Purpose: Based on our mouse xenograft model demonstrating that intermittent high-dose gefitinib sensitizes tumors to subsequent treatment with taxanes, we initiated this phase I trial to explore docetaxel in combination with escalating doses of intermittent gefitinib (Iressa) given prior to docetaxel.
Methods: This was a phase I study where patients with advanced cancer were treated with escalating doses of gefitinib (1,000, 1,500, 2,250, 3,000 mg) on days 1 and 2 followed by docetaxel (75 mg/m2) on day 3 of a 21 day cycle. Gefitinib pharmacokinetic data were obtained on days 1, 2, and 3 of cycles 1 and 2 at each dose level.
Results: 18 patients were enrolled in this study with the most frequent tumor types being non-small cell lung cancer and head and neck squamous cell cancer. The dose-limiting toxicity was neutropenia (n=1 at dose level 2, n=2 at dose level 4). Rash, diarrhea, and fatigue were the most common grade 1-2 toxicities. Pharmacokinetic data indicated no accumulation of gefitinib between cycles 1 and 2 and no clear correlation between gefitinib plasma levels and toxicity. Partial responses were observed in one patient with head and neck squamous cell carcinoma and one patient with anaplastic thyroid cancer.
Conclusion: The recommended dose for phase II studies is gefitinib 2,250 mg on days 1 and 2, followed by docetaxel 75 mg/m2 on day 3.