Regex not working in WPF

Hi,is there any chance that regex is not working properly in WPF? I have this code:

string itemdescription = "<description>Slovenky majú po štyroch zápasoch kvalifikácie majstrovstiev Európy 2013 na konte dve výhry a dve prehry.<![CDATA[Slovenky majú po štyroch zápasoch kvalifikácie majstrovstiev Európy 2013 na konte dve výhry a dve prehry.<center><script type='text/javascript' charset='windows-1250' src='http://go.cz.bbelements.com/please/code?i-11520.1.2.1.468.60.0.0.0.0.0.0._blank'></script><noscript><table border=0 cellpadding=0 cellspacing=0><tr><td><a href='http://go.cz.bbelements.com/please/redirect/11520/1/2/1/' target='_blank'><img src='http://go.cz.bbelements.com/please/showit/11520/1/2/1/?typkodu=img' border=0 width=468 height=60 alt='' /></a></td></tr></table></noscript></center>]]></description>";

            string pattern = "\\<!.*]]>";
            string replacement = " ";
            Regex rgx = new Regex(pattern);
            string result = rgx.Replace(itemdescription, replacement);

            Console.WriteLine(result);
            Console.Read();

Perfectly running in console. But when I put it in my WPF application, it doesn't do the effect of removing <! comment ]]> .