What a topsy-turvy year it has been for biotech leader Amgen (NASDAQ:AMGN).

Last week, the California-based biopharma giant released tepid third-quarter financial results. Posting quarterly top-line growth more in line with pharma giants like Pfizer (NYSE:PFE) than a burgeoning biopharma, Amgen's revenue was stagnant year over year because of difficulties surrounding its anemia franchise products.

Combined sales of anemia drugs EPOGEN and Aranesp were down 16%. Making up for shortfall with the anemia products were gains in sales of the anti-inflammatory Enbrel and an exchange rate movement that gave a healthy boost to product sales outside the U.S. Sales growth of colorectal cancer drug Vectibix also declined slightly from the second quarter as a result of March's negative phase 3 study data on progression-free survival with Vectibix combination use.

Amgen's bottom line didn't perform any better. Net income adjusted for one-time items and stock options was down 4% versus the third quarter last year, and adjusted earnings per share grew only $0.04 to $1.08 thanks to a 7% reduction in average share count for the quarter.

Amgen got a bit of good news last week when a jury ruled that Roche's anemia drug Mircera violated some of Amgen's patents. Roche is deciding whether to appeal. An FDA decision on Roche's marketing application for Mircera is expected Nov. 14, but Amgen's anemia franchise is safe in the U.S. at least for now.  

Most of Amgen's drugs on the market are mature products without a lot of sales growth left in them. Amgen does have a near-term growth opportunity with bleeding-disorder drug candidate romiplostim awaiting FDA regulatory review, but other than that it is reliant on an early-stage pipeline and on denosumab, a treatment for osteoporosis which increases bone density. Whether Amgen's growth looks more like Pfizer or Merck (NYSE:MRK) over the next few years increasingly looks like it will come down to how denosumab fares in data slated to be released in the second half of next year.  

Pfizer is an active Inside Value pick. Merck is a former Income Investor pick.

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