A. Loss of correlation of PFS with OS as a function of increasing PPS (post-progression survival, referred to below as SPP or survival post progression). B. Power to preserve a PFS effect. SPP (survival post progression).
Broglio KR, Berry DA. Detecting an overall survival benefit that is derived from progression-free survival. J Natl Cancer Inst 2009;101(23):1642-164927. Reprinted by permission of Oxford University Press.