Wall Street had a great week. The Dow topped 15,000. The S&P 500 also notched a record high. But few stocks blew the doors off like those of these three biotech companies. Here are the biggest booming biotechs over the past week.

The eyes have it
Regeneron Pharmaceuticals
(REGN 0.32%) reported first-quarter results this week -- and Mr. Market liked what he heard. Shares soared almost 23%.

The biotech's eye medication Eylea powered earnings to easily beat analyst estimates. Regeneron announced non-GAAP earnings of $1.78 per share, well above the consensus expectation of $0.98 per share.

Revenue skyrocketed by nearly 90% year-over-year to $440 million, with net product sales accounting for $319 million of that total. Eylea made up nearly all of those sales. The drug, which first hit the market in the U.S. for treating age-related macular degeneration in November 2011, also received approval in September for the treatment of patients suffering from macular edema following central retinal vein occlusion.

Impressive first quarter results led Regeneron to up its full-year guidance for Eylea sales also. The biotech now expects the drug to achieve sales of $1.25 billion to $1.33 billion. Previously, Regeneron projected Eylea sales in the range of $1.2 billion to $1.3 billion. 

Bad is good?
The first quarter was a different story altogether for Questcor Pharmaceuticals (NASDAQ: QCOR). The biotech missed estimates for revenue and earnings. Nevertheless, shares rose nearly 17% during the week.

How did this happen? My view is that many investors realized that Questcor's quarter wasn't as bad as it looked at first blush. There were a couple of temporary factors at work that probably affected sales of Acthar gel.

Better yet, Questcor stated that April turned into a banner month for Acthar sales, especially for multiple sclerosis prescriptions. The company is also seeing positive results for rheumatology indications with an expanded sales force.

Jumping Juxtapid
Aegerion Pharmaceuticals
(NASDAQ: AEGR) shares popped by nearly 14% this week. The biotech reported first-quarter results, with investors particularly eager to hear about the commercial launch of Juxtapid.

It looks like investors received the news they hoped to hear. Aegerion reported that more than 185 patient prescriptions were written in the first quarter with 75 patients on the medication, which treats the rare lipid disorder homozygous familial hypercholesterolemia, or HoFH. The biotech's goal was to have 250 to 300 patients taking Juxtapid by the end of 2013. 

Some were concerned that Aegerion's path to success with Juxtapid would be challenging in the face of competition from Kynamro, another HoFH drug developed by Isis Pharmaceuticals (IONS -0.32%) and marketed by Sanofi (SNY 2.00%). Kynamro's annual price tag per patient of $176,000 falls well below the $235,000- to $295,000-per-year cost for Juxtapid. However, Aegerion is counting on having physicians and patients see its drug as the safer option.

Biggest boom of all
Which of these three biotech companies could see shares boom the biggest of all by the end of this year? Possibly Questcor.

The biotech's shares are still more than 30% below levels reached last September. Fears run aplenty about the possibility that payers will stop reimbursing for use of Acthar. The stock currently has a short interest of nearly 60%. If the strong April results that Questcor is touting continue into subsequent months, this stock could soar. 

My hunch is that the other two biotech companies will have great years, barring any unforeseen crises. Regeneron claims a more solid track to nice gains with Eylea. However, Aegerion looks to be off to a good start with the launch of Juxtapid. All in all, these booming biotechs seem set to keep the boom going.