use strict;
use warnings;
my $string="TestVar(Test1->(xy))->Var2(Test2(10)(12))->Finalvar"; 
while ($string=~s/   # repeat while we make matches
\(                   #beginning of a parenthesised group
[^)(]+               # non parentheses charaters 
\)                   # end of group
//gx)
{}
print "$string\n";