For years, the rivalry between Idec Pharmaceuticals Corp. and Coulter Pharmaceutical Inc. over treatments for non-Hodgkin's lymphoma has been played out in an apples-to-oranges comparison between IDPH's Rituxan rituximab antibody and CLTR's Bexxar tositumomab antibody linked with iodine 131.

With last week's presentation of Phase III data for IDPH's Zevalin ibritumomab tiuxetan antibody linked to yttrium-90, it finally would seem possible to make an apples-to-apples comparison between the two radiolabeled antibodies in Rituxan-refractory patients. But the companies still can find reasons to deny that the data are comparable.