According to data released by GLOBOCAN 2020, lung cancer is currently the most prevalent malignant tumor with the highest mortality rate in China. Small cell lung cancer (“SCLC”) is the most aggressive subtype of lung cancer, accounting for approximately 15%-20% of all lung cancer cases with characteristics including rapid progression, early metastasis and a poor prognosis. SCLC is divided into limited-stage small cell lung cancer (“LS-SCLC”) and ES-SCLC. For patients with LS-SCLC, standard chemotherapy and radiotherapy can achieve an objective response rate of approximately 90% and a five-year survival rate of approximately 25%. However, most patients are diagnosed with ES-SCLC by the time they seek medical treatment, with a median survival time of less than one year and a two-year survival rate below 10%. SCLC, and particularly ES-SCLC, pose a significant and unresolved medical challenge.

The supplemental new drug application is mainly based on EXTENTORCH (NCT04012606), a randomized, double-blind, placebo-controlled, multi-center Phase 3 clinical study. EXTENTORCH aims to compare the efficacy and safety of toripalimab or placebo in combination with etoposide plus platinum for the first-line treatment of ES-SCLC. The principal investigator for this study is Professor Ying CHENG, who is from Jilin Cancer Hospital and serves as the vice president of the Chinese Society of Clinical Oncology (CSCO).

EXTENTORCH was launched in 51 centers nationwide, where patients were randomized in a 1:1 ratio to receive either toripalimab or placebo in combination with etoposide plus platinum. The treatment would be administered for 4-6 cycles, after which patients would receive maintenance treatment with toripalimab or placebo until disease progression, intolerable toxicity or other circumstances requiring termination of treatment as specified in the protocol.

In May 2023, the primary endpoints of EXTENTORCH met their pre-defined efficacy boundaries, and toripalimab thus became the first PD-1 inhibitor in the world that met the primary endpoints of both overall survival (“OS”) and progression-free survival (“PFS”) in a Phase 3 study for the first-line treatment of ES-SCLC.

The results showed that, compared to chemotherapy alone, toripalimab in combination with chemotherapy for the first-line treatment of ES-SCLC could significantly prolong the PFS and OS of patients. The safety profile of toripalimab was similar to previous studies, and no new safety signals were identified. Detailed data will be presented at an upcoming international academic conference.

“SCLC presents with less noticeable early symptoms, and due to its rapid tumor proliferation and high malignancy, many patients are already late-stage or have systemic metastasis at the time of their initial diagnosis,” said Professor Ying CHENG of Jilin Cancer Hospital. “For those diagnosed with ES-SCLC, their average survival time is only about a year. However, EXTENTORCH has successfully confirmed that combining toripalimab with chemotherapy as a first-line treatment for ES-SCLC can significantly improve patients’ PFS and OS. These results may offer a broader range of more effective treatment options for ES-SCLC patients.”

“It was my great pleasure today to witness the successful sNDA submission for toripalimab’s 10^th indication,” said Dr. Jianjun ZOU, the Global Research and Development President of Junshi Biosciences. “Since its clinical approval in late 2015, toripalimab has been addressing the unmet medical needs of patients in China and worldwide. Over 40 registered clinical trials have been conducted to further investigate toripalimab, which has continued to demonstrate stable and powerful anti-tumor activity across various tumor types. In lung cancer alone, toripalimab has been involved in 3 successful large-scale phase 3 clinical trials encompassing diverse subtypes and stages of disease progression. We will work diligently on marketing applications relevant to the indication and strive to help more cancer patients with our innovative therapies!”