It justifies the higher price of sorafenib saying it needs the revenue to pay for future innovation.

BBC: Do drugs really have to be so expensive?

Bayer and Onyx Pharmaceuticals presented data on their own cancer drug, sorafenib, and found that the drugs extended life, compared with a placebo.

FORBES: Pfizer Takes Cancer By Storm

The drug has been closely watched both by investors in Pfizer and those in Onyx Pharmaceuticals and Bayer, which submitted their own similar medicine, sorafenib, for kidney cancer last month.

FORBES: Magazine Article

Onyx has data showing that Sorafenib slows tumor growth, compared with a placebo, but in late-stage trials only 2% of patients had their tumors shrink enough to be counted in the response rate.

FORBES: Magazine Article

Some analysts believe Sutent's sales could eclipse sorafenib's.

FORBES: McKinnell's Pfizer Submits 'Revolutionary' Cancer Drug

One place where this may play out is in a likely battle for market share in kidney cancer between Sutent and Sorafenib, a drug developed by biotech Onyx (nasdaq: ONXX - news - people ) and drug giant Bayer (nyse: BAY - news - people ).

FORBES: When Shrinking Tumors Isn't Enough