When Amgen ( AMGN) reports fourth-quarter and full-year earnings after the market close Thursday, expect the potential of its colorectal cancer treatment to be foremost on investors' minds. The Street has high expectations for Vectibix, which was approved in September for patients who have failed other therapies. The earnings results will be important as well, of course. Amgen has a solid track record of meeting or beating Wall Street's expectations. The Thousand Oaks, Calif., biotech company's earnings exceeded consensus estimates in the past three quarters and haven't missed the number since the fourth quarter of 2004. Analyst consensus estimates call for earnings of 95 cents a share for the quarter and $3.93 for the full year on revenue of $3.77 billion and $14.19 billion respectively. The revenue figure for Vectibix is not expected to be very meaningful to overall earnings this quarter. However, a higher sales total could indicate a quicker acceptance by doctors to use the drug, leading investors and analysts to extrapolate the beginning of a better-than-expected launch. I believe anything around $40 million will be construed as positive. In November, Vectibix had already garnered 11% market share in third-line usage, according to Reuters. In a study conducted by Robert W. Baird in October, 13% of surveyed physicians had already used Vectibix, while 44% planned on using it in the next 90 days. Furthermore, 12% and 18% of those surveyed planned on using Vectibix off-label in first- and second-line treatment.