Mirai Bio has presented preclinical data at the American Society of Gene and Cell Therapy Annual Meeting 2026 demonstrating its machine learning platform can optimise lipid nanoparticles for delivery to adipocytes, cells central to obesity and metabolic diseases. The company screened over 400 proprietary ionizable lipids using in vivo biodistribution data and machine learning. Lead LNPs achieved high white adipose tissue expression whilst minimising off-target delivery to liver and spleen. Cellular profiling confirmed strong on-target adipocyte delivery with minimal liver accumulation. Founded by Flagship Pioneering, Mirai Bio develops delivery solutions for nucleic acid medicines beyond the liver. The findings demonstrate how the platform can address tissue-specific delivery challenges, creating pathways for adipocyte-directed programmes in obesity and related metabolic conditions.

Mirai Bio has presented preclinical data at the American Society of Gene and Cell Therapy Annual Meeting 2026 demonstrating its CD8-targeted lipid nanoparticle platform advanced from novel particle design to functional non-human primate proof-of-concept in just 10 months. The Cambridge-based company, founded by Flagship Pioneering, showed its platform achieved CD8+ T-cell specificity, reduced liver delivery, and functional activity in relevant models. In humanised mice, CD8-targeted LNPs loaded with CD20 CAR mRNA produced dose-dependent CAR expression and B-cell depletion. In non-human primates, a single systemic dose generated CAR-expressing CD8+ T cells and drove rapid depletion of circulating CD20+ B cells through seven days post-dose, with a supportive tolerability profile. The data was presented across two poster presentations at the conference.

Mirai Bio presents data showing rapid advancement of novel CD8+ t-cell targeted LNPs to functional NHP proof-of-concept at ASGCT 2026. * Mirai advanced a CD8-targeted LNP from concept to functional non-human primate (NHP) proof-of-concept data in only 10 months, showing how its integrated platform can turn novel delivery designs into valuable development programs * Systemic CAR mRNA delivery generated CAR-expressing T cells in vivo and drove B-cell depletion in NHPs * Cargo-ready CD8-targeted LNP vehicles gives partners a translational foundation to make faster, higher-confidence development progress for in vivo RNA CAR-T programs CAMBRIDGE, Mass., May 12, 2026 - Mirai Bio, the innovation delivery partner for companies developing next generation nucleic acid medicines, today announced new preclinical data at the American Society of Gene and Cell Therapy (ASGCT) Annual Meeting 2026 demonstrating the rapid advancement of its CD8-targeted lipid nanoparticle (LNP) platform from novel particle design to functional non-human primate (NHP) proof-of-concept in only 10 months. T cells are a high-value delivery frontier because of their central role in immune biology and relevance across autoimmune diseases, oncology, and other immune-mediated conditions. The two poster presentations show how Mirai's integrated platform addresses the core requirements for in vivo T-cell targeting, including T-cell specificity, reduced liver-directed delivery, scalable production, tolerability, and functional activity in relevant models, creating a cargo-ready foundation for partner programs. "Nucleic acid medicine programs can only move as fast as their delivery systems allow," said Jagesh V. Shah, Ph.D., SVP, Head of Platform at Mirai Bio. "These data show that Mirai can help partners move from delivery concept to functional NHP proof-of-concept with the speed and translational relevance needed to make confident development decisions. For in vivo T-cell programs, that means generating the proof points that matter, including functional activity, tolerability, and a clear path toward the clinic." In the first poster, Mirai described the discovery and evaluation of novel ionizable lipids and long-circulating LNP compositions designed to support extrahepatic, targeted mRNA delivery to T cells. Using a modular lipid discovery platform, Mirai generated structurally diverse ionizable lipid libraries and screened LNPs with dual mRNA cargoes to assess both liver expression and tissue distribution. Lead particles were reformulated into long-circulating compositions that reduced hepatic expression and supported extrahepatic delivery in mice. These optimized base particles were then converted into CD8-targeted LNPs, which showed selective CD8+ T-cell expression with minimal CD4+ T-cell or B-cell transfection and, when loaded with CD20 CAR mRNA, produced dose-dependent CAR expression and B-cell depletion in CD34+ humanized mice, connecting particle design to functional immune-cell activity. In the second poster, Mirai extended the CD8-targeted LNP platform into NHP-scale production and functional in vivo evaluation. Mirai generated CD8-targeted LNPs encapsulating mRNA encoding a second-generation human and cynomolgus cross-reactive anti-CD20 CAR and administered the particles systemically in NHPs. A single dose generated CAR-expressing endogenous CD8+ T cells and drove rapid depletion of circulating CD20+ B cells out to seven days post-dose, with reduced CD20+ cells also observed in the spleen at 72 hours. The data also showed a tolerability profile supportive of continued translational development, with cytokine and clinical chemistry findings that were monitored and controlled across studies and no major clinical observations in NHPs through the end of study. The data were presented at the ASGCT Annual Meeting 2026 in two poster presentations: * Abstract 2008: "Mirai Bio's CD8-targeted lipid nanoparticle delivery platform enables in vivo generation of CD20 CAR T cells and B cell depletion" was presented by Brian Duke, Ph.D., Principal Scientist, Translational Science at Mirai Bio, on May 12 from 5:00 p.m. to 6:30 p.m. ET. * Abstract 1073: "Novel ionizable lipids and long-circulating LNP compositions designed for extrahepatic delivery to enable targeted mRNA delivery to T cells," was presented by Chelsea Martinez, Ph.D., Senior Scientist I at Mirai Bio, on May 13 from 5:00 p.m. to 6:30 p.m. ET About Mirai Bio Mirai Bio is delivering genetic medicines from promise to performance. Founded by Flagship Pioneering, Mirai was built to solve one of the field's central challenges: achieving precise, scalable delivery of diverse nucleic acid payloads to specific cells and tissues, particularly beyond the liver. By combining a large and growing proprietary in vivo biodistribution dataset, machine learning-guided lipid nanoparticle optimization, modular targeted particle design, and integrated translation and manufacturing capabilities, Mirai helps partners accelerate development, reduce technical risk, and pursue high-value programs making delivery a strategic advantage. For more info, visit www.miraibio.com.