Phase 1 trial evaluating safety and pharmacokinetics of HIV-1 broadly neutralizing mAbs 10E8VLS and VRC07-523LS

Abstract

BACKGROUNDBroadly neutralizing monoclonal antibodies (bNAbs) represent a promising strategy for HIV-1 immunoprophylaxis and treatment. 10E8VLS and VRC07-523LS are bNAbs that target the highly conserved membrane-proximal external region (MPER) and the CD4-binding site of the HIV-1 viral envelope glycoprotein, respectively.METHODSIn this phase 1, open-label trial, we evaluated the safety and pharmacokinetics of 5 mg/kg 10E8VLS administered alone, or concurrently with 5 mg/kg VRC07-523LS, via s.c. injection to healthy non-HIV-infected individuals.RESULTSEight participants received either 10E8VLS alone (n = 6) or 10E8VLS and VRC07-523LS in combination (n = 2). Five (n = 5 of 8, 62.5%) participants who received 10E8VLS experienced moderate local reactogenicity, and 1 participant (n = 1/8, 12.5%) experienced severe local reactogenicity. Further trial enrollment was stopped, and no participant received repeat dosing. All local reactogenicity resolved without sequelae. 10E8VLS retained its neutralizing capacity, and no functional anti-drug antibodies were detected; however, a serum t1/2 of 8.1 days was shorter than expected. Therefore, the trial was voluntarily stopped per sponsor decision (Vaccine Research Center, National Institute of Allergy and Infectious Diseases [NIAID], NIH). Mechanistic studies performed to investigate the underlying reason for the reactogenicity suggest that multiple mechanisms may have contributed, including antibody aggregation and upregulation of local inflammatory markers.CONCLUSION10E8VLS resulted in unexpected reactogenicity and a shorter t1/2 in comparison with previously tested bNAbs. These studies may facilitate identification of nonreactogenic second-generation MPER-targeting bNAbs, which could be an effective strategy for HIV-1 immunoprophylaxis and treatment.TRIAL REGISTRATIONClinicaltrials.gov, accession no. NCT03565315.FUNDINGDivision of Intramural Research, National Institute of Allergy and Infectious Diseases, NIH.

Keywords: AIDS/HIV; Clinical trials; Immunoglobulins; Pharmacology.

Figure 1. CONSORT diagram.

One volunteer in Group 4 enrolled in the study but did not receive 10E8VLS and VRC07-523LS, and all other participants only received 1 administration of 10E8VLS and/or VRC07-523LS due to study termination.

Figure 2. Maximum solicited local and systemic reactogenicity following administration.

10E8VLS and VRC07-523LS were administered as separate injections at different sites on the same day and, therefore, have distinct local reactogenicity reported for each product.

Figure 3. Local reactogenicity experienced by participant 7 after product administration.

(A) Day 2 after product administration. RLQ reactogenicity quantified as 17 × 8 cm. RUQ reactogenicity quantified as 11 × 6.5 cm. (B) Day 3 after product administration. RLQ: 18 × 7 cm. RUQ 13 × 7 cm. (C) Day 7 after product administration. RLQ: 16 × 6 cm. RUQ 10 × 5 cm. VRC07-523LS was administered on the left side of the abdomen.

Figure 4. Pharmacokinetics of 10E8VLS.

(A) Mean antibody serum concentration and SD (µg/mL) of 10E8VLS administered at 5 mg/kg s.c. (B) PK parameters. All patients are included who received 10E8VLS (Group 1, 2, 3, and 4; n = 8) alone or in conjunction with VRC07-523LS. VRC07-523LS serum concentrations are depicted in Supplemental Figure 1. The black dotted line at y = 0.78 indicates the limit of detection. C_max, maximum serum concentration; T_max, time to maximum serum concentration; C_28D, Day 28 serum concentration; CL, clearance.

Figure 5. Neutralization characteristics of sera containing 10E8VLS.

Mean ± SD of experimental vs predicted IC₅₀ neutralization titers of 10E8VLS in Group 1 and 2 patients (n = 6) against genetically diverse HIV-1 Env–pseudoviruses. The black dotted line at y = 10 indicates the assay’s limit of detection. Experimental values were generated by HIV-1 pseudovirus neutralization assay, and predicated values were calculated as 10E8VLS serum concentration/control 10E8VLS IC₅₀.

Figure 6. Binding to preadipocytes and adipocytes by 10E8VLS and VRC01LS followed by IL-5 secretion.

(A) Binding of 10E8VLS or VRC01LS to primary human preadipocytes — or in vitro–differentiated adipocytes derived from 3 healthy donors at concentrations of 50, 25, and 12.5 mg/mL — was detected using an HRP-conjugated secondary antibody. The OD450 values indicative of binding are shown for each antibody concentration tested for each donor; the bar denotes the mean, with the error bars representing the SEM. (B) Primary human preadipocytes and adipocytes from 3 healthy donors were incubated with 50, 25, and 12.5 mg/mL 10E8VLS or VRC01LS. Culture supernatant was taken after a 4.5-hour incubation and assayed for secreted cytokine levels by a multiplex assay. The IL-5 levels are shown for each antibody concentration tested for each donor; the bar denotes the mean, with the error bars representing the SEM. For statistical analysis, a 2-way ANOVA using the Šidák multiple-comparison test was performed. ****P < 0.0001.

Figure 7. Serum aggregation and activation of complement proteins by 10E8VLS or VRC01LS.

(A) 10E8VLS or VRC01LS at different concentrations were incubated with either 10% or 50% HCS, and protein aggregation was measured by assessing OD at 600 nm. (B) 10E8VLS or VRC01LS at a concentration of 5 mg/mL, or no antibody control (PBS), were incubated with 20% HCS. The activation of complement was measured after a 30-minute incubation by quantifying levels of key complement proteins by a multiplex assay. The levels of C1q, C3, C3b/iC3b, and C4 are shown; the bar denotes the mean from 2 technical replicates. For statistical analysis, 1-way ANOVA using Tukey’s multiple-comparison test was performed. *P < 0.05 and **P < 0.01.

Figure 8. Monocyte activation by 10E8VLS or VRC01LS.

Monocytes derived from the peripheral blood from 3 healthy donors were incubated with 100 µg/mL of 10E8VLS, VRC01LS, or no antibody (PBS) for 3 days. The levels of different cytokines in the culture supernatants were assessed by a multiplex assay. The levels of IL-1β, IL-6, IL-8, IL-10, GM-CSF, and TNF-α are shown for each donor; the bar denotes the mean, with the error bars representing the SEM. For statistical analysis, 1-way ANOVA using Tukey’s multiple-comparison test was performed. **P < 0.01 and ***P < 0.005.