Regeneron Pharmaceuticals (REGN -0.84%) announced its second-quarter results prior to the market open on Tuesday. Here are the three key things you need to know.

1. Analysts weren't happy
Revenue for the quarter totaled $458 million, a 50% year-over-year increase. However, Wall Street expected around $474 million.

Regeneron reported non-GAAP earnings of $198 million, or $2.02 per basic share and $1.73 per diluted share. That reflected a big jump over the $102 million, or $1.07 per basic share and $0.90 per diluted share, reported in the second quarter of 2012. It still wasn't enough to make analysts happy, though. The average estimate of analysts polled by FactSet was for non-GAAP earnings of $1.81 per share.

On a GAAP basis, Regeneron announced earnings of $87 million, or $0.89 per basic share and $0.79 per diluted share. This compared favorably against the $77 million, or $0.81 per basic share and $0.70 per diluted share, reported in the same period last year.

2. Eyeing an early entrance for Eylea
Net sales for Eylea during the second quarter were $330 million -- up 70% year-over-year. That's strong growth, but it wasn't enough to please analysts.

However, Regeneron had some unexpected good news that offset the disappointment. After discussions with the U.S. Food and Drug Administration, the company now plans to file for regulatory approval of Eylea as a treatment for diabetic macular edema, or DME, later this year. That's about a year ahead of the original schedule.

Regeneron and Bayer Healthcare, which markets Eylea outside of the U.S., announced positive results Tuesday morning from a phase 3 study of the drug in treating DME. Bayer plans to submit for regulatory approval in Europe for the indication this year.

3. Zaltrap and the "dandy dozen" move ahead
While Eylea is the crown jewel for Regeneron, the company has several other irons in the fire. It partners with Sanofi (SNY -0.47%) on development and commercialization of colorectal cancer drug Zaltrap. Sanofi reported Zaltrap net sales of $19 million for the second quarter, up from $14 million from the first quarter of this year. Competition from established drugs have made gaining traction for Zaltrap a challenge, though.

Roche's Avastin generated sales of around $3.3 billion in 2012. Bristol-Myers Squibb (BMY 0.34%) and Lilly (LLY 1.19%) together generated sales of around $1.1 billion in North America for Erbitux. Faced with stiff competition primarily from these two drugs, Sanofi decided to offer Zaltrap at a steep discount from its initial price to bolster sales.

Regeneron counts 12 antibodies in development, seven of them in collaboration with Sanofi. The two companies are currently enrolling patients in a phase 3 study of cholesterol drug alirocumab. Enrollment is also under way for phase 2b trials of allergic asthma drug dupilumab.

Phase 3 results for sarilumab as a treatment for rheumatoid arthritis are expected early next year. The drug, which is also being developed with Sanofi, is set for a phase 2 study in the treatment of non-infectious uveitis to begin in the third quarter of 2013.

Looking ahead
Shares of Regeneron dropped more than 5% in early trading on Tuesday. While the market was clearly disappointed, do the revenue and earnings misses portend trouble ahead? Probably not.

Eylea is still going strong. If it picks up approval for the DME indication, Regeneron looks to be in great shape to capture even more market share away from Roche's Lucentis.

Sanofi and Regeneron have a tougher battle with Zaltrap. Avastin isn't likely to be toppled. Bristol and Lilly will mount a fierce fight to protect Erbitux's market position also.

Regeneron's business should rock along. However, with a forward price-to-earnings multiple of 43, the stock is priced for perfection. If things don't go perfectly (like with the second quarter financial results), share prices will fall. Don't be surprised if Tuesday's pullback lingers for a while.