If you only picked which stocks to buy based on performance in recent years, Amgen (NASDAQ:AMGN) would be the hands-down winner over Biogen (NASDAQ:BIIB). Amgen has delivered higher gains than Biogen over the last year, three years, and five years.

But there0's a lot more to consider when investing in biotech stocks than just recent performance. The companies' product lineups and pipelines are much more important. Here's a quick rundown of what you need to know to choose between Biogen and Amgen.

Scientist holding two test tubes

Image source: Getty Images.

The case for Biogen

Biogen made a name for itself with its multiple sclerosis (MS) franchise. The company's MS lineup includes three blockbuster drugs -- Tecfidera, Avonex, and Tysabri. However, overall MS sales are slipping somewhat as newer rival drugs take share away from Biogen. The company recently won FDA approval for Vumerity, though, which is a new MS drug that could boost sales. It also receives royalties from the sales of Roche's MS drug Ocrevus. 

The biotech's primary growth driver these days is Spinraza, which treats spinal muscular atrophy (SMA). Sales for the SMA drug continue to increase by double-digit percentages year over year, although the rate of growth is slowing.

Biogen also claims a solid biosimilars program. Sales for Imraldi and Flixabi (biosimilars to Humira and Remicade, respectively) are rising, but the company's Enbrel biosimilar, Benepali, has experienced sales declines recently.

In October, Biogen announced what is arguably the biggest bombshell news in years in the biotech market. After practically throwing in the towel on experimental Alzheimer's disease drug aducanumab in March, the company said that an analysis of a larger data set showed enough potential to file for U.S. approval for the drug. Should aducanumab reach the market, it holds the potential to achieve blockbuster sales.

While aducanumab is the crown jewel of Biogen's pipeline, the company's pipeline includes four other late-stage candidates, including amyotrophic lateral sclerosis (ALS) drug tofersen (also known as BIIB067). Biogen also has over a dozen phase 2 clinical programs, with MS drug opicinumab among the most promising candidates.

The case for Amgen

Immunology drug Enbrel continues to be Amgen's top moneymaker. And it's still delivering single-digit-percentage sales growth. But several other drugs are generating significantly higher growth, especially blockbuster osteoporosis drug Prolia. Newer products, including another osteoporosis drug, Evenity, and migraine drug Aimovig, are gaining significant momentum as well.

But Amgen also has products in its lineup that are weighing it down. Biosimilar competition is taking a toll on sales of bone marrow stimulants Neulasta and Neupogen. Generic rivals have taken market share from secondary hyperparathyroidism drug Sensipar. Sales are also sliding for anemia drugs Aranesp and Epogen.

Bristol-Myers Squibb's acquisition of Celgene was great news for Amgen. Antitrust regulators required that Celgene's immunology drug Otezla be divested to clear the path for the deal. Amgen bought Otezla for $13.4 billion, adding a growing blockbuster to its lineup.

Amgen's pipeline includes five late-stage programs, three of which are targeting additional indications for already-approved drugs. The two new drug candidates are omecamtiv mecarbil, which targets the treatment of heart failure, and tezepelumab, which is being evaluated in a phase 3 clinical study for treating asthma.

The company also has five phase 2 clinical programs, including one for tezepelumab targeting chronic obstructive pulmonary disease (COPD). Amgen's early stage pipeline is loaded with experimental cancer drugs.

Amgen has one thing going for it that most biotechs don't: a dividend. The company's dividend currently yields close to 2.5%. 

Better buy

If approval of aducanumab was a slam dunk, the decision between Biogen and Amgen would be a tough one. Biogen announced data on Thursday of last week, with the company seeking to explain why the experimental drug reduced cognitive decline in Alzheimer's disease patients in one late-stage study but failed to do so in another late-stage study. My view is that too many questions remain to have any confidence in aducanumab winning FDA approval.

With the future of aducanumab very murky, I think that Amgen is the better buy, if for nothing else, its solid dividend. While I like Amgen over Biogen, though, I'm not exactly enamored of either of these stocks. My view is that there are plenty of other stocks that provide better growth prospects than Biogen and Amgen.