FDA probably did not require another trial - if it was the case co had to disclose. (Look at BTCY approval cycle)
I am surprised that co did not disclose when they got questions from FDA for the 1st time and had to respond.
So to me it seems preparation of commercialization of drug - which includes ability to produce adequate quantity of drug with proper GMP - storage - packaging among others
Based on CEB delay - I clearly suspect it is manufacturing issues or GMP certification as the key issue