Dosing patterns, toxicity, and outcomes in patients treated with first-line sunitinib for advanced renal cell carcinoma in community-based practices.

BACKGROUND:This retrospective study by McKesson Specialty Health (MSH)/US Oncology Network (USON) evaluates dosing patterns of first-line sunitinib for patients with advanced renal cell carcinoma (aRCC) and its association with toxicities and clinical outcomes in community practices. PATIENTS AND METHODS:Patients with aRCC who started first-line sunitinib between June 1, 2007, and May 31, 2011, were identified from 17 MSH/USON practices. Clinical data were extracted from iKnowMed electronic medical records linked to the MSH/USON pharmacy database. RESULTS:In total, 134 patients were included; mean age was 63.9 years, 85% of the patients had an Eastern Cooperative Oncology Group performance score of 0 or 1, 82% had clear-cell renal cell carcinoma, and 65% had undergone nephrectomy. The median treatment duration was 4 cycles (range, 1-19). Overall, 113 patients discontinued sunitinib, mainly because of disease progression (45.1%) or toxicities (16.8%). Of all discontinuations, 77% occurred within the first 5 cycles. A total of 45 patients were dose-reduced, mostly because of toxicities (93%); 67% of all dose reductions occurred in the first 3 cycles. The objective response rate was 16.4%, median overall survival (OS) was 15.5 months, and progression-free survival (PFS) was 7.5 months. Multivariate analysis showed that OS and PFS were associated with sunitinib treatment duration. CONCLUSIONS:Patients with aRCC from community practices undergo sunitinib dose reductions more frequently because of toxicities and discontinue therapy sooner than in clinical trials. Clinical outcomes were inferior to those reported in clinical trials, potentially because of shorter duration of therapy. Sunitinib therapy optimization remains an important challenge in community practices.