SAILEXIN is a biosimilar drug of originator-branded product of Stelara® (Ustekinumab Injection). It is the our first product approved for marketing with BLA approval in the Company’s R&D pipeline, and it is also the first biosimilar drug of Ustekinumab Injection approved in China. QX001S was initially developed independently by the Company. In August 2020, the Company reached a collaboration with Zhongmei Huadong to jointly advance the Phase III clinical trial of QX001S. Zhongmei Huadong, as the marketing authorization holder (MAH), is in charge of product commercialization in Mainland China, while Cellularforce is in charge of production and supply of the product.

Ustekinumab Injection has been marketed globally for 16 years, and has accumulated extensive application experience in various clinical trials and real-world studies for psoriasis. Its mechanism of action is to block the combination of p40 subunit, shared by IL-12 and IL-23, to the IL-12Rβ1 receptor protein on the surface of target cells, thus inhibiting the signaling and cytokine cascade reaction mediated by IL-12 and IL-23. IL-12 and IL-23 are two natural cytokines, which play a key role in immune-mediated inflammatory diseases. The injection method for Ustekinumab Injection is an initial 45 mg subcutaneous injection, followed by the same dose after 4 weeks and every 12 weeks thereafter, and only four injections are needed per year over maintenance period, making it one of the biologics with the fewest number of injections for treating psoriasis currently available in clinical practice, and offering high convenience of use, good safety and tolerability, and long-lasting efficacy. According to the 2023 annual report of Johnson & Johnson, the global sales of Stelara® in 2023 amounted to US$10.858 billion (approximately RMB76.729 billion). The data from Menet showed that the sales of Stelara® in China in 2023 were RMB1.322 billion.

Psoriasis is a chronic, recurrent, and inflammatory disease primarily affecting the skin and joint systems, which is currently incurable and requires long-term or even lifelong treatment, with plaque psoriasis being the most common type, accounting for approximately 80% to 90% of all psoriasis patients. At present, psoriasis treatment in China has entered the era of biologics, which have significant advantages over traditional treatment in terms of onset time, efficacy, safety, and treatment duration, and have played an active and effective role in treating severe, refractory, and special types of psoriasis. Among them, interleukin inhibitors have advantages in efficacy and safety compared to TNF-α inhibitors, such as IL-12/23 inhibitors, IL-17A inhibitors and IL-23p19 inhibitors.