The Nasdaq Biotechnology Index was up 1.3% but slightly lagging the broader market Thursday, with the Nasdaq up 1.7% and the Dow up 1.3%.

Among those gaining in afternoon trading:
  • Amylin (AMLN) shares were rising 5% to $12.99 on news that billionaire investor Carl Icahn was building his position in the company as he tries to replace some board members.
  • Dendreon (DNDN), which announced it would give a company update via Webcast at the upcoming BIO CEO conferences, was lately up 4.8% to $3.68.
  • Medivation (MDVN) was up 1.7% to $19.56.
  • Elan (ELN) was down 0.5% to $8.01.
  • Genzyme (GENZ) was up 1.2% to $72.01.
  • Biogen Idec (BIIB - Get Report) was up 0.6% to $53.04.
  • Among those losing:
  • Genentech (DNA) shares were down 0.7% to $81.90.
  • Amgen (AMGN) was down 0.1% to $56.71.
  • Gilead Sciences (GILD - Get Report) was down 0.4% to $51.78.