Atezolizumab Versus Chemotherapy in Patients with Platinum-treated Locally Advanced or Metastatic Urothelial Carcinoma: A Long-term Overall Survival and Safety Update from the Phase 3 IMvigor211 Clinical Trial

Atezolizumab is an anti–PD-L1 immune checkpoint inhibitor recommended for the treatment of locally advanced or metastatic urothelial carcinoma (mUC) after prior platinum-containing chemotherapy, regardless of PD-L1 status, among other treatment settings. We conducted a long-term follow-up to the exploratory analysis of overall survival (OS) and safety for the IMvigor211 intent-to-treat (ITT) population. Patients with mUC and disease progression during or following platinum-based chemotherapy were randomised 1:1 to receive atezolizumab 1200 mg or chemotherapy (vinflunine 320 mg/m2, paclitaxel 175 mg/m2, or docetaxel 75 mg/m2 according to investigator choice) intravenously every 3 wk. Although the primary analysis did not demonstrate statistically significant longer OS for patients receiving atezolizumab versus chemotherapy, updated OS showed long-term durable remission. With a median of 33 mo of follow-up, the 24-mo OS rate was 23% with atezolizumab and 13% with chemotherapy. Safety findings were consistent with the primary analysis, with no new signals detected. Chemotherapy-treated patients experienced more grade 3/4 treatment-related adverse events (AEs; 43% vs 22%) and more AEs leading to treatment discontinuation (18% vs 9%). Atezolizumab-treated patients experienced more AEs of special interest (35% vs 20%), which tended to be grade 1–2. Our findings support the use of atezolizumab in platinum-treated patients with mUC regardless of PD-L1 status.