Drug Boosts Platelets in Hepatitis C Patients

It's not a cure, but this may be some of the best news patients infected with the hepatitis C virus (HCV) have heard in a long time: A new drug, eltrombopag, appears to be effective in boosting low platelet counts, one of the major reasons why patients can't endure antiviral treatments.

Other drugs that can restore normal platelet functions are infusions or injections; eltrombopag is a pill taken just once a day.

Researchers at Duke University Medical Center and other centers world-wide studied eltrombopag (marketed as Promacta in the U.S. and Revolade in Europe by GlaxoSmithKline) in 74 patients with low platelet counts and cirrhosis of the liver due to HCV infection. They found that it boosted platelet counts in a majority of patients at each of three dosage levels, enabling most of them to continue or start conventional antiviral treatment.

The findings appear in the current issue of the New England Journal of Medicine.

"We feel this is an important development for many people infected with the hepatitis C virus world-wide," says Dr. John McHutchison, professor of medicine and associate director of the Duke Clinical Research Institute. "A significant number of patients with HCV infection will at some point develop platelet problems that will compromise their getting the best treatments we have. Anything we can do to prevent that from happening would improve their care."

It's estimated that 4 million people in the U.S. and 170 million world-wide carry the hepatitis C virus. The virus causes inflammation and scarring in the liver, and while it is curable in about half of those who have it, it can lead to significant liver damage, liver cancer and death in others. HCV infection is a common cause of cirrhosis and the most common reason for a liver transplant.

Platelets are cells made in the bone marrow that are important in clot formation, and serious bleeding can occur if platelet levels fall too low. Some diseases, like HCV infection, can cripple the body's ability to manufacture platelets, but so can some medical treatments. Cancer patients, for example, can experience plummeting platelet levels when undergoing chemotherapy.

In the phase II, multi-center trial, participants were randomized to a control group or to receive 30, 50, or 75 milligrams of eltrombopag daily. The patients had platelet levels ranging from 20,000 to 70,000 (145,000 to 450,000 is normal).

A phase II trial is designed to test the safety and efficacy of a drug at different doses, and the Duke study found that eltrombopag worked in a dose-dependent manner, meaning that patients got a better response with increasing amounts of the drug. Seventy-four percent of those in the trial who took the lowest dose saw their platelet counts go up significantly, while 79 percent and 95 percent of the participants saw increases with the higher doses.

Eltrombopag does cause side effects. Some of the patients complained of headaches, dry mouth, abdominal pain and nausea.

"We are encouraged by these results and are already working on another multi-center, international, phase III trial where we hope these results will be confirmed," says McHutchison.

The study was sponsored by GlaxoSmithKline, which manufactures eltrombopag. McHutchison and many of the coauthors also report having received grants, consulting, advisory or speaking fees from the company.

Source: Duke University Medical Center

Related stories:

Global study shows telmisartan reduces outcome of cardiovascular death, heart attack or stroke
An international study led by Canadian researchers has found that telmisartan, a medication used to lower blood pressure, reduced the outcome of cardiovascular death, heart attack or stroke in people who are unable to tolerate a widely available and effective standard treatment.
Researchers tap into a new and potentially better source of platelets for transfusion
Japanese researchers may be one step closer to improving treatments for bleeding disorders. A group of researchers from the University of Tokyo has devised a way to maximize the numbers and function of clot-forming blood cells from mice. Their work will be published online in the Journal of Experimental Medicine on July 28.
Cancer 'cure' in mice to be tested in humans
Scientists at Wake Forest University Baptist Medical Center are about to embark on a human trial to test whether a new cancer treatment will be as effective at eradicating cancer in humans as it has proven to be in mice.
Reducing blockage fails to improve access to the bloodstream for kidney dialysis
Reducing early blockages in bloodstream access for kidney failure treatment does not increase the likelihood that the access will function adequately for long-term treatments, according to a study funded by the National Institutes of Health. Results were published May 14, 2008, in the Journal of the American Medical Association.
Ashwell receptor reduces mortality during sepsis
In research that solves the longest-standing mystery in glycobiology – a field that studies complex sugar chains called glycans – researchers at the University of California, San Diego School of Medicine have discovered that a molecule in the liver of all animals, called the Ashwell receptor, is critical in helping the body fight off the abnormal and lethal blood clotting caused by bacterial infection. Until now, it was suspected that this receptor might serve to remove abnormal proteins from circulation, but it wasn’t understood which proteins were affected or what biological purpose this receptor served.
Drug does not increase suitability for dialysis of surgically-enlarged blood vessels
The anti-platelet drug clopidogrel reduced the frequency of early blood clot formation in new surgically enlarged blood vessels (fistulas) created for patients requiring dialysis, but did not increase the proportion of these fistulas that subsequently became suitable for use during dialysis, according to a study in the May 14 issue of JAMA.
Naturally-occuring protein may be effective in limiting heart attack injury and restoring function
Medical College of Wisconsin researchers in Milwaukee have shown for the first time that thrombopoietin (TPO), a naturally occurring protein being developed as a pharmaceutical to increase platelet count in cancer patients during chemotherapy, can also protect the heart against injury during a heart attack.
New molecule could be key to anti-heart attack drug
When too many blood platelets stick together in the bloodstream, they form dangerous clots that can clog blood vessels and cause a heart attack. If a clot doesn’t get dissolved or rapidly removed, it can cause permanent damage or even death. But new research by Rockefeller University scientists suggests that it should be possible to create a clot-busting pill that targets a receptor on the blood cells’ surface, something that high-risk patients could take at the first sign of chest pain.

News discussion:

Medicine & Health news