Long-Term Response to Sunitinib Treatment in Metastatic Renal Cell Carcinoma: A Pooled Analysis of Clinical Trials

Background: We characterized clinical outcomes of patients with metastatic renal cell carcinoma (mRCC) treated with sunitinib who were long-term responders (LTRs), defined as patients having progression-free survival (PFS) > 18 months.

Patients and methods: A retrospective analysis of data from 5714 patients with mRCC treated with sunitinib in 8 phase II/III clinical trials and the expanded access program. Duration on-study and objective response rate (ORR) were compared between LTRs and patients with PFS ≤ 18 months ("others"). PFS and overall survival (OS) were summarized using Kaplan-Meier methodology.

Results: Overall, 898 (15.7%) patients achieved a long-term response and 4816 (84.3%) patients did not achieve long-term response. The median (range) duration on-study was 28.6 (16.8-70.7) months in LTRs and 5.5 (0-68.8) months in others. ORR was 51% in LTRs versus 14% in others (P < .0001). Median PFS in LTRs was 32.11 months and median OS was not reached. LTRs had higher percentage of early tumor shrinkage ≥ 10% at the first scan (67.1% vs. 51.2%; P = .0018) and greater median maximum on-study tumor shrinkage from baseline (-56.9 vs. -27.1; P < .0001) versus others. White race, Eastern Cooperative Oncology Group performance status 0, time from diagnosis to treatment ≥ 1 year, clear cell histology, no liver metastasis, lactate dehydrogenase ≤ 1.5 upper limit of normal (ULN), corrected calcium ≤ 10 mg/dL, hemoglobin greater than the lower limit of normal, platelets less than or equal to ULN, body mass index ≥ 25 kg/m², and low neutrophil-to-lymphocyte ratio were associated with LTR.

Conclusion: A subset of patients with mRCC treated with sunitinib achieved long-term response. LTRs had improved ORR, PFS, and OS.