When new safety issues emerge for a drugmaker's top drugs, its finances can take a hit. Amgen Inc. (Nasdaq: AMGN) is no exception, based on the first-quarter results it reported last month.

As expected, extra competition and safety issues shrank Amgen's sales of its lead anemia franchise drug, and worldwide sales of Epogen and Aranesp took a 20 percent hit year over year. The lower sales and the sluggish results for cancer treatment Vectibix after its disappointing clinical trial results last year drove Amgen's overall quarterly revenue down 2 percent from the year-earlier period.

Unfortunately for Amgen, its financial results could get worse before they get better. The FDA is set to make decisions this year on potential label changes for Aranesp that could further affect a sizable chunk of the company's sales. Amgen's other anemia drug, Epogen, might also face continually toughening competition in Europe and potentially in the United States.

Until Amgen can get some pipeline and regulatory victories, its lackluster results will likely continue. It still has a few tricks up its sleeve, though, including its potential osteoporosis treatment, Denosumab. Its quickest chance to bring a new drug onto the market will arrive this year, when the FDA issues a likely positive late-July opinion on its thrombocytopenia drug, Nplate. Until then, Fools, keep your fingers crossed.