Final skin toxicity (ST) and patient-reported outcomes (PRO) results from PRIME: A randomized phase III study of panitumumab (pmab) plus FOLFOX4 (CT) for first-line metastatic colorectal cancer (mCRC).
531^ Background: Final PRIME results showed that pmab + CT significantly improved progression-free survival (PFS) and objective response rate vs CT alone for first-line wild type (WT) KRAS mCRC. Efficacy and PRO by ST severity from the final descriptive analysis of PRIME are presented. Methods: Patients (pts) had no prior chemotherapy for mCRC, ECOG performance status ≤ 2, and tumor tissue available for biomarker testing. The final analysis occurred 30 months after the last pt was enrolled; the primary endpoint was PFS; secondary endpoints included OS, objective response, and safety. Pts who received treatment and were alive without progression at day 28 were included in the ST analysis. Results: 1183 pts were randomized. 1057 pts with WT or MT KRAS mCRC met the criteria for inclusion in the ST analysis. Maximum grade ST was observed by day 28 in > 50% of pts. Results are shown ( table ). Overall differences in change from baseline of the least square means from a mixed effects model of the EQ-5D Overall Health Rating for pmab + CT (n = 285) minus CT alone (n = 294) and for ST gr 0-1 (n = 53) minus ST gr 2-4 (n = 232) were −1.069 (95% CI: −3.6277 to 1.4896) and 0.8971 (95% CI: ‐4.0224 to 5.8167), respectively. The overall safety profile was broadly comparable across ST groups and treatment arms. Conclusions: Pts with WT KRAS mCRC receiving pmab with ST gr 2-4 had longer PFS and OS vs pts receiving CT alone. PRO were not adversely affected by ST severity. [Table: see text]