1) The biosimilar applicants will never see any proprietary data submitted with the branded BLA.
2) The FDA will not have to look at the proprietary data submitted with the branded BLA. Agreed that it would make the FDA's job easier if they were allowed to guide to a process they had already vetted - but this type of prohibition happens in industry all the time. Companies have to firewall off people working with one partner on one contract, from people working with a different partner on a different contract.
That said, I agree it is a good stalling tactic - but given that I never thought that MNTA biosimilars would be approved in less than about 6 to 8 years from now I don't see this as much effect on MNTA.