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

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  • 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., May 12, 2026 — 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.