Specifically "He told the BBC: "This is a novel target, an antibody against human CD28 on human white blood cells."
That makes so much sense! I won't be at all surprised to find that teh animals trials went without any issues. This very definitely is a human-only reaction.
He has a point here, too "He added: "Since this drug was targeted at leukaemia, it may be better to have tested it on leukaemia patients first who could conceivably have got benefit, rather than healthy volunteers." " But I just don't see that happening, due to ethical issues. I do have a very vague memory of hear such done that way, when prior testing showed that the drug would be very bad for healthy patients. Hmmmmm.