Purchasers of Amylin Pharmaceuticals Inc.'s previously announced $500 million private convertible note offering exercised their option to buy an additional $75 million worth of the notes.

The 3 percent convertible senior notes are due in 2014 and will convert at an initial rate of about $61.07 per share, a 40 percent premium to Monday's closing price. Shares of San Diego-based Amylin (NASDAQ:AMLN) dipped 79 cents on Wednesday to close at $42.24.

Amylin estimated that net proceeds from the offering, which is expected to close June 8, will be $558.9 million. Some of that will be used for continued commercialization of injectable diabetes drugs Byetta (exenatide) and Symlin (pramlintide acetate).

Byetta, an adjunctive therapy to improve glycemic control in Type II diabetics, chalked up $430.2 million in net sales last year through the efforts of Amylin and partner Eli Lilly and Co.

The drug originally was approved for patients who failed to achieve their glucose targets on metformin or sulfonylurea treatments, but last year it gained a label expansion for patients failing thiazolidinediones as well. Symlin, approved as an adjunctive therapy to improve glycemic control in Type I and Type II diabetics in whom insulin alone is not doing the job, brought in net sales of $43.8 million last year. (See BioWorld Today, March 18, 2005, and May 2, 2005.)

Proceeds from the offering also will be used to establish additional manufacturing sources. Sales of Byetta suffered because of supplier shortages last year, and Amylin has made moves to be more directly involved with manufacturing of the long-acting version, which is in late-stage trials. Results from a long-term comparator study are expected in the fourth quarter.

Additional proceeds may be used for acquisitions or to further the rest of Amylin's pipeline, which includes a nasal formulation of Byetta, a Byetta monotherapy clinical program, a late-stage pramlintide clinical program for obesity and various other obesity programs.

Amylin had $634.5 million in cash, equivalents and short-term investments as of March 31 and posted a net loss of $49.4 million for the quarter.

In other financing news:

• ArQule Inc., of Woburn, Mass., is planning a public offering of 7 million shares drawn from a $100 million universal shelf registration statement filed last month. Based on a June 5 closing price of $8 per share (NASDAQ:ARQL), the offering could generate gross proceeds of $56 million. An additional 1.05 million shares will be available to cover any overallotments. UBS Investment Bank and CIBC World Markets Corp. will serve as joint book-running managers, with Leerink Swann & Co. and Fortis Securities LLC acting as co-managers. Proceeds may be used for general purposes, acquisitions or research and development of the company's three oncology clinical programs.

• Dendreon Corp., of Seattle, priced its previously announced $75 million private offering of 4.75 percent convertible senior subordinated notes due 2014. The notes will convert at about $10.28 per share, a 17.5 percent conversion premium as of June 5. Proceeds will support activities relating to the cancer vaccine Provenge (sipuleucel-T) and other activities. Shares of Dendreon (NASDAQ:DNDN) got a 27 percent boost last week after the FDA said it would accept either a positive interim analysis or a positive final analysis from the ongoing D9902B (IMPACT) Phase III study as a response to its request for additional Provenge efficacy data. (See BioWorld Today, June 1, 2007.)

• Integra LifeSciences Holdings Corp., of Plainsboro, N.J., priced a private offering of $150 million in 2.75-percent senior convertible notes due in 2010 and $150 million in 2.375 percent senior convertible notes due in 2012. The 2010 notes will convert at about $66.26 per share, a 27.5 percent conversion premium as of June 5, while the 2012 notes will convert at $64.96 per share, a 25 percent conversion premium as of June 5. Proceeds will be used to repay a credit facility, to buy back $75 million worth of common stock, and to pay the cost of note hedge and warrant transactions that will reduce future dilution by increasing the conversion price of the 2010 notes to $77.96 per share and the 2012 notes to $90.95 per share. Additional proceeds from the offering, expected to close June 11, will be used for general corporate purposes such as developing and marketing surgical instruments and medical implants.

• Neurochem Inc., of Laval, Quebec, obtained shareholder approval for its previously announced $80 million private placement of convertible notes. Net proceeds from the private placement will be used for general corporate purposes including clinical development, research and capital expenditures. Neurochem expects a busy second quarter, including an FDA decision in July for Kiacta (eprodisate) in amyloid A amyloidosis and Phase III data for Alzhemed (tramiprosate) in Alzheimer's disease.

• WaferGen Biosystems Inc., of Fremont, Calif., completed a $10.7 million private placement of common stock and warrants. Rodman & Renshaw LLC acted as exclusive placement agent for the offering. Proceeds will be used to market the SmartSlide products, which allow time-lapse imaging studies to characterize, differentiate and proliferate difficult-to-cultivate cells; and to develop the SmartChip System for high-throughput, whole-genome analysis without advanced preparation of reagents.