Proving that not every sector is affected by downturns, Eli Lilly (NYSE: LLY) released its fourth-quarter results yesterday, showing a bit of pep in its top-line growth.

In the quarter, pro forma sales gained a strong 16% year over year, bringing Lilly's 2007 full-year revenue up 14% compared with 2006. The big sales gainer was depression and anxiety treatment Cymbalta, although revenue from most compounds like Cialis and diabetes drug Byetta also grew by double-digit percentages. Non-GAAP earnings per share came in at $3.54 for the year.

Most importantly, operating cash flow was up 25% in 2007 to $5 billion, thanks to cost-cutting and the sales gains. This is important because Lilly uses this cash to fund its generous 3.7% annual dividend and to acquire new drugs to stock up its pipeline ahead of all the major patent expirations on the horizon.

Speaking of the pipeline, Lilly expects to file a marketing application for its much-anticipated, longer-lasting version of Byetta by the end of the second quarter next year. My Foolish colleague Brian Orelli covered more of the Amylin Pharmaceuticals (Nasdaq: AMLN) Byetta news yesterday.

Lilly's other phase 3 drug candidate, its AIR inhalable insulin developed with partner Alkermes (Nasdaq: ALKS), lost another competitive threat when Novo Nordisk (NYSE: NVO) stopped development of its own inhaled insulin drug. Last quarter, Lilly's biggest pipeline candidate, anticoagulant prasugrel, produced mixed phase 3 data; Lilly recently filed a marketing application for it with the Food and Drug Administration anyway. 

As with all publicly traded companies, it's not the past that matters most but what the future holds. Lilly already announced its 2008 forecast back in December, and this year should be a respectable one, even with lead drug Zyprexa starting to face more generic competition.

I like to think of Lilly as a mini-Pfizer (NYSE: PFE). It will face many of the same generic troubles that Pfizer faces as both lose patent protection on their top drugs by 2011. Zyprexa accounted for about a quarter of Lilly's sales last year, but unlike Pfizer, Lilly has more opportunities to fill in the revenue hole because of its relatively stronger pipeline.