The most revealing comment about the BLA, IMO, was when Nader said, "we have to get the contract signed to do the certain assay that the FDA has asked us to do....". It's just after an hour and 6 minutes into the call.

What is the assay in question? Receptor occupancy seems like an obvious choice. Can that be done retroactively? I'm skeptical if it means rounding up former trial participants but maybe there is a workaround. I'd appreciate any thoughts on that.