Aug. 04--CARLSBAD -- Isis Pharmaceuticals Inc. said Wednesday it has successfully completed the fourth and last needed late-stage test of its flagship cholesterol-lowering drug, mipomersen.
However, shares of Isis fell 5.6 percent Wednesday after the announcement, apparently because of continuing indications of liver toxicity. Shares closed at $9.43, down 56 cents for the day.
Isis and its marketing partner, Cambridge, Mass.-based Genzyme Corp., say they intend to file applications with European and American regulators in the first half of 2011 to sell mipomersen.
The drug is a major test of Isis' gene-blocking "antisense" technology that seeks to stop diseases at the genetic level. It's also important in its own right, as a new way of treating heart disease, a major killer.
Mipomersen is intended to help patients at risk of heart disease who experience high cholesterol even after being treated with other drugs. Patients with severely high cholesterol experienced a 36 percent reduction in LDL, or "bad" cholesterol, compared with a 13 percent increase for placebo.
Patients with high cholesterol and also high risk of heart disease experienced a 37 percent reduction in LDL cholesterol, compared with a 5 percent reduction for placebo.
The applications will initially be for treating those with homozygous familial hypercholesterolemia, an inherited disease that causes extremely high levels of LDL, and possibly others.
If that goes well, Isis and Genzyme say they plan to seek approval to treat high cholesterol in the general population. Drugs already on sale for that purpose sell billions of dollars a year.
Stanley Crooke, Isis' CEO, was quizzed in a Wednesday conference call about the potential for liver damage, as indicated in elevated counts of liver enzymes.
Crooke said the most recent trial, and the three others, showed great effectiveness in reducing LDL, a major health benefit that outweighed the toxicity concerns.
In the clinical trials, Isis stuck with a "rigid" design including a standard dose, to generate the most useful medical information, Crooke said. But after approval, doctors will be free to adjust mipomersen's dosage to suit their individual patients, he said.
Call staff writer Bradley J. Fikes at 760-739-6641. Read his blogs at bizblogs.nctimes.com.
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