Institutional experiences with panitumumab monotherapy in metastatic colorectal cancer (mCRC) patients (pts) intolerant to cetuximab

14579 Background: Two monoclonal antibodies (mAbs) targeting the epidermal growth factor receptor are approved for the treatment (tx) of advanced mCRC - panitumumab(Vectibix™), a fully human mAb, and cetuximab(Erbitux®), a chimeric mAb. Potential for cross-reactivity between these two mAbs with regard to infusion reactions(IR) has not been fully explored. Given the lack of sequence homologybetween the 2 agents and the fully human nature of panitumumab, it is hypothesized that pts intolerant to cetuximabdue to IR could be tolerant to panitumumab. Methods: Single pt tx IND applications to administer panitumumabmonotherapy in pts with advanced mCRC were approved by the FDA and local institutions as part of the PanitumumabCompassionate Use program. Eligibility also included previous tx with standard chemotherapy and intolerability to cetuximab, ie. CTCAE v3.0 grade 3 (severe) or grade 4 (life-threatening) IR. Results: Upon informed consent, 4 pts (2M/ 2F) were enrolled in 4 centers. Median (range) age ...