4SCAR19 + 4SCAR20

**4SCAR19 + 4SCAR20** is a combination of two fourth-generation chimeric antigen receptor (CAR) T cell therapies, each genetically engineered to target distinct B cell antigens—CD19 and CD20, respectively. This combination aims to overcome single-antigen escape, a common mechanism of relapse after CAR-T therapy, by simultaneously targeting both CD19 and CD20 molecules on malignant B cells. The 4SCAR platform includes enhanced safety features, such as an inducible caspase 9 (iCasp9) suicide gene, designed to allow controlled elimination of CAR-T cells if needed, and optimized co-stimulatory domains for improved efficacy and persistence. It is primarily developed for treatment of relapsed or refractory B-cell malignancies, particularly B-cell lymphoma. Clinical trials report its use in patients who have failed previous therapies, and early-phase studies indicate promising efficacy and manageable toxicity profiles[3][5][9].