Vandetanib: An overview of its clinical development in NSCLC and other tumors

Abstract

Vandetanib is an oral inhibitor of vascular endothelial growth factor receptor 2 (VEGFR-2), epidermal growth factor receptor (EGFR) and Ret tyrosine kinases involved in tumor growth, progression and angiogenesis. Phase I studies indicated that the recommended dose of vandetanib as a single agent is 300 mg/day. Rash, diarrhea, hypertension and asymptomatic Q-Tc prolongation were the most common adverse events. Four randomized phase III clinical trials evaluated the efficacy of vandetanib in non-small cell lung cancer (NSCLC) in combination with docetaxel (ZODIAC), pemetrexed (ZEAL) or as a single agent (ZEST and ZEPHYR). Only the ZODIAC trial met its primary endpoint (progression-free survival [PFS]), while no study showed an advantage in overall survival with vandetanib. No significant antitumor activity has been observed in small cell lung cancer, advanced ovarian, colorectal, breast, prostate cancer and multiple myeloma. In advanced metastatic medullary thyroid cancer, one randomized phase III clinical trial has demonstrated that vandetanib can significantly improve response rate, PFS and time to worsening of pain. Several key questions remain to be addressed regarding the identification of clinical or molecular biomarkers predictive of response, the choice of the optimal dose or schedule of vandetanib and the safety of long-term administration. The results of ongoing trials in untreated patients with advanced NSCLC and other tumors should better define the optimal clinical application of vandetanib.