Outcomes of Starting Low-dose Pazopanib in Patients with Metastatic Renal Cell Carcinoma Who Do Not Meet Eligibility Criteria for Clinical Trials

Purpose: Eligibility for clinical trials is very strict and only patients who satisfy various criteria can enter trials. The individual use of pazopanib has not been adequately investigated. An optimal administration regimen for pazopanib in “real-world” patients with metastatic renal cell carcinoma (mRCC) is required. Our purpose was to determine the tolerability and efficacy of first-line pazopanib with a low starting dose in patients with mRCC who were ineligible for clinical trials. Materials and Methods: This study included patients with mRCC who underwent treatment with first-line pazopanib and were previously excluded from clinical trials because they did not meet the inclusion criteria. A 400 mg pazopanib starting dose is used routinely in patients with mRCC; if tolerated, dose escalation up to 800 mg may occur. Results: We identified 18 patients with mRCC who received first-line pazopanib and were previously determined ineligible for clinical trials. Pazopanib dose was escalated in 12 patients (66.6%), to 600 mg/day in 8 patients (44.4%) and to 800 mg/day in 4 patients (22.2%), and was not escalated in 6 patients (33.3%). In 3 patients (16.7%), pazopanib was discontinued owing to intolerability. The most common frequent adverse event was elevated alanine aminotransferase levels in 6 patients (33.3%), followed by a decreased platelet count in 5 patients (27.8%) and anorexia in 5 patients (27.8%). Partial response was seen in 5 patients (27.8%) and stable disease in 10 patients (55.6%); median progression-free survival was 11.9 months (95% confidence interval: 6.3–28.7 months). Conclusion: Our data indicated that a low starting dose of 400 mg pazopanib did not negatively affect treatment tolerability and efficacy in patients with mRCC ineligible for clinical trials. We found that lower starting doses may lead to better results. Additional studies are needed in a larger cohort and longer follow-up to attain authentic outcomes.