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. 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 with documented drug resistance were randomly assigned once weekly leronlimab (350 mg subcutaneously) or matching placebo for 1 week overlapping existing failing antiretroviral therapy, followed by a 24-week single-arm extension with weekly leronlimab combined with a new optimized background treatment. The primary end point was achieving ≥0.5 log 10 reduction in plasma HIV-1 RNA from baseline at the end of the 1-week double-blinded treatment period. RESULTS: Fifty-two participants were enrolled (25 leronlimab and 27 placebo). After the 1-week randomized phase, by the intent-to-treat analysis, 64.0% (16/25) receiving leronlimab achieved ≥0.5 log 10 reduction in plasma HIV-1 RNA versus 23.1% (6/26) receiving placebo ( P = 0.0032), whereas by per protocol analysis, 72.7% (16/22) receiving leronlimab achieved ≥0.5 log 10 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 serious adverse events 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 1 week after addition to failing antiretroviral therapy. After 24 weeks combined with an optimized background treatment, most participants had plasma HIV-1 RNA levels <50 copies per milliliter plasma, suggesting utility of leronlimab as a component of salvage therapy.