Mesoblast have always been steadfast in their view that Rem-L...

Mesoblast have always been steadfast in their view that Rem-L shows efficacy as demonstrated by the ODAC vote and that TNFR1 is the MOA, even though the FDA were/are adamant that Rem-L has multi-modality and therefore the MOA is more complex. However, for accelerated approval only one MOA needs to be established from my understanding, not all modalities, so MSB probably won't be proposing an additional MOA in conjunction with TNFR1, especially since activation of TNFR1 by IL-1 is what activates Rem-L and it's anti-inflammatory and immune regulatory functions.

The "substantial data" MSB refers to is probably to do with potency assays to measure CQAs to ensure batch-to-batch consistency during manufacturing and critical process parameters or CPPs. This would've required MSB to generate substantial data from several different donors and to create stockpiles for research purposes, which we know based on past inventories that they had previously done so. I suspect MSB will create a TNFR1 cut-off level to ensure quality between batches.