Lynk Pharmaceuticals Reports Positive Long-Term Phase III Results for Zemprocitinib in bDMARDs-Inadequate Responders with Moderate-to-Severe Rheumatoid Arthritis

HANGZHOU, China, SHANGHAI and BOSTON, Oct. 27, 2026 /PRNewswire/ -- Lynk Pharmaceuticals Co., Ltd. ("Lynk Pharmaceuticals"), a clinical-stage innovative drug development company focused on immune and inflammatory diseases, today announced positive long-term results from its pivotal Phase III clinical trial evaluating zemprocitinib, an investigational, selective, second-generation oral Janus kinase 1 (JAK1) inhibitor, in adult patients with moderate-to-severe active rheumatoid arthritis (RA) who had experienced inadequate response or intolerance to biologic disease-modifying antirheumatic drugs (bDMARDs).

The study met its primary endpoint of ACR20 response and key secondary endpoints at Week 24, demonstrating a statistically significant improvement with zemprocitinib versus placebo (p<0.0001). The Week 52 and Week 76 results further demonstrate continued improvements in all disease activity measurements and physical function during long-term treatment by Week 52 and sustained clinical responses through Week 76.

The double-blind, placebo-controlled Phase III study randomized 430 patients with moderate-to-severe active RA who had experienced an inadequate response or intolerance to prior bDMARDs, of whom 429 received at least one dose of study treatment. During the initial 24-week double-blind treatment period, patients received zemprocitinib 12 mg twice daily or placebo. Following this period, patients continued or transitioned to active treatment, with efficacy and safety assessed through Week 76.

Long-Term Sustained Efficacy Through Week 76

Among patients receiving continuous zemprocitinib treatment, ACR20, ACR50, and ACR70 response rates were 93.0%, 79.9%, and 52.5%, respectively, at Week 52. Responses remained at Week 76, with ACR20 and ACR50 rates of 91.8% and 80.5%, respectively, while ACR70 increased to 62.4%, demonstrating sustained ACR responses during long-term treatment.

Beyond ACR responses, zemprocitinib demonstrated sustained improvements across measures of disease activity, clinical remission and physical function through Week 76 (selected data are presented in the table below). At Week 52 and Week 76, among patients receiving continuous zemprocitinib treatment, 85.5% and 81.4% achieved low disease activity, respectively, defined as disease activity score (DAS28(CRP) ≤3.2). Based on the clinical disease activity index (CDAI), 81.5% and 81.0% of patients achieved low disease activity (CDAI ≤10), respectively. Improvements in physical function were also observed with 84.5% and 86.7% of patients achieving an improvement of at least 0.22 points in the health assessment questionnaire–disability index (HAQ-DI) from baseline at Week 52 and Week 76, respectively.

Selected efficacy results in patients receiving zemprocitinib 12 mg twice daily*:

Abbreviations: ACR, American College of Rheumatology; DAS28(CRP), Disease Activity Score 28 joints using C-reactive protein; CDAI, Clinical Disease Activity Index; HAQ-DI, Health Assessment Questionnaire–Disability Index.

*The 24-week results of efficacy and safety of zemprocitinib, in patients with rheumatoid arthritis from the Phase III COURAGE-RA study, were presented at the EULAR 2026 Congress (Abstract #OP0208). The EULAR 2026 abstract archive can be found here.

Patients who initially received placebo and switched to zemprocitinib at Week 24 also demonstrated increased clinical responses by Week 76, with ACR20, ACR50, and ACR70 response rates of 92.0%, 77.6%, and 55.1%, respectively, and achieved comparable responses in all other efficacy measurements comparing the patients with continuous dosing of zemprocitinib through Week 76. These findings complement the sustained ACR responses and provide a broader picture of long-term clinical outcomes in patients who had an inadequate response or intolerance to bDMARDs.

