If it is all in one line, you could split it on the ; and do something like the following:

while (<DATA>) {
    my @split=split/;/;
    foreach (@split) {
    if (/\bHERE IS THE DATA PLACED (\w+)/) {
        s/\bHERE IS THE DATA PLACED//;
        print $_;
        #print "Matched\n";
    }else{
    next;
    }
}
}
__DATA__
HERE IS THE DATA PLACED ABC; DO NOT ENTER PLACED BCD; HERE IS THE DATA
+ PLACED ABC; WHO ARE U PLACED ABC
;

__OUTPUT__
ABC ABC
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Neil