Hi @Fastback6666. I understand that Mesoblast has already had...

Hi @Fastback6666.

I understand that Mesoblast has already had discussions with the FDA on the adult trial protocol. Remember that on Feb 28 this year CEO Itescu mentioned during the Earnings Call that:

" ..we achieved the expected delivery of additional potency assay data, which was provided to the FDA. We have scheduled an upcoming meeting with the FDA that will be held in March. We've achieved completion and submission of a protocol for the adult program, and we plan to initiate enrollment in the next quarter for this adult trial.."

You'd have to think that BMT CTN signed off on that protocol between September 2023 and February 2024. We don't know what it contains, of course. However, there was nothing to indicate it was put forward seeking FDA endosement of access to the Accelerated Approval pathway. Recall that Remestemcel-l has several supportive designations e.g. ODD and Priority Review. But it doesn't have an RMAT designation, & AFAIK hasn't been assessed for whether it meets the criteria for Accelerated Approval.

So, I'm going to have to assume the adult trial protocol was put to the FDA for comment/ endorsement as the basis for at least a standard approval.

Still, I think MSB could have filed a protocol for accelerated approval & may well have been able to get BMT CTN to go with them IFF Mesoblast had only known back then that it was going to get the brilliant notice it announced to ASX on March 26. But, sadly, it didn't. So they would never have put all their eggs in that basket. And yet it remains a possibility that the protocol was put forward for the Type C meeting in the alternative i.e. here's our standard approval protocol, but if you think we can get the support of the AA pathway, then here's out alternative.

Again, we just don't know exactly what was put forward.

The other points are a bit complex & I'll come back to you on those. However, I would say that if Mesoblast thought that the BLA contained material which supported the label extending to include use for adult indications as well as paediatric indications, then it would need to be sought in the BLA itself at the time of filing. Otherwise, IMO it would risk being seen as a major amendment, which has timeframe implications. I think we got to that stage with the first BLA resubmission.

Cheers