Interim analysis of OS was done after 165 events: 96 deaths in the control group and 69 in the pertuzumab group. O81 IMpower110: interim overall survival (OS) analysis of a phase III study of atezolizumab (ATEZO) monotherapy vs platinum-based chemotherapy (CHEMO) as first-line (1L) treatment in … The stopping boundary was not crossed. The first interim OS analysis at time of PFS analysis (October 10, 2018) was immature, with 158 of 385 deaths (41%) needed for final OS analysis. Detailed results from the second interim OS analysis were presented during an oral session at the 2019 San Antonio Breast Cancer Symposium. MacroGenics announced top-line results from its second pre-specified interim overall survival (OS) analysis for its Phase 3 SOPHIA study. Analysis of the blinded interim data on OS of the ITT population (using SAS version 9.4) was performed 34 months after the midpoint of patient enrollment, and 16 months after the last patient was enrolled and randomized. We defined OS as the time from randomisation to death or date last seen. REFERENCE MacroGenics Announces Second Interim Overall Survival Data from Phase 3 SOPHIA Study of Margetuximab in Patients with HER2-Positive Metastatic Breast Cancer [news release]. Primary endpoints were OS based on a pooled analysis of the chemotherapy treatment groups with and without bevacizumab and the frequency and severity of AEs, centrally assessed at the second interim and final analysis by the Data and Safety Monitoring Board (DSMB). A second interim OS analysis was planned after 270 deaths and will be reported here.