AUTHOR=Santini Lorenzo , Duranti Claudia , Palandri Chiara , Giammarino Lucrezia , Musumeci Monica , Carlucci Lucia , Capitani Chiara , Colasurdo Rossella , Recchia Fabio , Cerbai Elisabetta , Coppini Raffaele , Arcangeli Annarosa 

TITLE=Cardiac safety assessment of a novel recombinant bispecific antibody targeting the ether-à-go-go related gene 1 (hERG1)-β1 integrin macromolecular complex

JOURNAL=Frontiers in Pharmacology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2023.1237431

DOI=10.3389/fphar.2023.1237431

ISSN=1663-9812

ABSTRACT=<p><bold>Introduction:</bold> In the last decades, mounting evidence has pointed out the human ether-á-go-go–related gene (hERG1) potassium channel as a novel biomarker in human cancers. However, hERG1 sustains the cardiac repolarizing current IKr and its blockade can induce a prolonged QT interval at the ECG, which increases the risk of life-threatening arrhythmias. This represents a major hindrance for targeting hERG1 for antineoplastic therapeutic purposes. Based on our discovery that hERG1 resides in a macromolecular complex with the β1 subunit of integrin adhesion receptors only in tumors, and not in the heart, we generated (and patented WO2019/015936) a novel engineered, single chain, bispecific antibody in the format of a diabody (scDb-hERG1-β1). This antibody has been proven to target with high affinity the hERG1/β1 integrin complex and to exert a good antineoplastic activity in preclinical mouse models.</p><p><bold>Methods:</bold> In the present study, we evaluated the cardiac safety of the scDb-hERG1-β1, determining the action potential duration (APD) of human cardiomyocytes, either atrial (from valve-disease patients) or ventricular (from aortic stenosis patients). Cardiac cells were incubated <italic>in vitro</italic> with i) the scDb-hERG1-β1, ii) the full length anti-hERG1 monoclonal antibody (mAb-hERG1) and iii) its single chain Fragment variable derivative (scFv-hERG1), from which the scDb-hERG1-β1 was assembled. All the tests were performed before and after treatment with the specific hERG1 blocker E4031. In addition, we have performed preliminary experiments, analyzing the effects of the scDb-hERG1/β1 <italic>in vivo</italic> measuring the QT interval length of the surface ECG after its injection intravenously in farm-pigs.</p><p><bold>Results:</bold> The scDb-hERG1-β1 did not produce any lengthening of APD compared to control (vehicle) conditions, either in atrial or ventricular cardiomyocytes, whereas both the hERG1-mAb and the scFv-hERG1 produced a significant APD prolongation. The addition of E4031 further prolonged APD. The scDb-hERG1-β1 did not produce any alterations of the QT (and QTc) interval values, once injected intravenously in farm pigs.</p><p><bold>Discussion:</bold> Overall, the above evidences plead for the cardiac safety of the scDb-hERG1-β1, suggesting that an application of this antibody for anti-cancer therapy will be untainted by cardiotoxicity.</p>