Phase III randomized sequential open-label study to evaluate efficacy and safety of sorafenib (SO) followed by sunitinib (SU) versus sunitinib followed by sorafenib in patients with advanced/metastatic renal cell carcinoma without prior systemic therapy (SWITCH Study): safety interim analysis results.

BACKGROUND: Several retrospective studies have investigated the sequential use of SO and SU. Some smaller trials support the use of SO followed by SU forming the rationale for this study. METHODS: Pts with metastatic RCC unsuitable for cytokines without prior systemic therapy, ECOG PS 0/1, MSKCC score low or intermediate, and ≥1 measurable lesion (CT/MRI every 12 weeks) were randomized to SO->SU or SU->SO in standard dosage (primary endpoint total PFS from randomization to event during 2nd line therapy). Treatment continues until progression or intolerability. Monitoring includes echocardiography and NT pro-BNP. RESULTS: Baseline characteristics of 361 randomized pts (116 completed) are balanced between arms. Safety data of 333 pts are evaluable. AE occurring in >10% of pts are listed in tab. 1. Left-ventricular ejection fraction (LVEF) at screening, switch of treatment, and end of study are given in tab. 1. AE occurred in 93.4% and 92.8%; grade 3/4 AE in 59.9% and 50%; and SAE in 46.7% and 42.2% in the SO->SU and SU->SO arm, respectively. Updated results will be presented. CONCLUSIONS: AE frequencies are higher in 1st than in 2nd line treatments. Typical AE profiles for SO and SU are observed. LVEF values are in a similar range.