Sunitinib scheduling in metastatic renal cell cancer: A single-center experience.

Abstract

554 Background: Sunitinib is a receptor tyrosine kinase inhibitor that has proven activity as first line treatment for metastatic renal cell carcinoma (mRCC). The recommended dose is 50mg once daily in a 4 week on 2 week off schedule. However this regimen has a significant side effect profile and alternative schedules have been used to minimize dose reductions and maintain dose intensity. We sought to identify the incidence of dose modifications and assess toxicity in patients treated with two sunitinib schedules in a National Cancer Center. Methods: Patients with mRCC who had sunitinib as first line treatment were identified retrospectively and patient data reviewed. Two patient groups were identified: those who received sunitinib 50mg day 1-28 in 6 week cycles (cohort 1) and those who received sunitinib 50mg day 1-14 in 3 week cycles (cohort 2). Primary end point was incidence of dose modification. Secondary end points included incidence of common sunitinib-related side effects. Known prognostic variables, including prior nephrectomy, body mass index (BMI) and use of angiotensin system inhibitors (ASI) were correlated with time to disease progression (TTP). Results: Between 2009 and 2014, 28 patients were identified. Of those, 23 (83%) patients were treated in cohort 1, and 5 (17%) patients in cohort 2. Dose modifications were required in 13 (56.5%) patients in cohort 1, but only 2 (40%) patients in cohort 2. Common sunitinib-related side effects in cohort 1 included hypertension in 19 (79%), weight loss in 10 (41.6%), fatigue in 9 (37.5%) and nausea in 8 (33.3%) patients respectively. Overall, the use of ASIs correlated significantly with longer median TTP (10.5 months) compared to non-users (4 months) (p = 0.04). BMI ≥ 25 (TTP 9 vs. 3 months, p = 0.008) demonstrated a similar correlation. However, no difference in median TTP was noted between patients who had prior nephrectomy compared to those who had not (5 vs. 4 months) (p = 0.18). Conclusions: In this small retrospective study, standard sunitinib scheduling was associated with a high incidence of dose modifications and side-effects. Consistent with previous studies, we identified known prognostic variables. The use of sunitinib 50mg day 1-14 in 3 week cycles may be more tolerable for patients.