SAILEXIN（R&D code: QX001S/HDM3001）is a biosimilar drug of originator-branded product of Stelara® (Ustekinumab Injection). It is our first product approved for marketing with NDA 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 Hangzhou Zhongmei Huadong Pharmaceutical Co., Ltd. (Zhongmei Huadong) (Stock code: 000963.SZ), a wholly-owned subsidiary of Huadong Medicine, 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.

On March 3, 2025, Zhongmei Huadong received the Notice of Approval of Supplemental Application for Drugs from the National Medical Products Administration (NMPA), and the supplemental application for adding pediatric plaque psoriasis indication to SAILEXIN was approved. In addition, the supplemental application of SAILEXIN for Crohn’s disease was submitted by Zhongmei Huadong in February 2025, and is expected to be approved in the first half of 2026. Qyuns expects that SAILEXIN will provide an affordable treatment option for patients with psoriasis and Crohn’s disease. In 2025, the domestic sales of SAILEXIN (including value-added tax) approached RMB 300 million.