Follow up Study From 1199.31(NCT01136174)

Inclusion criteria:

1. Written informed consent consistent with Good Clinical Practice (GCP) signed prior to entry into the study
2. Completion of 1199.31 study and still under treatment with pirfenidone at a stable dose

Exclusion criteria:

1. Any disease that may interfere with testing procedures or in judgement of investigator may interfere with trial participation or may put the patient at risk when participating in this trial. Reconsider carefully all exclusion criteria of trial 1199.31. However, patients may qualify for participation even though they meet the exclusion criteria (for 1199.31), if the investigators benefit-risk assessment remains favorable.
2. Any other investigational therapy received within 8 weeks before visit 1.

3. For female: Pregnant women or women who are breast feeding or of child bearing potential not using a highly effective method of birth control for both at least 4 weeks prior to enrolment and 10 weeks after last study drug intake.

   For male: Sexually active males not committing to using condoms both during the course of the study and ten weeks after last study drug intake (except if their partner is not of childbearing potential).

4. Known or suspected active alcohol or drug abuse.
5. Patients who require full-dose therapeutic anticoagulation (e.g. vitamin K antagonists, heparin), except low dose heparin and/or heparin flash as needed for maintenance of an indwelling intravenous device. As an example, prophylactic use of heparin, e.g. enoxaparin 2000 International unit (I.U.) subcutaneously (s.c.) per day, should be allowed.
6. Patients who require full-dose antiplatelet (e.g. acetyl salicylic acid, clopidogrel) therapy. As an example, chronic low-dose acetyl salicylic acid, below or equal to 100 mg per day, should be allowed.
7. Patient not compliant in previous trial, with trial medication or trial visits.