Thanks, Bob Though it might help if I summarise that Jonathan Edwards interesting post below. He was replying to a post by Esther12 about the value of a small study given the larger Norwegian one. His answer seems to boil down to a concern that the larger Norwegian study might find a lesser effect next time around [which often happens after a big bang initial result], and that could derail Rituximab. Wheras if that did happen, but a UCL study found a clear sub-group that responded well to Rituximab, then it would still be a live game. So it seems to me the argument for a small UK study is partly as insurance in case five years down the line the Norwegian results are 'complicated', and partly to better understand how the B-cell approach fits different patients. Please correct me if I have got this wrong.