How do you treat metastatic renal cell carcinoma with unclassified histology without sarcomatoid features?

There is limited data on optimal treatment of advanced non-clear cell RCC in general, including unclassified RCC. I have summarized the available data that I am aware of:

• The phase II study ASPEN randomized advanced nccRCC patients, including 20% with unclassified RCC, to sunitinib vs everolimus. Of the 22 patients with unclassified RCC, objective response rates were 0/8 with sunitinib and 1/14 with everolimus. However, median progression-free survival was 11.5 months with sunitinib and 5.7 mont...