Remove pattern from string in Java

I am currently working on a tool, which helps me to analyze a constantly growing String, that can look like this: String s = "AAAAAAABBCCCDDABQ". What I want to do is to find a sequence of A's and B's, do something and then remove that sequence from the original String.

My code looks like this:

while (someBoolean){

    if(Pattern.matches("A+B+", s)) {
        //Do stuff
        //Remove the found pattern
    }

    if(Pattern.matches("C+D+", s)) {
        //Do other stuff
        //Remove the found pattern
    }

}
return s;

Also, how I could remove the three sequences, so that s just contains "Q" at the end of the calculation, without and endless loop?