Abstract
BACKGROUND: Previous studies have shown a modest impact of tyrosine kinase inhibitors on primary renal tumors. Those studies were mostly retrospective or heterogeneous in their eligibility criteria with regard to histology, disease stage, duration of therapy, and time off therapy prior to surgery. OBJECTIVE: To prospectively investigate the safety and efficacy of axitinib in downsizing tumors in patients with nonmetastatic biopsy-proven clear cell renal cell carcinoma (ccRCC). DESIGN, SETTING, AND PARTICIPANTS: This was a single-institution, single-arm phase 2 clinical trial. Patients with locally advanced nonmetastatic biopsy-proven ccRCC were eligible. INTERVENTION: Patients received axitinib 5mg for up to 12 wk. Axitinib was continued until 36h prior to surgery. Patients underwent partial or radical nephrectomy after axitinib therapy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was objective response rate prior to surgery. Secondary outcomes included safety, tolerability, and quality of life. A dedicated radiologist independently reviewed all computed tomography scans to evaluate for response using Response Evaluation Criteria in Solid Tumors (RECIST). RESULTS AND LIMITATIONS: A total of 24 patients were treated. Twenty-two patients continued axitinib for 12 wk; 1 patient continued axitinib for 11 wk and underwent surgery as planned. One patient stopped treatment at 7 wk due to adverse events (AEs). Median reduction of primary renal tumor diameter was 28.3%. Eleven patients experienced a partial response per RECIST; 13 had stable disease. There was no progression of disease while on axitinib. The most common AEs were hypertension, fatigue, oral mucositis, hypothyroidism, and hand-foot syndrome. Postoperatively, 2 grade 3 and 13 grade 2 complications were noted. No grade 4 or 5 complications occurred. Functional Assessment of Cancer Therapy-Kidney Specific Index-15 changed over time, with quality of life worsening while on therapy, but by week 19, it was not statistically different from screening. Limitations include single-arm design and small patient numbers. CONCLUSIONS: Axitinib was clinically active and reasonably well tolerated in the neoadjuvant setting in patients with locally advanced nonmetastatic ccRCC. PATIENT SUMMARY: In this prospective clinical trial, we found that axitinib, when given prior to surgery, results in significant shrinking of kidney cancers. Larger studies are needed prior to further clinical use. TRIAL REGISTRATION: This clinical trial was registered with clinicaltrials.gov (NCT01263769).