Pharmacokinetics, safety, and tolerability of a new patritumab formulation in patients with advanced, refractory solid tumors.

e14026 Background: Patritumab, currently in phase 3 study for non–small cell lung cancer, is a fully human monoclonal antibody directed against human epidermal growth factor receptor 3 (HER3). To support a new manufacturing process, an open-label bridging study was conducted to assess pharmacokinetics (PKs), safety, and tolerability of the new formulation (Process 2 patritumab [P2P]), relative to the original (Process 1 patritumab [P1P]), in patients (pts) with advanced cancer. Methods: Pts with known HER3+ tumor types, Eastern Cooperative Oncology Group performance status ≤ 2, and refractory to/refused standard treatment were eligible. P2P was administered on day 1 at a loading dose of 18 mg/kg (cycle 1), then maintenance with 9 mg/kg (cycles 2–5) every 21 days. PK was assessed following single-dose (18 mg/kg) P2P. Data assessed include area under the curve from day 0 to 21 (AUC0–21) and maximum concentration (Cmax; primary end points), treatment-emergent adverse events (TEAEs), serious AEs (SAEs), anti–...