Liberate Bio Presents New Preclinical Data Supporting First Clinical Evaluation of In Vivo CAR-M Program LIB820 in Autoimmune Disease

Data expands mechanistic and translational evidence for selective in vivo programming of monocytes and macrophages, potent peripheral B-cell depletion, and a differentiated cytokine profile

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Liberate Bio, Inc., a biotechnology company developing genetic medicines that deliver RNA therapies directly to immune cells, today announced new pre-clinical data supporting LIB820, the company’s lead in vivo CAR-M program for autoimmune disease. LIB820 is Liberate’s first-in-human (FIH) study and is currently on track for initiation at the end of 2026. The data will be presented at the American Society of Gene and Cell Therapies conference in Boston by Dr. Walter R. Strapps, CSO of Liberate Bio.

LIB820 is Liberate’s lead in vivo CAR-M program, comprising a four-component LNP incorporating a novel cationic lipid generated from Liberate’s ML-enabled RAPTOR™ LNP screening platform and an mRNA encoding an anti-CD19 chimeric antigen receptor (CAR) designed to reprogram monocytes and macrophages in vivo. The presentation expands on Liberate’s previously reported non-human primate data showing selective delivery of CAR-encoding mRNA to monocytes and macrophages drove up to 99% peripheral B-cell depletion at well-tolerated doses. New data from cellular systems, mouse models, and non-human primates further support the mechanism of CAR-expressing myeloid cells as direct effector cells and reinforce the differentiated tolerability profile observed to date, including modest and transient cytokine changes without evidence of T-cell-driven proliferation and other measures of toxicity.

“We’ve made great strides over the last six months on demonstrating the robustness of our novel LNP,” said Walter R. Strapps, Ph.D., Chief Scientific Officer of Liberate Bio. “We’re able to demonstrate that CAR-expressing myeloid cells can act as effector cells to deplete B-cells in circulation, and we see no evidence of the cytokine spikes that likely drive CRS. We’re excited by the fact that this is a novel approach to target B-cells with a CAR – one that doesn’t require expressing CAR in T-cells.”

Liberate’s proprietary RAPTOR™ platform allows direct screening of lipid nanoparticles (LNPs) in non-human primates to identify delivery vehicles that target extrahepatic cells. The company’s lead LNP is a simple four-component nanoparticle without conjugated targeting moieties that selectively delivers CAR-encoding mRNA to monocytes and macrophages in circulation and bone marrow, creating the potential for a repeatable, systemically administered approach to in vivo immune programming.

Ongoing dose-optimization studies are designed to extend the duration of CAR-M activity and deepen tissue distribution across disease-relevant compartments, including circulation, lymphoid tissue, and bone marrow, to support full-compartment immune reset. Updated data are expected in the second half of 2026.

“The field has seen the promise of in vivo CAR-T and the potential to broaden access to this important class of therapeutics, but T-cell programming is not the only path to immune reset,” said Shawn P. Davis, Ph.D., Chief Executive Officer of Liberate Bio. “LIB820 is designed to harness monocytes and macrophages as programmable effector cells — delivering cell-therapy-like activity through a repeatable, off-the-shelf medicine while avoiding the T-cell activation biology associated with cytokine release syndrome and neurotoxicity. If successful, CAR-M could expand immune programming beyond the most severe patients and into broader autoimmune, oncology, and immune-mediated diseases where CAR-T has not been a practical option.”

Liberate plans to support an investigator-initiated trial of LIB820 in diffuse cutaneous systemic sclerosis (dcSSc) in the third quarter of 2026, with proof-of-concept data on B-cell depletion and durability anticipated by the end of 2026. This milestone will mark the transition of Liberate’s platform from preclinical validation to human proof of concept, advancing a new therapeutic class designed to safely reprogram immune cells in vivo. The company’s initial clinical focus will include autoimmune indications, such as systemic lupus erythematosus and multiple sclerosis, as well as oncology programs through anti-BCMA CAR-M (LIB810). LIB810 will be explored for the treatment of relapsed/refractory multiple myeloma (rrMM), in which malignant plasma cells persist primarily in the bone marrow and remain difficult to fully eradicate.

Presentation Details
Title: Precision Engineering of Myeloid Cells In Vivo for Global-Scale Treatments
Presenter: Walter R. Strapps, Ph.D., Chief Scientific Officer, Liberate Bio
Conference: American Society of Gene and Cell Therapies Annual Meeting
Date and Time: May 13, 2026, 4:22 p.m. ET
Location: Boston, Massachusetts

About Liberate Bio

Liberate Bio is building the next generation of genetic medicines by solving the most fundamental challenge in the field: delivery beyond the liver. The company’s proprietary RAPTOR™ platform combines high-throughput in vivo screening in non-human primates with AI-driven design and optimization, creating the first biological dataset powerful enough to train artificial intelligence on real delivery outcomes.

Using this feedback loop, Liberate Bio has engineered lipid nanoparticles that target specific immune and bone marrow–resident cell types, including monocytes, macrophages, and hematopoietic stem cells (HSCs). This approach enables the programmable delivery of mRNA, gene editing, and other payloads directly to the cells that drive disease — unlocking the potential to treat oncology, autoimmune, and rare genetic disorders from within the body.

Liberate Bio’s first programs focus on in vivo CAR-M therapies to reprogram immune cells safely and at scale. Longer term, the company’s platform provides a foundation for a new class of AI-informed, systemically delivered genetic medicines that extend to multiple organs and therapeutic areas.

For more information about the company’s technologies, team, and mission, visit www.liberatebio.com