Phase III study (20050181) of panitumumab (pmab) with FOLFIRI versus FOLFIRI alone as second-line treatment (tx) in patients (pts) with metastatic colorectal cancer (mCRC): Pooled safety results.

4064 Background: Pmab is a fully human anti-EGFr monoclonal antibody (MAb) with activity as a single agent in refractory mCRC. Study 20050181 is the first global, phase III trial investigating an anti-EGFr MAb combined with FOLFIRI as 2nd-line tx for pts with mCRC.,This is a randomized, multicenter, phase III study with pt eligibility criteria that include: histologically/cytologically- confirmed adenocarcinoma of the colon or rectum with metastatic disease; only 1 prior fluoropyrimidine-based chemotherapy regimen for mCRC; ECOG performance status (PS) 0 to 2. No prior EGFr staining is required for inclusion. Pts are randomized 1:1 to receive Pmab 6.0 mg/kg Q2W + FOLFIRI Q2W (Pmab+FOLFIRI) or FOLFIRI Q2W alone (FOLFIRI). Co-primary endpoints are progression-free survival and overall survival. Secondary endpoints include overall objective response rate, time to progression, duration of response, and safety. Study endpoints will be investigated by pts' KRAS mutational status in both arms as a potential biomarker for pmab activity combined with FOLFIRI. The study includes multiple, planned safety interim analyses conducted by an independent Data Monitoring Committee (DMC); the latest safety interim analysis included 701 pts of approx. 1,100 planned target accrual.,352 pts are in the Pmab+FOLFIRI arm and 349 pts are in the FOLFIRI arm. Of all pts, 431 (61%) are men, median age is 61 yrs (range, 29-85), ECOG PS 0: 47%, PS 1: 45%, PS 2: 7%. Of all pts, 99% received at least 1 cycle of study therapy, and 59 % have stopped study tx. Median follow-up time was 15 weeks. Adverse events of interest are shown ( table ).,After the safety interim analysis of the first 701 pts conducted by the DMC, study 20050181 continues per protocol. Study 20050181 enrollment is anticipated to be completed in Q1 2008. Updated pooled safety data for approx. 1,100 pts will be presented. [Table: see text] [Table: see text].