Lynk Pharmaceuticals Announces Completion of Patient Enrollment in Phase III Clinical Trial of Zemprocitinib for Ankylosing Spondylitis

HANGZHOU, China and SHANGHAI and BOSTON, July 15, 2026 /PRNewswire/ -- Lynk Pharmaceuticals Co., Ltd. ("Lynk Pharmaceuticals"), a clinical-stage innovative drug development company focused on immune and inflammatory diseases, today announced that patient enrollment was completed on July 9 in the Phase III clinical trial evaluating its core product zemprocitinib capsules for the treatment of active ankylosing spondylitis (AS). The successful completion of enrollment marks an important milestone in the development of zemprocitinib for ankylosing spondylitis and brings the program one step closer to providing a new oral treatment option for patients with this chronic inflammatory disease.

Study Design and Progress

The Phase III study is a randomized, double-blind, placebo-controlled, multicenter clinical trial designed to evaluate the efficacy and safety of zemprocitinib in patients with active ankylosing spondylitis. The primary endpoint is the proportion of patients achieving an Assessment of SpondyloArthritis international Society 40% response (ASAS40) at Week 16. A total of 352 patients have now been enrolled, and the study is proceeding as planned with ongoing treatment, follow-up, and data collection.

Ankylosing spondylitis is a chronic, progressive inflammatory disease that primarily affects the spine and sacroiliac joints, leading to pain, stiffness, and impaired physical function, significantly affecting patients' quality of life. Despite available therapies such as nonsteroidal anti-inflammatory drugs and biologics, a substantial proportion of patients fail to achieve adequate disease control or have concerns regarding long-term treatment safety, leaving significant unmet medical needs.

Differentiated Profile of Zemprocitinib

Zemprocitinib is a second-generation selective JAK1 inhibitor with the potential to become a best-in-class therapy. Compared with first-generation JAK inhibitors with lower selectivity, zemprocitinib's higher selectivity for JAK1 has the potential to maintain efficacy while reducing safety risks associated with off-target inhibition.

Preclinical and clinical studies have shown that zemprocitinib potently and dose-dependently inhibits multiple JAK1-related inflammatory signaling pathways, supporting its therapeutic potential across multiple indications. Previously reported 24-week Phase III data in rheumatoid arthritis and 52-week Phase III data in atopic dermatitis demonstrated that zemprocitinib achieved the primary and key secondary endpoints, while showing rapid and sustained efficacy together with a favorable safety and tolerability profile. Rates of serious adverse events and adverse events of special interest (AESIs) were comparable to placebo, and laboratory safety parameters were also favorable.

Dr. Henry Wu, who is responsible for overseeing and directing the overall clinical research program, said: "Based on the encouraging efficacy and favorable safety profile demonstrated by zemprocitinib in Phase III studies in rheumatoid arthritis and atopic dermatitis, we look forward to further evaluating its efficacy and safety in patients with ankylosing spondylitis and generating robust clinical evidence to support subsequent regulatory submissions."

Dr. Zhao-Kui (ZK) Wan, Founder, Chairman and Chief Executive Officer of Lynk Pharmaceuticals, said: "The completion of patient enrollment in the Phase III study for ankylosing spondylitis represents another important milestone in the development of zemprocitinib. We look forward to further validating the clinical value of zemprocitinib in this indication and quickly bringing a safer and more effective oral treatment option to patients."

About Lynk Pharmaceuticals

Lynk Pharmaceuticals is a clinical-stage innovative drug company focused on autoimmune and inflammatory diseases, committed to addressing unmet clinical needs through first-in-class innovation, developing differentiated small-molecule therapies, and providing superior oral alternatives to biologics. The company was founded by senior R&D leaders from Pfizer, MSD, and Johnson & Johnson, focusing on the JAK-STAT and expanding to TYK2 signaling pathways, and mastering targeted protein degradation.

The company combines AI-assisted drug design, comprehensive biological evaluation, and protein degradation technologies into an integrated innovative R&D platform spanning target discovery, molecular design, translational research, and clinical development to advance differentiated therapies for patients worldwide. To date, Lynk Pharmaceuticals has successfully developed and progressed multiple Class 1 new drug candidates and advanced multiple pipeline programs through internal research and development as well as global partnerships.

Forward-Looking Statements

This press release contains certain forward-looking statements. These statements relate to future events and may include, but are not limited to, expectations, plans, or objectives regarding the Company's future research and development programs, business development, collaboration arrangements, and other future matters.

Because future events are subject to numerous uncertainties, these forward-looking statements are based on the Company's management's current information, views, assumptions, estimates, and judgments at the time such statements are made. They do not constitute guarantees of future performance, development, or results. Actual events, outcomes, or developments may differ materially from those expressed or implied by such forward-looking statements.

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SOURCE Lynk Pharmaceuticals Co., Ltd.