Neoadjuvant chemoradiation (CRT) with or without panitumumab (Pan) in patients with K-ras unmutated, locally advanced rectal cancer (LARC): Final results of a randomized multicenter phase II trial (SAKK 41/07).

Abstract

762 Background: We conducted a randomized phase II multicenter trial evaluate the anti-epidermal growth factor receptor (EGFR) panitumumab (P) in combination with CRT with standard-dose capecitabine as neoadjuvant treatment for wild-type KRAS LARC. Methods: Patients with wild-type KRAS, T3-4 and/or N+ LARC were randomly assigned to receive CRT either with or without P (6 mg/kg). The primary end-point was pathological near-complete or complete tumor response (pNC/CR), defined as grade 3 (pNCR) or 4 (pCR) histological regression by Dworak classification (DC). Secondary end-points were pathological response, R0-resection, sphincter preservation, downstaging, time to local relapse, time to distant failure and disease-free survival (DFS). Results: Patients with wild-type KRAS, T3-4 and/or N+ LARC were randomly assigned to receive CRT either with or without P (6 mg/kg). The primary end-point was pathological near-complete or complete tumor response (pNC/CR), defined as grade 3 (pNCR) or 4 (pCR) histological regression by Dworak classification (DC). Secondary end-points were pathological response, R0-resection, sphincter preservation, downstaging, time to local relapse, time to distant failure and disease-free survival (DFS). Conclusions: An addition of panitumumab to neoadjuvant CRT in patients with KRAS wild-type LARC resulted in a high pNC/CR rate, mostly grade 3 DC. Up to date no local recurrence occurred and DFS compared favorably to other trials. Clinical trial information: NCT00814619.