Pfizer this morning says a court in Spain has become the latest to uphold a patent covering the firm’s cholesterol-lowering agent, Lipitor (atorvastatin) - the world’s best selling drug, with annual sales in excess of $11 billion dollars.

It has been a cheery end to the year for the US giant, which in the last few days saw a US judge uphold two patents for Lipitor, thereby blocking the entry of copycat offerings until 2011 and protecting its not-insignificant revenue stream, subject to appeal by challenger Ranbaxy of India.

In a statement this morning, Pfizer said the latest lawsuit was brought by Ratiopharm Espana S.A, and concerned patent number EP 409,281, which expires in July 2010 and is subject to other pending challenges in Spain.

Ratiopharm may still appeal the decision, but Pfizer sees it as good news for the pharmaceutical industry. Pfizer Vice Chairman and General Counsel Jeffrey B. Kindler commented: “The Spanish court decision is important for Pfizer and other medical innovators who invest in high-risk research to develop life-saving medicines

for millions of patients.”

Pfizer also won a case against Ranbaxy in the UK in October and in Norway in November, and added that victories in the Andean Court of Justice in Quito, Ecuador, this week would also protect its Lipitor patents in Peru, Ecuador and Venezuela. This decision is not appealable.

Lipitor is sold in Spain under the brand names Zarator and Cardyl.