Leronlimab Treatment for Multidrug-Resistant HIV-1 (OPTIMIZE): a Randomized, Double-Blind, Placebo-Controlled Trial.

Background: Leronlimab is a humanized κ-IgG4 monoclonal antibody that blocks C-C chemokine receptor type 5 (CCR5). We investigated leronlimab as a treatment option for people living with multidrug-resistant HIV-1.

Setting: and Methods: In a phase 2b/3, multicenter, randomized, double-blind, placebo-controlled study conducted in 21 hospital centers in the United States, treatment-experienced people living with HIV (PLWH) with documented drug resistance were randomly assigned once weekly leronlimab (350 mg subcutaneously) or matching placebo for one week overlapping existing failing antiretroviral treatment (ART), followed by a 24-week single-arm extension with weekly leronlimab combined with a new optimized background treatment (OBT). The primary endpoint was achieving ≥0.5 log10 reduction in plasma HIV-1 RNA from baseline at the end of the one-week double-blinded treatment period.

Results: 52 participants were enrolled (25 leronlimab and 27 placebo). After the one-week randomized phase, by the intent-to-treat analysis 64.0% (16/25) receiving leronlimab achieved ≥0.5 log10 reduction in plasma HIV-1 RNA versus 23.1% (6/26) receiving placebo (p=0.0032), while by per protocol analysis 72.7% (16/22) receiving leronlimab achieved ≥0.5 log10 reduction in plasma HIV-1 RNA versus 24.0% (6/25) receiving placebo (p=0.0008). Leronlimab was generally well tolerated with no drug-related SAEs reported. Overall, 175 adverse events were reported by 34/52 participants, with 120 (68.6%) adverse events categorized as mild.

Conclusions: Leronlimab resulted in significantly reduced plasma HIV-1 within one week after addition to failing ART. After 24 weeks combined with an OBT, most participants had plasma HIV-1 RNA levels <50 copies per mL plasma, suggesting utility of leronlimab as a component of salvage therapy.