The New Generation of Cardiac Drugs
David Rutlen, MDMedical College of Wisconsin Cardiologist;
Director, Froedtert & Medical College of Wisconsin Cardiovascular Center;
Chief, Cardiovascular Medicine
Millions of Americans take medications to prevent and treat cardiovascular disease, and drug researchers are always seeking new and better treatment methods. Dr. David Rutlen discusses two new drugs currently in trials. One — torcetrapib — shows promise in better managing cholesterol levels; the other — ximelagatran — helps to prevent blood clots with fewer side effects than the medication now used.
Q. How does the drug torcetrapib better manage cholesterol levels?Torcetrapib is a medication that raises HDL cholesterol - that's the good cholesterol. Putting that in perspective, we've known for 10 years that it is critical to lower the LDL cholesterol — that's the bad one. Lowering the LDL cholesterol can prevent people from getting coronary disease. And in patients who already have the disease, lowering the LDL cholesterol can lead to fewer cardiac events and a longer life. But the data we have now demonstrate the importance of raising the HDL cholesterol. In a modest number of trials that have been done, individuals on medication that raises the HDL cholesterol end up having fewer cardiac events. Currently there are two agents we can use that raise the HDL cholesterol. One is gemfibrizil and the other is niacin. But they don't raise the HDL cholesterol very much. Although there's a benefit to using these medications, it is probably limited.
Q. Does torcetrapib do a better job of raising the HDL cholesterol?In a recent study, torcetrapib had a profound effect on the HDL cholesterol. When it was given as just 120 milligrams, torcetrapib raised the HDL cholesterol anywhere from 46 to 61 percent. The higher percentage was seen in patients who were also taking a statin, a drug that lowers the LDL cholesterol. And when the dose of torcetrapib was doubled – to 120 milligrams twice a day — it raised the HDL cholesterol 106 percent.
Now this study was done on a very small number of patients to see if torcetrapib was safe and what its affect was on HDL cholesterol. And it wasn’t studied long enough to see if it had any beneficial effect in preventing cardiac events. But if the drug pans out as it did in this early trial, it could be very, very important. In fact, we know if a patient has a high level of HDL cholesterol, we can subtract a risk factor when we do an assessment.
Q. What are the indications of use for the other new drug, ximelagatran?Ximelagatran is being examined to see if it can replace the drug warfarin. Warfarin is used to prevent blood clots from forming or growing larger. It is most commonly used in patients who are in atrial fibrillation, an irregular heart action in the heart's upper chambers. Blood isn't effectively pumped out ofthe chambers and may pool and clot. These clots can travel to the brain and cause a stroke. Warfarin reduces this risk. Warfarin is also used to prevent blood clots in patients with mechanical artificial heart valves, and in patients who had a deep vein thrombosis that went on to become a pulmonary embolism.
The problem with warfarin is it's a tough medication to take because patients must get frequent blood tests to monitor the thinning of their blood. When warfarin is first administered, patients have to have their blood tested every several days, and once they're stable, they still need to be tested every three to four weeks for the rest of their lives.
Early reports indicate that ximelagatran can be taken instead of warfarin with the same benefits but without the need for frequent blood tests. This is really big because there are many patients who are incredibly reluctant to take warfarin because the frequent checks interfere with their lifestyle.
Torcetrapib and ximelagatran have the potential of benefiting thousands if not millions of patients and it is expected both will be available for use in the near future.
Author: David Rutlen, MD
Source: Every Day
Date: May - August 2005