If you know that you are always going to not want that exact phrase, why not use substr()? Like so:

my @list = ('A test line',
            'foo bar',
            'A pdb file that I have',
            'this other thing');

foreach my $item (@list) {
  if (substr($item, 0, 10) ne 'A pdb file') {
    print "$item\n";    # Or do whatever...
  }
}
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