FibroGen Inc. said it would advance the clinical development of pamrevlumab after the drug was shown to benefit idiopathic pulmonary fibrosis patients in phase 2 studies.

Pamrevlumab-treated patients had a significantly lower rate of decline in lung function as compared to the placebo-treated patients. The drug was also well-tolerated as a monotherapy as well as in combination with pirfenidone and nintedanib.

"We believe that the promising outcomes of these studies enable us to advance pamrevlumab into phase 3 clinical development," FibroGen CEO Thomas Neff said in a statement.

FibroGen shares were up 48.20% to $49.50 apiece at market close on Aug. 9.

Pamrevlumab is also being evaluated as a treatment of cancer.