Pfizer loses top "AAA" rating from Fitch

NEW YORK, Dec 12 (Reuters) - Pfizer Inc PFE.N lost its top "AAA" rating from Fitch on Wednesday as the world's largest drugmaker struggles with patent expirations and girds for more through 2012.

Fitch downgraded Pfizer’s rating by one notch to “AA-plus” and changed the outlook to negative from stable, indicating another downgrade is likely over the next one to two years.

Pfizer makes the blockbuster anti-cholesterol drug Lipitor and the erectile dysfunction drug Viagra. The company is bracing for generic competition as soon as 2010, however, for the $13 billion-a-year Lipitor.

The downgrade reflects Pfizer’s maturing product portfolio and a limited number of promising late-stage drug candidates, Fitch said in a report.

“Pfizer devotes the highest investment in the pharmaceutical industry to its research and development program,” Fitch said in a statement. However, the company’s current late-stage program is thin compared to its peers, and is not expected to fully replace potential losses from looming patent expirations in 2011 and 2012, Fitch said.

Global sales of Pfizer’s array of medicines fell 4 percent in the third quarter, hurt by recent patent expirations on its Zoloft anti-depressant and Norvasc medicine for high blood pressure.

Zoloft sales plunged 73 percent to $124 million, while sales of Norvasc fell 47 percent to $640 million.

The company also suffered a sharp fall in third-quarter earnings because of a $2.8 billion charge to end its involvement with the poorly selling inhaled insulin drug Exubera. (Reporting by Dena Aubin and Ransdell Pierson; Editing by James Dalgleish)