Time to discard old concepts once and for all
Prior exposure to cytokine inhibitors
Parenchymal lung disease and pulmonary hypertension complicating sJIA was first highlighted in a series of 25 cases reported by Kimura et al. in 2013. These authors raised the question of the possible relationship of this and the increasing use of anti–IL-1 and anti–IL-6 biologics in sJIA treatment.
Following this lead, Dr. Mellins started looking into this new clinical entity in 2015. By then, she was identifying some past cases by autopsy records and current cases by clinical presentation. She saw a dramatic shift over time. From 2002 to 2011, she identified four cases, half of which had been exposed to IL-1/IL-6 inhibitors. From 2012 to 2014, eight new cases came to light, and seven had been exposed to those drugs. The crescendo continued from 2015 to 2017. During those years, Dr. Mellins and associates identified 10 new patients, 7 of whom had taken interleukin-inhibiting biologics. The mean time from initial drug exposure to diagnosis was a little more than 1 year.
An adjusted analysis comparing sJIA-LD patients and sJIA patients without lung disease didn’t find any significant difference in drug exposure. However, children with lung disease were more likely to have taken anakinra before the symptoms developed. Additionally, the symptoms of clubbing, abdominal pain, eosinophilia, hyperenhancing lymph nodes, and pulmonary alveolar proteinosis were much more common in children who’d taken the drugs.
The authors pointed out that this association does not prove causality and is confounded by the concomitant reduction in glucocorticoids with IL-1/IL-6 inhibitor use. And the vast majority of children with sJIA take cytokine inhibitors with no problems.
“Possibly, drug exposure may promote lung disease in a subset of children with sJIA, among the substantially larger group of patients who derive striking benefit from these drugs,” Dr. Mellins said, “Importantly, our results argue strongly for more investigation into a possible connection.”
Survival
After a mean follow-up of 1.7 years, the Stanford group saw high mortality. The 5-year survival rate translated to a mortality incidence of 159 deaths per 1,000 person-years, compared with 3.9 per 1,000 person-years in a historical cohort of sJIA patients who required biologic therapy.
Diffuse lung disease was the cause of 12 deaths; 5 of these patients also had macrophage activation syndrome at the time of death. Factors significantly associated with shortened survival included male sex, hypoxia at presentation, and neutrophilic bronchoalveolar lavage with more than 10 times the normal count. In an adjusted analysis, all of these variables fell out. However, none of the children with excessively high neutrophilic bronchoalveolar lavage survived.
Does it affect adults?
Could adults be experiencing the same disorder? There is some evidence to support it: The Food and Drug Administration adverse event website shows alveolar disease or pulmonary hypertension in 39 adults who have been exposed to IL-1 or IL-6 inhibition. Of these, 23 had RA, 11 adult-onset Still’s disease, and 5 unclassified rheumatic disorders.
The research groups were supported by grants from the sJIA Foundation, the Lucile Packard Foundation for Children’s Health, Stanford graduate fellowships, the Life Sciences Research Foundation, the Bill & Melinda Gates Foundation, Cincinnati Children’s Research Foundation, the Childhood Arthritis and Rheumatology Research Alliance, the Arthritis Foundation, and the National Institutes of Health. Many authors on both papers reported financial ties to Genentech, which markets tocilizumab, and other pharmaceutical companies*. Dr. Nigrovic reported receiving consulting fees and research support from Novartis and other companies.
SOURCES: Saper V et al. Ann Rheum Dis. 2019 Sep 27. doi: 10.1136/annrheumdis-2019-216040; Schulert GS et al. Arthritis Rheumatol. 2019 Aug 5. doi: 10.1002/art.41073; Nigrovic PA. Arthritis Rheumatol. 2019 Aug 7. doi: 10.1002/art.41071.
*Correction, 10/12/19: An earlier version of this article misstated the manufacturer of Actemra (tocilizumab).
This article was updated 10/14/19.