Relief for sufferers of rheumatoid arthritis-related interstitial lung disease

Almost two in every 100 Australians suffer from rheumatoid arthritis (RA), an insidious autoimmune disease in which the body’s immune system attacks its own tissues. Globally, almost 8% of RA sufferers will go on to develop interstitial lung disease, a complication with no current treatment and which can lead to an early death.

Rheumatoid arthritis symptoms in hands (swollen, deformed joints)
Rheumatoid arthritis commonly leads to swelling, heat, pain and deformation in joints such as fingers. Credit: Chaowalit406/Getty Images

An anti-scarring medicine known as pirfenidone is showing promise as a prospective treatment for rheumatoid arthritis-related interstitial lung disease (ILD).

RA is the most common form of autoimmune disease. The most common symptoms of the disease include swelling, pain, stiffness and heating in the joints, along with mental and physical fatigue. It can lead to joint deterioration, disability and death.

In some cases, RA can also attack organs such as the heart and lungs. In the latter, it can lead to ILD which is characterised by a progressive thickening and scarring of the lung tissue – known as fibrosis.

Read more: How rheumatoid arthritis inflammation spreads between the joints of mice

“ILD is a relatively common complication in people with RA and can progress and lead to premature death in up to 10% of these patients,” says Joshua Solomon, MD, director of the Interstitial Lung Disease Program at National Jewish Health and first author of the study investigating pirfenidone’s potential use in treating ILD.

The study was a randomised, double blind, placebo-controlled phase 2 trial run across 34 institutions. Over a year, trial participants were administered either pirfenidone or a placebo and their forced vital capacity (FVC) measured.

The FVC is the maximum amount of air you can forcibly exhale from your lungs after fully inhaling and a decline in FVC is associated with an earlier mortality. Patients given pirfenidone showed a reduced rate of decline in FVC over the year, suggesting that the medicine – which has anti-inflammatory and antifibrotic properties – may improve the lifespan of those with ILD.

Pirfenidone is already used to treat idiopathic pulmonary fibrosis (lung tissue scarring and thickening without a cause).

3d molecular structure of pirfenidone
A 3D representation of the molecular structure of Pirfenidone – an anti-inflammotory and antifibrotic compound showing some promise in Phase II trials as a treatment for slowing the progression of rheumatoid arthritis-related interstitial lung disease. Credit: Ollawell/Getty Images

“With this study, we are demonstrating that anti-fibrotics as a class of medications have a reproducible effect in reducing the rate of disease progression when measured by force vital capacity,” says Dr. Ivan Rosas, corresponding author of the paper, and professor of medicine and section chief of pulmonary, critical care and sleep medicine at Baylor College of Medicine, in Houston, Texas. “This could have an impact on the overall survival of these patients.”

Recruitment of participants for the trial was interrupted by the pandemic, meaning not enough participants were able to be enrolled in the program for the study to be considered complete.

However, this study has demonstrated pirfenidone shows promise worthy of further investigation in terms of its safety and tolerance in patients and in slowing down the rate of progression of ILD over the course of a year.

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