Is Vivacta Bio’s GT801 the next frontier in CAR-T therapy? Early human data reveal scalable, chemo-free promise

Vivacta Biotechnology Co., Ltd., an emerging biotechnology firm spun out of Grit Biotherapeutics, has unveiled early results that could signal a breakthrough in the field of in vivo CAR-T therapy. At the 2025 American Society of Hematology (ASH) Annual Meeting held in Orlando, Vivacta Bio presented first-in-human data for GT801, a systemically delivered CAR-T candidate that uses T-cell–targeted lipid nanoparticles to encode anti-CD19 CARs via mRNA.

Unlike traditional CAR-T therapies that require lymphodepleting chemotherapy and time-intensive ex vivo cell engineering, GT801 was administered in multiple doses to patients with relapsed or refractory CD19-positive non-Hodgkin’s lymphoma without prior chemotherapy. The findings, presented by Dr. Pin Wang of Grit Biotherapeutics, suggested functional CAR-T generation in vivo, high selectivity for T cells, and robust B-cell depletion across blood and lymphoid tissues—all achieved with favorable safety and tolerability.

According to Vivacta Bio Chief Executive Officer Dr. Yarong Liu, the results mark a major step toward achieving scalable, repeatable, and accessible CAR-T therapy. The Shanghai-based firm believes that GT801 represents a platform-level shift in how T-cell immunotherapy can be delivered to patients, especially those who may not qualify for conventional lymphodepleting regimens.

What differentiates GT801 from traditional CAR-T approaches in lymphoma treatment?

GT801 is engineered to bypass some of the most resource-intensive steps of conventional CAR-T manufacturing. Traditional therapies require the harvesting of a patient’s T cells, laboratory-based genetic modification, expansion in culture, and re-infusion after chemotherapy that clears out existing immune cells to make space. GT801 eliminates this complex chain by delivering optimized mRNA directly to T cells inside the body using a T-LNP (T-cell–targeted lipid nanoparticle) vehicle.

This approach enables CAR expression in circulating T cells without the need for lymphodepleting agents. It also allows for repeat dosing, a feature not typically feasible with one-time, autologous CAR-T infusions. Vivacta Bio’s platform uses Grit Biotherapeutics’ CLAMP (Controllable Ligand Attachment Modification and Purification) technology, which enables precise control over antibody attachment and ligand density on the nanoparticle surface. This specificity is designed to reduce off-target uptake and enhance safety.

In the Phase 1 trial presented at ASH 2025, two patients received multiple doses of GT801. Patient 1 was administered three doses at 0.5 mg, and Patient 2 received four doses at 1.5 mg. Neither patient underwent lymphodepletion prior to dosing. GT801 was well tolerated in both cases, with no dose-limiting toxicities reported. High levels of CAR expression were observed in T cells, and crucially, no CAR expression was detected in peripheral blood monocytes—suggesting a favorable selectivity profile.

How strong are the pharmacodynamic responses and efficacy signals?

Vivacta Bio reported that both patients experienced rapid and profound pharmacodynamic effects. Circulating B cells were depleted in peripheral blood, while tissue biopsies from lymph nodes and bone marrow also revealed deep B-cell clearance. By the fourth week after their final infusion, both patients had achieved a partial response, as assessed by investigators.

Repeat dosing led to consistent and durable CAR-T cell expansion. Unlike traditional CAR-T models where persistence is driven by a single manufacturing run, GT801’s repeat-dose framework allowed for multiple waves of immune activation. This opens the door to modulating immune response in real time based on clinical needs.

While these findings are preliminary and limited to two patients, they offer compelling evidence of GT801’s ability to induce clinically meaningful responses in heavily pretreated B-cell malignancies. The absence of chemotherapy also significantly reduces the toxicity burden and could expand eligibility to older or frailer patients.

Why does the CLAMP platform matter for next-generation immunotherapy?

At the heart of GT801 is a modular and tunable delivery system. The CLAMP platform, developed by Grit Biotherapeutics, allows antibody ligands to be precisely attached to lipid nanoparticles at defined densities and orientations. This offers two key advantages: selective targeting of T cells and minimal off-target delivery.

Conventional LNPs used in vaccines or siRNA-based drugs often suffer from biodistribution challenges, triggering innate immunity or being sequestered by the liver. The CLAMP system enhances targeting specificity by engaging T-cell markers through engineered ligands, enabling the nanoparticles to deliver mRNA payloads only where they are needed.

This selectivity could be particularly useful in the autoimmune space, where precise immune modulation is required to avoid triggering broad immunosuppression. The ability to control dosage, avoid chemotherapy, and achieve in vivo CAR-T conversion gives Vivacta Bio an edge in designing therapies that are both safer and more adaptable.

