Retreatment with anti-EGFR based therapies in metastatic colorectal cancer: impact of intervening time interval and prior anti-EGFR response

Table 4 Multivariate models for clinical benefit and PFS on anti-EGFR-based clinical trial retreatment

Characteristic	Clinical Benefit			PFS
	OR	95 % CI	p ^a	HR	95 % CI	p ^b
Responded on prior anti-EGFR treatments, yes vs. no	3.38	(1.27, 9.31)	0.019	0.70	(0.43, 1.15)	0.156
Interval length, ≥ median vs. < median	2.37	(0.89, 6.31)	0.086	0.72	(0.45, 1.16)	0.177
Race, White vs. non-White	0.41	(0.13, 1.25)	0.116	1.75	(1.02, 3.01)	0.043
Age, ≥ 60 years vs. < 60 years	0.70	(0.25, 1.96)	0.500	1.10	(0.65, 1.87)	0.718
Gender, male vs. female	1.28	(0.50, 3.25)	0.611	0.78	(0.49, 1.24)	0.295
RMH Score, ≥ 2 vs. < 2	0.79	(0.29, 2.11)	0.633	1.32	(0.81, 2.16)	0.273
PS by ECOG, ≥ 1 versus < 1	0.76	(0.28, 2.10)	0.597	1.25	(0.76, 2.05)	0.381

^aBased on a multivariable logistic regression model
^bBased on a multivariable Cox proportional hazards model
OR Odds Ratio, HR Hazard Ratio
Multivariable models were tested for a possible interaction between response on prior anti-EGFR therapy vs. non-response on prior therapy (1, 0) and interval length at or above the median vs. below the median (1, 0). The interaction term between response on prior anti-EGFR therapy vs. non-response on prior therapy (1, 0) and interval length at or above the median vs. below the median (1, 0) was not significant in either model. Thus, the interaction term was not included in the final multivariable models