New data that support using higher doses of Lipitor may provide another plank in Pfizer’s strategy to drive sales during its best-selling drug’s sunsetting patent window.

Reported in a recent study in Annals of Internal Medicine, the data showed that high-dose atorvastatin confers additional cardiovascular benefit to older adults with coronary heart disease. The secondary analysis, done as part of a Pfizer-supported study called Treating to New Targets, shows that patients 65 or older who received 80 mg. had a reduced risk for major cardiovascular events that approximately equaled that observed for patients younger than 65 who received 10 mg.

While the researchers could not determine whether the lower risk was due to the higher statin dose, lower achieved cholesterol levels, or both factors, the findings could be important as Pfizer seeks to wring sales out of Lipitor, which is set to go off patent in the 2010-2011 timeframe. This year the firm launched new DTC ads to try and increase new patient starts and minimize patient switches for the statin. That’s a priority for the firm, with multiple generic entries of Zocor (simvastatin) available and with branded competition from AstraZeneca’s Crestor and Merck/Schering-Plough’s Vytorin growing at a much faster rate than Lipitor in terms of US sales.

Stressing higher doses of Lipitor has paid off for Pfizer before. Last year another Pfizer study appearing in The New England Journal of Medicine showed that Lipitor in high doses reduces the chance that stroke survivors will be stricken again. Prescriptions for higher doses of the statin jumped in the weeks following the study, as the firm dispatched reps to detail physicians on the new data.

Pfizer’s Ian Read, president, worldwide pharmaceutical operations, said this year that the company is stressing more aggressive cholesterol targets and a higher starting dose—50% reduction of LDL, or “bad” cholesterol, with a 40 mg. starting dose of atorvastatin. By comparison, AZ touts 52% LDL lowering with a starting dose of only 10 mg.

The National Cholesterol Education Program recommends that those at very high cardiovascular risk “consider” LDL-C of less than 70 mg./dL. But that’s not a guideline.

Pfizer’s tactic of stressing potency comes as US sales of Lipitor rose just 4% from 2005-2006 to $6.58 billion, according to Verispan’s Vector One: National. Vytorin US sales grew 105% during the two-year period to $2.17 billion, Zetia from MSP sales rose 26% to $1.14 billion and Crestor sales grew 56% to $1.06 billion.