Vivacta Bio and Grit Bio Announce FDA Orphan Drug Designation for In Vivo CAR-T Therapy GT801 in Autoimmune Hemolytic Anemia

Vivacta Biotechnology (Shanghai) Co., Ltd. ("Vivacta Bio"), a company spun out of the in vivo CAR-T platform of Beijing Grit Biotherapeutics Co., Ltd. ("Grit Bio"), today announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) to GT801, Vivacta Bio's lead investigational product, for the treatment of autoimmune hemolytic anemia (AIHA). The designation marks an important step in GT801's development for autoimmune diseases and enables potential access to incentives supporting GT801's further development in AIHA in the United States.

Addressing Unmet Need in AIHA Through B Cell Targeting

AIHA is an autoimmune disorder characterized by excessive, autoantibody-mediated destruction of red blood cells. Symptoms may include anemia, fatigue and shortness of breath, and severe cases can be life-threatening. Some patients continue to experience inadequate disease control despite multiple lines of therapy, underscoring the need for new treatment options.[1,2]

Recent clinical investigations of CD19 CAR-T in refractory AIHA have opened a new treatment avenue through B-cell depletion. Simplifying treatment and improving access, while continuing to evaluate safety and efficacy, remain key areas for further development.[2]

Early Clinical Activity Supports Development in Autoimmune Diseases

GT801 is an investigational in vivo CAR-T therapy that combines mRNA with T-cell-targeted lipid nanoparticle (LNP) delivery technology. By delivering mRNA encoding an anti-CD19 chimeric antigen receptor (CAR) into patients' T cells, GT801 is designed to generate CAR-T cells directly in the body to recognize and eliminate CD19-positive B cells.

Preliminary clinical results for GT801 in patients with autoimmune diseases were presented in a poster at the 2026 American Society of Gene & Cell Therapy (ASGCT) Annual Meeting. Two patients with AIHA both achieved complete response (CR) following GT801 treatment. One patient achieved CR at Week 4 and remained in CR at the Week 8 and Month 3 assessments; the other achieved CR at Week 10. Sustained peripheral B-cell depletion was also observed, together with increased hemoglobin levels and reductions in lactate dehydrogenase, indirect bilirubin and reticulocyte counts. These preliminary findings indicated promising clinical prospect of GT801 in AIHA.[3]

FDA Orphan Drug Designation Supports GT801's Global Development

Orphan Drug Designation is intended to encourage the development of treatments for rare diseases. Subject to applicable requirements, sponsors of designated products may be eligible for incentives including tax credits for qualified clinical trial expenses, exemption from marketing application user fees, and the potential for seven years of orphan drug market exclusivity following marketing approval.[4]

"GT801's Orphan Drug Designation is an important milestone in the project's global development in autoimmune diseases. It also reflected continued progress in advancing therapies originated from Grit Bio's in vivo CAR-T platform, particularly in rare autoimmune diseases," said Yarong Liu, Ph.D., Founder, Chairperson and Chief Executive Officer of Grit Bio. "Grit Bio and Vivacta Bio will continue to advance research and clinical translation guided by patient needs, build a stronger body of clinical evidence, and make innovative treatment options more accessible to patients."

About Vivacta Bio

Vivacta Bio is a biotechnology company focused on in vivo CAR-T innovation, with the aim of advancing transformative therapies in oncology and autoimmune diseases. Established on June 25, 2025, the company was spun out of Grit Bio's in vivo CAR-T platform. Its therapies use targeted LNP delivery to express CAR directly in patients' T cells, offering a new approach to treating hematologic malignancies and autoimmune diseases. This approach also eliminates the need for cell isolation, ex vivo expansion and lymphodepletion. By addressing the high costs, lengthy treatment timelines and toxicity associated with such processes, Vivacta Bio's platform has the potential to broaden patient access. Its lead candidate, GT801, has shown promising potentials in hematologic malignancies and autoimmune diseases.

About GT801

GT801 is an investigational anti-CD19 in vivo CAR-T therapy based on T-cell-targeted LNP technology. The product combines ionizable cationic lipids with CLAMP technology platform, featuring a distinctive T-cell-targeting VHH antibody, site-specific conjugation, and precisely controlled ligand density. The design enhances T cell targeting efficiency while minimizing nonspecific uptake, enabling efficient CAR expression in vivo. GT801 is engineered to generate potent, durable CAR-T cells within the patient and to support repeat dosing. With  low cost, strong therapeutic activity and ease of administration, GT801 aims to address challenges in manufacturing economics and production timelines that constrain the commercialization of ex vivo cell therapies.

References

[1] MedlinePlus. Immune hemolytic anemia. https://medlineplus.gov/ency/article/000576.htm

[2] Li R, et al. CD19 CAR T-Cell Therapy for Autoimmune Hemolytic Anemia. N Engl J Med. 2026;394:253–267. doi:10.1056/NEJMoa2509820.

[3] Sun J, Zhu X, Jin J, et al. Targeted mRNA-LNP Delivery Enables In Vivo CAR-T Generation by GT801 with Potent B-Cell Depletion in Humans. Poster presented at the 2026 American Society of Gene & Cell Therapy (ASGCT) Annual Meeting.

[4] U.S. Food and Drug Administration. Designating an Orphan Product: Drugs and Biological Products. https://www.fda.gov/industry/medical-products-rare-diseases-and-conditions/designating-orphan-product-drugs-and-biological-products

Vivacta Contact

Yanwen Zhang
Email: [email protected]
Telephone: +86-21-50828029

SOURCE Vivacta Bio