Despite little movement in the value of their shares, 2006 was an eventful year for investors in drug developer Endo Pharmaceuticals (NASDAQ:ENDP). The company concluded a patent dispute with Purdue Pharma over sales of generic OxyContin, launched its Opana pain drug, and expanded its marketing force by 60% to spur faster sales of its top products.

Endo gave its business outlook for 2007 on Monday, and it looks like this will be another busy year. The company hopes to gain an expanded marketing label on the migraine drug Frova, and it is preparing to file New Drug Applications in the first half of 2008 for its two pain treatments in phase 3 clinical trials.

On the income statement side of things, Endo guided for sales to be just more than $1 billion this year, representing low double-digit growth over the roughly $900 million it expects to take in during 2006. Revenues would have been up even higher, but Endo stopped marketing its generic version of OxyContin, which should bring in $50 million to $60 million in 2006, as part of the settlement with Purdue Pharma.

Despite the loss of the generic OxyContin revenues, sales growth of Endo's top product, the pain patch Lidoderm, will remain strong, up at least 20% over last year to $650 million-$675 million. Opana sales are also expected to pick up after its launch in the third quarter of last year.

Unfortunately, due to the ramping up of its sales force, its expanded R&D expenditures, and the loss of $0.22 a share in earnings (at the midpoint) from OxyContin sales, Endo's adjusted earnings will come in at no more than $1.72 a share this year versus the $1.55-$1.60 it earned last year.

Ordinarily, this sort of stagnating earnings growth is something to get worried about, but sales of the Lidoderm patch should more than make up for the lost OxyContin sales going forward. If Endo is successful in launching its two additional pain treatments in late 2008 or early 2009, then it will have three newly marketed drugs to drive earnings growth for years to come.

Shares of Endo aren't even particularly expensive, trading at 17 times its adjusted 2007 earnings per share. Exclusivity on a lead product and numerous near-term growth drivers, combined with a cheap valuation, can often be a recipe for pharmaceutical investing success. Shares of Endo are worth a look for anyone interested in investing in this sector.

For a look at some good companies poised for truly exceptional returns, take a free trial of Motley Fool Rule Breakers, our ultimate growth-stock newsletter.

Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has a disclosure policy.