CStone Pharmaceuticals announced that the GEMSTONE-302 registrational clinical study of sugemalimab for the first-line treatment of metastatic (stage IV) non-small cell lung cancer (NSCLC) met the overall survival (OS) endpoint. The results demonstrated that sugemalimab in combination with chemotherapy showed statistically significant and clinically meaningful OS improvement in patients. Based on the previously reported impressive progression-free survival (PFS) data, the National Medical Products Administration (NMPA) of China approved sugemalimab in combination with chemotherapy for the first-line treatment of patients with metastatic squamous and non-squamous NSCLC in December 2021.

The anti-PD-L1 monoclonal antibody sugemalimab was discovered by CStone using OmniRat® transgenic animal platform, which allows creation of fully human antibodies in one step. Sugemalimab is a fully human, full-length anti-PD-L1 immunoglobulin G4 (IgG4) monoclonal antibody, which may allow a reduced the risk of immunogenicity and toxicity for patients, a unique advantage over similar drugs. Currently, the NMPA of China has approved sugemalimab (Cejemly®) in combination with pemetrexed and carboplatin as first-line treatment of patients with metastatic non-squamous NSCLC, lacking EGFR and ALK genomic tumor aberrations; and in combination with paclitaxel and carboplatin as first-line treatment of patients with metastatic squamous NSCLC.

In addition, sugemalimab is being investigated in a number of ongoing clinical trials, including one Phase 2 registrational study for lymphoma and four Phase 3 registrational studies in stage IV NSCLC, stage III NSCLC, gastric cancer, and esophageal cancer, respectively. CStone formed a strategic collaboration agreement with Pfizer Inc. that includes the development and commercialization of sugemalimab in mainland China, and a framework to bring additional Oncology medicines to the Greater China market.