Compared with getting the drug approved in the first place, raising more than $200 million to fund its commercialization is a snap.

Following a three-year battle to get Bydureon (exenatide) approved by the FDA, Amylin Pharmaceuticals Inc. filed a new underwritten public offering, hoping to bring in $203 million.

Amid an increasingly tough regulatory environment for drugs in the diabetes and cardiovascular space, Amylin had to submit Bydureon three times before the agency gave it the go-ahead.

Now the company is raising a war chest for the next battle, getting the drug out into the marketplace.

The offering comprises 13 million shares at $16.02 per share, with an underwriter's 30-day option to purchase 1.95 million additional shares.

Amylin's stock (NASDAQ:AMLN) closed at $15.77 Thursday, down 40 cents. There were about 147.8 million shares outstanding as of March 1.

In its prospectus, the San Diego-based company said net proceeds will be used primarily for expenses related to commercialization of Bydureon, as well as for general corporate purposes.

According to BMO Capital Markets analyst Jim Birchenough, the launch for the once-weekly version of the GLP-1 agonist is going well. Birchenough wrote, "Bydureon growth remains strong into the fourth week of launch."

Trends of increasing prescriptions of Bydureon were mirrored by downward trends in other GLP-1 drugs. According to BMO, total Bydureon prescriptions grew 40.9 percent in the fourth week of the drug's launch compared to the third week. New prescription growth for the same period was 39.9 percent.

Conversely, total prescriptions for other GLP-1 drugs fell 0.6 percent in the fourth week of Bydureon's launch, compared to the third week, and new prescriptions also declined 0.6 percent.

Bydureon had captured a 1.4 percent market share of total prescriptions and 3.8 percent for new prescriptions. Birchenough noted that week four total prescription growth seemed to come primarily from Byetta (twice-daily exenatide), while overall market share since launch has come from Byetta and Victoza (liraglutide, Novo Nordisk A/S).

Bydureon initially received a complete response letter in 2010 requesting clarification around the drug's manufacturing risk evaluation and mitigation strategy.

However, responding to those concerns did not get Bydureon to the finish line. Instead, the FDA issued a second complete response letter requesting a QTc study for cardiovascular safety. (See BioWorld Today, March 16, 2010, and Oct. 21, 2010.)

Data from that study finally won Amylin an approval for the drug. (See BioWorld Today, Jan. 30, 2012.)

The long wait for approval led to a falling out between Amylin and its partner Eli Lilly and Co.

During that delay, Indianapolis-based Lilly signed a deal with Boehringer Ingelheim GmbH related to diabetes drug Tradjenta (linagliptin), which it planned to market with the same sales force promoting Byetta. Amylin went to court to block Lilly from selling both drugs with the same team.

Additionally, Lilly had its own GLP-1 agonist, LY2189265, which could have been a competitor as early as 2013.

To resolve those conflicts, Lilly agreed to exit the partnership, handing over all U.S. sales of exenatide to Amylin, while continuing to sell the drug outside the U.S. through Dec. 31, 2013.

In its prospectus, Amylin noted $431.6 million in net costs associated with reacquisition of economic interest in exenatide products.

Now that Bydureon is on the market, its biggest differentiator may be side effects. As many as 60 percent of people with diabetes stop a new medication within the first six months for a variety of reasons, but mainly because of side effects.

Bydureon's lower rates of nausea and vomiting incidents compared to Victoza in its DURATION-6 trial may give it an advantage against the Novo Nordisk product, although Victoza edged out Bydureon in terms of efficacy.

Bydureon also has the advantage of convenience. As a once-weekly injection, Bydureon requires six fewer pokes than once-daily Victoza or twice-daily Byetta.

Eight percent of Bydureon sales revenue will go to Amylin's partner, Alkermes plc. The Dublin, Ireland-based firm provided the Medisorb technology enabling the developing of the long-acting version of exenatide.

In other financings news:

• Bellicum Pharmaceuticals Inc., of Houston, raised $20 million in a Series B financing to advance CaspaCIDe and DeCIDe programs through Phase II. The funding will be disbursed in two tranches, with about $10 million paid immediately. The balance will be paid upon initiation of the next phase of trials for the two lead products, around the third quarter of 2012. (See BioWorld Today, Nov. 15, 2011.)

• NeuroPhage Pharmaceuticals Inc., of Cambridge, Mass., secured $9 million in a Series B-1 financing for development of NPT002, a neurodegenerative disease candidate. The round included participation from existing investors Merieux Development, Shire plc and private investors. Total equity capital raised by the company since 2006 is $28.6 million.

• Sosei Co. Ltd., of Tokyo, will enter an agreement with JAFCO Super V3 for a nonbrokered private placement of preferred shares for gross proceeds of up to ¥836 million (US$10.2 million) to support development of SO-1105, an antifungal for oropharyngeal candidiasis in immunocompromised patients.