Ibalizumab plus an optimized background regimen in treatment-experienced patients infected with multidrug resistant HIV-1: A phase 3, multicenter, expanded access study.

BACKGROUND

Patients infected with multidrug-resistant (MDR) HIV-1 have limited treatment options and poor clinical outcomes. For effective suppression of viral replication, regimens with distinct mechanisms of action and nonoverlapping patterns of resistance are needed.

SETTING

Studies of post-attachment inhibitor ibalizumab plus optimized background regimen (OBR) are needed to evaluate efficacy and safety of long-term use in patients with MDR HIV-1, potentially providing more treatment options.

METHODS

TMB-311 was a multicenter, open-label, expanded access phase 3 study that provided a compassionate bridge to commercial availability of ibalizumab for patients with and without prior exposure to drug.

RESULTS

In patients with prior exposure to ibalizumab, 23/39 (59%) had viral load (VL) <50 RNA copies/mL at study initiation and 26/34 (76%) had VL <50 copies/mL at Week 24. In ibalizumab-naïve patients receiving compassionate access, 0/38 (0%) had VL <50 copies/mL at study initiation compared to 11/24 (46%) at Week 24. Mean CD4+ cell counts increased from Baseline to Week 24 across both patient groups. Rates of serious treatment-emergent adverse events (TEAEs) up to Week 120 were low. Discontinuations due to TEAEs were 0% in the patients with prior ibalizumab exposure and 8% in those who were ibalizumab-naïve.

CONCLUSIONS

Long-term ibalizumab treatment in combination with an OBR was considered safe and well tolerated with no new safety signals identified in people living with MDR HIV-1. Additionally, ibalizumab-naïve patients experienced notable and early reductions in viral load with sustained increases in CD4+ cell counts over 24 weeks.