Abstract 1752: Nonclinical safety and pharmacokinetics of Sym004: A synergistic anti-EGF receptor antibody mixture

Abstract

Abstract Epidermal growth factor receptor (EGFR) is a well validated oncology target for monoclonal antibodies (mAb's). Symphogen is developing a novel and more efficacious anti-EGFR therapy to treat cancer patients with EGFR-dependent tumors. Sym004 is a recombinant antibody product consisting of a 1:1 mixture of two chimeric IgG1 mAb's targeting non-overlapping epitopes of EGFR. Preclinical proof-of-concept studies have shown that the Sym004 mixture is superior to existing anti-EGFR mAb's currently in clinical use (1). The nonclinical safety data of Sym004 are presented. The studies were designed to evaluate toxicity and pharmacokinetics of Sym004 as well as the individual antibodies comprising Sym004. No apparent accumulation was observed upon weekly dosing of Sym004 to non-human primates for eight consecutive weeks, whereas, a prolonged half life and accumulation were noted for both of the individual antibodies if these were administered alone. Weekly administration of Sym004 to non-human primates was well tolerated although dose limiting toxicity was observed in a dose-range-finding toxicology study. In a head-to-head comparison with the licensed anti-EGFR mAb, cetuximab (Erbitux®), weekly administration of Sym004 did not induce any distinct or novel adverse findings in the animals. However, and in accordance with the enhanced pharmacological profile of Sym004, an accelerated onset of anticipated anti-EGFR-mediated effects (skin rash and liquid faeces) was observed compared to cetuximab. None or only minor effects were observed in the animals treated with the individual antibodies comprising Sym004. All experimental observations, except a single case of rash, showed reversibility during the 4-week treatment free recovery period. In tissue cross reactivity studies, Sym004 had a staining pattern similar to cetuximab in a full tissue panel from both human and non human primates. In conclusion, Sym004 is considered to be safe, and the nonclinical safety data supported the initiation of the currently ongoing Phase I/II trial. 1. Pedersen MW et al. Cancer Res; 70(2) January 15, 2010 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1752. doi:10.1158/1538-7445.AM2011-1752