Works for me!

use Data::Dump 'pp';

my $line = q{<item name="pdf_link">
           <value>http://www.yahoo.com</value>

</item>};

pp $line=~/(.*)(<item name=\"pdf_link\">\s*<value>)(.*)(<\/value>)(.*)
+/i;
__END__
(
  "",
  "<item name=\"pdf_link\">\n           <value>",
  "http://www.yahoo.com",
  "</value>",
  "",
)
[download]