HOW IS CHRONIC HEPATITIS B TREATED?

雪绒花

Interferon alpha and nucleoside analogues are the important treatments at this time for hepatitis B. At this time interferon alpha-2b is the standard agent but experts expect the nucleoside analogue lamivudine to replace it as the primary agent. Lamivudine is not only effective, it also less expensive than the interferon. Researchers speculate that future therapy for hepatitis B may need to involve combination treatment to achieve the greatest possible viral reduction and to minimize the chances of drug resistance.

Interferon Alpha for Hepatitis B
Interferon alpha-2b (Intron) is the standard drug for hepatitis B. It has eliminated the virus and sustained significant remission in 25% to 40% of patients with chronic hepatitis B. The drug is usually taken by injection every day for 16 weeks. (It does not appear to be effective for hepatitis D.) Unfortunately, even in hepatitis B, the virus recurs in almost all cases, although this recurring mutation may be weaker than the original strain.

Administering the drug for longer periods may produce sustained remission in more patients while still being safe. Interferon is also effective in eligible children, although long-term effects are unclear. A 2001 study suggested that it may temporarily disrupt growth, but it should be noted that hepatitis itself, even without interferon treatment, can compromise growth. [For a detailed description of Interferon and eligibility, see Box Interferons.]

Lamivudine and Other Nucleoside Analogues
Nucleoside analogues are drugs that can block viral replication, and they are important in hepatitis B. The primary agent used in hepatitis is lamivudine. It can be taken orally, has few severe side effects, and is less expensive than interferon. Experts expect it to become the first-line treatment for hepatitis B. Preliminary data suggest that other nucleoside analogues, including ganciclovir, adefovir, entecavir, and famciclovir, are also active against the hepatitis B virus and may useful in combination to reduce drug resistance to lamivudine.

Success Rates. The nucleoside analogue lamivudine (Zeffix) has reduced viral count in over half of hepatitis B patients who have taken it as sole therapy for about a year. It also appears to significantly reduce the risk for liver damage and cirrhosis. The drug even suppresses hepatitis B viral replication in HIV-positive patients and liver transplant recipients. It appears to be effective for children as well as adults. The drug may reduce the risk for cirrhosis, although it is not clear if it protects against liver cancer, particularly in patients who have harbored the virus since childhood.

Loss of Effectiveness. Although response rates can be very high for about a year, they tend to decrease with time in many patients. This is caused by emergence of mutated viruses that are resistant to the drug. Resistance may be particularly high in populations where the virus is common, according to a Korean study from an area where incidence of hepatitis B is high. The specific genetic hepatitis B strain may be an important marker for predicting resistance. Other nucleosides, such as adefovir and entecavir, may be able to suppress these mutated viruses.

Side Effects. Lamivudine causes muscle aches and chills but does not appear to have some of the distressing side effects of interferon, such as depression, hair loss, weight loss, or a drop in white blood cells (leukopenia). Of some concern, however, is eventual resistance to the drug in many patients.

Immunotherapy
A number of drugs are being studied that boost the body's own immune system to fight the virus.

Thymalfasin. Thymalfasin (Zadaxin) is a synthetic version of a peptide derived from the thymus gland (which produces immune factors call T-cells). It is injected and has few side effects. It appears to be safe for hepatitis B patients when used alone or in combination. Response rates of over 60% have been reported in combination with an interferon. A trial using thymalfasin with lamivudine is under way.

Vaccines as Treatments. Some hepatitis B vaccines, including Hepagene, are being investigated for treating as well as preventing hepatitis B.

Whey Protein. When a protein in milk called casein coagulates, a watery liquid called whey and solid white lumps called curds form. (Curds are the basis for cheese.) One interesting trial studied patients who consumed a supplement made from whey (Immunocal) twice a day. After 12 weeks hepatitis B patients showed improved biochemical measurements indicating possible benefits on the disease process. (It had no effect on hepatitis C patients.)