Topical Pan-JAK Inhibitor LNK01004 Shows Promising Efficacy and Safety in Phase 2 AD Trial

Lynk Pharmaceuticals has announced encouraging results from its phase 2 clinical trial evaluating LNK01004, a skin-restricted soft pan-JAK inhibitor formulated as a topical ointment, in adults with moderate-to-severe atopic dermatitis (AD).¹ The findings highlight both meaningful clinical activity and a favorable safety profile, positioning LNK01004 as a potential non-systemic therapeutic option for patients requiring more intensive disease management.

Trial Design

The randomized, double-blind, vehicle-controlled trial enrolled 75 adult patients with moderate-to-severe AD, defined by a validated Investigator’s Global Assessment for Atopic Dermatitis (vIGA-AD) score of 3 or 4 and 5–35% body surface area (BSA) involvement. Participants were randomized 1:1:1 to receive LNK01004 ointment at concentrations of 0.3% or 1.0%, or vehicle ointment, applied twice daily for 8 weeks. Positive topline data for this trial was first announced in 2023.²

“Controlling itch and clearing skin lesions are the most urgent treatment needs for AD patients,” Professor Jianzhong Zhang, the principal investigator of the study, the 13th director in the Dermatology Division of the Chinese Medical Association, and director of the Dermatology Department at Peking University People's Hospital, said in an earlier news release. "The results of this study suggest that LNK01001 has the potential to provide clinical benefits to adult patients with moderate to severe AD. We will continue to conduct further research and look forward to validating the efficacy and safety of LNK01001 in phase 3 clinical trials to benefit more patients."²

Efficacy Outcomes

At week 8, both concentrations of LNK01004 demonstrated superior efficacy compared with vehicle, with the most pronounced responses observed in patients with higher baseline BSA involvement. Among patients with BSA ≥10%, EASI-75 response rates were 61.1% for the 0.3% group and 46.2% for the 1.0% group, compared with 20% for vehicle. Similarly, vIGA-AD response rates (0/1 with ≥2-point improvement) were 44.4% and 38.5% for the 0.3% and 1.0% groups, respectively, versus 10% for vehicle.

Notably, patients with BSA involvement ≥20% exhibited even greater relative benefit, reinforcing the potential clinical value of LNK01004 in populations with more extensive disease. These results suggest that the drug’s skin-restricted mechanism—designed to concentrate activity in affected tissue while minimizing systemic exposure—may offer a targeted approach to controlling inflammation in severe AD.

Safety and Pharmacokinetics

LNK01004 was well tolerated, with no treatment-related serious adverse events reported. All treatment-related adverse events were mild or moderate (Grade 1–2). Pharmacokinetic analyses revealed low systemic exposure, with mean Cmax values of 0.06 ng/mL for the 0.3% dose and 0.15 ng/mL for the 1.0% dose. These findings align with the drug’s “soft” design: it is engineered to act locally within the skin and be rapidly inactivated upon entering systemic circulation, reducing the risk of systemic JAK-related immunosuppressive effects.

Expert Commentary

Henry Wu, MD, Chief Development Officer of Lynk Pharmaceuticals, emphasized the significance of these results. "The phase 2 results for LNK01004 demonstrated encouraging efficacy and favorable safety in patients with moderate-to-severe atopic dermatitis, particularly in those with larger affected areas or more severe disease,” he said. “These findings highlight LNK01004 as a promising topical JAK inhibitor and underscore its potential clinical value in dermatologic indications.”¹

Zhao-Kui (ZK) Wan, PhD, Chairman and CEO of Lynk Pharmaceuticals, echoed these statements. "LNK01004, as a topical formulation, no systemic immunosuppression–related adverse reactions were observed in clinical studies, demonstrating good safety and compliance, as well as improvement in patients' quality of life. We will continue advancing its clinical development in AD and other indications to bring more innovative treatment options to patients with dermatological diseases worldwide,” he concluded.¹

References

1. Lynk Pharmaceuticals Announces Key Phase II Clinical Results of LNK01004 for the Treatment of Patients with Moderate-to-Severe Atopic Dermatitis. News release. Published November 19, 2025. Accessed November 28, 2025. https://www.prnewswire.com/news-releases/lynk-pharmaceuticals-announces-key-phase-ii-clinical-results-of-lnk01004-for-the-treatment-of-patients-with-moderate-to-severe-atopic-dermatitis-302618650.html

2. Lynk Pharmaceuticals announced positive topline data from phase II clinical trial of LNK01001 in the treatment of atopic dermatitis. News release. Published August 9, 2023. Accessed November 28, 2025. https://prnmedia.prnewswire.com/news-releases/lynk-pharmaceuticals-announced-positive-topline-data-from-phase-ii-clinical-trial-of-lnk01001-in-the-treatment-of-atopic-dermatitis-301895890.html