First Targeted Drug for Hepatitis D Every NEET PG Aspirant Must Know
Why is Hepatitis D Important?
Hepatitis D virus (HDV) leads to faster progression of chronic viral hepatitis and can even lead to Fulminant hepatic failure.
It cannot survive on its own because it is a defective RNA virus that requires the HBsAg (Hepatitis B surface antigen) of Hepatitis B virus to enter hepatocytes and replicate.
Golden Rule:
No Hepatitis B = No Hepatitis D
Patients with HDV progress much faster to:
- Cirrhosis
- Liver failure
- Hepatocellular carcinoma (HCC)
Introducing Hepcludex (Bulevirtide)
Bulevirtide (Brand: Hepcludex) is the first approved drug specifically designed for chronic Hepatitis D infection.
Mechanism of Action
HDV enters hepatocytes by binding to the NTCP receptor (Sodium Taurocholate Cotransporting Polypeptide) present on liver cells.
Bulevirtide blocks the NTCP receptor, thereby preventing:
- Entry of HDV
- Entry of HBV
- Infection of new hepatocytes
Easy Mnemonic
Bulevirtide = BLOCKS the Liver Entry of Hepatitis B and Hepatitis D viruss
Indications
Approved for:
- Chronic Hepatitis D
- Patients with compensated liver disease
- Usually given along with suppression of HBV replication using nucleos(t)ide analogues when indicated.
Route
- Subcutaneous injection
- Once daily
Major Side Effects
Common adverse effects include:
- Injection site reactions
- Elevated bile acids (expected because NTCP transports bile acids)
- Headache
- Fatigue
- Nausea
Why is This Drug Unique?
Unlike conventional antivirals that inhibit viral replication,
Bulevirtide prevents viral entry into liver cells.
It is therefore called an entry inhibitor.
Previous Standard Therapy
Earlier treatment relied mainly on:
- Pegylated Interferon-α
Limitations:
- Low response rates
- Significant adverse effects
- Poor tolerability
Bulevirtide has provided a major advance in the management of chronic HDV.
NEET PG MCQ
A patient with chronic Hepatitis D is started on Hepcludex. Which of the following best describes its mechanism of action?
- Inhibits HBV DNA polymerase
- Inhibits viral RNA polymerase
- Blocks NTCP receptor-mediated viral entry into hepatocytes
- Inhibits viral protease
Answer: C
Explanation: Bulevirtide is the first HDV entry inhibitor. It blocks the sodium taurocholate cotransporting polypeptide (NTCP) receptor on hepatocytes, preventing HBV and HDV entry into liver cells.
Take-Home Message
If you remember just one line for your exam:
Hepcludex (Bulevirtide) = NTCP blocker = Entry inhibitor = First targeted drug for chronic Hepatitis D