Fostemsavir: a new CD4 attachment inhibitor

Purpose of review Even in the era of modern HAART, antiretroviral (ARV) failure and emergence of drug resistance is still a problem worldwide. New classes with different mechanisms of action are needed to overcome this challenge. After the integrase inhibitors were launched, more than a decade ago, no new classes were added to the ARV armamentarium. Recent findings Fostemsavir (FTR) is an attachment inhibitor, active regardless of viral tropism, without cross-resistance to any of the existing ARV compounds. A phase 3 study showed a reduction in plasma viral RNA of 1.21-1.73 log10 copies/ml from baseline after 8 days of functional monotherapy; at 48 weeks, up to 82% of patients treated with FTR and an optimized background ARV regimen achieved virological suppression below 50 copies/ml. Summary FTR is an investigational HIV drug with a novel mechanism of action that demonstrates virologic activity in HIV-infected treatment-experienced individuals.