Geometrically, open strings are characterized by free endpoints, whereas closed strings are characterized by connected endpoints [19].
However, care must be taken to distinguish between survival and progression-free endpoints, which are not necessarily correlated.
At the time of the analysis, the median follow-up was 24.0 months (range: 0.03 56.0), 54.7% patients had died and 68.6% had met the progression-free survival endpoint.
A progression-free survival endpoint was not used intentionally because in the setting of cetuximab use in various lines of therapy, it could be influenced by the distribution of cetuximab therapy line in various categories of biomarkers under study.
A planned interim analysis of efficacy data showed an inferior trend that was unlikely to demonstrate a statistically significant improvement in the primary progression-free survival endpoint for sunitinib as compared with bevacizumab.
We showed here that substantive differences between fitted models, and the data indicated greater data support within the ACCENT database for the log-normal than the Cox model in the important first 3 years for the FDA-approved disease-free survival endpoint.
Both are large, well-powered trials with primary disease-free survival endpoints and secondary overall survival endpoints.
As preferred potential surrogates in each digestive tumour site, event-free survival endpoints should be first evaluated, with particular interest for QoL or composite endpoints including QoL in the metastatic setting.
Event-free survival endpoints, such as DFS and PFS, were preferred to early treatment effect evaluation, such as R0 resection and response.
One other large randomized double-blind study in Hodgkin lymphoma also showed no significant difference in overall and progression-free survival endpoints 41.
