Introduction: Muscle and skin involvement are well defined in dermatomyositis but
other symptoms contribute significantly to the disease burden and their treatment
is not well characterized. This post hoc analysis of ProDERM assessed the effect of
intravenous immunoglobulin (IVIg) treatment on other manifestations of dermatomyositis
beyond muscular and cutaneous involvement. Methods: ProDERM was a randomized, placebo-controlled
study. For weeks 0-16, patients with dermatomyositis received 2.0 g/kg IVIg (Octagam,
10%) or placebo every 4 weeks. Eligible patients entered the open-label extension,
where all received IVIg to week 40. Pulmonary, skeletal, constitutional, gastrointestinal,
and cardiovascular disease activity was assessed using the myositis disease activity
assessment tool, comprising a visual analog scale (VAS; 0-10 cm) and myositis intention-to-treat
activity index. Results: Of 95 patients enrolled, 47 received IVIg and 48 received
placebo to week 16. At baseline, 37.9% of patients experienced pulmonary, 64.2% experienced
skeletal, 76.8% experienced constitutional, 33.7% experienced gastrointestinal, and
15.8% experienced cardiovascular involvement (VAS > 0.5). Among these patients, for
those on IVIg, the following mean VAS scores decreased from baseline to week 16: pulmonary
(37.7%; P = 0.001), skeletal (52.6%; P < 0.001), constitutional (44.4%; P < 0.001),
and gastrointestinal (49.2%; P = 0.005). No corresponding improvement was seen with
placebo except for constitutional VAS. With IVIg, the proportions of patients with
arthritis (36.2 to 17.8%; P = 0.01), arthralgia (68.1 to 0.0%; P < 0.001), and fatigue
(68.1 to 3.3%; P = 0.008) decreased from baseline to week 16. In the combined cohort,
the proportions of patients with dysphonia (20.0 to 8.1%; P = 0.04), arthralgia (66.3
to 39.8%; P < 0.001), weight loss (10.5 to 3.4%; P = 0.04), fatigue (75.8 to 50.0%;
P < 0.001), and dysphagia (40.0 to 18.4%; P < 0.001) decreased from baseline to week
40. Conclusion: IVIg was effective in treating pulmonary, skeletal, constitutional,
and gastrointestinal manifestations of dermatomyositis. We advocate exploring IVIg
as treatment for dermatomyositis, beyond muscle and skin manifestations.
