TIMP1 and idiopathic pulmonary fibrosis: However, regarding CTGF as a known driver of SERPINE1 and TIMP1 levels, we note that local upregulation of CTGF by a type of alveolar cell, resulting in proliferation of local fibroblasts, has been proposed as a surrogate biomarker of idiopathic pulmonary fibrosis (IPF);55 CTGF is therefore the target of ongoing IPF clinical trials of the fully human monoclonal antibody Pamrevlumab by FibroGen (San Francisco CA) (trial NCT01890265 at ClinicalTrials.gov).