In the August issue of JAMA Internal Medicine, Prasad et al1 conduct an analysis of existing surrogacy “validation” meta-analysis publications. Their results indicate varying strengths of association or correlation between the treatment effects on potential surrogate end points and overall survival (OS). However, due to the high bar needed to be confident in a surrogate end point declaration, they conclude that evidence is weak for widespread adoption of progression-free survival (PFS) or clinical response rate (RR) surrogates for overall survival in cancer.
LeBlanc M, Tangen C. Surrogates for Survival or Other End Points in Oncology. JAMA Oncol. 2016;2(2):263-264. doi:10.1001/jamaoncol.2015.4711