Long-Term Safety and Tolerability Through Week 76

During the initial 24-week double-blind, placebo-controlled period, the safety profile of zemprocitinib was generally comparable to that of placebo as reported at EULAR 2026*. The safety profile remained consistent through Week 76 with no new safety signals identified during long-term treatment. An additional observation was the cleaner lab parameters suggesting a cleaner profile of zemprocitinib, particularly with the increase in mean hemoglobin levels, rare incidence of grade 3 or 4 in ALT elevations and grade 3 in AST elevations, and the lack of reports on grade 4 AST elevations. These findings provide additional information on the safety and tolerability of zemprocitinib during long-term treatment in patients with RA.

Professor Xiaofeng Zeng, Principal Investigator of the study from Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, said: "Treatment options remain limited for patients with difficult-to-treat rheumatoid arthritis, leaving significant unmet medical needs. The long-term results from the Phase III clinical study of zemprocitinib are very encouraging. We observed favorable efficacy not only in patients who had an inadequate response or intolerance to bDMARDs, but also in patients who had an inadequate response to prior JAK inhibitor therapy. Zemprocitinib also demonstrated a favorable long-term safety profile. These findings suggest that zemprocitinib may offer an important additional treatment option for patients whose disease remains inadequately controlled with existing therapies."

"These long-term results represent an important milestone in the clinical development of zemprocitinib," said Dr. Zhao-Kui (ZK) Wan, Founder and CEO of Lynk Pharmaceuticals. "We are encouraged by the sustained clinical responses and safety profiles observed through Week 76 in patients who had an inadequate response or intolerance to prior biologic therapies. These findings add to the clinical evidence supporting the continued development of zemprocitinib for patients with rheumatoid arthritis."

"We are encouraged by the long-term efficacy and safety results from the Phase III study of zemprocitinib, which provide further clinical evidence of its best-in-class potential as a treatment option for patients with moderate-to-severe rheumatoid arthritis," said Dr. Aik Goh, Chief Medical Officer of Simcere Pharmaceutical Group. "As the commercialization partner for zemprocitinib in Greater China, we look forward to helping address the unmet treatment needs of patients with rheumatoid arthritis in China soon."

About Zemprocitinib

Zemprocitinib is an investigational, orally administered, selective second-generation JAK1 inhibitor discovered and developed by Lynk Pharmaceuticals. It is being developed for inflammatory and autoimmune diseases, including rheumatoid arthritis, atopic dermatitis, and ankylosing spondylitis. In addition to its RA development program, zemprocitinib has completed a pivotal Phase III study in atopic dermatitis, and a New Drug Application has been submitted to and accepted for review by China's National Medical Products Administration. A Phase III clinical program in ankylosing spondylitis is also underway. In March 2022, Lynk Pharmaceuticals entered into a commercialization collaboration with Simcere to jointly advance the commercialization of zemprocitinib for rheumatoid arthritis and ankylosing spondylitis in Greater China.

About the Phase III Rheumatoid Arthritis Study

The Phase III study was a randomized, double-blinded, placebo-controlled clinical trial evaluating the efficacy and safety of zemprocitinib in adults with moderate-to-severe active rheumatoid arthritis (RA) who had experienced an inadequate response or intolerance to prior biologic disease-modifying antirheumatic drugs (bDMARDs).

A total of 430 patients were randomized, of whom 429 received at least one dose of study treatment. The primary efficacy endpoint was the proportion of patients achieving an ACR20 response at Week 24. Key secondary endpoints included ACR50 response and DAS28(CRP) ≤3.2 at Week 24.

Following the initial 24-week double-blind treatment period, patients continued or transitioned to active treatment, with long-term efficacy and safety assessed through Week 76, followed by a 4-week safety follow-up period.

About Simcere:

Simcere Pharmaceutical Group Limited (02096) is a pharmaceutical company driven by innovation and focusing on four therapeutic areas including Neuroscience, Oncology, Autoimmune Diseases and Anti-infection. We proactively explore areas with significant unmet needs, and our mission is for patients, for life. Driven by our in-house R&D efforts and synergistic innovation, Simcere has established strategic cooperation partnerships with many innovative companies and research institutes.

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.

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SOURCE Lynk Pharmaceuticals Co., Ltd.