The first quarter of 2007 was not kind to Amgen (NASDAQ:AMGN), the world's No. 2 biotech. This was a quarter of setbacks and diminished market opportunity, as several of the Amgen's most important compounds, like Aranesp and Vectibix, hit clinical trial or regulatory snags that will result in a reduced sales potential for these compounds.

Yesterday Amgen reported its first-quarter financial results. In 2006, year-over-year sales growth was consistently in the mid-teen percentage points, and Amgen continued this trend in 2007, with sales up 15% and adjusted net income up by the same for the first quarter.

It will take a few quarters for the negative clinical trial results from anemia treatment Aranesp and newly-launched cancer therapy Vectibix to creep into Amgen's top-line figures. However, revenue from Aranesp, which accounts for nearly a third of Amgen's sales, was up much less than in previous quarters -- 10% in the U.S. This was after Amgen issued a letter to doctors warning them of the risk of off-label usage of the drug.

Sales of Vectibix, on the other hand, appear to be making inroads against similar agents on the market like ImClone's (NASDAQ:IMCL) Erbitux. But the results of negative clinical trial results and a delayed enrollment in label-expanding clinical studies have not yet been felt. Over the coming months, the setbacks with both of these compounds should result in slower sales growth, particularly with Aranesp, where international sales have not yet been affected by the drug's developments.

As a result of the issues with Vectibix, and more importantly, Aranesp, shares of Amgen have been cut down nearly 10% this year. These concerns with its marketed products increase the importance of Amgen's clinical stage programs, like osteoporosis drug candidate denosumab. This candidate is currently in late-stage testing, and yesterday Amgen announced that it was successful in an important phase 3 study.

This quarter has seen some stumbles for Amgen, and unexciting top- and bottom-line growth figures. But once Amgen's R&D spending starts to ablate after completing several of its "mega" clinical studies, the biotech's net income should be able to finally scale faster than its revenue growth. And shares of Amgen aren't particularly expensive, trading at barely more than 15 times its 2007 GAAP earnings forecast. Longer-term investors willing to wait for Amgen's drug pipeline to mature may be getting their chance to own a proven Ferrari at Ford prices.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has a disclosure policy.