Presentations will feature nonhuman primate and other preclinical findings highlighting the differentiated dose-efficiency profile of its lead product candidate and its ability to drive deep B-cell depletion across blood and tissues, including bone marrow and lymph nodes

CAMBRIDGE, Mass., April 27, 2026 – Sail Biomedicines, a Flagship Pioneering company and leader in RNA-based programmable medicines, today announced that it will present preclinical updates from its vanguard In Vivo eRNA and targeted nanoparticle (TNP) CAR-T program and lead product candidate for autoimmune diseases at the American Society of Gene & Cell Therapy (ASGCT) Annual Meeting and TIDES USA 2026, taking place in Boston.

The presentations will highlight Sail’s In Vivo eRNA-TNP CAR-T [JY1] program that pairs sustained eRNA-based CAR expression with a proprietary targeted nanoparticle to specifically deliver eRNA constructs to CD4 and CD8 T cells. This payload and delivery system is designed to drive highly potent and specific in vivo programming, creating a CAR-T therapeutic window to enable a potentially curative treatment for autoimmune diseases.

“The power of In Vivo CAR-T for curative treatments in autoimmune diseases could completely disrupt treatment paradigms for patients by achieving deep B-cell depletion in the right places for the right amount of time to achieve a full immune reset,” said John Mendlein, Ph.D., Executive Chairman and Co-Founder of Sail Biomedicines and Executive Partner at Flagship Pioneering. “These data provide evidence for how Sail’s eRNA and targeted nanoparticle approach achieves low-dose potency and CD8/CD4 engagement, with the potential for a superior product profile within the emerging In Vivo CAR-T field for autoimmune diseases.”

Presentation details are as follows:

ASGCT Annual Meeting 2026

Title: Reprogramming of T Cells In Vivo with CD19 CAR eRNA™ Constructs to Unlock Cures for Patients with an Optimal Therapeutic Index

Presenter: Michaël Mingueneau, Ph.D., SVP, Head of Immunology at Sail Biomedicines

Session Type: Scientific Symposia

Session: Innovations in Nonviral Therapeutic Delivery for Neurologic and Immunologic Disorders

Date and Time: May 13, 11:07 a.m. to 11:33 a.m. ET

TIDES USA 2026

Title: In Vivo Transient Programming of T Cells with Targeted Nanoparticles Encapsulating eRNA™-encoded hCD19 CAR Achieves Deep Depletion of B Cells in Blood and Lymphoid Tissues

Presenter: Viorel Simion, Ph.D., Director of Immunology at Sail Biomedicines

Date and Time: May 14, 4:30 p.m. to 5:00 p.m. ET

About Sail Biomedicines

Sail Biomedicines is pioneering AI-driven design and deployment of fully programmable RNA medicines to transform patient care. Sail’s platform combines eRNA™ constructs, a first-in-class programmable circular RNA product form, and an industry-leading platform of targeted nanoparticles to unlock comprehensive programming of medicines for the first time. Using its cutting-edge eRNA and nanoparticle deployment platform, Sail is building a pipeline of In Vivo CAR-T based products. Sail was founded by Flagship Pioneering. For more, visit www.sail.bio and follow us on X (@SailBiomeds) and LinkedIn.

Contact

press@sail.bio

CAMBRIDGE, Mass., October 23, 2025 – Sail Biomedicines, a Flagship Pioneering company and leader in RNA-based programmable medicines, today announced that Martin Mackay, Ph.D., has joined its Board of Directors. Mackay is a globally recognized biopharmaceutical leader with more than three decades of executive experience driving drug discovery and development at some of the world’s leading pharmaceutical and biotechnology companies.

“Martin’s appointment to our Board comes at an important moment for Sail, as he has guided the development of transformative medicines across therapeutic areas and guided companies from early innovation through commercialization,” said John Mendlein, Ph.D., Executive Chair of Sail Biomedicines and Executive Partner, Flagship Pioneering. “His depth of experience leading global R&D organizations will be invaluable as we advance our vanguard in vivo CAR-T program to the clinic for autoimmune disease patients in 2026 and harness the full potential of our Endless RNA and programmable targeted nanoparticles to treat disease in entirely new ways.”

“Sail is charting a new course for medicine, where RNA and delivery systems are becoming programmable components that can be engineered with precision,” said Mackay. “By integrating eRNA, targeted nanoparticles, and AI, Sail created a platform that redefines how medicines are designed and delivered. Sail’s in vivo CAR-T program demonstrates the power of this integration, with the potential to bring a best-in-class transformative treatment for autoimmune disease patients in a more accessible way. I am honored to join the Board at this pivotal stage and to support Sail as it advances its CD19 in vivo CAR-T program to the clinic.”

After a number of years at large pharmaceutical companies, Mackay co-founded and is Board Chair of Rallybio, a publicly traded biotechnology company developing treatments for patients with devastating ultra-rare diseases. Previously, he served as President and Head of R&D at AstraZeneca. Prior to that, he spent more than 15 years at Pfizer, culminating as President and Head of Pharmatherapeutics R&D, where he led worldwide discovery, development, and technology functions. Mackay was also Executive Vice President and Head of R&D at Alexion Pharmaceuticals, overseeing a portfolio of 60 programs across hematology, neurology, nephrology, and other therapeutic areas.

In addition to his role at Rallybio, Mackay serves on the Boards of Directors of Novo Nordisk and Charles River Laboratories, where he is Lead Independent Director. He previously served on the Board of SpringWorks Therapeutics through its acquisition by Merck KGaA in 2025.

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.

Contact

press@sail.bio 

Preclinical data show that Sail’s eRNA vaccine candidates induce robust anti-malaria immune responses and protect against infection in a mouse challenge model

CAMBRIDGE, Mass., June 2, 2025 – 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.

Contact

press@sail.bio 

SAIL-0804 shows rapid and deep B cell depletion along with repopulation by mostly immature phenotypes in preclinical models, supporting its advancement into IND-enabling studies