LONDON — For patients with juvenile dermatomyositis, a rare autoimmune disease that affects children, anti–tumor necrosis factor (TNF) agents appear to be an exciting new treatment option, results from a large observational cohort study suggest.
"We found that there was a striking reduction in all outcome measures in terms of skin and muscle involvement and that anti-TNF agents seem to be well tolerated in children," said Raquel Campanilho-Marques, MD, from the Lisbon Academic Medical Center in Portugal.
Dr Campanilho-Marques presented the findings here at the European League Against Rheumatism (EULAR) Congress 2016.
"Data from the literature suggested that TNF-alpha plays an important role in idiopathic inflammatory myopathies. For that reason, we felt that TNF-alpha inhibitors could be a potential target for the treatment of this disease," Dr Campanilho-Marques told Medscape Medical News.
The study was conducted at the Institute of Child Health at University College London, in collaboration with Great Ormond Street Hospital for Children NHS Trust in London, United Kingdom, where Dr Campanilho-Marques was doing her fellowship.
More than 500 children with juvenile dermatomyositis are being treated at the Institute of Child Health, despite the fact that the disease occurs annually in only two or three children per million, she reported. The median age of onset is approximately 7 years, but it can occur in children younger than 4 years.
Dr Campanilho-Marques and her colleagues analyzed data from the Juvenile Dermatomyositis Cohort and Biomarker Study and Repository for children who met the Bohan-Peter diagnostic criteria for dermatomyositis (N Engl J Med. 1975;292:344-347 and 403-407).
The team identified 66 children who were receiving TNF-alpha inhibitors, mostly infliximab, and who had received treatment for at least 3 months. The majority of the children were also receiving background prednisolone, which has long been the standard of care, and methotrexate azathioprine, hydroxychloroquine, or a combination of these agents.
The mean age at diagnosis was 7.3 years, and the mean duration of disease at the start of anti-TNF therapy was 3.4 years. The mean duration of anti-TNF therapy was 2.7 years.
The team assessed muscle symptoms with the Childhood Myositis Assessment Scale (CMAS) and the Manual Muscle Testing (MMT8). In addition, they administered the Physician Global Assessment (PGA), measured levels of muscle enzymes, and assessed skin involvement with a modified disease activity score.
"Muscle and skin involvement significantly improved," Dr Campanilho-Marques reported, "as did measures of global disease activity."
Table. Outcomes Before and After the Initiation of an Anti-TNF Blocker
| Measure | Before Treatment | After Treatment | P Value |
| Median CMAS score | 45.50 | 53.00 | <.0001 |
| Median MMT8 score | 74.00 | 79.00 | =.0097 |
| Modified disease activity score | 4.00 | 1.00 | <.0001 |
| PGA disease activity score | 2.91 | 0.50 | <.0001 |
Reduction in Steroids
Anti-TNF agents allowed physicians to reduce prednisolone doses from a median of 6 mg prior to initiation to 2.5 mg after 12 months of treatment (P < .0001).
During the treatment interval, approximately one quarter of the patients were switched to adalimumab, another anti-TNF agent. In 62% of these cases, the switch was the result of a lack of efficacy.
Route of administration was the reason for the switch in slightly more than 12% of the patients.
However, one quarter of the switches were related to adverse events. Of the 21 adverse reactions reported, seven were considered serious (anaphylactic reactions to infliximab infusion). More than three quarters of the remaining adverse reactions were related to infection.
"Juvenile dermatomyositis can be a very debilitating disease, with high morbidity and mortality rates if not properly treated," Dr Campanilho-Marques explained.
"We desperately need more options to treat it, and we were very pleased to see that the anti-TNF agents really helped these patients."
Mixed Results in Adults
The field has moved away from the idea that anti-TNF therapy could be helpful in dermatomyositis, because in adult forms of the disease, study results have been extremely mixed, said Lisa Rider MD, deputy chief, Environmental Autoimmunity Group, National Institute of Environmental Health Sciences, National Institutes of Health, Bethesda, Maryland.
"That's a helpful point about this study because the data here are more striking: there is clearly benefit from anti-TNF treatment in this treatment-refractory group of juvenile dermatomyositis patients for both muscle and skin," she told Medscape Medical News.
Dr Rider also pointed out that she and her colleagues are currently evaluating how successful pediatric rheumatologists are in treating juvenile dermatomyositis.
"We used to think that juvenile dermatomyositis patients largely got off treatment in a few years' time, but in our large referral cohort, we're finding that not to be the case," she said. "Patients are needing long-term treatment, so we do need new treatments to better manage this disease."
Dr Campanilho-Marques and Dr Rider have disclosed no relevant financial relationships.
European League Against Rheumatism (EULAR) Congress 2016: Abstract OP0221. Presented June 10, 2016.
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Cite this: TNF Blockers Treat Muscles, Skin in Juvenile Dermatomyositis - Medscape - Jun 16, 2016.
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