- Subjects currently receiving oral corticosteroids, cytotoxic drugs (e.g. chlorambucil, azathioprine, cyclophosphamide, methotrexate), antifibrotic drugs (e.g. pirfenidone), vasodilator therapies for pulmonary hypertension (e.g bosentan), unapproved (e.g. Interferon-γ, penicillamine, cyclosporine, mycophenolate) and/or investigational therapies for IPF or administration of such therapies within 4 weeks of initial screening.