Comment on: Hostettler K, et al. Bosentan for patients with steroid-resistant pulmonary sarcoidosis: a randomised controlled trial

We read with great interest the article entitled: “Bosentan for patients with steroid-resistant pulmonary sarcoidosis: a randomised controlled trial” [1]. The authors assessed the effect of bosentan in patients with steroid-resistant sarcoidosis, and with impaired exercise capacity and/or resting lung function. Although they found no evidence to support efficacy of bosentan as an antifibrotic treatment for patients with steroid-resistant pulmonary sarcoidosis, we would like to emphasise the possible role of bosentan in reducing endothelin-1 in the urine of these patients, as we demonstrated after prednisone treatment in a previous paper entitled: “Endothelin-1 excretion in urine in active pulmonary sarcoidosis and in other interstitial lung diseases” [2]. In our study, urinary endothelin-1 decreased significantly after steroid therapy, and the decrease was accompanied by improved clinical status. Even if an early antifibrotic effect could not be seen in the study of Hostettler et al, we encourage the authors to evaluate urinary endothelin-1 before and after treatment with bosentan. The antifibrotic effect might not be evident soon, whereas a decrease in urinary endothelin-1 might be a good prognostic factor with which to establish the role of bosentan for patients with steroid-resistant pulmonary sarcoidosis.