Pulmonary manifestations of rheumatologic diseases

New developments related to lung complications in pediatric rheumatic disease

PURPOSE OF REVIEW

While substantial progress has been made understanding lung disease in adult patients with rheumatic disease, pediatric lung disease has not been well addressed. Several recent studies provide new insights into diagnosis, management and treatment of lung disease in children with rheumatic disease.

RECENT FINDINGS

Building on previous research, newly diagnosed patients may have abnormalities in pulmonary function tests and chest computed tomography imaging even when asymptomatic. New guidelines for screening for rheumatic-associated lung disease provide important recommendations for clinicians. New theories have been proposed about immunologic shifts leading to the development of lung disease in children with systemic juvenile idiopathic arthritis. Additionally, there are new antifibrotic agents that are being explored as treatments in pediatric patients with fibrotic lung diseases.

SUMMARY

Patients appear to have frequent lung function abnormalities while being clinically asymptomatic, emphasizing importance for rheumatologists to refer for pulmonary function tests and imaging at diagnosis. New advances are helping define optimal approaches to treatment of lung disease, including use of biologic agents and antifibrotic medicines for pediatric patients with rheumatologic diseases.

Nintedanib in children and adolescents with fibrosing interstitial lung diseases

BACKGROUND

Childhood interstitial lung disease (ILD) comprises a spectrum of rare ILDs affecting infants, children and adolescents. Nintedanib is a licensed treatment for pulmonary fibrosis in adults. The primary objectives of the InPedILD trial were to determine the dose-exposure and safety of nintedanib in children and adolescents with fibrosing ILD.

METHODS

Patients aged 6-17 years with fibrosing ILD on high-resolution computed tomography and clinically significant disease were randomised 2:1 to receive nintedanib or placebo for 24 weeks and then open-label nintedanib. Dosing was based on weight-dependent allometric scaling. Co-primary end-points were the area under the plasma concentration-time curve at steady state (AUC_τ,ss) at weeks 2 and 26 and the proportion of patients with treatment-emergent adverse events at week 24.

RESULTS

26 patients received nintedanib and 13 patients received placebo. The geometric mean (geometric coefficient of variation) AUC_τ,ss for nintedanib was 175 µg·h·L^-1 (85.1%) in patients aged 6-11 years and 160 µg·h·L^-1 (82.7%) in patients aged 12-17 years. In the double-blind period, adverse events were reported in 84.6% of patients in each treatment group. Two patients discontinued nintedanib due to adverse events. Diarrhoea was reported in 38.5% and 15.4% of the nintedanib and placebo groups, respectively. Adjusted mean±se changes in percentage predicted forced vital capacity at week 24 were 0.3±1.3% in the nintedanib group and -0.9±1.8% in the placebo group.

CONCLUSIONS

In children and adolescents with fibrosing ILD, a weight-based dosing regimen resulted in exposure to nintedanib similar to adults and an acceptable safety profile. These data provide a scientific basis for the use of nintedanib in this patient population.

Serum KL-6 as predictive and prognostic marker of interstitial lung disease in childhood connective tissue diseases: a pilot study

This study was aimed to evaluate serum KL-6 levels to determine if this marker can be used for diagnosing and assessing severity of interstitial lung disease (ILD) in children with connective tissue disorders. In total, 40 patients [18 patients with juvenile systemic lupus erythematosus (JSLE), 10 patients with juvenile idiopathic arthritis (JIA), 8 patients with juvenile mixed connective tissue disease (JMCTD), 3 patients with juvenile systemic sclerosis (JSSc), and 1 patient with juvenile dermatomyositis (JDM)] and 20 healthy controls were included in this study. Age, sex, and duration of CTD and ILD (if any) were recorded. Blood samples from all the patients and controls were examined by ELISA. 20 of the 40 patients with CTD (50%) had ILD, 12 were mild and 8 were severe as assessed by spirometry. The median serum KL-6 level was 102.7 U/mL (76.1-180.8) in the CTD with severe ILD group, 72.2 U/mL (58.4- 100.5) in the CTD with mild ILD group, 56.7 U/mL (35.8-68.5) in the CTD without ILD group, and 52.3 U/mL (32.8-62.4) in the control group. KL-6 levels were significantly higher in the CTD with ILD (p<0.05), at a cutoff of 63.4 U/ml identified by ROC curve, serum KL-6 showed a sensitivity of 95.2% and specificity of 89.7%. KL-6 is a valuable biomarker for diagnostic purposes and to detect severity in ILD in childhood CTD.

Why is a paediatric respiratory specialist integral to the paediatric rheumatology clinic?

Systemic connective tissue diseases (CTDs) are characterised by the presence of autoantibodies and multiorgan involvement. Although CTDs are rare in children, they are associated with pulmonary complications, which have a high morbidity and mortality rate. The exact pathophysiology remains unclear. The pleuropulmonary complications in CTD are diverse in their manifestations and are often complex to diagnose and manage. The most common CTDs are discussed. These include juvenile systemic lupus erythematosus, juvenile dermatomyositis, juvenile systemic sclerosis, Sjögren's syndrome and mixed connective tissue disease. We describe the clinical features of the pleuropulmonary complications, focusing on their screening, diagnosis and monitoring. Treatment strategies are also discussed, highlighting the factors and interventions that influence the outcome of lung disease in CTD and pulmonary complications of treatment. Early detection and prompt treatment in a multidisciplinary team setting, including respiratory and rheumatology paediatricians and radiologists, is paramount in achieving the best possible outcomes for these patients.

Approaching Clinical Trials in Childhood Interstitial Lung Disease and Pediatric Pulmonary Fibrosis

Childhood interstitial lung disease (chILD) comprises a spectrum of rare diffuse lung disorders. chILD is heterogeneous in origin, with different disease manifestations occurring in the context of ongoing lung development. The large number of disorders in chILD, in combination with the rarity of each diagnosis, has hampered scientific and clinical progress within the field. Epidemiologic and natural history data are limited. The prognosis varies depending on the etiology, with some forms progressing to lung transplant or death. There are limited treatment options for patients with chILD. Although U.S. Food and Drug Administration-approved treatments are now available for adult patients with idiopathic pulmonary fibrosis, no clinical trials have been conducted in a pediatric population using agents designed to treat lung fibrosis. This review will focus on progressive chILD disorders and on the urgent need for meaningful objective outcome measures to define, detect, and monitor fibrosis in children.