Switch from Ibalizumab to Lenacapavir in a Rescue Regimen for a Heavily Treatment-Experienced (HTE) Patient with Multidrug-Resistant (MDR) HIV-1 Infection.

Despite the progress of antiretroviral therapy, there are still some patients with (MDR) HIV infection. In this case, international guidelines suggest using new-generation drugs, such as Ibalizumab (IBA) or Lenacapavir (LEN), in combination with an optimized background regimen. Our clinical case concerns a Heavily Treatment-Experienced (HTE) patient with MDR HIV-1 infection. Rescue therapy began in April 2022, combining residual drugs with low-level resistance and IBA. At this time, HIV-RNA results included 37.800 copies/mL, and CD4+ included 147 cells/µL. IBA was administered intravenously every 15 days. After 12 months, to optimize adherence, IBA was re-placed by LEN, which has long-acting posology, with subcutaneous injections every 6 months. IBA achieved viral suppression in only one month with an improvement in the CD4+ count and showed a progressive disappearance of viral mutations in the reservoir. It was well tolerated except for the onset of hypertension after infusions. After 12 months, IBA was switched to LEN, which showed good tolerability, preserving efficacy and stable pressure on HIV-DNA. Our case report about an HTE patient shows that IBA was efficacious in the rescue regimen, while also acting on the reservoir. LEN, adopted in a switch strategy which differed from that described in the literature, preserved efficacy and stable pressure on HIV-DNA.