Isis, Genzyme Cholesterol Drug Passes Test, But Investors Get Nervous About Liver Safety

The big new cholesterol-lowering drug from Genzyme and Isis Pharmaceuticals, which both companies are counting on as a future profit driver, passed its first major clinical trial, but investors didn’t like what they saw when full details were released this morning at a major medical meeting.

Carlsbad, CA-based Isis Pharmaceuticals (NASDAQ: [[ticker:ISIS]]) fell 16 percent to $11.17 at 1:30 pm Eastern time after details from the trial of the drug, mipomersen, were released at the American Heart Association’s scientific sessions in Orlando, FL. Cambridge, MA-based Genzyme (NASDAQ: [[ticker:GENZ]]), which isn’t nearly as dependent on the drug, saw its shares climb 2.6 percent.

Expectations have been running high for this drug for years, with many seeing it as the next big thing for cholesterol after the invention of multi-billion dollar statin drugs such as Pfizer’s atorvastatin (Lipitor). Isis’ very bullish CEO Stanley Crooke told me last month that the drug represents an historic advance. The drug is thought to have promise because it is the first of its class that’s made of specially engineered strands of RNA drugs to block a problematic protein in the body, which often can’t be hit by conventional small-molecule drugs. In this case, mipomersen is engineered to block the production of a protein called apoB that carries the so-called “bad” LDL cholesterol in the bloodstream. The drug is originally being tested among patients with a one-in-a-million genetic condition that causes them to die young from their extremely high cholesterol, although Genzyme and Isis envision this drug becoming more widely used among wider populations of people with extremely high cholesterol that can’t be controlled by existing meds.

“Mipomersen may well be a valuable addition to the therapeutic armamentarium,” said Frederick Raal, the primary investigator of the pivotal study of mipomersen, during a webcast from today’s scientific meeting. Raal is the director of the Carbohydrate and Lipid Metabolism Research Unit at the University of the Witwatersrand in South Africa.

So what was in the data that made Isis investors, at least, skittish? First off, it should be noted that the headline results were released back in May, when Isis and Genzyme said that mipomersen reached its goal of lowering “bad” LDL cholesterol by 25 percent, compared with a 3 percent reduction on placebo, in a study of 51 patients with homozygous familial hypercholesterolemia. This meant that patients had a 100 milligram per deciliter drop in their LDL scores, which significantly lowers their risk of dangerous cardiovascular events like heart disease and stroke, Raal said. Isis and Genzyme added further detail on the effect at today’s meeting, essentially showing that secondary goals, such as lowering total cholesterol and triglycerides, also were achieved among patients on the drug.

But the treatment, which was given in a once-weekly 200 milligram injection, had some side effects worth noting. Four of the 34 patients $12 percent) who were treated with mipomersen had

Author: Luke Timmerman

Luke is an award-winning journalist specializing in life sciences. He has served as national biotechnology editor for Xconomy and national biotechnology reporter for Bloomberg News. Luke got started covering life sciences at The Seattle Times, where he was the lead reporter on an investigation of doctors who leaked confidential information about clinical trials to investors. The story won the Scripps Howard National Journalism Award and several other national prizes. Luke holds a bachelor’s degree in journalism from the University of Wisconsin-Madison, and during the 2005-2006 academic year, he was a Knight Science Journalism Fellow at MIT.