The future of treatment in systemic sclerosis: can we design better trials?

Abstract

Strides have been made in the treatment of pulmonary arterial hypertension and interstitial lung disease in patients with systemic sclerosis, with successful trials of combination therapies in pulmonary arterial hypertension and of new drugs that slow the decline of lung function in interstitial lung disease. However, many trials in patients with early diffuse cutaneous systemic sclerosis have been negative, including trials of tocilizumab, abatacept, and riociguat, despite improvements in skin scores and other endpoints that approached statistical significance. Trials of macitentan for digital ulcers in these patients have also been disappointing. Trials that do not meet their primary endpoint do not necessarily signify ineffective therapies, as there are many other possible reasons for negative trial results, including features of trial design, insufficient trial duration, or insufficient power to detect differences between groups. In this Series paper, I discuss some of these reasons and what the research community can learn from negative trials to inform future trial design going forward.