Phase I trial of thalidomide and Interleukin-2 in patients with metastatic renal cell carcinoma

Summary Background: The treatment of advanced renal cell cancer remains unsatisfactory, therefore new combination regimens such as thalidomide and IL-2 are of interest. A phase I trial of SC IL-2 and oral thalidomide was performed to identify the toxicity, maximum tolerated dose (MTD) and preliminary clinical activity of this regimen. Methods: 33 patients with advanced/metastatic RCC were enrolled. An established 8-week outpatient schedule of subcutaneously administered IL-2 in escalating doses, days 1–5, for 6 weeks with a 2 week rest was utilized with daily oral thalidomide. Cohorts of 4–6 patients were treated at 4 dose levels. Results: Toxicity was moderate to severe and related to dose level. All patients developed fever, chills and fatigue. 29/33 patients developed ≤ Grade 2 desquamation of hands and feet and/or rash. Dose limiting toxicity (DLT) included Grade 3 neutropenia and pulmonary embolus. The maximum tolerated dose (MTD) of IL-2 and thalidomide was 9.0 MIU/m² SC days 1–5, weeks 1 to 6 and 100 mg po daily, respectively. A median of 2 cycles of therapy was administered (range 1–9). 2/33 patients responded (1 CR—prior IL-2 therapy, 1 PR—no prior therapy) with an overall response of 6% (95% CI, 1–20%). One minimal response was converted to a surgical CR (remains disease free at 24 + months). Conclusion: Outpatient administration of IL-2 and thalidomide is possible with acceptable toxicity. Further evaluation of this regimen is underway.