Hi,Sorry for the confusion, I think I have had one too many...

Hi,

Sorry for the confusion, I think I have had one too many sleepless nights!

There have been a number of single arm publications by Dr Kertzberg regarding MSCs and GVHD in children so deciding on a number to use for survival/response rate is a little difficult. However looking at the MSB website they quote a day 28 response
rate to Remestemcel-l as 66% overall and 65% in grade C/D patients. This is compared to a historical control reported as 45%. There are two articles quoted when referencing 45% as a control in a 2020 article by Dr Kertzberg, the first is an earlier case series using MSCs for GVHD published by her team and the second is the following article published in 2002.



Again, it is hard to work out exactly how they reason out the historical control of 45% from here, maybe they have access to more data? The best I can see is this graph where if you combine the grade 3&4 cases it’s maybe a 45% response rate to steroids. Also note that this is in all comers and not just paediatric patients.

Up to recently that’s fair enough, we haven’t really had another comparison. But the recent GRAVITAS trial has changed that so we ask ourselves: Is this 20yo study a good control? Or is this recent data a better control group?

So let’s imagine that the remestemcel L is a third arm in the GRAVITAS study and showed an OR of 65%. Compared to the below data:



You’ll see in that 65% is similar to both arms in high risk patients lies within the 95% confidence interval so would not be statistically significant. Therefore if mesoblast used this study as a control then they wouldn’t have any evidence that remestemcel l works. That is what I was pointing out in my earlier posts.

At the end of the day it doesn’t matter what I think though, it is in the hands of the FDA. I hope I answered your question.