Statistical analysis
CRS
SECONDARY, EMD
Efficacy and safety were evaluated in all patients enrolled who received at least one dose of elranatamab (safety analysis set). A sample size of 120 patients was estimated to give a power of at least 98% to establish an ORR of more than 30% at a one-sided significance level of 0.025, assuming an ORR of at least 48%. As specified in the protocol and statistical analysis plan, if the null hypothesis for ORR by BICR (defined as ≤30% by IMWG) was rejected for cohort A, the key secondary endpoint of ORR by BICR for those without EMD at baseline was tested in a hierarchical fashion using the gatekeeping procedure that the ORR is ≤38% with a one-sided significance level of 0.025. If the null hypothesis for ORR by BICR for those without EMD at baseline was rejected for cohort A, the key secondary endpoint of ORR by BICR for those with EMD at baseline was tested in a hierarchical fashion using the gatekeeping procedure that the ORR is ≤12% with a one-sided significance level of 0.025. No other adjustments for multiple comparisons were made. Descriptive statistics were used for efficacy and safety outcomes unless otherwise stated. Exact two-sided 95% CIs were included for response endpoints. Time-to-event endpoints—except TTR—were summarized using the Kaplan–Meier method. Medians, rates at 15 months and their two-sided 95% CIs were included. The CIs for the median were calculated according to Brookmeyer and Crowley, and the CIs for the survival function estimates at particular time points were derived using the log(−log) method. Data cutoff for efficacy and safety was March 14, 2023, except for CRS and ICANS data, which was based on January 12, 2023.