Passive Prophylactic Administration with a Single Dose of Anti-Fel d 1 Monoclonal Antibodies REGN1908-1909 in Cat Allergen-induced Allergic Rhinitis: A Randomized, Double-Blind, Placebo-controlled Clinical Trial

Abstract

Rationale: Sensitization to Fel d 1 (Felis domesticus allergen 1) contributes to persistent allergic rhinitis and asthma. Existing treatment options for cat allergy, including allergen immunotherapy, are only moderately effective, and allergen immunotherapy has limited use because of safety concerns. Objectives: To explore the relationship among the pharmacokinetic, clinical, and immunological effects of anti-Fel d 1 monoclonal antibodies (REGN1908-1909) in patients after treatment. Methods: Patients received REGN1908-1909 (n = 36) or a placebo (n = 37) in a phase 1b study. Fel d 1-induced basophil and IgE-facilitated allergen binding responses were evaluated at baseline and Days 8, 29, and 85. Cytokine and chemokine concentrations in nasal fluids were measured, and REGN1908-1909 inhibition of allergen-IgE binding in patient serum was evaluated. Measurements and Main Results: Peak serum drug concentrations were concordant with maximal observed clinical response. The anti-Fel d 1 IgE/cat dander IgE ratio in pretreatment serum correlated with Total Nasal Symptom Score improvement. The allergen-neutralizing capacity of REGN1908-1909 was observed in serum and nasal fluid and was detected in an inhibition assay. Type 2 cytokines (IL-4, IL-5, and IL-13) and chemokines (CCL17/TARC, CCL5/RANTES [regulated upon activation, normal T-cell expressed and secreted]) in nasal fluid were inhibited in REGN1908-1909-treated patients compared with placebo (P < 0.05 for all); IL-13 and IL-5 concentrations correlated with Total Nasal Symptom Score improvement. Ex vivo assays demonstrated that REGN1908 and REGN1909 combined were more potent than each alone for inhibiting FcεRI- and FcεRII (CD23)-mediated allergic responses and subsequent T-cell activation. Conclusions: A single, passive-dose administration of Fel d 1-neutralizing IgG antibodies improved nasal symptoms in cat-allergic patients and was underscored by suppression of FcεRI-, FcεRII-, and T-helper cell type 2-mediated allergic responses. Clinical trial registered with www.clinicaltrials.gov (NCT02127801).

Keywords: Fel d 1; IgG monoclonal antibodies; blocking antibodies; cat allergy; immunotherapy.

Figure 1.

Peak blood concentrations of two anti–Fel d 1 (Felis domesticus allergen 1) monoclonal antibodies (REGN1908 and REGN1909) were concordant with the maximal observed clinical response, supporting a direct pharmacodynamic effect. Concentrations of REGN1908 and REGN1909 in the serum of REGN1908–1909–treated patients. (A) Visual analog scale (VAS) score and (B) peak nasal inspiratory flow (PNIF) were also measured in REGN1908–1909–treated patients and placebo-treated patients at Day −14 (screening), Day 8, Day 29, Day 57, and Day 85. Analyses are based on analysis of covariance with treatment as a factor and baseline as a covariate. The proportion of patients who responded to REGN1908–1909 treatment also supports a pharmacodynamic effect. Nasal symptom VAS scores were reported by REGN1908–1909–treated patients and placebo-treated patients on Day 8, Day 29, Day 57, and Day 85 and were analyzed using a test for proportion with Yate's correction. Data are presented as proportions of patients who had a reduction in their VAS score by (C) 50%, (D) 75%, and (E) 90%. Time points were treated as factors and Day −14 was treated as a covariate. *P < 0.05, **P < 0.01, and ***P < 0.001. AUC_{0–1 hr} = area under the curve over the first hour after nasal allergen challenge; Conc. = concentration; S = least squares.

Figure 2.

Significant relationships were observed between anti–Fel d 1 (Felis domesticus allergen 1)/anti–cat dander IgE and the Total Nasal Symptom Score (TNSS) AUC_{0–1 hr} response. (A) Anti–cat dander IgE is inversely correlated with percentage improvement in TNSS (Spearman’s correlation). (B) Anti–Fel d 1 IgE inversely correlated with percentage improvement in TNSS (Spearman’s correlation). (C) The anti–Fel d 1 IgE/anti–cat dander IgE ratio directly correlated with percentage improvement in TNSS (Spearman’s correlation). (D) Percentage improvement in TNSS at Day 8 correlated with percentage inhibition of Fel d 1 binding to endogenous IgE by anti–Fel d 1 monoclonal antibodies (REGN1908–1909) (Pearson’s correlation). AUC_{0–1 hr} = area under the curve over the first hour after nasal allergen challenge.

Figure 3.

