Objective: We conducted a retrospective analysis of two clinical trials in treatment-naïve patients (n = 402) with advanced renal cell carcinoma (RCC) treated with axitinib. Our objective was to compare duration of treatment (DT) and clinical outcome in patients who achieved DT >18 months (longer DT) versus ≤18 months (shorter DT).
Patients and methods: DT, objective response rate (ORR), tumor shrinkage, and overall survival (OS) were summarized for patients with longer and shorter DT.
Results: Overall, 152 patients (37.8%) had longer DT and 250 (62.2%) had shorter DT (median, 34.7 vs. 6.5 months, respectively). ORR in all 402 patients with advanced RCC was 43.5%. ORR was 75% for longer DT versus 24.4% for shorter DT (p < 0.0001). More patients with longer DT versus shorter DT had ≥10% tumor shrinkage at first scan (74.8% vs. 55.3%; p = 0.0001) and maximum on-study tumor shrinkage was greater in longer-DT versus shorter-DT group (-51.8% vs. -22.1%; p < 0.0001). Median OS was 32.6 months in the overall population while in the patients with longer DT the median was not reached. Treatment-related adverse events (AEs) grade ≥3 were more frequent in longer-DT versus shorter-DT and included hypertension (25.7% vs. 18.8%), diarrhea (15.1% vs. 4.4%), and weight decrease (11.2% vs. 3.2%); however, these AEs decreased over time in both groups. Eastern Cooperative Oncology Group performance status 0, favorable hematology values, no bone or liver metastases, and baseline tumor burden below the overall median were associated with longer DT.
Conclusions: Longer duration (>18 months) of axitinib treatment was associated with increased frequency of early tumor shrinkage, greater magnitude of tumor shrinkage, and a favorable OS.