Long-term efficacy and pharmacodynamic parameter analysis in pretreated KRAS-mutant metastatic colorectal carcinoma (mCRC) patients treated with RG7160 (GA201), an antibody-dependent cellular cytotoxicity (ADCC)-enhanced monoclonal anti-EGFR antibody.

379 Background: EGFR-positive, KRAS-mutant mCRC patients (pts) do not benefit from anti-EGFR treatment. In this pt population we investigated the efficacy of single-agent GA201, a novel dual acting, anti-EGFR antibody which was glycoengineered to enhance ADCC on top of signaling blockage. This stimulation of immune effector cells may improve long term clinical outcomes. Methods: In an open-label, multicenter, non-randomized study, KRAS-mutant mCRC pts (1-2 prior chemotherapy lines) were treated with GA201 (1400 mg on day 1 and 8 then by 1400 mg q2W). The primary endpoint was to investigate tumor response. Here we report response rates, overall survival (OS) and pharmacodynamics analyses from archival, pre- and on-treatment biopsies and blood samples. Results: 25 pts received a median of 5 GA201 infusions (range 2–24), for up to 414 days. Median overall survival was 9.3 months (range 1.2 – 21.2). Best overall response was stable disease (40% of patients at 8 weeks), which was maintained in 24% of pts at 16...