Data from the phase III VALOR trial indicate that the TYK2–JAK1 inhibitor brepocitinib could improve muscle and skin symptoms and reduce glucocorticoid use in patients with dermatomyositis. The clinical benefits of the treatment were apparent as early as week 4 and were sustained over the 52-week double-blind trial period.

“Brepocitinib is a first-in-class, selective TYK2–JAK1 inhibitor, a mechanistic profile that maps closely to pathways strongly implicated in dermatomyositis biology,” explains Ruth Ann Vleugels, co-corresponding author of the paper reporting the results. By inhibiting TYK2 and JAK1, brepocitinib targets the signalling pathways of several cytokines linked to the immunopathogenesis of dermatomyositis, including type I and II interferons, IL-6, IL-12 and IL-23.