CARsgen scores key EU patent win for GPC3-targeted CAR-T

China-based biotech CARsgen Therapeutics (HKEX: 2171) has strengthened its grip on intellectual property in the CAR-T space after a US rival dropped its legal challenge to one of the company’s cornerstone patents in Europe.

The European Patent Office (EPO) has now closed opposition proceedings relating to CARsgen’s patent EP3445407, which underpins its GPC3-targeted CAR-T therapy program. On July 3, a US biotech formally withdrew its appeal against the EPO's earlier decision to uphold the patent in amended form, making the ruling final and unchallengeable at the European level.

The patent, first granted in 2022, was contested in 2023 by two opponents. Following oral hearings, the EPO’s Opposition Division confirmed the patent's validity with modifications that preserved key claims. These include protection for GPC3-directed CAR-T cells used in combination with lymphodepletion therapy—specifically cyclophosphamide and fludarabine—in treating a range of solid tumors, including liver, lung, ovarian, breast, gastric, and thyroid cancers.