CStone announces phase 2 GEMSTONE-201 trial met primary endpoint of objective response rate (ORR) in patients with relapsed or refractory extranodal natural killer/T-cell lymphoma (R/R ENKTL)

Sugemalimab has the potential to become the world's first immunotherapy to be approved for patients with relapsed or refractory extranodal natural killer/T-cell lymphoma (R/R ENKTL)

The National Medical Products Administration (NMPA) of China has granted the Breakthrough Therapy Designation (BTD) to sugemalimab for the treatment of adult patients with R/R ENKTL

GEMSTONE-201 is the first successful registrational clinical study to date evaluating an anti-PD-L1 antibody targeting patients with R/R ENKTL

The topline data has demonstrated notable anti-tumor activity,durable objective response,and well-tolerated safety profile of sugemalimab in patients with R/R ENKTL

SUZHOU,China,Jan. 13,2022 -- CStone Pharmaceuticals ("CStone",HKEX: 2616),a leading biopharmaceutical company focused on research,development,and commercialization of innovative immuno-oncology therapies and precision medicines,today announced that the registrational clinical study (GEMSTONE-201) of sugemalimab in patients with relapsed or refractory extranodal natural killer/T-cell lymphoma (R/R ENKTL) met the primary endpoint. Results showed that sugemalimab significantly enhanced the objective response rate (ORR),as assessed by the Independent Radiology Review Committee (IRRC),compared with historical control. The investigator-assessed ORR was consistent with the evaluation by IRRC. Sugemalimab also demonstrated a well-tolerated safety profile in patients with R/R ENKTL,and no new safety signals were observed. CStone plans to submit a new drug application (NDA) in the near term to the National Medical Products Administration (NMPA) of China for sugemalimab as the treatment of R/R ENKTL and will present the topline results at an upcoming international academic conference.

Professor Huiqiang Huang of Sun Yat-sen University Cancer Center,the Principal Investigator of the GEMSTONE-201 study,said,"R/R ENKTL is highly malignant and aggressive. For a long time,there was no effective therapeutic drug in clinic,leading to a low cure rate and poor prognosis. The success of the GEMSTONE-201 study demonstrated that sugemalimabmay become a new treatment option for patients with R/R ENKTL to fulfill the extremely urgent medical needs of this patient population."

Dr. Jason Yang,Chief Medical Officer of CStone,"We are very glad that the registrational study of sugemalimab in treatment of R/R ENKTL met the primary endpoint. This is the third success in pivotal clinical studies of sugemalimab after the prior two Phase 3 trials in stage III and stage IV non-small cell lung cancer (NSCLC) also met the primary endpoint. Until now,no anti-PD-(L)1 monoclonal antibody has been approved for R/R ENKTL,so we very much look forward to seeing that more patients would benefit from sugemalimab."

The NMPA of China has approved the NDA of sugemalimab in combination with chemotherapy for treatment-naïve metastatic (stage IV) NSCLC patients. In addition,another NDA of sugemalimab in stage III NSCLC is under regulatory review. Sugemalimab is expected to provide a new treatment option for both stage III and stage IV NSCLC patents in the future. Sugemalimab has also demonstrated the tremendous potential with its unique mechanism of action and attractive clinical data in the treatment of lung cancer,lymphoma and other tumors.

About ENKTL

Extranodal natural killer/T-cell lymphoma (ENKTL) is a subtype of mature T cell and NK cell lymphoma. In 2012,a multicenter pathological classification survey of 10,002 lymphoma patients from China showed that ENKTL accounted for approximately 6% of all lymphomas and 28% of mature T-cell and NK-cell lymphomas. There is no existing effective salvage treatment for patients with R/R ENKTL whose disease has progressed on a L-asparaginase-based standard regimen. Patients also typically respond poorly to conventional treatments. Clinicians often have limited treatment options for such patients due to rapid disease progression and poor survival outcomes with a one-year survival rate of less than 20%. In China,the currently available targeted monotherapy for these patients has a complete response (CR) rate of approximately 6%. Thus,there are significant unmet medical needs in patient who did not respond to first-line treatment.

About sugemalimab

The potential best-in-class anti-PD-L1 monoclonal antibody sugemalimab is an investigational anti-PD-L1 monoclonal antibody discovered by CStone. Authorized by the U.S.-based Ligand Corporation,sugemalimab is developed by the OmniRat® transgenic animal platform,which can generate fully human antibodies in one stop. As a fully human,full-length anti-PD-L1 monoclonal antibody,sugemalimab mirrors the natural G-type immunoglobulin 4 (IgG4) human antibody,which reduces the risk of immunogenicity and potential toxicities in 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,with no EGFR or ALK genomic tumor aberrations; and in combination with paclitaxel and carboplatin as first-line treatment of patients with metastatic squamous NSCLC. In addition,sugemalimabis 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 III NSCLC,stage IV NSCLC,gastric cancer,and esophageal cancer,respectively.

About the GEMSTONE-201 study

GEMSTONE-201 study is a single-arm,multicenter,Phase 2 pivotal study designed to evaluate the efficacy and safety of sugemalimab as monotherapy for the treatment of adult patients with R/R ENKTL. Based on the encouraging preliminary efficacy results,sugemalimab was granted Orphan Drug Designation for the treatment of T-cell lymphoma and BTD for the treatment of R/R ENKTL by the U.S. FDA in October 2020. It has also been granted BTD by the NMPA of China. The study includes investigational sites in both China and the U.S..

About CStone

CStone Pharmaceuticals (HKEX: 2616) is a biopharmaceutical company focused on researching,developing,and commercializing innovative immuno-oncology and precision medicines to address the unmet medical needs of cancer patients in China and worldwide. Established in 2015,CStone has assembled a world-class management team with extensive experience in innovative drug development,clinical research,and commercialization. The company has built an oncology-focused pipeline of 15 drug candidates with a strategic emphasis on immuno-oncology combination therapies. Currently,CStone has received five drug approvals in Greater China,including three in Mainland China,one in Hong Kong,and one in Taiwan. CStone's vision is to become globally recognized as a world-renowned biopharmaceutical company by bringing innovative oncology therapies to cancer patients worldwide.

For more information about CStone,please visit: www.cstonepharma.com.

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