Suzhou, China, September, 25 2023 -- CStone Pharmaceuticals (“CStone”, HKEX: 2616), a leading biopharmaceutical company focused on the research, development, and commercialization of innovative immuno-oncology therapies and precision medicines, today announced that the British Journal of Cancer, a highly-cited general cancer journal, has published the first-in-human trial (CS1003-101) data on their anti-PD-1 antibody nofazinlimab for the treatment of advanced solid tumors.

The CS1003-101 study, conducted from May 2018 to May 2021 in Australia and New Zealand, is a Phase 1, open-label, dose-escalation, and dose-expansion trial. The research data show that nofazinlimab monotherapy demonstrates good safety and tolerability, with no observed dose-limiting toxicities. Preliminary anti-tumor activity was also observed in multiple tumor types. The study explored different dosing frequencies and found that the safety and efficacy of nofazinlimab at doses of 200 mg every three weeks and 400 mg every six weeks are essentially equivalent. Furthermore, the trial investigated the use of nofazinlimab in combination with regorafenib, and the data reveal a manageable safety profile for patients with heavily pre-treated metastatic colorectal cancer.

To date, multiple milestones have been achieved in the registrational clinical study of nofazinlimab. Patient enrollment for the global, multi-center, phase 3 study (CS1003-305) of nofazinlimab in combination with lenvatinib as a first-line treatment for advanced hepatocellular carcinoma (HCC) was completed in March 2022. The topline results are expected to be disclosed in the first quarter of 2024 and will be used to support the new drug applications of nofazinlimab globally. Nofazinlimab in combination with lenvatinib could potentially become a new therapeutic option for the patients with advanced HCC.

Liver cancer is a common malignant tumor of digestive system worldwide. According to GLOBOCAN 2020 (Global Cancer Incidence, Mortality and Prevalence) data of the International Agency for Research on Cancer (IARC), a specialized agency of the World Health Organization, global new cases of liver cancer is more than 900,000, and death cases are more than 830,000 per year. The number of death cases is close to the number of new cases. HCC accounts for the majority of liver cancer cases, comprising approximately 75% to 85% of all cases. Due to its insidious onset, fewer than 30% of liver cancer patients are suitable candidates for curative treatment upon initial diagnosis. Systemic anti-cancer therapies play a critical role in the treatment of advanced-stage liver cancer.^[1] Overall, patients with advanced HCC experience rapid disease progression and have a poor prognosis, with a 5-year survival rate of only 12.1%.^[2]

CS1003-305 is a global, multi-center, double-blind, randomized, phase 3 registrational clinical trial to evaluate the efficacy and safety of nofazilimab in combination with lenvatinib compared with placebo in combination with lenvatinib in subjects with unresectable advanced HCC. The trial is conducted at 74 study centers worldwide. The primary endpoint is overall survival (OS).

In addition, multiple research of nofazinlimab have been showcased at international academic conferences, including the preliminary data from CS1003-101 study presented at the 2020 European Society for Medical Oncology (ESMO) Annual Meeting and the phase 1b data from CS1003-102 study disclosed at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting. The data from a CS1003-102 phase 1b arm of Chinese patients with unresectable HCC demonstrated promising efficacy and manageable safety of nofazinlimab in combination with lenvatinib as a first-line treatment, i.e. objective response rate (ORR) of 45.0%; median duration of response (DoR) not reached as of the data cutoff date (range: 4.2 to 18.7+ months); median progression free survival (PFS) of 10.4 months.

About nofazinlimab（CS1003）

Nofazinlimab is a humanized recombinant IgG4 monoclonal antibody targeting human programmed cell death protein 1 (PD-1) being developed in solid tumors. Nofazinlimab shows comparable high binding affinities to the PD-1 of humans, cynomolgus monkey, and mouse, and can block the interaction of PD-1 with its ligands PD-L1 and PD-L2.

The U.S. FDA has granted nofazinlimab Orphan Drug Designation (ODD) in July 2020 for the treatment of patients with HCC.

In March 2022, the Phase 3 international multi-regional registrational study CS1003-305 of nofazinlimab plus lenvatinib for the first-line treatment of advanced HCC has already achieved the prespecified target on patient enrollment.

About CStone

CStone (HKEX: 2616) is a biopharmaceutical company focused on research, development, and commercialization of 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 management team with extensive experience in innovative drug development, clinical research, and commercialization. The company has built an oncology-focused pipeline of 14 drug candidates with a strategic emphasis on immuno-oncology combination therapies. Currently, CStone has received eleven NDA approvals for its four drugs. Multiple late-stage drug candidates are now under pivotal clinical trials or registration. CStone’s vision is to bring innovative oncology therapies to cancer patients worldwide.

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

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