A. Corruption- not unknown at the FDA. Bribes from GSK? Why not? Very possible at Iljin, which means 'gangsters' in Korean. Virtually zero possibility at AUPH.
B. Incompetence- The FDA is a gov't entity. Bureaucrats too frequently make surprisingly bad judgments. I can picture some fool saying "They already have Benlysta, why do they need another LN drug?"
Both reasons seem very far fetched. In an honest and competent world, VCS is a lock.