CARsgen Therapeutics Holdings Limited (Stock Code: 2171.HK), a China-based company involved in developing innovative CAR T-cell therapies, announced on Sunday a favourable outcome in opposition proceedings before the European Patent Office (EPO) concerning its European patent EP3445407, which covers its GPC3-targeted CAR-T cell therapy.

The company says that on July 3, 2025, a US-based biotechnology company, the sole appellant among the original two opponents, formally withdrew its appeal against the EPO Opposition Division's earlier decision to maintain the patent. This withdrawal renders the EPO's decision final and binding for the opponents, effectively concluding their part in the opposition process.

The patent was granted by the EPO in 2022 and opposed by two parties in 2023. Following oral proceedings, the EPO Opposition Division issued a decision to maintain the patent in amended form, upholding key claims related to the use of GPC3 CAR-T cell therapy following cyclophosphamide and fludarabine lymphodepletion pretreatment, in the treatment of liver cancer, lung cancer, ovarian cancer, breast cancer, gastric cancer, and thyroid cancer. Following the decision, only one opponent filed an appeal within the allowable period. That appeal has now been withdrawn.

Under EPO procedures, the opponents or any other third party can no longer challenge the patent at the EPO. CARsgen says that this development further reinforces its intellectual property position in the field of GPC3-targeted CAR-T therapies for the treatment of solid tumours.