We don't have much to go on. As far as we know FDA has NOT yet spoken to the issue directly though in theory they have admitted that clinical trails are not always required.
My guess is that FDA wants a clinical trial - call it 90%. If they could come to an agreement with FDA as to what they want, it should not be a long trial since it appears they can focus on immunogenicity. Still it is going to be at least a year if a clinical is required.
I would also say there is some chance that Sandoz will sue FDA - call it 20%.
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There are times when rules and precedents cannot be broken; others when they cannot be adhered to with safety. (Thomas Joplin)