On December 6, 2025 Vivacta Bio, a spin-off company of Grit Biotherapeutics advancing in vivo CAR-T therapies for oncology and autoimmune diseases, reported encouraging initial data from an investigator-initiated, first-in-human study of GT801, a T-LNP/mRNA–based in vivo CAR-T candidate targeting CD19. The results were presented in an oral session by Dr. Pin Wang, Chief Scientific Officer of Grit Biotherapeutics, at the 2025 American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting in Orlando, Florida. The presentation, titled "Precision In Vivo CAR-T Generation via CLAMP-Enabled mRNA Delivery: Toward Scalable and Translatable Cell Therapy," highlighted early clinical activity of GT801 and its potential to reshape CAR-T treatment delivery.
Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:
Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing
Schedule Your 30 min Free Demo!
The Phase 1 investigator-initiated study is evaluating the safety, tolerability, and preliminary efficacy of repeat GT801 dosing in patients with relapsed or refractory CD19-positive B-cell malignancies. As of the November 30, 2025 data cutoff, two patients with non-Hodgkin’s lymphoma had completed multiple GT801 administrations without lymphodepleting chemotherapy, demonstrating the feasibility of generating functional CAR-T cells in vivo in the absence of cytotoxic conditioning.
Patient 1 received three doses of 0.5 mg, and Patient 2 received four doses of 1.5 mg. GT801 was generally well tolerated. Both patients showed high CAR expression within circulating T cells. Durable and repeatable CAR-T expansion was observed following each GT801 administration. No CAR expression was detected in peripheral blood monocytes, suggesting negligible off‑target delivery of GT801 and supporting high selectivity of the T‑LNP platform.
GT801 induced rapid and profound pharmacodynamic activity, resulting in deep B-cell depletion in peripheral blood and across multiple tissues, with B cells effectively cleared in bone marrow and lymph node biopsies. By Week 4 following the final GT801 infusion, both patients achieved a partial response based on investigator assessment.
"We are encouraged by the promising safety profile and compelling efficacy signals observed with GT801 in heavily pretreated NHL patients," said Dr. Yarong Liu, Founder and CEO of Vivacta Bio. "These initial findings demonstrate GT801’s ability to generate potent, repeatable CAR-T responses without lymphodepleting chemotherapy – a major step forward for scalability, patient accessibility, and commercial viability."
About GT801
GT801 is an investigational, systemically administered in vivo CAR-T product candidate that uses T-cell–targeted lipid nanoparticles (T-LNPs) to deliver optimized mRNA encoding an anti-CD19 CAR. The platform integrates Grit Bio’s proprietary CLAMP (Controllable Ligand Attachment Modification and Purification) technology, enabling site-specific antibody conjugation, precise ligand density control, and selective T-cell targeting with minimal off-target uptake. GT801 is designed to generate potent and persistent CAR-T cells directly inside the patient, supporting repeat dosing and eliminating the need for conventional ex vivo cell manufacturing.
(Press release, Vivacta, DEC 6, 2025, View Source [SID1234661220])