Before the Bell: Medarex, Biogen Rise  NEW YORK (Reuters) - Shares of Biogen Idec &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=BIIB.O target=/stocks/quickinfo/fullquote"&gt;BIIB.O&lt;/A&gt; climbed  6 percent before the bell on Monday, after better test results  for a multiple sclerosis drug it developed with Elan Corp.