According to research, this drug sounds very promising, taking into account that it addresses the TGF-β1 pathway which hasn't been targeted before.
To be realistic, two professors that I consulted both are not convinced of that drug. In their studies the remission rate is quite low and they both assume that the remission rates that were first published were a bit - let's say - improved. There are always ways if you let someone drop out for a reason while the true reason is that in this group remission is more difficult to achieve etc.
A friend of mine participated in that trial, open label, but did not see any improvements, so he was switched to another clinical trial now (Abbvie).
Looks as if Mongersen is not going to be the revolution everyone has been waiting for.