OBJECTIVE: We assessed adverse events and changes in forced vital capacity (FVC) in patients treated with open-label nintedanib over 148 weeks of SENSCIS-ON, the extension of the SENSCIS trial. METHODS: Adverse events and changes in FVC over 148 weeks of SENSCIS-ON were assessed in patients who received nintedanib in SENSCIS and continued nintedanib in SENSCIS-ON ('continued nintedanib' group) and in patients who received placebo in SENSCIS or received nintedanib for ≤28 days in a drug-drug interaction study and then received nintedanib in SENSCIS-ON ('initiated nintedanib' group). RESULTS: The continued nintedanib group comprised 197 patients, and the initiated nintedanib group comprised 247 patients (231 from SENSCIS). Diarrhoea was the most frequent adverse event, reported in 152 (77.2%) and 183 (74.1%) patients in the continued nintedanib and initiated nintedanib groups, respectively. Among patients in the continued and initiated nintedanib groups, respectively, 53 (26.9%) and 148 (59.9%) had ≥1 dose reduction, 72 (36.5%) and 131 (53.0%) had ≥1 treatment interruption and 29 (14.7%) and 72 (29.1%) had adverse events that led to treatment discontinuation. Mean (SE) changes in FVC (mL) at week 148 were -189.1 (29.5) in the continued nintedanib group and -126.4 (26.4) in the initiated nintedanib group. CONCLUSION: The safety profile of nintedanib over 148 weeks of SENSCIS-ON was consistent with that reported in SENSCIS. Changes in FVC during SENSCIS and SENSCIS-ON supported a continued effect of nintedanib on slowing the decline in lung function, but showed continued progression of SSc-ILD.