidates leverage Sail’s proprietary Endless RNA format, which is engineered to resist degradation and extend translation, providing the opportunity for stronger, longer-lasting immune responses compared to conventional vaccine modalities.
"By engineering RNA for extended stability and translation, we are demonstrating the potential of Sail’s eRNA platform to support the next generation of vaccines,” said Dr. Espeseth. “The manufacturability of eRNA coupled with its ability to generate robust immune responses supports its use as a vaccine platform for a wide range of infectious diseases."
Collaborators at the Johns Hopkins Malaria Research Institute performed all challenge studies.
About Sail Biomedicines
Sail Biomedicines is pioneering the integrative design and deployment of fully programmable medicines to transform patient care. Sail’s platform combines first-in-class programmable circular RNA technology (Endless RNA™ or eRNA™), and an industry-leading platform of programmable nanoparticles, to unlock comprehensive programming of medicines for the first time. By leveraging cutting-edge eRNA and nanoparticle deployment technology, Sail is building a wealth of data, enabling unparalleled use of generative AI techniques to identify and design fully programmable medicines that are potent, targeted, versatile, and tunable. Sail was founded by Flagship Pioneering. For more, visit www.sail.bio and follow us on X (@SailBiomeds) and LinkedIn.
This research is based on work funded by the Gates Foundation. The findings and conclusions contained within are those of the authors and do not necessarily reflect positions or policies of the Gates Foundation.
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"By engineering RNA for extended stability and translation, we are demonstrating the potential of Sail’s eRNA platform to support the next generation of vaccines,” said Amy Espeseth, Ph.D., SVP, Head of Integrated Sciences at Sail Biomedicines.
