Abstract 4491: FGFR2-ADC potently and selectively inhibits growth of gastric and breast cancer xenograft models

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Antibody-drug conjugates (ADCs) represent a promising therapeutic approach for treatment of cancer. We have developed a novel ADC directed against fibroblast growth factor receptor 2 (FGFR2). FGFR2 is overexpressed in several cancer indications, such as gastric cancer and breast cancer, thus representing an interesting therapeutic target for the treatment of FGFR2 positive cancer patients with an ADC-based therapy. The FGFR2-ADC consists of the fully human anti-FGFR2-mAb BAY 1179470 conjugated via a stable linker to a novel auristatin cytotoxic agent (technology licensed from Seattle Genetics). The FGFR2-mAb BAY 1179470, which is cross-reactive with human, mouse, rat and monkey, induces internalization of FGFR2. Quantitative data on FGFR2 antibody bound per cell (ABC) were determined with the QuantiBrite assay using BAY 1179470. FGFR2-ADC has a potency in the single digit nM to sub nM range in a panel of FGFR2-positive cells lines (e.g., SNU-16, KatoIII, SUM52-PE, MFM-223) and shows more than 100-fold selectivity versus FGFR2-negative cell lines. High levels of FGFR2 on cancer cells correlate with internalization efficacy and cytotoxic activity in vitro. FGFR2-ADC is highly efficacious in monotherapy and results in tumor growth inhibition in the gastric cancer xenograft model SNU-16 and tumor regression in the breast cancer xenograft model MFM-223. At doses efficacious in mice, FGFR2-ADC is well tolerated. The pre-clinical efficacy and tolerability data obtained for FGFR2-ADC suggest a therapeutic index and support clinical testing. Citation Format: Anette Sommer, Carl F. Nising, Christoph Mahlert, Charlotte C. Kopitz, Hans-Georg Lerchen, Simone Greven, Beatrix Stelte-Ludwig, Joachim Schuhmacher, Ruprecht Zierz, Sabine Wittemer-Rump, Christoph Schatz, Frank Reetz, Heiner Apeler, Rolf Jautelat, Bertolt Kreft, Karl Ziegelbauer. FGFR2-ADC potently and selectively inhibits growth of gastric and breast cancer xenograft models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4491. doi:10.1158/1538-7445.AM2014-4491