• Introduction

Entry inhibitors are antiviral drugs that prevent viruses from entering host cells, blocking infection at an early stage. They target viral proteins or host cell receptors involved in attachment and fusion. These inhibitors are crucial in treating diseases like HIV and hepatitis C, helping reduce viral replication and disease progression. Their ongoing development offers promising advances in antiviral therapy.

• Illustrated mechanism of action 

Mechanism:

1. HIV normally enters a host cell by attaching its gp120 protein to the CD4 receptor on the surface of T-cells.

2. This attachment triggers a conformational change allowing HIV to bind to a co-receptor (CCR5 or CXCR4).

3. Fusion of the viral envelope with the host cell membrane occurs, allowing viral RNA to enter the cell.

Entry inhibitors interfere with this process in two main ways:

CCR5 antagonists block the CCR5 co-receptor (e.g., Maraviroc). Fusion inhibitors prevent the fusion of the virus with the host cell 

• Indication

Used in combination with other antiretroviral agents for the treatment of HIV-1 infection.    Typically prescribed when other treatments are not effective or when drug resistance is present.

Monographs

Enfuvirtide