In patients with inflammation and dermatomyositis (DM) widespread across the skin, treatment with baricitinib proved efficacious as early as 4 weeks after therapy began, according to study findings published in a letter in the British Journal of Dermatology.

Not much is known about how DM, an uncommon recurrent autoimmune disease, develops, and current treatment of DM is often ineffectual, the researchers noted. The recent discovery of type I interferon and interferon stimulated genes in DM patients suggests that blocking their Janus kinase (JAK) receptor signals would be an effective treatment. Researchers sought to treat patients with DM with baricitinib and investigate the results.

To accomplish this, they conducted a prospective study that involved 3 patients with adult DM. Patient 1 had been treated for DM for decades with mild success. Researchers said a current flareup “with violaceous erythema prone to the face, décolleté, neck and periungual area but normal muscle enzymes,” caused them to stop previous treatment and begin baricitinib 4 mg daily which resulted in complete regression of neck, facial, and periungual erythema within 5 months.


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Researchers noted, “Patient 2 had been suffering from anti-NXP2-antibody positive DM with severe muscle weakness, facial and abdominal erythema and an erythematous, painful and ulcerated sclerosing plaque in the lower back that was histologically confirmed as panniculitis.” Partial success with previous treatments including prednisolone, azathioprine, methotrexate, and IVIG infusions, were ineffectual treating the ulcerative panniculitis. Prednisolone and once a month IVIG infusions were continued along with baricitinib 4 mg daily, resolving the panniculitis in less than 5 months.

According to researchers, “Patient 3 was diagnosed with anti-MDA5-antibody positive DM with prominent and severe skin involvement,” without interstitial lung or muscle involvement. Limited success came with treatment of prednisolone, hydroxchloroquine, and methotrexate. Baricitinib treatment in Patient 3 resolved erythema and pain.

A patient reported labial herpes, otherwise baricitinib produced no serious side effects. Within 4 weeks of treatment with baricitinib, the Cutaneous Dermatomyositis Area and Severity Index version 2 and the Dermatology Life Quality Index indicated skin lesions showed recovery. In the same timeframe, blocking of the Janus kinases resulted in a measurable decrease of interferon stimulated genes.

Researchers concluded, “Our findings suggest a therapeutic benefit of the JAK inhibitor baricitinib in patients with adult DM,” with concomitant IVIG. Treatment with baricitinib to block the Janus kinase pathway may prove significant for patients with DM, including panniculitis inflammations, they believe.

Reference

Fischer K, Aringer M, Steininger J, et al. Improvement of cutaneous inflammation and panniculitis in dermatomyositis patients by the JAK-inhibitor baricitinib. Br J Dermatol. Published online March 23, 2022. doi:10.1111/bjd.21252