Rituximab Helps to Treat Interstitial Lung Disease Linked to Rheumatoid Arthritis, Study Finds

Rituximab Helps to Treat Interstitial Lung Disease Linked to Rheumatoid Arthritis, Study Finds

The biologic rituximab is an acceptable and safe treatment choice for people with rheumatoid arthritis (RA)-related interstitial lung disease (ILD), and can help to maintain lung function — especially if given before the lung disease turns severe, according to a decade-long observational study published in the journal Rheumatology.

RA treatment has improved in recent years with the introduction of biologic therapies, including rituximab (also known by its brand names, Rituxan and MabThera). But use of such agents in RA patients with ILD has been restricted due to safety concerns, even thought some 30% of RA patients go on to develop ILD. This development is associated with poor outcomes.

In most clinical trials, patients with RA-related interstitial lung disease (RA-ILD) are not included because of comorbidities, so the potential benefits of biological therapies are not known. Some studies, however, suggest that biologics such as rituximab, which target immune B-cells, could help these patients.

In this study, “Effect of rituximab on the progression of rheumatoid arthritis–related interstitial lung disease: 10 years’ experience at a single centre” researchers at the University of Leeds did a retrospective evaluation, using the Leeds Biologics Database, of RA patients treated with rituximab between January 2004 and May 2015, including those with RA-ILD.

Of  the 700 patients included, 56 (8%) had RA-ILD, and three (0.4%) were newly diagnosed with ILD during the study period. The 56 RA-ILD patients underwent 181 cycles of treatment, with each cycle consisting of 100 mg of methylprednisolone, a steroid, and 1,000 mg of rituximab given intravenously on days 1 and 14.

The researchers found rituximab of benefit to RA-ILD patients, as shown by changes in measures of lung function: a 1.2% improvement in forced vital capacity, and a 3.7%  improvement in diffusion capacity of carbon monoxide. Overall, they observed through lung assessments over the study period improvements in 16% of rituximab-treated patients with RA-ILD, stable disease in 52%, and disease progression in 32%.

“It is worth noting that RTX [rituximab] was given primarily for articular symptoms in this study. Although only 16% of the patients had improvement in ILD after therapy, post-RTX HRCT [high-resolution CT] was not routinely performed in all patients (if stable), which could reduce the calculated response rate,” the authors wrote.

Post-therapy ILD progression was found to be associated with interstitial pneumonia, and a previous history of lung disease progression. Rituximab was also seen to be of lesser efficacy in those whose ILD was severe prior to the start of treatment. This finding, the researchers said, highlights the importance of early ILD diagnosis and treatment of ILD in this patient population.

“Our findings offer reassurance that RTX appears to be an acceptable treatment choice for a group of patients with non-overlapping RA-ILD and severe arthritis who require a biologic,” they concluded, recommending further study. “These data also support a definitive study of RTX for the management of RA-ILD from both an articular and a respiratory perspective.”

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