Improvement in Dermatomyositis Observed in Patients Given Intravenous Immune Globulin

Rohit Aggarwal, MD

A recent study found that a significant number of patients given intravenous immune globulin (IVIG) for dermatomyositis saw improvement.

Prior to the study, the use of IVIG had not been extensively evaluated in patients with dermatomyositis, the rare autoimmune disorder. The disorder is known to involve skin and muscle inflammation followed by rashes and even muscle weakness.

The study, led by Rohit Aggarwal, MD, Professor of Medicine at University of Pittsburgh's Division of Rheumatology, sought to expand upon the use of IVIG in dermatomyositis patients as the treatment is often used only as a third-line therapy alongside immunosuppressive drugs.

“In this 16-week, randomized, controlled trial of four infusion cycles of IVIG, the percentage of patients with dermatomyositis who had at least minimal improvement according to a composite score of disease activity was significantly greater with IVIG than with placebo; however, IVIG was associated with adverse infusion events and thromboembolism,” Aggarwal and colleagues wrote.

Research and Methods

The investigators used a randomized, placebo-controlled trial, recruiting patients dealing with active dermatomyositis. Inclusion criteria for patients recruited for the trial included being within the ages 18 to 80 and diagnoses of definite or probable active dermatomyositis. A total of 95 patients were randomized during the trial.

The researchers assigned 47 participants to the IVIG arm and 48 to the placebo arm. They were either given a placebo or treated with an IVIG dose of 2.0 g per kilogram of bodyweight every 4 weeks for 16 weeks. Those who were given a placebo and those without confirmed clinical deterioration while being treated with IVIG were permitted to enter an open-label extension phase for 24 more weeks.

The research team’s primary endpoint was a Total Improvement Score (TIS) score of 20—which would suggest minimal improvement—by week 16 of the trial, in addition to having no confirmed deterioration by the same time frame. The investigators’ secondary endpoints included patients having at least moderate TIS score improvement (≥40), a major TIS score improvement (≥60), and a Cutaneous Dermatomyositis Disease Area and Severity Index score change.

Study Results

The investigators found that by week 16, 37 of the participants in the IVIG group (79%) and 21 of the placebo group (44%) reported a TIS score of at least 20 (difference, 35 percentage points; 95% CI, 17 to 53; P<0.001).

The secondary endpoints of at least moderate improvement and major improvement were assessed and found to align with the direction of the primary endpoint analysis results. The only notable difference referenced by the investigators was the change in participants’ creatine kinase level—an individual core TIS measure—which did not differ significantly between both arms of the study.

Additionally, the investigators noted that over 40 weeks, there were 282 treatment-related adverse events in the IVIG arm. These included reports of headaches for 42% of participants, pyrexia for 19%, and nausea for 16%. They found 9 serious adverse events occurred that were believed to be IVIG-related, including 6 thromboembolic events.

“In this 16-week trial involving adults with dermatomyositis, the percentage of patients with a response of at least minimal improvement based on a composite score of disease activity was significantly greater among those who received IVIG than among those who received placebo,” they wrote. “IVIG was associated with adverse events, including thromboembolism.”

This study, “Trial of Intravenous Immune Globulin in Dermatomyositis,” was published online for the The New England Journal of Medicine.