Pharmacology
FDA Approves Entecavir for the Treatment of Chronic Hepatitis B Infection in Adults
By Akanksha, Pharmacology Correspondent
Mar 31, 2005, 08:56

Bristol-Myers Squibb Company announced today that the U.S. Food and Drug Administration (FDA) approved BARACLUDE(TM) (entecavir). Entecavir is indicated for the treatment of chronic hepatitis B infection in adults with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (ALT or AST) or histologically active disease.

Entecavir is an oral antiviral therapy specifically designed to block the replication of hepatitis B virus (HBV) in the body by interfering with the virus's ability to infect cells. The drug will be available in the United States as early as April 8, 2005.

"With the approval of Entecavir, Bristol-Myers Squibb will now be able to address another area of significant unmet medical need, building on our growing presence in fighting cancer, HIV/AIDS, schizophrenia and other diseases," said Peter R. Dolan, chairman and chief executive officer.

"Entecavir represents the company's fourth new pharmaceutical approved in less than two and a half years, and has the potential to help many adult patients with chronic hepatitis B infection. Developed in our own laboratories, Entecavir is an important step forward for patients and our company, as we seek to realize our mission of extending and enhancing human life by focusing on discovering, developing and providing innovative treatments for serious diseases."

"In clinical trials, Entecavir demonstrated greater levels of viral suppression compared to lamivudine after 48 weeks of treatment," said Robert Gish, M.D., medical director of the California Pacific Medical Center's Liver Transplant Program. "With today's FDA approval of Entecavir, physicians have an important new medication to treat chronic hepatitis B."

Chronic hepatitis B infection is a potentially life-threatening disease. More than half a million people worldwide die each year from primary liver cancer, and up to 80 percent of primary liver cancers are caused by chronic hepatitis B.

In the United States, more than one million people have developed chronic hepatitis B infection and more than 5,000 Americans die from hepatitis B and hepatitis B-related liver complications each year.

"Despite these alarming statistics, it is estimated that only a small percent of diagnosed chronic hepatitis B patients in the U.S. are currently receiving treatment for their disease," said Timothy Block, Ph.D., president, Hepatitis B Foundation and professor, Drexel Medical College. "The availability of Entecavir is an important development that provides a new option for therapy."

Entecavir is a nucleoside analogue with a recommended dosage of a single 0.5-milligram tablet once-daily for chronic hepatitis B patients beginning treatment for the first time (nucleoside-na�ve patients), and a single 1- milligram tablet once-daily for patients experiencing resistance to lamivudine (lamivudine-refractory patients).

The Entecavir clinical trial program was the largest-ever conducted in chronic hepatitis B, and the first to compare two antivirals, Entecavir versus lamivudine (the most commonly used oral antiviral therapy for the treatment of chronic hepatitis B worldwide).

In these studies after 48 weeks, Entecavir demonstrated statistically significant improvements compared to lamivudine in liver histology, HBV viral load reductions to undetectable levels (defined as less than 300 copies/mL) and normalization of alanine aminotransferase (ALT) levels (less than or equal to 1 times the upper limit of normal), a measure used to determine the degree of liver damage.

In these studies, Entecavir demonstrated comparable safety to lamivudine with a favorable resistance profile. Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues alone or in combination with antiretrovirals. Severe acute exacerbations of hepatitis B have been reported in patients who have discontinued anti-hepatitis B therapy, including Entecavir and lamivudine.

The most common side effects of Entecavir in clinical studies were headache, tiredness, dizziness, and nausea. Cross resistance has been observed among HBV nucleoside analogues. Lamivudine-resistant patients may not respond as well as nucleoside-na�ve patients to Entecavir therapy.

BARACLUDE (entecavir) is a prescription medicine for the treatment of chronic hepatitis B infection in adults with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (ALT or AST) or histologically active disease.

Entecavir does not cure HBV or stop the spread of HBV to others.

People should not take Entecavir if they are allergic to it or any of its ingredients. Entecavir has not been studied in children and is not recommended for anyone less than 16 years of age.

People taking Entecavir should tell their healthcare provider right away if they feel very weak or tired, have unusual muscle pain, have trouble breathing, have stomach pain with nausea and vomiting, feel cold - especially in their arms and legs, feel dizzy or lightheaded, or have a fast or irregular heartbeat, as they may be signs of a serious condition called lactic acidosis (buildup of an acid in the blood). Lactic acidosis is a medical emergency and must be treated in the hospital.

Some people who have taken medicines like Entecavir have developed serious liver problems called hepatotoxicity. This may occur with liver enlargement (hepatomegaly) and fat in the liver (steatosis).

People should call their healthcare provider right away if they get any of the following signs of liver problems:

-yellowing (jaundice) of the skin or the white part of the eyes,
-darkening of the urine,
-lightening in the color of bowel movements (stools),
-not feeling like eating food for several days orlonger,
-feeling sick to the stomach (nausea), or
-having lower stomach pain.

Lactic acidosis and hepatotoxicity have happened in some people taking medicines like Entecavir.

In some people, hepatitis B symptoms may get worse or become very serious when they stop taking Entecavir. People should not stop Entecavir without talking to their healthcare provider. Healthcare providers will need to follow their patients and do blood tests to check the liver when Entecavir is stopped.

People should tell their healthcare provider if they have or develop kidney problems because their healthcare provider may want to do tests to see if a lower dose is needed.

It is not known if Entecavir is safe to use during pregnancy. It is not known if Entecavir helps to prevent a pregnant mother from passing HBV to her baby. A pregnant woman and her healthcare provider will need to decide if Entecavir is right for her. A woman should not breast-feed if she is taking Entecavir.

People should discuss with their healthcare provider all prescription and non-prescription medicines, vitamins, herbal supplements, and other health preparations they are taking or plan to take.

Entecavir may interact with medicines that leave the body through the kidneys. The most common side effects of Entecavir in clinical studies were headache, tiredness, dizziness, and nausea. This list of side effects is not complete at this time because Entecavir is still under study. People should report any new or continuing symptom to their healthcare provider.

Entecavir should be taken once daily on an empty stomach (at least 2 hours after a meal and 2 hours before the next meal).

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