During most of 2016, when shares of AbbVie (ABBV -0.59%) went up, so did shares of GlaxoSmithKline (GSK 1.17%). However, after the U.S. election surprise, the paths of these two drugmakers' stocks have diverged. AbbVie is up, but Glaxo isn't. That's just a short-term snapshot, though. Which of these stocks is the better choice for investors over the long run? Here's how AbbVie and GlaxoSmithKline stack up.

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The case for AbbVie

Let's first address a couple of problem areas for AbbVie. Sales for hepatitis C drug Viekira tanked in the third quarter. Perhaps more ominous, though, is that momentum for AbbVie's perennial powerhouse Humira seemed to slow during the quarter.

I wouldn't count on any comeback for Viekira. While the hep-C drug will still probably generate over $1.5 billion this year, it's likely that its best days are now over. However, AbbVie doesn't seem to be worried about Humira just yet. CEO Rick Gonzalez said that the anti-inflammatory drug is tracking along with expectations. AbbVie CFO Bill Chase attributed the seeming slowdown in the third quarter to a seasonal effect.

For now, Humira remains one of the big reasons to own AbbVie's stock. The drug pulled in nearly $11.8 billion in the first nine months of this year, up 14.5% from the prior-year period. Continued growth is expected over the next few years.

Sooner or later, however, AbbVie won't be able to depend so heavily on Humira. What's the company's plan for a post-Humira world? Imbruvica should play a major role. Sales for the cancer drug topped $1.3 billion in the first nine months of 2016. More indications for Imbruvica could be on the way soon. AbbVie is waiting for regulatory approval for treatment of relapsed/refractory marginal zone lymphoma. The company also plans to submit for approval for treating chronic graft-versus-host disease in the first half of 2017.

AbbVie's pipeline includes 15 late-stage programs. Several of these candidates could emerge as winners. Two that especially stand out are anti-inflammatory drug risankizumab and elagolix, which targets treatment of endometriosis and uterine fibroids. Risankizumab targets several of the same indications that Humira currently treats. Analysts expect the drug could reach peak annual sales of $4 billion if approved. Peak annual sales for elagolix are expected to approach $2.5 billion if the drug is approved for both targeted indications.

Another thing for investors to like about AbbVie is its dividend. The dividend yield currently stands just over 4%. 

The case for GlaxoSmithKline

While AbbVie awaits the inevitable day when Humira's sales begin to slide, GlaxoSmithKline is already experiencing that pain with some of its key products. Sales for Glaxo's top-selling drug, Seretide/Advair, fell in the first nine months of 2016 compared with the prior-year period. So did sales of its biggest vaccines, Infanrix and Pediarix.

GlaxoSmithKline does have some bright spots in its current lineup, though. Sales for HIV drugs Tivicay and Triumeq are soaring. Several respiratory drugs are also performing well, including Anoro Ellipta and Relvar/Breo Ellipta. And despite weakness for Infanrix and Pediarix, Glaxo's vaccines segment continues to produce solid growth overall.

There's plenty to like in Glaxo's pipeline, which includes over 100 clinical programs. Notably, 15 of those are late-stage studies. I think that shingles vaccine Shingrix will be a huge winner for Glaxo. Look also for the drugmaker to build on its growing HIV portfolio with a combination treatment of Tivicay and Edurant. It seems likely that GlaxoSmithKline will be able to achieve growth over the next few years thanks to its big pipeline. 

Of course, we couldn't discuss the case for GlaxoSmithKline without mentioning the dividend. Glaxo has historically been one of the best big pharma dividend stocks. With a dividend yield of 4.77%, it still ranks at the top. The downside, though, is that the drugmaker is paying out more in dividends than it's earning. That situation won't be able to continue indefinitely.

Better buy

I think that AbbVie wins in a head-to-head match-up with GlaxoSmithKline. Humira's success won't last forever, but it's doing quite well for now. AbbVie also appears to be taking the right steps to position itself for when it can't count so heavily on its lead drug.

Imbruvica is just getting warmed up. The cancer drug should become an even bigger winner for AbbVie in the years ahead. And while the company's pipeline looks pretty good, I wouldn't be surprised if AbbVie were to acquire more candidates in the near future.