It was a crossover trial, and they have real live patients living as long as 20+ years. The survival data cannot be faked. Using the external multiple trials and the immensely carefully done comparative statistical analysis will be more than adequate to validate those survival statistics.
However, even if they got approval subject to further trials, that would be as good as most other treatments, many of which did not actually complete those other trials and yet the regulators determined, despite their NOT extending survival, they provided patients with substantial benefit. Bit here we have survival AND quality of life.