Table 3. Cox proportional hazard regression for ERCC1 expression by PFS.

	ERCC1 (FL297) N=88		ERCC1 (4F9) N=88		ERCC1 (8F1) N=90
	Estimate (95% CI)	P-value	Estimate (95% CI)	P-value	Estimate (95% CI)	P-value
A. Continuous ERCC1 expression
Hazard ratio (e.g. H-score of 3 vs 2 or 2 vs 1)	2.5 (1.1–5.9)	0.03*	3.0 (1.2–7.8)	0.02*	1.4 (0.8–2.5)	0.21
B. ERCC1 expression categorised by pre-determined H-score cutpointsa
Hazard ratio
Normal/increased vs decreased	3.4 (0.4–25.9)	0.24	1.8 (0.4–8.1)	0.42	—	—
Increased vs normal/decreased	4.8 (1.7–13.2)	0.003*	5.5 (1.6–18.9)	0.007*	—	—
C: Categorised ERCC1, also controls for p16 (p16-positive oropharyngeal tumour vs other)a
Hazard ratio
Normal/increased vs decreased	3.4 (0.4–25.5)	0.24	1.9 (0.4–8.3)	0.40	—	—
Increased vs normal/decreased	4.6 (1.6–13.2)	0.004*	5.2 (1.5–18.3)	0.01*	—	—

Models were stratified by randomization strata (including N-stage) and controlled for treatment arm.

^aExploratory analysis, excluding 8F1 antibody based on results of primary analysis (3A).

^*Indicates statistical significance.