[New therapeutic schedules of Sunitinib: Current evidence regarding the 2:1 scheme.]

INTRODUCTION: In 2006, sunitinib approval by the FDA was a real revolution for the treatment of metastatic renal cell carcinoma (mRCC). However, considerable rates of dose reductions and therapeutic suppressions with the standard regimen (4:2) have forced the search for new schedule proposals in order to optimize the balance between side effects and oncologic efficacy. Among these new proposals, the 2:1 scheme is the one that has generated more expectations.

OBJECTIVE: The objective of this paper is to make a review and critical discussion of current evidence about the new schedules of treatment with sunitinib.

METHODS: Unstructured review of the literature on the various therapeutic regimens with sunitinib, making a comparison in terms of progression-free survival (PFS), overall survival (OS) and toxicity.

RESULTS: We summarize the data from all relevant studies published to date comparing the standard 4:2 schedule versus the new 2:1. Most patients treated with 2:1 scheme are grouped in three retrospective observational studies and mostly correspond to patients who were initially treated with a 4:2 scheme and then moved to 2:1. A phase II randomized clinical trial comparing 4:2 and 2:1 schemes from the beginning has also been conducted. None of these studies found significant differences between the two regimens in terms of PFS or OS. Regarding the toxicity profile, the 2:1 scheme has proved to be more advantageous than the 4:2.

CONCLUSIONS: Despite the still limited amount of data, current evidence supports the use of a 2:1 schedule, as it provides patients substantial advantages because of its better tolerability profile, without a loss in oncological efficacy. Currently, the 2:1 scheme is an appropriate alternative therapeutic strategy, especially in patients with poor tolerance to the standard 4:2 regimen.