What do we know about Vivacta Bio and its relationship with Grit Biotherapeutics?

Vivacta Bio is a dedicated in vivo CAR-T developer based in Shanghai. It was spun out from Grit Biotherapeutics to focus on bringing scalable, repeat-dose immunotherapy solutions to market. Its research and development program spans both hematologic malignancies and autoimmune disorders, with a pipeline that builds on Grit’s immunotherapy innovations.

Grit Biotherapeutics, founded in 2019, is known for its work in tumor-infiltrating lymphocyte (TIL) therapies. Its lead candidate, GT101, became the first TIL therapy approved for clinical trials in China and is now undergoing Phase II pivotal studies. Grit’s second major asset, GT201, incorporates a membrane-bound IL-15 complex to enhance TIL persistence and has cleared regulatory hurdles in both China and the United States.

Together, Vivacta Bio and Grit Biotherapeutics form a vertically integrated ecosystem for immuno-oncology, with Grit focused on next-gen cell products and Vivacta Bio translating that science into practical, scalable therapies that can be administered without lab infrastructure.

How could GT801 reshape the commercial model for CAR-T therapy?

Analysts tracking the evolution of cell therapy platforms believe that GT801 could offer a new business model for immunotherapy delivery. By eliminating ex vivo manufacturing, shortening treatment timelines, and potentially lowering cost per patient, GT801 may unlock new markets for CAR-T adoption—including emerging economies and outpatient settings.

Repeat dosing also introduces the potential for more predictable revenue streams, compared to the one-time, high-cost treatment paradigm of conventional CAR-Ts. Moreover, the ability to titrate or redose based on biomarker feedback gives physicians greater control over immunotherapy exposure.

Vivacta Bio’s platform may also prove attractive for pharmaceutical partners seeking to develop CAR-T–like therapies without building internal manufacturing capabilities. The CLAMP-enabled T-LNP system could serve as a backbone for multiple indications, including solid tumors where CAR-T has historically struggled due to delivery and persistence challenges.

What clinical milestones and strategic shifts will shape GT801’s momentum in 2026?

While the ASH 2025 results represent an early proof of concept, stakeholders will be closely watching Vivacta Bio’s next clinical moves. A formal Phase 1 dose escalation study could validate safety across broader cohorts and pave the way for Phase 2 expansion.

Analysts expect future trials to explore higher dose levels, longer-term durability, and possible combination regimens with checkpoint inhibitors or bispecific antibodies. Another area of interest will be whether GT801 can induce complete responses or achieve measurable minimal residual disease (MRD) negativity in blood cancers.

In addition to oncology, investors are paying attention to the pipeline’s autoimmune angle. The ability to generate transient CAR expression in specific immune cell subsets could make GT801-style platforms viable for diseases like lupus, multiple sclerosis, or autoimmune cytopenias, where immune overactivity needs fine-tuned suppression.

Institutional sentiment toward Vivacta Bio and its parent company Grit Biotherapeutics remains cautiously optimistic. The successful translation of CLAMP-based delivery into a repeat-dose therapeutic model represents a leap forward in cell-free immunotherapy. If future data continue to show favorable tolerability and sustained response, Vivacta Bio could emerge as a key player in redefining how cell therapies are deployed at scale.

What are the key takeaways from Vivacta Bio’s GT801 debut at ASH 2025?

• Vivacta Biotechnology Co., Ltd. unveiled first-in-human data for GT801, its lead in vivo CAR-T candidate, at the 2025 ASH Annual Meeting in Orlando.

• GT801 uses T-cell–targeted lipid nanoparticles (T-LNPs) to deliver anti-CD19 CAR-encoding mRNA directly into patients, eliminating the need for ex vivo cell processing.

• The therapy was administered to two patients with relapsed or refractory non-Hodgkin’s lymphoma without any lymphodepleting chemotherapy.

• Both patients achieved partial responses within four weeks of their final GT801 dose, with robust CAR-T cell expansion and deep B-cell depletion in blood and tissues.

• No CAR expression was detected in monocytes, supporting the selectivity and safety of the CLAMP-enabled T-LNP delivery platform.

• GT801 was well tolerated across multiple doses, with no dose-limiting toxicities or severe adverse events reported.

• The repeat-dose design demonstrated consistent in vivo CAR-T generation, enabling a potentially titratable, adaptive immunotherapy model.

• Vivacta Bio is a spin-off of Grit Biotherapeutics and leverages its proprietary CLAMP platform for precise immune cell targeting.

• Analysts expect a dose-escalation study and potential expansion into autoimmune indications to be the next key milestones in 2026.

• GT801’s off-the-shelf format could reduce CAR-T complexity, costs, and logistics—positioning it as a scalable alternative to autologous cell therapies.