Association Of Ecog Performance Status With Efficacy In Patients Receiving Panitumumab With Best Supportive Care (Bsc) Vs Bsc Alone For Chemorefractory Metastatic Colorectal Cancer

e15018 Background: Historically, performance status (PS) has been used as a factor to predict treatment tolerability to cytotoxic chemotherapy. Panitumumab (pmab), a fully human monoclonal antibody directed against human epidermal growth factor receptor, is used to treat wild type (WT) RAS metastatic colorectal cancer (mCRC) in combination with cytotoxic chemotherapy or as monotherapy. Methods: Patients (pts) in study 20100007 (NCT01412957) were randomized (stratified by Eastern Cooperative Oncology Group [ECOG] PS ≤ 1 vs 2 and region) 1:1 to receive either pmab (6 mg/kg every 14 days, IV) + BSC or BSC alone. Here, we present a pre-specified descriptive analysis of efficacy by PS in WT RASpts based on the primary analysis. Results: 270 WT RAS mCRC pts were included for this analysis. Efficacy analyses of overall survival (OS) and progression-free survival (PFS) by PS are shown (Table). The results favored the pmab + BSC arm in both PS ≤ 1 and PS = 2 groups (hazard ratio [HR] 0.721 and 0.335 for OS; and HR 0.463 and 0.339 for PFS) with nominal P-values all less than 0.05. Although pts with PS = 2 had a trend for more adverse events (AEs) ≥ 3 compared to pts with PS ≤ 1, the percentage of AEs ≥ 3 were comparable in each arm for PS = 2 (66.7% in pmab + BSC; 54.5% in BSC). Treatment discontinuation rates were relatively low in both PS ≤ 1 (7.1%) and PS = 2 (13.3%) groups. Conclusions: Addition of pmab provided survival advantage not only in pts with PS ≤ 1 but appears to do so in pts with PS = 2 despite the expected challenges associated with diminished PS. The results suggest that pmab may be a viable treatment for pts whose options are further constrained due to decline in PS. Clinical trial information: NCT01412957. Baseline PS 0 or 1 Baseline PS 2 Pmab + BSC (N = 127) BSC (N = 117) Pmab + BSC (N = 15) BSC (N = 11) OS Median (95% CI) - (months) 10.5 (9.1 – 12.8) 7.4 (5.6 – 10.3) 7.9 (4.3 – 9.7) 3.4 (1.0 – 3.8) Hazard ratio (95% CI) 0.721 (0.536, 0.970) 0.335 (0.138, 0.812) Log-rank P-value 0.0295 0.0116 PFS Median (95% CI) - (months) 5.3 (3.6 – 5.4) 1.8 (1.6 – 2.3) 3.4 (1.7 – 7.1) 1.1 (0.9 – 1.6) Hazard ratio (95% CI) 0.463 (0.353, 0.607) 0.339 (0.137, 0.839) Log-rank P-value < 0.0001 0.0152