N>character removing code until char

I have strings generated by my program ex. {Eff_stun,Eff_poison},{},{},,,,,,
I want to remove all "," from the rightside until it reaches "}"

TO make it short I need:

{Eff_stun,Eff_poison},{},{},,,,,, -> {Eff_stun,Eff_poison},{},{}
{Hello},{},{},,, -> {Hello},{},{}

I tried using replace with some other string functions but I'm not making the needed results.
Anyone can help me?? THx n Advance !!!