Lessons: Investigators into the botched UK drug trial which left six men desperately ill have released an in-depth report. The drug, TGN1412, a monoclonal antibody, caused a massive immune response which flooded the volunteers' blood with inflammatory agents and triggered organ failure. The doctors say that the drug should have been used more cautiously and that the men should have been tested at least two hours apart, rather than at 10-minute intervals.