A Phase I Pharmacologic Study of Necitumumab (IMC-11F8), a Fully Human IgG1 Monoclonal Antibody Directed Against EGFR in Patients with Advanced Solid Malignancies

Purpose: This study aimed to determine a maximum tolerated dose (MTD) and recommended dose for disease-directed studies of necitumumab (IMC-11F8), a fully human IgG1 monoclonal antibody directed at the epidermal growth factor receptor, and to characterize the safety profile, pharmacokinetics, preliminary antitumor activity, and immunogenicity of necitumumab. Experimental Design: Patients with advanced solid malignancies were treated with 100 to 1,000 mg (flat dosing) necitumumab followed by a 2-week pharmacokinetics sampling period, before beginning 6-week cycles of therapy. Results: Sixty patients received necitumumab weekly (29 patients) or every other week (31 patients). Two patients receiving 1,000 mg every 2 weeks experienced dose-limiting toxicities (DLT; grade 3 headache), accompanied by grade 3 nausea and vomiting in one patient. Occurring hours after the initial dose, these DLTs established 800 mg as the MTD. Mild dose-related skin toxicity was the most common drug-related toxicity (80%). One patient in each arm experienced grade 3 acneform rash, which responded to oral antibiotics and topical therapy. Toxicity was similar on both schedules. Necitumumab exhibited saturable elimination and nonlinear pharmacokinetics. At 800 mg (both arms), its half-life was approximately 7 days. All patients treated with ≥600 mg necitumumab achieved target trough concentrations (≥40 μg/mL). Antibodies against necitumumab were not detected. Partial response and stable disease were experienced by 2 and 16 patients, respectively. Conclusion: Well tolerated, necitumumab is associated with preliminary evidence of antitumor activity, and achieves biologically relevant concentrations throughout the dosing period. The recommended dose of necitumumab for further clinical development is 800 mg (flat dose) weekly or every 2 weeks based on the clinical setting. Clin Cancer Res; 16(6); 1915–23