Sustained EKR inhibition by EGFR targeting therapies is a predictive factor for synergistic cytotoxicity with PDT as neoadjuvant therapy

► We here evaluate PDT as neoadjuvant to EGFR targeting therapeutics. ► Cetuximab, Erlotinib and Tyrphostin were combined with PDT in two cancer cell lines. ► Synergy was observed when the EGFR targeting drug exerted prolonged ERK inhibition. ► Synergistic cytotoxicity was linked to synergistic ERK inhibition.