Efficacy and Safety of Combination Treatment With Apatinib and Osimertinib After Osimertinib Resistance in Epidermal Growth Factor Receptor-Mutant Non-small Cell Lung Carcinoma—A Retrospective Analysis of a Multicenter Clinical Study

Abstract

Currently, there are limited treatment options for patients who developed resistance to osimertinib, a third-generation epidermal growth factor receptor (EGFR) inhibitor. Resistance to EGFR inhibitors is frequently associated with enhanced vascular endothelial growth factor (VEGF) levels. This multicenter, retrospective study aimed to evaluate the efficacy of the combination treatment with apatinib and osimertinib in 39 patients with EGFR-mutant non-small cell lung carcinoma (NSCLC) who developed osimertinib resistance. The patients received the combination of oral apatinib 250 mg qd and osimertinib 80 mg qd. The efficacy was evaluated after the first month then every 2 months thereafter. The primary endpoint was progression-free survival (PFS). The overall response rate (ORR) and the disease control rate (DCR) of the combination of apatinib and osimertinib was 12.8% (5/39) and 79.5% (31/39), respectively. The median PFS was 4 months [95% confidence interval (CI): 3.5–4.5 months]. Fourteen patients were administered with at least 6 months of combination therapy, and 11 of them remained on treatment programs. The 6-month PFS rate was 38%. Nine patients underwent biopsies after failing osimertinib treatment, and five of six patients with TP53 mutations had PFS of less than 3 months. The spectrum of resistance to osimertinib mechanisms included c-mesenchymal-epithelial transition factor (c-Met) amplification, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gain-of-function mutation, phosphatase and tensin homolog (PTEN) loss-of-function mutation, Erb-B2 receptor tyrosine kinase 2 (ERBB2) amplification, and insulin-like growth factor 1 receptor (IGF1R) mutation. The most common adverse events were hypertension (30.7%, 12/39), diarrhea (15.4%, 6/39), and proteinuria (12.8%, 5/39). The combination of apatinib and osimertinib improved the ORR and the DCR of patients with osimertinib-refractory EGFR-positive NSCLC, thus making it a reasonable treatment choice after the development of osimertinib resistance.