Safety and efficacy of chimeric antigen receptor (CAR)–T cell therapy (BRG01) targeting the Epstein-Barr virus (EBV) envelope protein in EBV+ lymphoproliferative disease patients.

7079 Background: Epstein-Barr virus (EBV) is a type I carcinogen which has infected more than 95% of population. EBV infection is closely associated with infectious mononucleosis and various malignancies. The envelope glycoprotein gp350 is present on EBV-infected host cells and serves as a potential tumor-specific antigen for the treatment of EBV + solid tumors like nasopharyngeal cancer as reported previously (NCT05864924) 1,2 . Anti-gp350 CAR-T also demonstrated robust inhibition for EBV replication and lymphoproliferation in a humanized mouse EBV infection model 3 . Here we explored the safety and efficacy of anti-gp350 CAR-T (BRG01) against EBV + T cell lymphoproliferative disease (LPD) in an exploratory pilot trial study. Methods: Patients with EBV + T cell LPD failing at least two lines of standard therapies were enrolled. Other criteria include EBER + and Gp350 + expression on tumor biopsies. A single dose of EBV CAR-T cells (BRG01) were infused after a lymphodepletion regimen (cyclophosphamide 250-350 mg/m 2 /day, fludarabine 25-30 mg/m 2 /day for three days). Safety profile, pharmacokinetics (PK), EBV DNA copy number in the peripheral blood and tumor burden were monitored after BRG01 treatment. Results: From September 2021 to June 2023, a total of three patients with EBV + T cell LPD, subject 01, 02 and 03 were treated with 3*10 6 /kg, 9*10 6 /kg and 1.5*10 7 /kg BRG01 respectively. The cells expanded and proliferated well in the patients. The EBV DNA copies in the peripheral blood of subject 01 and 03 decreased significantly post BRG01 infusion and remained at less than 500 copies/ml for subject 02. The disease control rate for the three patients is 100% (3/3) and the overall response rate is 66.7% (2/3) based on Lugano 2014 criteria. One patient showed complete metabolic remission 28 days post 9*10 6 /kg BRG01 infusion and remained disease free for over three years. Conclusions: BRG01 is well tolerated and expanded in all treated patients. The durabler efficacy in all treated patients supports its further clinical investigation in various subtypes of EBV + lymphomas and LPD. 1. Zhang X, Wang T, Zhu X, et al: GMP development and preclinical validation of CAR-T cells targeting a lytic EBV antigen for therapy of EBV-associated malignancies. Frontiers in Immunology 14:1103695, 2023. 2. Zhang L, Zhao H, Ma Y, et al: 899P Safety and efficacy of a novel CAR-T cell therapy (BRG01) targeting the Epstein-Barr Virus envelope glycoprotein in advanced metastatic nasopharyngeal cancer patients. Annals of Oncology 35:S636, 2024. 3. Slabik C, Kalbarczyk M, Danisch S, et al: CAR-T cells targeting Epstein-Barr virus gp350 validated in a humanized mouse model of EBV infection and lymphoproliferative disease. Molecular Therapy-Oncolytics 18:504-524, 2020. Clinical trial information: ChiCTR2100044497 .