Cancer risk possibly attributable to Gattex as well as the clinical meaningfulness of reductions in intravenous feeding will be the two major issues tackled by the experts on Tuesday's FDA advisory panel. Aegerion Pharmaceuticals: Homozygous familial hypercholesterolemia (HoFH) is a rare and life-threatening genetic condition in which a person inherits damaged genes from both parents, rendering the body unable to clear LDL cholesterol -- the "bad" form of cholesterol -- from their bloodstream. HoFH patients, an estimated 3,000 in the U.S., can have LDL cholesterol levels four to ten times higher than normal people and cannot be reduced with conventional lipid-lowering drugs. As a result, these patients have severely clogged arteries that lead to heart attacks in their 20s and death in their 30s from cardiovascular disease. Aegerion's lomitapide is a once-daily pill that works by blocking a protein responsible for the production of very-low-density lipoproteins (VLDL), which are the precursors for LDL cholesterol. By inhibiting this protein, lomitapide prevents the liver and kidneys from secreting lipids into the bloodstream. In a phase III study, 29 HoFH patients treated with lomitapide for 26 weeks saw their LDL cholesterol levels reduced by 40%. These patients were all on a background of statin therapy and some were also on apheresis, a dialysis-like process that filters cholesterol from blood. Twenty-three of 29 HoFH patients continued on lomitapide therapy during a 78-week safety extension phase of the phase III study. At 78 weeks, these patients had a 38% reduction in LDL cholesterol and some were able to reduce their background lipid-lowering medications. Lomitapide causes a buildup of fat in the liver, elevated liver enzymes and gastrointestinal problems including diarrhea, nausea and vomiting. The drug's liver-related toxicities are of particular concern but will be weighed against the life-threatening nature of HoFH. Isis Pharmaceuticals and Genzyme: Mipomersen is a once-weekly injection that inhibits apo-B, a protein that carries forms of cholesterol, including LDL-cholesterol, throughout the bloodstream. Isis and Genzyme, a subsidiary of Sanofi, are developing mipomersen for broader range of high cholesterol-related disease than just HoFH -- heterozygous hypercholesterolemia, severe hypercholesterolemia and patients with high cholesterol at risk for heart disease.