I believe she (Rachel) is wrong on this. As I posted on SI, the short median PFS advantage is mostly an artifact. As the Merck briefing docs calculate, a 6 week PFS advantage based on the HR is a more realistic number (which is less than what it is at both 40% and 60% PFS).
They had an SPA and hit it easily. A survival trial is impractical (by Merck's calculations would require 1100 patients over 6 years).