Data from Development of a [<sup>89</sup>Zr]Zr-labeled Human Antibody using a Novel Phage-displayed Human scFv Library

Abstract

<div>AbstractPurpose:<p>Tax-interacting protein 1 (TIP1) is a cancer-specific radiation-inducible cell surface antigen that plays a role in cancer progression and resistance to therapy. This study aimed to develop a novel anti-TIP1 human antibody for noninvasive PET imaging in patients with cancer.</p>Experimental Design:<p>A phage-displayed single-chain variable fragment (scFv) library was created from healthy donors’ blood. High-affinity anti-TIP1 scFvs were selected from the library and engineered to human IgG1. Purified Abs were characterized by size exclusion chromatography high-performance liquid chromatography (SEC-HPLC), native mass spectrometry (native MS), ELISA, BIAcore, and flow cytometry. The labeling of positron emitter [<sup>89</sup>Zr]Zr to the lead Ab, L111, was optimized using deferoxamine (DFO) chelator. The stability of [<sup>89</sup>Zr]Zr-DFO-L111 was assessed in human serum. Small animal PET studies were performed in lung cancer tumor models (A549 and H460).</p>Results:<p>We obtained 95% pure L111 by SEC-HPLC. Native MS confirmed the intact mass and glycosylation pattern of L111. Conjugation of three molar equivalents of DFO led to the optimal DFO-to-L111 ratio of 1.05. Radiochemical purity of 99.9% and specific activity of 0.37 MBq/μg was obtained for [<sup>89</sup>Zr]Zr-DFO-L111. [<sup>89</sup>Zr]Zr-DFO-L111 was stable in human serum over 7 days. The immunoreactive fraction in cell surface binding studies was 96%. In PET, preinjection with 4 mg/kg cold L111 before [<sup>89</sup>Zr]Zr-DFO-L111 (7.4 MBq; 20 μg) significantly (<i>P</i> < 0.01) enhanced the tumor-to-muscle standard uptake values (SUVmax) ratios on day 5 compared with day 2 postinjection.</p>Conclusions:<p>L111 Ab targets lung cancer cells <i>in vitro</i> and <i>in vivo</i>. [<sup>89</sup>Zr]Zr-DFO-L111 is a human antibody that will be evaluated in the first in-human study of safety and PET imaging.</p></div>