First-line onartuzumab plus erlotinib treatment for patients with MET-positive and EGFR mutation-positive non-small-cell lung cancer.

INTRODUCTION: The phase II JO28638 study evaluated first-line onartuzumab plus erlotinib in patients with MET-positive advanced, metastatic, or post-operative recurrent non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. The study was stopped following termination of the global METLung study (OAM4971g), which showed lack of efficacy in the onartuzumab/erlotinib arm. We present immature efficacy and safety data from JO28638. MATERIALS AND METHODS: Chemotherapy-naïve patients aged ≥ 20 years were enrolled. Patients received onartuzumab (15 mg/kg every 3 weeks) plus erlotinib (150 mg once daily) until progression or unacceptable toxicity. The co-primary endpoints were investigator (INV)-assessed progression-free survival (PFS) and safety. Secondary endpoints: overall response rate (ORR), disease control rate (DCR), overall survival (OS), duration of response (DOR), and pharmacokinetics. Exploratory biomarker analyses were also conducted. RESULTS: 61 patients received treatment. Median age was 67 years and most patients had stage IV NSCLC (71%), MET-IHC score 2 (87%), and exon 19 deletion EGFR mutation (53%). Median PFS (INV) was 8.5 months (95% confidence interval [CI] 6.8-12.4); median OS was 15.6 months (95% CI 15.6-not evaluable); ORR was 68.9% (95% CI 55.7-80.1); median DOR was not reached; DCR was 88.5% (95% CI 77.8-95.3). Pharmacokinetics were similar to previous studies. All patients experienced an adverse event (AE); 26 patients discontinued treatment due to AEs; no grade 5 AEs were reported. No significant correlation was found between biomarkers and efficacy outcomes. CONCLUSION: The results presented are inconclusive due to the early termination of the study.

Phase I study of the anti-MET antibody onartuzumab in patients with solid tumors and MET-positive lung cancer.

Onartuzumab is a monovalent, humanized, monoclonal antibody that showed significant survival benefits in combination with erlotinib in MET-positive non-small-cell lung cancer (NSCLC) in pre-specified subgroup analyses of a randomized phase II study. We conducted a two-stage, open-label, multicenter, phase I study of onartuzumab in Japanese patients. Stage 1 investigated the safety, tolerability, pharmacokinetics (PK), and recommended dose of onartuzumab in patients with solid tumors, and Stage 2 determined the safety, tolerability, and PK of onartuzumab plus erlotinib in patients with MET-positive NSCLC. Nine patients received onartuzumab monotherapy (4, 15, or 30 mg/kg on Day 1 of each 21-day cycle) in Stage 1, and six patients received onartuzumab (15 mg/kg) plus erlotinib (150 mg/day) in Stage 2. There were no dose-limiting toxicities in either stage. Serious adverse events (AEs) occurred in one patient in Stage 1 (convulsion), and two patients in Stage 2 (once case each of diarrhea, vomiting, and pulmonary embolism), but there were no grade 4 AEs or AEs leading to death. Onartuzumab PKs were linear in the dose range of 4 to 30 mg/kg, and were not affected by co-administration with erlotinib. PK parameters of onartuzumab were similar to those reported in non-Japanese patients. A partial response was observed in a patient with MET immunohistochemistry 3+ NSCLC without MET gene amplification. Based on these results, the recommended dose of onartuzumab in Japanese patients with solid tumors is 15 mg/kg every 21 days. The combination of onartuzumab with erlotinib is feasible in Japanese patients with MET-positive lung cancer.