Updated from 5:10 p.m. EST

Amylin Pharmaceuticals ( AMLN) reported a widened fourth-quarter loss after Monday's market close but surprised investors with stronger-than-expected revenue and sales of its Byetta injection for type II diabetes.

The San Diego-based biotechnology company's shares closed up 25 cents, or 0.8%, at $32.71, but fell 11 cents from there in recent post-market trading.

Amylin reported a net loss of $76.9 million, or 57 cents a share, for the quarter compared to a net loss of $58.4 million, or 45 cents a share, for the same period in 2006. The loss in the recent quarter includes a full-year, non-cash expense of $17 million associated with the adoption of an employee stock ownership plan.

Revenue came in at $222 million, surpassing expectations of analysts who were looking for an adjusted loss of 44 cents a share on revenue of $202 million.

For the year, the company reported a loss of $211 million, or $1.59 a share, on revenue of $781 million. Analysts expected an adjusted loss of $1.46, on revenue of $761 million.

Sales of Byetta, a drug for which Amylin partners with Eli Lilly ( LLY), came in ahead of estimates at $176.3 million, compared to a $170 million consensus estimate, $137 million in the fourth quarter of 2006 and $161 million in the third quarter of this year. The increase marks the largest sequential, or quarter-to-quarter, sales increase for the drug in 2007.

Revenue under collaborative agreements was $27.3 million for the quarter, compared to $12.8 million in the year-prior period. "The increase reflects higher cost-sharing payments from Lilly and Company to equalize development expenses for Byetta and exenatide once weekly," according to the company.

Amylin CFO Mark Foletta said on the company's quarterly conference call that the sequential growth rate in sales of about 10% in comparison to the prescription growth of about 4% primarily reflects wholesaler stocking due to year-end buying patterns.

Shares have declined more than 30% since the company reported third-quarter results in October, largely on investor concerns that Byetta sales growth is flattening.

At the JP Morgan Healthcare conference earlier this month, Amylin's CEO Dan Bradbury emphasized that primary care doctors are prescribing more of the drug. And on the Monday night conference call, Bradbury reiterated that general practitioners, who account for about 80% of diabetes drug prescriptions overall, are now prescribing more Byetta than early adopters of the drug, which included endocrinologists and diabetes specialists. Use of Byetta by specialists declined in 2007 but stabilized late in year, Bradbury noted.

Away from Byetta, Amylin reported $18.4 million for its Symlin injection for patients with type I and type II diabetes, vs. $13.6 million in the year-ago quarter.

Looking ahead, Amylin said it expects full-year revenue of between $900 million and $1 billion in 2008, and expects no milestone payments. The guidance brackets the Thomson Financial consensus target of revenue of $954 million for the year.

On the expense side, the company expects research and development to total between $325 million and $375 million, and general administrative costs of between $425 million and $475 million.

Amylin is planning to seek approval for Byetta as a monotherapy, or standalone treatment, in the first half of 2008, and plans to submit an new-drug application with the Food and Drug Administration for exenatide once-weekly (Byetta LAR) by the first half of 2009.

The company said on the call it has three superiority studies planned for Byetta LAR -- the earliest data for those trials are expected in the first half of 2009.