Azathioprine and Mycophenolate Mofetil Offer Comparable Efficacy in SSc-ILD

No mortality differences exist between patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD) who are treated with azathioprine vs mycophenolate mofetil, according to research presented at the American Thoracic Society (ATS) 2021 International Conference, held virtually from May 14 to 19, 2021.

Challenges abound in the identification of patients with SSc-ILD most at risk of mortality. While evidence is available to guide disease management, there is a lack of robust data to support treatment decision making during the early stages of SSc-ILD. A cornerstone of therapy is the early initiation of disease-modifying drugs, which are used to reduce progressive lung deterioration risk.

Drugs that have been studied in SSc-ILD include corticosteroids, cyclosporine, mycophenolate mofetil, and azathioprine. Mycophenolate mofetil is often preferred over cyclosporine because of the former drug’s better side effect profile, but few studies have directly compared mycophenolate mofetil to azathioprine in terms of safety and efficacy for SSc-ILD.

The study presented at ATS 2021 was an analysis of 233 patients with SSc-ILD who were registered in the Canadian Scleroderma Research Group Database. Investigators examined mortality rates at both 5 and 10 years among the patients treated with either mycophenolate mofetil (n=64) or azathioprine (n=44).

Women made up most of the patients in the mycophenolate mofetil and azathioprine groups (78.1% vs 84.1%, respectively). Patients treated with mycophenolate mofetil had a significantly longer time since ILD diagnosis (1.74 vs 0.87 years; P =.05).

No other differences were found between the 2 treatment groups in regard to age (P =.37), 5-year changes in forced vital capacity percent predicted (P =.27) and diffusing capacity for carbon monoxide percent predicted (P =.85), or coexisting pulmonary hypertension (P =.71).

At 5 years, approximately 14.1% of patients in the mycophenolate mofetil group and 15.9% of patients in the azathioprine group had died (P =.79). At 10 years, 17.2% of patients treated with mycophenolate mofetil and 29.5% of patients treated with azathioprine had died (P =.13). The study authors concluded that their findings suggest there is no significant difference in survival or change in lung function between the 2 drugs.

Reference

Shell J, Kapralik J, Jones A, et al. Azathioprine compared to mycophenolate mofetil treatment in patients with interstitial lung disease associated with systemic sclerosis. Presented at: the American Thoracic Society (ATS) International Conference 2021; May 14-19, 2021. Abstract #A1915.