Targeting immunodominant Bet v 1 epitopes with monoclonal antibodies prevents the birch allergic response

Abstract

Bet v 1 REGN5714 REGN5713 REGN5715Targeting immunodominant Bet v 1 epitopes with monoclonal antibodies prevents the birch allergic responseBet v 1, major birch tree allergen; FcER1, human receptor for Fc-fragment of IgE; Ig, immunoglobulin; mAbs, monoclonal antibodies.Cryo-electron microscopy reveals a planar and roughly symmetrical complex formed by REGN5713/14/15 bound to Bet v 1 Activation of allergic signaling cascade by Bet v 1 in birch allergic subjects REGN5713/14/15 binds to immunodominant epitopes on Bet v 1 preventing IgE engagement Substantial areas of Bet v 1 remain exposed in the complex suggesting that targeting specific epitopes of an allergen is sufficient to block the allergic responseBackground: Blocking the major cat allergen, Fel d 1, with mAbs was effective in preventing an acute cat allergic response.Objectives: This study sought to extend the allergen-specific antibody approach and demonstrate that a combination of mAbs targeting Bet v 1, the immunodominant and most abundant allergenic protein in birch pollen, can prevent the birch allergic response. Methods: Bet v 1-specific mAbs, REGN5713, REGN5714, and REGN5715, were isolated using the VelocImmune platform.Surface plasmon resonance, x-ray crystallography, and cryoelectron microscopy determined binding kinetics and structural data. Inhibition of IgE-binding, basophil activation, and mast cell degranulation were assessed via blocking ELISA, flow cytometry, and the passive cutaneous anaphylaxis mouse model. Results: REGN5713, REGN5714, and REGN5715 bind with high affinity and noncompetitively to Bet v 1. A cocktail of all 3 antibodies, REGN5713/14/15, blocks IgE binding to Bet v 1 and inhibits Bet v 1-and birch pollen extract-induced basophilFrom a Regeneron Pharmaceuticals, Inc, Tarrytown. This study was funded by Regeneron Pharmaceuticals, Inc.

Novel antibody cocktail targeting Bet v 1 rapidly and sustainably treats birch allergy symptoms in a phase 1 study

“…21 In agreement with this, we observe cross-reactive binding of our Bet v 1 mAbs to structurally similar allergens from alder and hazel, as well as the major apple allergen, Mal d 1. 37 Following treatment with REGN5713/14/15, there was significant suppression of basophil responsiveness to alder (rAlng 1), hazel (rCor a 1) pollen extract, and apple (rMal d 1). These data are also consistent with the SPT results that showed that REGN5713/14/15 significantly reduced mean wheal diameter after SPT with alder pollen extract.…”

“…REGN5713, REGN5714, and REGN5715 were shown to bind to homologous allergens in alder, hazel and hornbeam, while REGN5715 also bound to those in apple. 37 For the REGN5713/14/15 treatment group, there was an inverse correlation between the percentage change in TNSS AUC (0-1 hour) and EC50 for birch allergen on day 8 (r 5 20.71;…”

“…AIT: Allergen immunotherapy AR: Allergic rhinitis AUC: Area under the curve BAT: Basophil activation test EC50: Allergen concentration required to achieve 50% of maximal basophil activation NAC: Nasal allergen challenge OAS: Oral allergy syndrome PNIF: Peak nasal inspiratory flow SPT: Skin prick test TEAE: Treatment-emergent adverse event TNSS: Total nasal symptom score TOSS: Total ocular symptom score ex vivo and mast cell degranulation in vivo. 37 Preclinical pharmacokinetic and pharmacodynamic data demonstrated that a single 900-mg subcutaneous dose of REGN5713/14/15 would provide systemic concentrations for maximal inhibition of mast cell degranulation over the duration of the 2-month birch allergy season. The current study aimed to assess the safety, tolerability, pharmacokinetics, and efficacy of REGN5713/14/15 to reduce the early allergic response to nasal, skin, and basophil responsiveness to challenge with birch and other birch homologous tree allergens.…”

Isolation of nanobodies with potential to reduce patients' IgE binding to Bet v 1

“…Dissociation rates that are determined independently from the concentration of injected reagents, were proven for all three nanobodies to be in the range of 10 −4 /s demonstrating equal dissociation rates reported for allergen-specific monoclonal antibodies. 18,20 Since those monoclonal antibodies were effective in proof-of-principle clinical studies, 19,21 our generated Bet v 1-specific nanobodies represent promising tools as well for prospective clinical use.…”

“…Very recently, studies have demonstrated that passively administered allergen-specific monoclonal antibodies comparably reduce allergic responses as those induced in the course of AIT if they are directed to or overlap with IgE epitopes. [18][19][20][21] These trials showed for the first time that passive immunization with allergenspecific IgG antibodies able to inhibit patients' IgE binding to major allergens is a rapid, effective, and well-tolerated treatment to reduce allergic inflammation. [18][19][20][21] Since the generation and identification of blocking monoclonal human or humanized antibodies are laborious and expensive, recombinant antibody fragments including nanobodies turned out to be attractive molecules extensively studied for diverse applications in the recent past.…”