Safety, Tolerability, and Pharmacokinetics of the Broadly Neutralizing Human Immunodeficiency Virus (HIV)-1 Monoclonal Antibody VRC01 in HIV-Exposed Newborn Infants

Abstract

Background: Although mother-to-child human immunodeficiency virus (HIV) transmission has dramatically decreased with maternal antiretroviral therapy, breast milk transmission accounts for most of the 180 000 new infant HIV infections annually. Broadly neutralizing antibodies (bNAb) may further reduce transmission.

Methods: A Phase 1 safety and pharmacokinetic study was conducted: a single subcutaneous (SC) dose of 20 or 40 mg/kg (Dose Groups 1 and 2, respectively) of the bNAb VRC01 was administered to HIV-exposed infants soon after birth. Breastfeeding infants (Dose Group 3) received 40 mg/kg SC VRC01 after birth and then 20 mg/kg/dose SC monthly. All infants received appropriate antiretroviral prophylaxis.

Results: Forty infants were enrolled (21 in the United States, 19 in Africa). Subcutaneous VRC01 was safe and well tolerated with only mild-to-moderate local reactions, primarily erythema, which rapidly resolved. For multiple-dose infants, local reactions decreased with subsequent injections. VRC01 was rapidly absorbed after administration, with peak concentrations 1-6 days postdose. The 40 mg/kg dose resulted in 13 of 14 infants achieving the serum 50 micrograms (mcg)/mL target at day 28. Dose Group 3 infants maintained concentrations greater than 50 mcg/mL throughout breastfeeding.

Conclusions: Subcutaneous VRC01 as single or multiple doses is safe and well tolerated in very young infants and is suitable for further study to prevent HIV transmission in infants.

Keywords: HIV-1; VRC01; broadly neutralizing antibodies; mother-to-child transmission of HIV; neonates.

Figure 1.

Pharmacokinetics of VRC01 after a single subcutaneous dose administered within 72 hours of birth. Plasma concentrations of VRC01 (micrograms [mcg]/mL) determined as described in Methods at study visit days 1, 3, 7, 14, 28, 56, 112, and 168 (Dose Group 2 only) for Dose Group 1 (20 mg/kg) in red and for Dose Group 2 (40 mg/kg) in blue. Dose Group 3 (purple bars) received a single dose of 40 mg/kg within 5 days of birth, followed by monthly doses of 20 mg/kg. Levels from day 28 on represent trough levels. Solid black line indicates targeted trough of 50 mcg/mL. Error bars indicate standard deviation

Figure 2.

VRC01 concentrations (Conc) at day 28 in Dose Groups 1 (20 mg/kg), 2 (40 mg/kg), and 3 (40 mg/kg).

Figure 3.

VRC01 trough concentrations for repeated doses: 40 mg/kg subcutaneous (SC) once, then 20 mg/kg SC every 4 weeks. Individual lines represent each Dose Group 3 participant. The solid black line indicates the target VRC01LS trough of 50 micrograms (mcg)/mL.