Pfizer has filed a fresh suit against Dr Reddy’s Laboratories in the US District Court of Delware. The suit was filed by Pfizer Ireland Pharma for the anti-cholesterol drug Lipitor, the world’s largest selling drug. The suit presses for action against Dr Reddy’s which has developed a generic version of Pfizer’s Lipitor. Pfizer had earlier commented that it would be irrepairably harmed if Dr Reddy?s were to be allowed to sell the drug in the US. Pfizer holds an approved New Drug Application for Atorvastatin calcium formulations, including 10 mg, 20 mg, 40 mg, and 80 mg dosage strengths, which it sells under the brand Lipitor.