Phase I evaluation of vandetanib with radiation therapy (RT) ± cisplatin in previously untreated advanced head and neck squamous cell carcinoma (HNSCC)

Abstract

6016 Background: Vandetanib is a once-daily oral anticancer agent that selectively targets VEGF, EGF and RET receptor tyrosine kinases. We report preliminary results from an ongoing open-label phase I study of vandetanib with RT ± cisplatin in patients (pts) with previously untreated, unresected, locally advanced (stage III-IV) HNSCC. Methods: Eligible pts received once-daily vandetanib for 14 days followed by either 1) concomitant vandetanib + RT (2 Gy/d, 5 d/wk; total 70 Gy) + cisplatin (30 mg/m2, 2 h iv infusion/wk) for 7 wks, or 2) concomitant vandetanib + RT (2.2 Gy/d accelerated fractionation, 5 d/wk; total 66 Gy) for 6 wks. The primary objective was to determine the safety, tolerability and maximum tolerated dose (MTD) of vandetanib in both regimens. The first pt cohort received vandetanib 100 mg/day; escalation to 200 mg and 300 mg in subsequent cohorts was permitted providing <2/6 (33%) pts in the preceding cohort experienced a dose-limiting toxicity (DLT). Cohort expansion at the MTD of vandetanib was also planned. Results: As of Dec 1 2008, 24 pts (median age 53.5 yrs; 19 male; all M0) had received treatment with vandetanib + RT + cisplatin (n=18) or vandetanib + RT (n=6). In the triplet arm, no DLTs occurred in the initial vandetanib 100 mg cohort (n=6); an additional 6 pts were enrolled to receive vandetanib 200 mg but this dose was considered to exceed the MTD since DLTs were reported in 3/5 evaluable pts (Table). Vandetanib 100 mg was therefore declared the MTD with RT + cisplatin and cohort expansion at this dose continues. In regimen 2), 6 pts have received vandetanib 100 mg + RT and evaluation of this initial cohort is ongoing. Conclusions: This study, which continues to recruit, is the first to evaluate dual targeting of VEGFR/EGFR tyrosine kinases with chemoradiation or radiation alone in HNSCC pts. Among the 24 treated pts, 2 have completed the 2-year follow up, 1 death occurred that was causally related to cisplatin, and 21 remain in follow up or continue to receive treatment. [Table: see text] [Table: see text]