Image source: Regeneron Pharmaceuticals.

What: Rising demand for its top-selling vision drug, Eylea, and FDA approval of its new cholesterol-busting therapy, Praluent, led to shares in Regeneron Pharmaceuticals (NASDAQ:REGN) soaring 32.3% in 2015, according to Capital IQ.

So what: Regeneron Pharmaceuticals' Eylea has already delivered billion-dollar blockbuster sales as a treatment for age-related macular degeneration (AMD), but sales have really taken off following its approval for use in diabetic macular edema (DME) patients early last year.

In the third quarter, U.S. sales of Eylea grew 65% to $734 million, bringing global sales of the drug to $1.1 billion, up 53% year over year.

Adding to enthusiasm for Eylea's $4 billion run-rate is the FDA's approval this past June of Praluent, a cholesterol-lowering drug that was co-developed by Sanofi (NASDAQ:SNY).

In clinical trials, adding Praluent to traditional statin therapy reduced bad cholesterol by up to 60% more than statins alone, and that (and a $14,000 annual price tag) has industry watchers believing Praluent has what it takes to become the company's second multibillion-dollar blockbuster therapy.

Now what: Although Regeneron Pharmaceuticals splits profit overseas on Eylea with Bayer (OTC:BAYR.Y), Eylea is still massively profitable for the company.

In the third quarter, Eylea's growing worldwide sales resulted in Regeneron Pharmaceuticals reporting non-GAAP earnings per share of $3.47, up 38% year over year.

Given that 10,000 baby boomers turn 65 daily, and AMD and DME prevalence increases with age, there are plenty of tailwinds supporting additional Eylea sales growth in 2016.

Regeneron Pharmaceuticals should also begin generating meaningful revenue from Praluent in 2016 now that insurers are reimbursing for it, too. As of December, drug formularies covering more than 100 million patients had announced agreements to cover the drug.

As a result, Wall Street thinks Regeneron Pharmaceuticals could deliver some of the best EPS growth of any of the large-cap biopharma stocks. Currently, consensus expectations are for EPS of $14.97 in 2016, up 18.5% from the $12.63 expected for the full year 2015.

Overall, the improving profitability should give Regeneron Pharmaceuticals plenty of financial firepower to develop drugs in its pipeline, including the autoimmune disease drugs sarilumab and dupilumab and the osteoporosis pain drug fasinumab. Those drugs are in late-stage studies, and each could offer significant sales growth that could lead to shares heading even higher this year. 

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