On May 8, 2026 Azalea Therapeutics, Inc., a biotechnology company redefining precision genomic medicines in vivo, reported that first-in-primate data from its proprietary in vivo CAR T cell platform have been accepted as a late-breaking abstract for oral presentation at the American Society of Gene and Cell Therapy (ASGCT) (Free ASGCT Whitepaper) 2026 Annual Meeting, taking place May 11 – 15, 2026 in Boston, Massachusetts.

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The late-breaking abstract, titled "A first-in-primate demonstration of in vivo TRAC-CAR T cell engineering via cell-selective delivery and genomic locus-specific integration," describes the first in vivo generation of genomic site-specific engineered TRAC-CAR T cells in non-human primates. Azalea’s platform is designed to generate CAR T cells directly inside the body through a dual-vector approach that combines CD3-targeted enveloped delivery vehicles (EDVs) delivering transient Cas9 complexes with a T cell-tropic AAV (AAV-T) carrying a promoterless CAR gene flanked by TRAC homology arms. This approach enables precise insertion of the CAR gene at the TRAC locus, placing CAR expression under control of the endogenous T cell promoter.

In the study, six rhesus macaques received a single intravenous administration of EDV and AAV-T vectors at different dose levels without prior lymphodepletion. The study assessed in vivo TRAC-CAR T cell generation, TRAC-CAR-mediated B cell depletion in peripheral blood, lymph nodes and bone marrow, and safety parameters.

"These first-in-primate data represent a major milestone for Azalea and for the broader field of in vivo cell engineering," said Jenny Hamilton, Ph.D., co-founder, president and chief executive officer of Azalea Therapeutics. "In immune-competent non-human primates, a single intravenous administration of our dual-vector platform generated TRAC-CAR T cells in vivo and achieved complete target B cell depletion across peripheral blood, lymph nodes and bone marrow without lymphodepletion. We believe that achieving precise insertion at a defined genomic locus will be foundational to the safety, durability and physiologic regulation of future in vivo cell therapies. We believe these findings provide important translational support for our approach and the potential to make powerful cell therapies more accessible by eliminating the need for individualized ex vivo manufacturing."

First-in-Primate In Vivo TRAC-CAR T Cell Engineering

In the study, animals demonstrated in vivo generation of TRAC-CAR T cells, with TRAC-CAR T cells peaking as high as 41% of all peripheral T cells on Day 11. All six animals demonstrated deep B cell aplasia of greater than 90% in peripheral blood by Day 10.

The study also demonstrated potent target B cell clearance beyond peripheral blood. In lymph nodes and bone marrow, B cells were deeply depleted by greater than 90% in five of six animals at the highest dose level within two weeks following treatment.

Treatment was generally well tolerated, with no deaths, no neurotoxicity and a favorable safety profile. Molecular analyses confirmed no off-target CAR expression or integration in non-T cells in the blood.

"To our knowledge, this is the first demonstration of site-specific gene integration in T cells in a non-human primate in vivo. This study demonstrates that Azalea’s platform can achieve cell-selective delivery, genomic locus-specific CAR insertion and robust pharmacodynamic activity in a clinically relevant non-human primate model," said Connor Tsuchida, Ph.D., scientific co-founder, vice president of research and development at Azalea Therapeutics and presenting author of the abstract. "The combination of TRAC-targeted integration, endogenous promoter-driven CAR expression and activity across multiple tissue compartments supports continued advancement of this genome editing-based in vivo CAR T platform toward clinical translation."

Azalea will present these data at the ASGCT (Free ASGCT Whitepaper) 2026 Annual Meeting.

Abstract Title: A first-in-primate demonstration of in vivo TRAC-CAR T cell engineering via cell-selective delivery and genomic locus-specific integration
Presenting Author: Connor A. Tsuchida, Ph.D., Azalea Therapeutics
Session: Oral Abstract Sessions – Late-breaking abstracts
Date/Time: Friday, May 15, 2026, 8:00 am – 9:45 am ET
Location: Westin Seaport Commonwealth Ballroom ABC (Concourse Level)

(Press release, Azalea Therapeutics, MAY 8, 2026, View Source [SID1234665405])