Interferon-α in combination with either imatinib (Gleevec) or gefitinib (Iressa) in metastatic renal cell carcinoma:: a phase II trial

Treatments for metastatic renal cell carcinoma (MRCC) are limited. RCCs frequently overexpress epithelial growth factor receptor and express c-Kit and platelet-derived growth factor receptor-beta. Combination of interferon with tyrosine kinase inhibitors of epithelial growth factor receptor [gefitinib (Iressa)] or c-Kit and platelet-derived growth factor receptor-beta [imatinib (Gleevec)] was evaluated for efficacy and safety. Patients with MRCC received 12-week cycles of interferon [3 million units (MU) subcutaneously thrice in week 1 and 6MU thrice weekly thereafter] and either gefitinib (500 mg daily) or imatinib (600 mg daily). The gefitinib/imatinib dose was reduced as needed owing to toxicity. The primary endpoint was objective tumor response. Secondary endpoints were time to tumor progression, overall survival, and safety. Seventeen patients were enrolled. Most had clear cell [36% (6/17)] or papillary [36% (6/17)] tumors. Most (n=14) were treated on the gefitinib arm, including two patients who crossed over from the imatinib arm after experiencing disease progression. Objective tumor responses were evaluable in 14 patients (82%). Of these 14, partial responses occurred in three (21%), stable disease in seven (50%), and progressive disease in four (29%). The most frequent treatment-related adverse events were skin rash, flu-like symptoms, and fatigue (both treatment arms); diarrhea (gefitinib arm only); and thrombocytopenia and leukopenia (imatinib arm only). Median time to tumor progression (range) for patients on the gefitinib arm only was 4.27 (1.13-15.97) months and median overall survival (range) was 11.42+ (1.13-29.07+) months. Combination of gefitinib with interferon safely delays progression of refractory MRCC. Further studies in this setting are warranted.