Serif Biomedicines Presents Data at ASGCT 2026 Demonstrating the Potential of Modified DNA as a New Class of Genetic Medicines

• Platform data establish Modified DNA’s potential to overcome two of the barriers that have kept DNA from becoming a practical medicine: innate immune activation and inefficient nuclear access
• Preclinical results span systemic tolerability in non-human primates, proprietary mRNA co-factor enhanced expression, sustained and durable liver expression, and in vivo CAR expression with complete B-cell depletion in a humanized mouse model

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Serif Biomedicines, a Flagship Pioneering company pioneering Modified DNA as a new class of medicines, today announced preclinical data supporting the potential of its platform to overcome key barriers that have historically limited DNA as a therapeutic modality. The results establish early proof points across the platform’s core requirements, including reduced innate immune activation, increased expression with proprietary mRNA co-factors, tolerability following intravenous administration in non-human primates, and sustained gene expression with functional activity in preclinical models for rare disease and immune cell programming.

“DNA has always had extraordinary therapeutic potential, but it has remained just out of reach because of immunogenicity and nuclear access challenges,” said Jacob Rubens, Ph.D., Co-Founder and Chief Executive Officer of Serif Biomedicines and Origination Partner at Flagship Pioneering. “These data show that we are making meaningful progress against both barriers and beginning to define a new space between mRNA and gene therapy, where DNA can express genes for longer than RNA without relying on permanent genome integration or engineering.”

DNA has long represented one of medicine’s highest potential opportunities, but its use as a therapeutic modality has been limited by innate immune detection and inefficient access to the cell nucleus. Serif’s platform is designed to address both barriers through Modified DNA forms that reduce innate immune activation and co-delivered mRNA co-factors that enhance Modified DNA activity. In studies presented at ASGCT 2026, Serif’s Modified DNA showed minimal to undetectable activation of cGAS/STING activation and innate immunogenicity compared with unmodified DNA while maintaining high-levels of gene expression. Following intravenous administration in non-human primates, LNP-formulated Modified DNA was well-tolerated, with limited inflammation. Serif also showed that its proprietary mRNA co-factors dramatically increased gene expression from Modified DNA in hepatocytes and T cells in vitro and in vivo.

Serif also presented preclinical proof-of-concept data in its initial areas of focus: rare diseases and immune cell programming. In a liver-directed rat model, Modified DNA achieved sustained expression of therapeutic levels of human Factor IX for more than six weeks after a single dose, supporting its potential application in rare diseases. Separately, in a humanized mouse model of immune cell programming, a single dose of T cell-targeted LNPs carrying Modified DNA encoding a CD19 CAR led to CAR expression for more than a week and complete B-cell depletion in peripheral blood and spleen.

“These results reflect the core elements we believe are required to support the development Modified DNA as a new therapeutic modality, including reduction of innate immune activation, sustained expression, and demonstration of functional activity in vivo,” said Matt Kennedy, Ph.D., SVP, Head of Platform at Serif Biomedicines. “Together, they highlight Modified DNA’s potential to enable multiple categories of medicines for diseases where longer expression, cell-specific control, and the ability to dose again could create advantages over existing genetic medicine approaches.”

The data were presented by Dr. Kennedy in an oral presentation titled, “Modified DNA: a new therapeutic modality for scalable, programmable, durable, and redosable genetic medicines” at the American Society of Gene and Cell Therapy (ASGCT) Annual Meeting 2026.

About Serif Biomedicines

Serif Bio­medicines is pioneering Modified DNA as a new class of biotechnology. Founded in 2021 within Flagship Labs, the innovation foundry of Flagship Pioneering, Serif integrates nucleic acid chemistry, syn­thetic biology, delivery science, and artificial intelligence to enable programmable, scalable, durable, and redosable DNA medicines. The company’s initial focus is on genetically defined diseases and reprogram­ming the immune system. For more information, visit www​.ser​if​bio​med​i​cines​.com.

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