Xiaolexin® (R&D code: QX001S/HDM3001) is a biosimilar to the originator product Stelara® (Ustekinumab Injection). It is the first product in Qianxin Biologics’ R&D pipeline to receive marketing approval, and also the first ustekinumab injection biosimilar approved in China. Initially developed independently by Qianxin Biologics, QX001S entered into a collaboration agreement in August 2020 with Hangzhou Sino-US Huadong Pharmaceutical Co., Ltd. (hereinafter referred to as “Sino-US Huadong”), a subsidiary of East China Pharmaceutical Group Co., Ltd. (stock code: 000963.SZ). Under this collaboration, both parties jointly advanced the Phase III clinical trials for QX001S. Sino-US Huadong, as the marketing authorization holder, is responsible for commercialization in mainland China, while Jiangsu Saifushi Biotechnology Co., Ltd. (a wholly-owned subsidiary of Qianxin Biologics) is tasked with product manufacturing and supply.

Since its global launch 16 years ago, ustekinumab injection has accumulated extensive clinical experience through numerous clinical trials and real-world studies targeting psoriasis. Its mechanism of action involves blocking the binding of the shared p40 subunit of IL-12 and IL-23 to the IL-12Rβ1 receptor protein on the surface of target cells, thereby inhibiting IL-12- and IL-23-mediated signal transduction and the cytokine cascade. IL-12 and IL-23 are two naturally occurring cytokines that play a critical role in immune-mediated inflammatory diseases. Ustekinumab injection is administered initially as a 45-mg subcutaneous injection, followed by the same dose every 12 weeks starting four weeks later. During the maintenance phase, only four injections are required per year—making it one of the biologic therapies for psoriasis with the fewest injections currently available in clinical practice. It offers high convenience, excellent safety and tolerability, and durable efficacy. According to Johnson & Johnson’s 2023 annual report, Stelara® generated global sales of US$10.858 billion (approximately RMB 76.729 billion) in 2023. Data from Menet show that in 2023, Cosentyx® achieved sales of RMB 1.322 billion in China.

Psoriasis is a chronic, recurrent, inflammatory disease that primarily affects the skin and joints. Currently, there is no cure for psoriasis, and treatment must be ongoing—often for life. Plaque-type psoriasis accounts for approximately 80% to 90% of all psoriasis patients and is the most common form of the disease. Today, psoriasis treatment in China has entered the era of biologic therapies. Compared with traditional treatments, biologics offer significant advantages in terms of onset time, efficacy, safety, and treatment duration. They have played a positive and effective role in the treatment of severe, refractory, and special types of psoriasis. Among these biologics, interleukin inhibitors demonstrate superior efficacy and safety compared to TNF-α inhibitors—for example, IL-12/23 inhibitors, IL-17A inhibitors, and IL-23p19 inhibitors.