CAR-T (Chimeric Antigen Receptor T-cell) therapy represents a major breakthrough in personalized cancer immunotherapy. The basic principle: extract T cells from the patient, use gene engineering (typically viral vector transduction) to express a chimeric antigen receptor (CAR) on the T cell surface enabling recognition of specific tumor cell surface antigens; expand the modified cells and reinfuse them into the patient — the engineered T cells then precisely identify and kill tumor cells expressing the target antigen.
## Clinical Achievements
CAR-T achieved milestone results in CD19-targeting B-cell hematologic malignancies (ALL, DLBCL, multiple myeloma): some heavily pre-treated patients who had failed multiple chemotherapy lines achieved long-term complete remission (CR) — considered “functional cure.”
**Approved products** (as of 2025): Kymriah (Novartis, tisagenlecleucel); Yescarta (Gilead/Kite, axicabtagene ciloleucel); Carvykti (Legend Biotech + J&J, ciltacabtagene autoleucel, BCMA-targeting for multiple myeloma) — Legend Biotech is a Chinese company; Carvykti is a landmark example of Chinese CAR-T reaching global markets.
## Core Challenges
**Cost**: autologous CAR-T manufacturing is complex (collection-transport-manufacture-reinfusion), with single treatment costs of RMB 1.2–2.5 million in China and $400,000–500,000 in the US — with limited insurance coverage.
**Solid tumors**: CAR-T is less effective in solid tumors (lung, colorectal cancer) versus hematologic malignancies, due to the immunosuppressive tumor microenvironment (TME), physical barriers (insufficient vascularization), and lack of sufficiently specific solid tumor targets.
**Cytokine release syndrome (CRS)**: CAR-T activation triggers strong immune responses, potentially causing life-threatening CRS, requiring administration at centers equipped to manage it.
See [CRISPR Gene Editing](https://sunqi.org/crispr-gene-editing-en/) and [Legend Biotech official site](https://www.legendbiotech.com/).
