Overall survival (OS) is the gold standard of demonstrating clinical benefit for anti-cancer drugs, while progression free survival (PFS) is increasingly used as a key endpoint for evaluation and approval of oncology drugs. Several challenges and often controversial issues arise in clinical oncology trials with the use of PFS. We will discuss issues related to statistical evaluation of PFS and OS, and their relationship.

Key Questions: 1.How best to deal with crossover to an unapproved therapy? 2.When should analyses be performed when assessing PFS for accelerated approval and OS for full approval? 3.How should analyses of PFS be done?