This is a Phase III, multi-centre, multi-national, prospective, open-label extension clinical trial that will be conducted once the benefit-risk evaluation is shown to be positive in the pivotal Phase III program. Throughout this protocol, the precedent BI 1015550 Phase III trials (i.e. 1305-0014 and 1305-0023) are referred to as the parent trials. With approximately 2270 patients in total randomised into the parent trials, it is estimated that approximately 1700 patients with IPF/PPF will be eligible and participate in this extension trial (assuming discontinuation rate of ~25% over the whole of the parent trials and >90% of eligible patients agreeing to participate in this trial). Patients who prematurely discontinued trial medication permanently in the parent trials will not be eligible for this extension trial.

For each of the parent trials, all eligible patients can roll over into this extension trial at the end of the parent trial, without treatment interruption between the parent and extension trials, whenever possible. In the case where roll-over without interruption is not possible, eligible patients can start participation and treatment in the extension trial with a maximum interruption of 12 weeks between the respective parent trial and the open-label extension study.