Type of Copula      τ Global Power                          PFS                           OS         1st Interim Final Analysis Power 1st Interim Final Analysis Power Independence 0 0.979 0.156 0.696 0.852 0.172 0.859 0.859 Normal 0.10 0.973 0.152 0.701 0.853 0.155 0.857 0.857   0.30 0.956 0.154 0.694 0.848 0.158 0.855 0.856   0.50 0.939 0.151 0.707 0.858 0.158 0.861 0.861   0.70 0.914 0.151 0.703 0.855 0.156 0.856 0.856 Frank 0.10 0.970 0.156 0.689 0.845 0.161 0.853 0.854   0.30 0.953 0.154 0.693 0.847 0.161 0.854 0.854   0.50 0.938 0.147 0.703 0.850 0.157 0.851 0.851   0.70 0.913 0.146 0.703 0.849 0.159 0.852 0.853 Gumbel 0.10 0.968 0.156 0.696 0.851 0.158 0.852 0.853   0.30 0.952 0.153 0.696 0.849 0.157 0.860 0.861   0.50 0.930 0.150 0.700 0.850 0.151 0.858 0.858   0.70 0.914 0.154 0.670 0.853 0.163 0.860 0.861

Table 4: Empirical global Power and power for each endpoint and proportion of terminating the trial early assuming equal allocation of type I error rate of 0.025 for each endpoint and using Pampallona-Tsiatis boundaries; results based on 10,000 simulations.