Lynk Pharmaceuticals has completed patient enrolment in its Phase III clinical trial of zemprocitinib capsules for active ankylosing spondylitis.
The study enrolled 352 patients and is now proceeding with treatment, follow-up and data collection. The randomised, double-blind, placebo-controlled, multicentre trial is designed to evaluate the efficacy and safety of zemprocitinib, with ASAS40 response at Week 16 as the primary endpoint.
Ankylosing spondylitis is a chronic inflammatory disease that primarily affects the spine and sacroiliac joints. Patients can experience pain, stiffness, impaired mobility and reduced quality of life, particularly when inflammation is not adequately controlled.
Current treatment options include nonsteroidal anti-inflammatory drugs and biologics, but not all patients achieve sufficient disease control. Some patients also face concerns around long-term safety, injection burden or access to biologic therapy. This creates demand for differentiated oral therapies that can offer efficacy with convenient administration.
Zemprocitinib is a second-generation selective JAK1 inhibitor. Lynk is positioning the candidate as a potential best-in-class therapy, with higher JAK1 selectivity intended to maintain efficacy while reducing safety risks linked to off-target inhibition.
Preclinical and clinical studies cited by the company indicate that zemprocitinib dose-dependently inhibits multiple JAK1-related inflammatory signalling pathways. This mechanism is relevant across several immune-mediated diseases where JAK-STAT signalling contributes to inflammation.
The ankylosing spondylitis programme builds on Lynk’s broader Phase III experience with zemprocitinib. Previously reported Phase III data in rheumatoid arthritis and atopic dermatitis met primary and key secondary endpoints, with rapid and sustained efficacy and a favourable safety and tolerability profile, according to the company.
