Could JAK Inhibitors Treat Dermatomyositis?

JAKinh had a positive, sustained effect in most patients with dermatomyositis (DM).

The use of Janus kinase (JAK) inhibitors (JAKinh) for the treatment of dermatomyositis (DM) found support in results from a pilot study, published in the Journal of the American Academy of Dermatology.

Dermatomyositis is a difficult-to-treat dermatologic disorder and the availability of effective management strategies remains a gap in care. There has been increasing evidence indicating that the interferon pathway may play a key role in the disease, which may suggest that JAKinh may have beneficial effects.

This open-label, single center study was conducted in France. Medical records were reviewed for patients with DM (N=16) who received JAKinh for 3 or more months. The primary outcome was clinical cutaneous improvement, defined as Cutaneous Disease Area and Severity Index (CDASI) decrease of 5 or more points compared with baseline.

The JAKinh regimens in this study included 4 mg daily baricitinib (n=6), 2 mg daily baricitinib (n=6), 30 mg daily ruxolitinib (n=2), and 20 mg daily ruxolitinib (n=2).

In this study JAKinh was associated with a beneficial effect in most patients, mainly within the first 3 months of treatment, and was sustained at long-term follow-up.

The patients were 18 to 84 years of age, all but 1 of the patients were women, they had been diagnosed with DM between 0.1 and 37 years previously, all but 1 patient had received previous DM treatments, 88% had active cutaneous disease activity, 56% had active muscle disease, and 44% had  both.

At baseline, the average CDASI score was 27±13 points. At the 3-month follow-up, CDASI scores had decreased to 14±11 (P £.05) and continued to decrease to 8±6 (P £.05) at month 6 and 5±4 (P £.05) at the final follow-up (mean, 1.8 years).

The average 8-muscle Manual Muscle Test (MMT8) score at baseline was 120±31, which remained unchanged at follow-up.

At baseline, 13 patients were receiving more than 5 mg daily prednisone and 5 were receiving intravenous immunoglobulins. At follow-up, 67% of patients were able to decrease their prednisone dose to 5 mg or fewer per day and 4 of the 5 intravenous immunoglobulin recipients had discontinued treatment.

At the final follow-up, 13 patients were still receiving JAKinh therapy, 1 patient had died from progressive interstitial lung disease, and 2 patients had relapsed muscle disease. Adverse events of a thromboembolic event (n=1) and febrile neutropenia (n=1) occurred. Researchers noted that no cancer diagnoses occurred during the study period.

 “In this study JAKinh was associated with a beneficial effect in most patients, mainly within the first 3 months of treatment, and was sustained at long-term follow-up,” the study authors wrote. They continued, “This study supports the efficacy of JAKinh in the management of cutaneous DM. We recently started a randomized controlled trial (NCT04972760) to further assess JAkinh efficacy and long-term safety in DM patients.”

References:

Landon-Cardinal O, Guillaume-Jugnot O, Toquet S, et al. JAK inhibitors for the treatment of adult dermatomyositis: a pilot study. J Am Acad Dermatol. 2022;S0190-9622(22)02983-8. doi:10.1016/j.jaad.2022.10.055