Clinical Outcomes for Patients with Metastatic Renal Cell Carcinoma Treated with Alternative Sunitinib Schedules

Purpose: We identified sunitinib alternative schedules that maintained dose intensity while decreasing adverse events in patients with metastatic renal cell cancer. We also determined the impact of alternative schedules on clinical outcomes. Materials and Methods: We retrospectively reviewed the records of patients 18 years old or older with clear cell metastatic renal cell cancer who received first line sunitinib between January 26, 2006 and March 1, 2011 at our major comprehensive cancer center. A subset of patients was switched at the first intolerable adverse event from the traditional schedule of 28 days on and 14 days off to a schedule of 14 days on and 7 days off or other alternative schedules. A control group underwent standard dose reduction. We estimated progression-free and overall survival by the Kaplan-Meier method. Predictors of progression-free and overall survival were analyzed using Cox regression. Results: A total of 187 patients were included in analysis, of whom 87% were on the traditional schedule at baseline. During treatment 53% of patients continued on the traditional schedule and 47% began or were transitioned to alternative schedules. Baseline characteristics were similar. Adverse events prompting schedule modification included fatigue in 64% of cases, hand-foot syndrome in 38% and diarrhea in 32%. Median time to alternative schedules was 5.6 months. Median overall survival was 17.7 months (95% CI 10.8-22.2) on the traditional schedule compared to 33.0 months (95% CI 29.3-not estimable) on alternative schedules (p <0.0001). On multivariable analysis poor Eastern Cooperative Oncology Group (ECOG) performance status, increased lactate dehydrogenase, decreased albumin, unfavorable Heng criteria and the traditional schedule were associated with decreased overall survival (p <0.05). Conclusions: Sunitinib administered on alternative schedules may mitigate adverse events while achieving outcomes comparable to those of the traditional schedule in patients with metastatic renal cell cancer. Prospective investigations of alternate dosing schemas are warranted.