Which Drug Combination and Sequence Works Best Against Hepatitis B?

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Which Drug Combination and Sequence Works Best Against Hepatitis B?

Source: HBV Advocate July 1, 2005

M. Kukka

With the availability of several new antiviral medications and pegylated

interferon, doctors are trying to define what drug or drug combinations will

work best to lower the amount of virus in the body (HBV DNA), strengthen the

immune system, and prevent liver damage.

Because over time patients can develop viral resistance to antivirals, which

work by

preventing viral reproduction, doctors must select the best drugs and the

right drug sequence to avoid viral resistance.

According to an article in the May 2005 issue of the Journal of

Antimicrobial Chemotherapy,

hepatitis B virus (HBV) that can resist lamivudine's (Epivir-HBV) antiviral

effects can also resist the effects of the antiviral emtricitabine.

The good news is that the antiviral adefovir (Hepsera) is effective against

these resistant HBV, as is the promising antiviral telbivudine. However,

entecavir (Baraclude) is not as effective, for example, against

lamivudine-resistant HBV.

Clevudine, another antiviral under development, is not effective against the

lamivudine-resistant strains, but it appears to be effective against

adefovir-resistant HBV, according to early studies.

Elvucitabine, another new antiviral, is not effective at clearing

lamivudine-resistant HBV, but it is effective against adefovir-resistant

strains.

Tenofovir is effective against lamivudine-resistant strains, but is only

slightly effective against adefovir-resistant HBV. There are also

tenofovir-resistant HBV that doctors are now studying.

" Given the cross-resistance profile of these drugs, the rationale is to

combine the drugs that would inhibit the emergence of drug-resistant strains

to one or the other drug. This may lead to an improved management of

antiviral therapy of chronic HBV infection in the long term, " the author

suggested.

To avoid the complexities of viral resistance, pegylated interferon therapy

may be the best first-step because it requires only short-term treatment and

carries the hope of a complete cure. But many patients will probably require

longterm treatment with antivirals to control viral replication and liver

disease. For them, clevudine and emtricitabine may be the best antiviral,

according to the article.

" Clevudine, with its unusual antiviral activity profile, may be the first

(antiviral) to be used as a relative short-term treatment and to achieve

sustained control of viral

replication even after treatment withdrawal, " the researcher wrote.

" On the other hand, emtricitabine, as well as other drugs in development,

offers a

new option for combination of nucleoside analogues that do not share the

same crossresistance profile. For instance, it may be used in combination

with adefovir or tenofovir. "

_________________________________________________________________

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[Guest guest]

Which Drug Combination and Sequence Works Best Against Hepatitis B?

Source: HBV Advocate July 1, 2005

M. Kukka

With the availability of several new antiviral medications and pegylated

interferon, doctors are trying to define what drug or drug combinations will

work best to lower the amount of virus in the body (HBV DNA), strengthen the

immune system, and prevent liver damage.

Because over time patients can develop viral resistance to antivirals, which

work by

preventing viral reproduction, doctors must select the best drugs and the

right drug sequence to avoid viral resistance.

According to an article in the May 2005 issue of the Journal of

Antimicrobial Chemotherapy,

hepatitis B virus (HBV) that can resist lamivudine's (Epivir-HBV) antiviral

effects can also resist the effects of the antiviral emtricitabine.

The good news is that the antiviral adefovir (Hepsera) is effective against

these resistant HBV, as is the promising antiviral telbivudine. However,

entecavir (Baraclude) is not as effective, for example, against

lamivudine-resistant HBV.

Clevudine, another antiviral under development, is not effective against the

lamivudine-resistant strains, but it appears to be effective against

adefovir-resistant HBV, according to early studies.

Elvucitabine, another new antiviral, is not effective at clearing

lamivudine-resistant HBV, but it is effective against adefovir-resistant

strains.

Tenofovir is effective against lamivudine-resistant strains, but is only

slightly effective against adefovir-resistant HBV. There are also

tenofovir-resistant HBV that doctors are now studying.

" Given the cross-resistance profile of these drugs, the rationale is to

combine the drugs that would inhibit the emergence of drug-resistant strains

to one or the other drug. This may lead to an improved management of

antiviral therapy of chronic HBV infection in the long term, " the author

suggested.

To avoid the complexities of viral resistance, pegylated interferon therapy

may be the best first-step because it requires only short-term treatment and

carries the hope of a complete cure. But many patients will probably require

longterm treatment with antivirals to control viral replication and liver

disease. For them, clevudine and emtricitabine may be the best antiviral,

according to the article.

" Clevudine, with its unusual antiviral activity profile, may be the first

(antiviral) to be used as a relative short-term treatment and to achieve

sustained control of viral

replication even after treatment withdrawal, " the researcher wrote.

" On the other hand, emtricitabine, as well as other drugs in development,

offers a

new option for combination of nucleoside analogues that do not share the

same crossresistance profile. For instance, it may be used in combination

with adefovir or tenofovir. "

_________________________________________________________________

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