Short-Term Relapse Quantitation as a Fully Surrogate Endpoint for Long-Term Sustained Progression of Disability in RRMS Patients Treated with Natalizumab

Table 4

Validation of 1-year relapses as the surrogate endpoint for EDSS at 2 years.

		Hypothesis testing approach*
		Association between relapse and EDSS		Treatment effect on EDSS w/o adjusting relapse		Treatment effect on EDSS with adjusting relapse		Quantification approaches
True endpoint	Surrogate endpoint	HR	𝑃 value	HR	𝑃 value	HR	𝑃 value	PTE	LRFa	PIG
EDSS at 2-yr	Relapse at 1-yr	2.26	<0.0001	0.61	0.0011	0.91	0.5486	0.801	0.892	0.995

*: All Cox proportional hazards model for the time to sustained disability are adjusted for the baseline EDSS score and age group (<40 versus ≥40).
*Analysis was restricted to the patients who had no missing values of the endpoints.