Background/Purpose: There are limited treatment options and no published double-blind randomized placebo-controlled trials for the treatment of skin manifestations of dermatomyositis (DM).  There is no information about patients enrolled in trials to study efficacy of treatments of skin involvement in DM.  Anabasum is a non-immunosuppressive, synthetic, preferential CB2 agonist that resolves inflammation in animal and human models of innate immune responses and reduces cytokine production by isolated mononuclear cells from DM patients. 

Methods:  A double-blind randomized placebo-controlled Phase 2 trial (JBT101-DM-001) with NIH as a collaborator was designed to test efficacy and safety of anabasum in adults with DM and refractory skin involvement.  The trial is done at a clinic specializing in skin involvement in DM which allows comparison of trial subjects to the general DM population at the same clinic.

Results:  Selection criteria included Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) activity score of ≥ 14, minimal active muscle involvement, failure or intolerance to hydroxychloroquine, and stable DM medications including immunosuppressive drugs.  Trial subjects (N = 22) and the general clinic population (N = 221) were predominantly middle-aged white, non-Hispanic women (Table 1).  Trial subjects had high skin disease activity compared to the clinic population and widespread use of immunosuppressive drugs (86%), including second-line immunosuppressive drugs (64%), with the mostly commonly used immunosuppressive drugs being antimalarial drugs (45%), mycophenolate (32%), methotrexate (23%), and systemic corticosteroids (23%).

Table 1. Comparison of demographics and disease characteristics between trial and overall DM population

Conclusion:  This is the first report of subject demographics and disease characteristics in a clinical trial focused on safety and efficacy in skin-predominant dermatomyositis.  Trial subjects had similar demographics to the overall DM clinic population. However, skin disease activity and patient-reported skin symptoms were greater in the trial subjects than in the overall DM clinic population, despite much higher use of second-line immunosuppressive medications.  Disease activity in trial subjects was much higher than required by inclusion criteria.  Combined, these data show that subjects enrolled in trials of treatment of skin involvement in DM may have disease that is more active and more difficult to control than the general population of patients, reminiscent of early efficacy trials in other systemic autoimmune diseases.