Associations between dermatologic toxicity severity, patient characteristics, and efficacy among patients treated with panitumumab (Pmab) and chemotherapy

Abstract

Background: The identification of patient ( pt) characteristics associated with dermatologic toxicity severity during treatment with anti-epidermal growth factor receptor (EGFR) monoclonal antibodies could inform treatment choices for patients with metastatic colorectal cancer. Methods: Data from the randomized, first-line, phase 3 PRIME trial of pmab + FOLFOX vs FOLFOX and the randomized, second-line, phase 3 20050181 trial of pmab + FOLFIRI vs FOLFIRI were analyzed to evaluate the association of dermatologic toxicity severity with pt characteristics/laboratory values and treatment outcomes. This study was supported by Amgen Inc. Results: In the pmab arms from 20050181 and PRIME, pts with grade 2-4 dermatologic toxicity consistently had a trend of lower neutrophil-to-lymphocyte ratio (NLR) vs those with grade 0-1 at baseline, weeks 2-3, 4-5, 6-7, and 8-9 (Table; baseline, week 8-9 shown). Carcinoembryonic antigen was elevated in pts with grade 0-1 dermatologic toxicity in the pmab + FOLFOX group but reduced in grade 0-1 pts in the pmab + FOLFIRI group when each was compared with grade 2-4 dermatologic toxicity pts (Table). Among pts with progression-free survival ≥28 days, those with grade 2-4 dermatologic toxicity had improved overall survival and progression-free survival compared with pts with grade 0-1 toxicity (Table). Conclusions: This study did not clearly identify pt characteristics that are potential dermatologic toxicity biomarkers; further studies are required to understand the relationship between NLR and dermatologic toxicity severity. Increased dermatologic toxicity severity was associated with improved clinical outcomes. (Table presented).