Mixed results from two Phase II clinical trials could delay Pfizer's launch
of its next-generation Lipitor product by as long as two years, according to
a Wall Street analyst.
The trial results, which Pfizer presented recently at the American Heart Association's (AHA) annual meeting, suggest that while Pfizer's Lipitor (atorvastatin) follow-on, known as torcetrapib, can dramatically lower cholesterol, it may also cause hypertension. Patients taking 60 mg of torcetrapib with Lipitor experienced an increase in systolic blood pressure, Pfizer said. The company said it intends to further examine the hypertension issues during Phase III studies.
Despite the positive aspects of the studies, including a 41 percent to 60 percent decline in patients' LDL cholesterol levels, Merrill Lynch analyst David Risinger said the data could delay Pfizer's launch of torcetrapib.
"We believe Phase II data indicates that hypertension is an issue at 60 mg and warrants more conservative approval/launch timing assumptions," Risinger wrote in a recent research note. "Previously we assumed a late 2007 approval and early 2008 launch. We now assume FDA will issue an approvable letter in late 2007, delaying launch to 2010."
Pfizer's first patent on Lipitor is set to expire in September 2009, according to the FDA's Orange Book. Currently the world's best-selling statin, Lipitor is expected to generate an estimated $12 billion in revenues this year, according to analysts.
In addition to the potential setback on torcetrapib, Pfizer reported mixed results for a clinical trial comparing the effectiveness of Lipitor and Merck's competing statin drug Zocor (simvastatin), Risinger said.
The Incremental Decrease in End Points Through Aggressive Lipid Lowering (IDEAL) trial showed that there was no advantage to taking a high dose of Lipitor over a normal dose of Zocor. The head-to-head study just missed its primary goal of demonstrating that the higher Lipitor dose was significantly better at reducing heart attacks and heart-related deaths among patients who have already had heart problems.
Although Lipitor outperformed Zocor on several fronts, such as lowering cholesterol and preventing nonfatal heart attacks, Risinger called the IDEAL results "disappointing" and said Merrill Lynch is revising its Lipitor revenue projections downward. "We believe this [data] can help insurers and [pharmaceutical benefit managers] on the margin as they work to push generic Zocor starting in mid-2006," Risinger writes. Merck's two patents on Zocor are set to expire in December 2005 and June 2006, according to the FDA's Orange Book.