Prolonged exposure to tyrosine kinase inhibitors or early use of everolimus in metastatic renal cell carcinoma: are the two options alike?

We retrospectively analyzed metastatic renal cell carcinoma (RCC) patients treated with 3 targeted agents. Patients started the sequence with a tyrosine kinase inhibitor (TKI), sunitinib or sorafenib, and were divided into 2 groups based on the order in which they received the other reciprocal TKI and everolimus (EVE): TKI-TKI-EVE group (n = 19) and TKI-EVE-TKI group (n = 14). Median progression-free survival (PFS) with first TKI was 13 months in the TKI-TKI-EVE group and 10 months in the TKI-EVE-TKI group. PFS with the second agent showed a trend in favor of the TKI-TKI-EVE sequence, with a median of 11 versus 6.5 months, whereas median PFS with the third agent was 6 months in both groups. Total PFS also showed a trend in favor of the TKI-TKI-EVE sequence with a median of 31 versus 23 months. Median overall survival (OS) was 38 months in both groups, with more patients receiving subsequent treatment in the TKI-EVE-TKI group. The subgroup of patients no long-term responders (≤9 months) to first TKI showed similar outcomes irrespective of the sequence. The subgroup of long-term responders to first TKI (>9 months) who received the other TKI instead of EVE had better outcomes in terms of median PFS with the second agent (13 vs. 5.5 months; p = 0.0271), median total PFS (39.5 vs. 23.5 months; p = 0.0415), and median OS (46 vs. 38 months). In conclusion, no apparent advantage was observed with early use of EVE in advanced RCC, even in those patients who did not benefit long from first-line TKI, whereas long-term duration of first-line TKI seems to be predictor of second-line TKI efficacy.