Objective: To determine the efficacy of gefitinib in patients with advanced thyroid cancer.
Design: In this open-label phase II trial, 27 patients with radioiodine-refractory, locally advanced, or metastatic thyroid cancer were treated with 250 mg of daily gefitinib. Histologic subtypes included papillary (41%), follicular (22%), anaplastic (19%), medullary (15%), and Hürthle cell carcinomas (4%). The primary endpoint was overall response rate. Secondary endpoints were toxicity, progression-free survival (PFS), and overall survival (OS).
Main outcomes: There were no objective responses among the 25 patients evaluated. After 3, 6, and 12 months of treatment, 48%, 24%, and 12% of patients had stable disease (SD), respectively. Median PFS and OS were 3.7 and 17.5 months, respectively. Five patients with SD had a decrease in thyroglobulin (Tg) to <90% of baseline that was maintained for at least 3 months.
Conclusions: Although gefitinib therapy did not result in any tumor responses, 32% of patients had reductions in tumor volume that did not meet criteria for partial response rate. Along with falling Tg levels and prolonged SD in a subset of patients, this may indicate biologic activity.