Shares of Amgen (AMGN) have moved into the green in after-hours trading following a late-day Wall Street sell-off that had the Dow tanking by over 500 points. As I wrote earlier today, Amgen was able to both exceed profit and sales expectations for 3Q08 and raise its full-year profit guidance as it had done three months ago when reporting 2Q08 results. Even with the current pop in after-hours to around $54 per share, Amgen is only trading at a PE of 12X on the mid-point of its 2008 profit guidance of $4.45 to $4.55 per share.Amgen posted EPS of $1.23 versus $1.08 consensus estimates on revenue of $3.88B versus $3.7B consensus estimates. Results of key drugs for the Company include:

- Epogen sales up 5% to $634M

- Aranesp sales up 3% to $845M

- Neulasta + Neupogen sales up 8% to $1.19B

- Enbrel sales up 9% to $893M

- Sensipar sales up 32% to $161M

Amgen ended 3Q08 with $9.8B in cash and $11.2B in debt. The Company raised both it revenue guidance ($14.9-$15.2B) and profit guidance ($4.45-$4.55 per share) for the full-year. Amgen is currently trading at a market cap around $53B, which results in a price/sales ratio of about 3.5X and a price/earnings ratio of about 12, based on full-year guidance for 2008. As a comparison, Genetech (DNA) trades at over 7X sales and a forward PE of over 20X, with an outstanding buyout bid from Roche (RHHBY) to buy out its remaining stake in the company.