Patients with the most common form of hepatitis B in the United States who are treated with Pegasys ( Peginterferon alfa-2a ) are more likely to achieve a sustained response than those treated with Lamivudine ( Epivir ), the current standard of care.

In a Phase III study patients treated with Pegasys displayed improvement in response rates vs. Lamivudine for both HBeAg, an antigen correlating with early and active hepatitis B infection, and HBsAg, an antigen that elevates before the onset of clinical symptoms.

The addition of Lamivudine to Pegasys did not improve the response rates at the end of 24-week follow-up.

" Treatment success in this study is measured by HBeAg seroconversion, and these results demonstrate that more patients achieved seroconversion when treated with Pegasys than with Lamivudine," said study investigator, Michael Fried of The University of North Carolina at Chapel Hill. " This is promising news for the 1.25 million people in the United States who are currently infected with hepatitis B."

Conclusions regarding comparative efficacy of Pegasys and Lamivudine treatment based upon the end of follow-up results are limited by the different mechanisms of action of the two compounds. Most treatment effects of Lamivudine are unlikely to persist 24 weeks after therapy is withdrawn.

Pegasys was approved in May 2005 for the treatment of hepatitis B and is the first and only pegylated Interferon FDA-approved for treatment of both variations of the virus -- HBeAg-positive and HBeAg-negative chronic hepatitis B.
Pegasys has a dual mode of action: it slows replication of the hepatitis B virus and boosts the immune system.

Hepatitis B can lead to cirrhosis, hepatocellular carcinoma, and death. It is estimated that hepatitis B can cause more than 5,000 deaths in the United States each year.

The Phase III study included 814 patients with HBeAg-positive chronic hepatitis B and evidence of compensated liver disease, evidence of viral replication and liver inflammation.
Patients were treated with either Pegasys monotherapy plus oral placebo, Pegasys plus Lamivudine, or Lamiduvine alone for 48 weeks.
Patients were followed for an additional 24 weeks post-treatment.

The results of the study at the end of follow-up showed:

- 32 percent of patients treated with Pegasys achieved HbeAg seroconversion, compared with 19 percent of those treated with Lamivudine. Pegasys and Lamivudine combination therapy did not improve the treatment outcome ( 27 percent of those on this combination achieved HBeAg seroconversion ).

- HBsAg seroconversion was reported in 16 patients treated with Pegasys ( with or without Lamivudine) and in none of the patients treated with Lamivudine alone. " HBsAg loss or seroconversion after therapy is considered the ultimate therapeutic goal of anti-HBV therapy, since it is associated with positive long-term clinical outcomes," the authors note.

- Conclusions regarding comparative efficacy of Pegasys and Lamivudine treatment based upon the end of follow-up results are limited by the different mechanisms of action of the two compounds. Most treatment effects of Lamivudine are unlikely to persist 24 weeks after therapy is withdrawn.

- The most common adverse events in the study included pyrexia, fatigue, headache, myalgia, alopecia and anorexia, all known to occur with Interferon alfa therapy.

Pegasys was approved in 2002 by the FDA for use alone and in combination with Copegus ( Ribavirin ) for the treatment of adults with chronic hepatitis C.
In February 2005, Pegasys became the first and only FDA-approved therapy alone and in combination with Copegus for the treatment of chronic hepatitis C in patients co-infected with hepatitis C and clinically stable HIV.

In the U.S., the most common modes of transmission of the hepatitis B virus are through sexual and blood-to-blood contact, although the disease can also be transmitted from pregnant women to their infants.

The number of new infections in the U.S. has decreased in recent years, in part due to the introduction of the hepatitis B vaccine in 1982. Almost all ( 90-95 percent ) adults who contract hepatitis B clear the virus from their systems within a few months and develop immunity. The remainder of the infections become chronic, which is when the virus stays in the blood, infecting liver cells and possibly damaging them.

Source: The New Englang Journal of Medicine, 2005


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