Hepatitis Antivirals

Question 1

What is the treatment for HBV?

Answer 1

Lamivudine with Pegylated Interferon-alpha

Other antivirals - Entecavir, tenofovir, adefovir dipivoxil, telbivudine

Question 3

M.O.A of Pegylated Interferon Alpha

- What does “pegylated” mean?

Answer 3

IFN-a

• cytokine protein
• inhibits viral replication by inducing host cell enzymes which inhibit viral RNA translation leading to degradation of viral mRNA and tRNA
• activates NKCs and macrophages
• increases antigen presentation to lymphocytes
• induces resistance of host cells to virus - seroconversion of HbeAg to HbeAb

Pegylated = conjugated to polyethylene glycol - makes it last 7x longer in serum

Question 4

What is the treatment for HCV?

Answer 4

Pegylated IFN-a + Ribavirin

Both teratogenic

Question 5

M.O.A of Nucleoside Analogs;

• Lamivudine (cytosine analogue)
• Adefovir Dipivoxil (adenosine analogue)
• Entecavir (guanosine analogue)
• Tenofovir (adenosine analogue)
• Telbivudine (thymidine analogue)

Answer 5

All have to be phosphorylated intracellularly to their active analog forms.
They inhibit HBV DNA poly (reverse transcriptase) by:
- competing with the endogenous nucleoside for incorp into DNA (Lamivudine, Entecavir)
- are incorp into the DNA where they terminate further elongation of DNA chain (adefovir, telbivudine, tenofovir)

Question 7

M.O.A of Ribavirin

Answer 7

Pro-drug for synthetic guanosine nucleoside analog
Converted to 5’ phosphate derivatives, the main product being ribavirin-triphosphate, which inhibits guanosine triphosphate formation, preventing viral mRNA capping and blocking RNA-dep RNA poly