Rare Daily Staff

The U.S. Food and Drug Administration granted approval to Octapharma USA for Octagam 10% [Immune Globulin Intravenous (Human)], the first and only intravenous immunoglobulin to be indicated for the treatment of adult dermatomyositis, a rare immune-mediated inflammatory disease.

Dermatomyositis (DM) is a rare idiopathic autoimmune disorder of unknown cause affecting approximately 10 out of every million U.S. residents. Patients commonly suffer from skin rashes, chronic muscle inflammation and progressive muscle weakness, usually affecting adults in their late 40s to early 60s and children between the ages of 5 and 15. Complications include difficulty swallowing, aspiration pneumonia, breathing problems, and calcium deposits on muscles, skin, and connective tissues. DM patients have more than a three-fold higher risk of mortality compared with the matched general population.

The FDA approval is based on the results of ProDERM, a pivotal randomized clinical trial and the first study to evaluate the long-term efficacy and safety of intravenous immunoglobulin (IVIg) for adults with dermatomyositis. The prospective, double-blind, placebo-controlled phase 3 clinical trial enrolled 95 patients at 36 sites globally, including 17 sites in the United States, and is the largest study to evaluate intravenous immunoglobulin as a treatment option for dermatomyositis.

“The ProDERM study will have a significant impact on clinical practice because IVIg is likely to become an important treatment option for patients with dermatomyositis,” said Rohit Aggarwal, medical director of the Arthritis and Autoimmunity Center at the University of Pittsburgh School of Medicine and a member of the ProDERM study Steering Committee. “The study gives clinicians much more confidence in the efficacy and safety of intravenous immunoglobulin and provides valuable information about what type of patient is best suited for the treatment.”

The ProDerm clinical trial included an initial 16-week, double-blind, placebo-controlled period where patients were randomized to receive either high-dose Octagam 10% (2g/kg) or placebo every four weeks. The initial treatment period was followed by a 24-week open label extension phase. Patients were allowed to switch treatment if they deteriorated during the trial. Patient response to treatment was measured using the 2016 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) myositis response criteria.

During the initial 16-week phase, 78.7 percent of patients receiving Octagam 10% responded positively to treatment as compared to 43.8 percent of those receiving placebo. After switching to IVIg in the extension period, the placebo group attained a similar response rate at Week 40 as did the Octagam 10% treated patients at Week 16 (approximately 70 percent for minimal improvement). In line with the overall primary endpoint, secondary endpoints, including all the subcomponents of Total Improvement Score except muscle enzyme, and Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI), also showed statistically significant improvement under IVIg treatment compared to placebo. The safety and tolerability profile of IVIg was consistent with previously reported safety outcomes for IVIg administration.

Octagam 10% is also approved to treat chronic immune thrombocytopenic purpura in adults. As with most IVIg products, it carries a boxed warning for thrombosis and renal dysfunction.

Photo: Rohit Aggarwal, medical director of the Arthritis and Autoimmunity Center at the University of Pittsburgh School of Medicine and a member of the ProDERM study Steering Committee

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