RT Journal Article SR Electronic T1 Efficacy and Toxicity of Panitumumab After Progression on Cetuximab and Predictive Value of MiR-31-5p in Metastatic Wild-type KRAS Colorectal Cancer Patients JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 4955 OP 4959 VO 36 IS 9 A1 KISS, IGOR A1 MLCOCHOVA, JITKA A1 BORTLICEK, ZBYNEK A1 POPRACH, ALEXANDR A1 DRABEK, JIRI A1 VYCHYTILOVA-FALTEJSKOVA, PETRA A1 SVOBODA, MAREK A1 BUCHLER, TOMAS A1 BATKO, STANISLAV A1 RYSKA, ALES A1 HAJDUCH, MARIAN A1 SLABY, ONDREJ YR 2016 UL http://ar.iiarjournals.org/content/36/9/4955.abstract AB Background: In metastatic colorectal cancer (mCRC), panitumumab is generally considered to be ineffective after the progression on cetuximab therapy. However, few studies have demonstrated that a small subset of mCRC patients may benefit from panitumumab in this setting. Patients and Methods: In our study, wild-type KRAS mCRC patients, enrolled into the nationwide Czech registry CORECT between January 2007 and December 2012, were screened for panitumumab therapy after progression on cetuximab. Results: We identified 26 mCRC in the registry with well documented progression on cetuximab in combination with irinotecan-based chemotherapy (FOLFIRI or irinotecan alone) who received panitumumab monotherapy. Partial response (PR) was achieved in 3 (11.5%) patients and stable disease (SD) in 7 (26.9%) patients after 8 weeks of therapy. Thirteen (50.0%) patients had evidence of progressive disease (PD) and in 3 (11.5%) cases response was not available. Furthermore, we confirmed that higher expression levels of newly described biomarker, miR-31-5p, in tumor are significantly associated with shorter progression-free survival (PFS) in patients treated with cetuximab (p=0.038); however, we did not observe association between miR-31-5p and response to panitumumab in mCRC patients after progression on cetuximab. Conclusion: It remains possible that a subset of mCRC patients may benefit from panitumumab after progression on cetuximab.