Summary of most relevant changes: • Study-specific stopping rules per FDA recommendations were introduced, • ECG discharge criteria from hospital on Day 1 and on the first day of re-initiation following treatment interruption were clarified, • Respiratory system criteria for interruption / premature discontinuation of study treatment per FDA recommendations were revised, • The safety endpoint/variable Occurrence of treatment-emergent decrease of FEV1 or FVC was modified, • Analysis of pulmonary safety events was to include treatment-emergent decrease of FEV1 or FVC to < 85% of baseline values instead of < 80% of baseline values, • Since at Visit 3 and re-initiation visits, study drug was not to be allocated by the IRT system, the compliance could not be calculated automatically in the eCRF. During these visits, a compliance review based on study drug accountability was to be performed by the investigator (or delegate) and recorded in the eCRF, • In case of no medical justification available for study treatment interruption, compliance < 80% was to be reported as a protocol deviation, • Clarifications were added in the laboratory sections, • In order to shorten the time window between assessments during the follow-up period (at 6 and 16 weeks after last dose of study treatment intake), a follow-up assessment via telephone was added at 11 weeks after last dose of study treatment intake to collect SAEs and pregnancy test results, • Informed Consent Form was amended to reflect the changes introduced by the amendment.