A French National Real-World Survey of People With Multiresistant HIV-1 Viruses Receiving an Antiretroviral Regimen Including Fostemsavir or Ibalizumab.

Background: Attachment inhibitor fostemsavir (FTR) and postattachment inhibitor ibalizumab (IBA) are used in people with HIV-1 (PWH) who are highly treatment experienced and harboring multidrug-resistant viruses, and real-world data remain limited. We describe population characteristics and pharmacovirologic outcomes of PWH initiating FTR- or IBA-based regimens. Methods: We conducted a French retrospective observational study within the AIDS Research National Agency | Emerging Infectious Diseases virology and pharmacology network. Virologic failure (VF) was defined as 2 consecutive plasma viral loads (VLs) ≥50 copies/mL; nonvirologic response was considered a VL decrease <1 log Results: Among 70 PWH receiving FTR-based treatment, 50% were virologically suppressed at initiation; median VL among viremic cases was 3.6 log Conclusions: PWH receiving FTR or IBA had extensive multidrug resistance and limited therapeutic options. Among PWH who were viremic and initiating FTR- and IBA-based regimens, virologic success was achieved in 63% and 36%, respectively, and maintained in 91% who were virologically suppressed and starting an FTR-based regimen.