The NWBO trials were over a much longer period of time with a more complicated treatment process. I suspect that had a significant effect on the required size of their submission along with the manufacturing information for their novel and complicated manufacturing process. Their manufacturing process is customized for each patient and involves living cells with all of the biological contamination protocols involved.
AVXL is a small molecule that is manufactured in dry pill form and a liquid form. It is a much simpler process to produce the drug.
On the other hand, Anavex has to submit EU labeling and marketing materials in multiple languages as part of the approval process.
I would suspect that many of the 1.7 million pages will never see the light of day
The vast majority of 'pages' of a regulatory submission consist of data items that may be part of various assessments done in the approval process, but unlikely that all is covered and used for anything.
There are cases of drugs that shouldn't have been approved based on data 'hinding' in all those 'pages', but were not covered by the regulatory review.