Lichen planus: a future indication for baricitinib?

In phase 2, baricitinib demonstrated a response rate of over 90% without raising safety concerns in a first-in-human trial. Although too early to tell, the JAK inhibitor shows promise as an upcoming treatment for lichen planus (LP).

“Interferon is critical in LP,” Ms Angelina Hwang (Mayo Clinic College of Medicine, AZ, USA) explained in her introduction of the first-in-human phase 2 study (NCT05188521) of baricitinib in LP [1]. This knowledge of LP pathophysiology led to the rationale for the study to examine the JAK1/2 inhibitor that suppresses the production of IFN-γ. Currently, there is still a great unmet need for disease-specific medication in LP, as treatment options only include drugs like corticosteroids, topical calcineurin inhibitors, and phototherapy.

Ms Hwang presented the interim analysis of the open-label study, which included data on 12 patients with LP, 41.7% of whom had hypertrophic disease. The mean age of the participants was 63.6 years, most were women (91.7%), and all participants but 1 had failed previous treatments. Participants received 2 mg of baricitinib.

The primary endpoint of a Physician Global Assessment (PGA) response at week 16 was defined as reaching a PGA score of 0-3, with 0 standing for clear skin/ no evidence of disease, while a score of 4 or 5 was deemed nonresponsive. The primary endpoint was met  by 90.9% of the participants. At this point, 45.5% presented a PGA of 0 (i.e. clear skin). Responses were observed as of week 1 in 37.5% of participants. At weeks 12 and 20, the response rate was 100%. Moreover, significant ameliorations were also found in all secondary endpoints that included pruritus, body surface area, and Skindex-16, the latter measuring the effects of skin disease on the quality of life. Out of 12 adverse events, only 1 case of neutropenia was deemed treatment-related, but not serious in severity. All other adverse events were not adjudicated to the baricitinib treatment.

These promising, initial results on baricitinib at a dose of 2 mg for LP could justify further evaluation of the agent in randomised-controlled trials.

1. Hwang A. Baricitinib in the treatment of cutaneous lichen planus – interim analysis. S025, AAD 2023 Annual Meeting, 17–21 March, New Orleans, USA.