"Why oh why didn't he do that starting years ago??"
I suspect your question is somewhat rhetorical!
But to me, the answer is fairly obvious - Osiris conducted two well constructed placebo controlled, randomised clinical trials which showed no effect in adults. So unless the changes to manufacturing had produced a radical improvement in potency (and there is no good statistical evidence they had) then the chances of a small scale third RCT in adults succeeding were slim indeed. As you correctly point out, the whole clinical trial strategy was therefore built on a post hoc analysis of the earlier trial which showed a (statistically insignificant) positive trend in children - and the hope that the positive signal could be replicated in a small single arm study.
But as we know, hope is not a strategy, and MSB now faces the prospect of pitting a new small scale adult "study" against two well designed trials. Good luck with that, I say! Much better to focus limited resources on the other opportunities in the portfolio IMHO.
(20min delay)