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Entry Entry and attachment inhibitors

Mechanism of action

Maraviroc blocks the CCR5 co-receptor (R5-tropic virus only); fostemsavir's active moiety temsavir binds gp120 and prevents attachment to CD4.

Genetic barrier to resistance

Reserved for multiclass resistance.

Class effects to know

  • Maraviroc: hepatotoxicity, postural hypotension
  • Fostemsavir: QT prolongation at high exposure
HIV-1 replication cycle and antiretroviral targets Seven steps from attachment to maturation, each labelled with the antiretroviral class that blocks it. CD4⁺ T cell Nucleus — host DNA provirus HIV virion new infectious virion Attachment & fusion gp120 binds CD4 then CCR5/CXCR4 Capsid transport & uncoating capsid docks at the nuclear pore Reverse transcription RNA → double-stranded DNA Integration integrase inserts provirus Transcription & translation host machinery makes viral RNA/protein Assembly & budding Gag/Gag-Pol at the membrane Maturation protease cleaves Gag-Pol Entry Capsid NRTI NNRTI INSTI Capsid PI

This class acts at the step labelled Entry (entry).

Drugs in this class

Maraviroc (MVC) SmPC not downloaded Fostemsavir (FTR) SmPC not downloaded