Table 2.

Multivariable analysis of M‐protein dynamic features and identified baseline variables for PFS in the CASTOR (n = 498) study

Variable	HRs (95% CIs) based on M‐protein data up to the indicated time cutoffs
	Baseline	1 month	2 months	3 months	6 months	All Data
Maximum % reduction of M‐protein, %	‐	1.42 (1.06–1.92)	1.09 (1.04–1.15)	1.08 (1.03–1.13)	1.21 (1.16–1.25)	1.21 (1.17–1.25)
Last observed M‐protein change from baseline, %	‐	0.838 (0.63–1.11)	1.08 (1.04–1.12)	1.11 (1.08–1.15)	1.02 (1.01–1.04)	1.02 (1.01–1.04)
Rate of M‐protein change, % per week	‐	1.09 (0.92–1.28)	0.987 (0.927–1.05)	0.934 (0.874–0.999)	0.998 (0.945–1.05)	0.996 (0.943–1.05)
Time from MM diagnosis to randomized, years	0.819 (0.764–0.879)	0.839 (0.785–0.897)	0.868 (0.813–0.926)	0.873 (0.817–0.932)	0.857 (0.801–0.917)	0.855 (0.799–0.915)
Number of lytic bone lesions	1.3 (1.16–1.47)	1.83 (1.22–2.77)	2 (1.31–3.05)	1.87 (1.23–2.85)	1.8 (1.18–2.74)	1.82 (1.2–2.77)
IgG concentration, g/dL	1.01 (1.01–1.02)	1.01 (1–1.02)	1.01 (1–1.02)	1.01 (1–1.02)	1.01 (1–1.02)	1.01 (1–1.02)
Alkaline phosphatase, IU/L	1.01 (1–1.01)	1.04 (1.02–1.08)	1.04 (1.02–1.08)	1.04 (1.01–1.07)	1.04 (1.01–1.07)	1.04 (1.01–1.07)
Prior lenalidomide yes vs. no	2.260 (1.62–1.47)	1.65 (1.16–2.33)	1.62 (1.15–2.29)	1.5 (1.05–2.12)	1.55 (1.1–2.18)	1.47 (1.04–2.07)
Number of prior therapy lines	1.880 (1.25–2.82)	1.24 (1.09–1.42)	1.18 (1.04–1.35)	1.18 (1.04–1.35)	1.2 (1.06–1.37)	1.21 (1.06–1.37)
ISS, II or III vs. I	1.600 (1.14–2.40)	1.36 (0.971–1.92)	1.43 (1.02–2)	1.26 (0.893–1.77)	1.63 (1.15–2.3)	1.62 (1.15–2.3)
Prior radiotherapy yes vs. no	1.510 (1.09–2.1)	1.25 (0.9–1.74)	1.29 (0.921–1.8)	1.13 (0.802–1.58)	1.3 (0.929–1.83)	1.28 (0.914–1.8)
ECOG score, 1 or 2 vs. 0	0.950 (0.697–1.29)	0.954 (0.704–1.29)	0.985 (0.726–1.34)	1.1 (0.81–1.5)	0.927 (0.679–1.27)	0.923 (0.676–1.26)

For maximum reduction of M‐protein (%) and last observed M‐protein change from baseline (%), the hazard ratio is associated with each 10‐unit increase.