Currently over 1400 subjects have been treated with pirfenidone in 15 clinical trials. This drug has been approved by the Food and Drug Administration (FDA) for use in Idiopathic Pulmonary Fibrosis, a different type of ILD, but requires special permission for use in your condition. The use of pirfenidone has not been approved for the treatment of FHP. It is considered experimental treatment in this study.