Single subcutaneous injection of a combination of anti–Fel d 1 (Felis domesticus allergen 1) monoclonal antibodies (REGN1908–1909) but not placebo suppressed cat allergen–induced, FcεRII (CD23)–mediated proallergic responses. Inhibition of CD23-mediated allergen–IgE binding to B cells was measured in the serum (REGN1908–1909, n = 27; placebo, n = 33; top left panel) and nasal fluid (REGN1908–1909, n = 37; placebo, n = 36; top right panel) at baseline, Day 8, Day 29, Day 57, and Day 85. The effect of inhibitory activity in the sera of REGN1908–1909–treated patients or placebo-treated patients (both, n = 12; bottom panels) at increasing concentrations of Fel d 1 allergen at baseline and Day 8 is shown. *P < 0.05, **P < 0.01, and ***P < 0.001 using Mann-Whitney U test.

Figure 4.

Single-injection of combined anti–Fel d 1 (Felis domesticus allergen 1) monoclonal antibodies (REGN1908–1909) inhibited type 2 cytokines and chemokines at a 6-hour time point. Levels of (A) IL-4, (B) IL-5, (C) IL-13, (D) TARC, and (E) RANTES (regulated upon activation, normal T-cell expressed and secreted) were measured in nasal fluid samples (Day 8) after 6 hours of intranasal cat allergen challenge. Samples were collected from REGN1908–1909– (n = 37) and placebo-treated (n = 36) patients. Data are shown as the mean ± SEM. *P < 0.05 using Mann-Whitney U test with Benjamini-Hochberg correction for multiple comparisons.

Figure 5.

Anti–Fel d 1 (Felis domesticus allergen 1) monoclonal antibodies (mAbs) (REGN1908, REGN1909, and REGN1908–1909) inhibited Fel d 1–induced basophil activation and histamine release in vitro. The whole blood was stimulated with increasing concentrations of Fel d 1 (0, 1, 3, 10, 33, 100 ng/ml; 100 ng/ml Fel d 1 is equivalent to 5.56 × 10⁻⁹ M). (A) Representative fluorescence-activated cell sorter plot analysis of CD63⁺CRTH2⁺ basophils in cat-allergic donors and nonatopic control donors at 3 ng/ml Fel d 1. (B) Proportion of CD63⁺CRTH2⁺ basophils in cat-allergic donors (n = 8) and nonatopic control donors (n = 9) in response to Fel d 1 at 3 ng/ml. ***P < 0.001. (C) Representative fluorescence-activated cell sorter plots of CD63⁺CRTH2⁺ and DAO⁻CD63⁺ basophils in cat-allergic donors after stimulation with 3 ng/ml Fel d 1 in the presence of either REGN1908, REGN1909, REGN1908–1909 or control mAbs at 10 ng/ml. Proportions of (D) CD63⁺CRTH2⁺ and CD203c^HiCRTH2⁺, and (E) DAO⁻CD63⁺ and DAO⁻CD203c^Hi were quantified in cat-allergic donors by flow cytometry. Data are shown as the mean ± SEM. For D–E, *P < 0.05 and **P < 0.01 for REGN1908 versus control mAbs, ^≠P < 0.05 and ^≠≠P < 0.01 for REGN1909 versus control mAbs; and ^ωP < 0.05 and ^ωωP < 0.01 for REGN1908–1909 versus control mAbs. All P values were calculated using the Mann-Whitney U test. DAO = diamine oxidase.

Figure 6.

Inhibition of FcεRII (CD23)–mediated IgE-facilitated allergen binding to B cells and presentation to T cells by anti–Fel d 1 (Felis domesticus allergen 1) monoclonal antibodies (mAbs) (REGN1908, REGN1909, and REGN1908–1909). (A) Representative fluorescence-activated cell sorter plots of allergen–IgE complexes binding to CD23 on B cells from cat-allergic donors and nonatopic control donors. (B) Sera from cat-allergic (n = 12) and nonatopic control donors (n = 9) were incubated with increasing concentrations of Fel d 1 at 37°C to allow the formation of allergen–IgE complexes. Binding of cat allergen–IgE complexes to B cells was quantified by flow cytometry. (C) Half-maximal inhibitory concentration graph representing the inhibition of cat allergen–IgE complexes binding to B cells in cat-allergic donors. Data are represented as a normalized value of 100% of maximal binding response at 0.03 μg/ml Fel d 1. (D) Flow cytometry analysis showing Fel d 1–induced proliferated CD4⁺ T cells in cat-allergic and nonatopic control donors. (E) The effect of REGN1908, REGN1909, REGN1908–1909, and control mAbs on proliferated CD4⁺ T cells was evaluated in cat-allergic donors (n = 7). Levels of (F) IL-13, (G) IL-17A, and (H) IL-23 in cell culture supernatants were measured by using a MagPix Luminex assay. Data are shown as the mean ± SEM. *P < 0.05, **P < 0.01, and ***P < 0.001 using Mann-Whitney U test. FSC = forward scatter; SSC = side scatter.