The drug's inventors called their creation a "superantibody." They hoped that it would be capable of activating immune cells other antibody drugs could not on their own. The moniker for the compound, targeted at autoimmune disease or leukemia, was TGN1412, made by TeGenero, based in Wrzburg, Germany. On March 13 six previously healthy volunteers given the antibody in a routine test of its safety were sent to intensive care.

Although all the men are out of critical condition, one patient who went into a three-week coma after taking the drug may lose bits of his fingers and toes. Several medical experts assert that these results, which came after experiments with TGN1412 on rabbits and monkeys at up to 500 times the human dose, highlight the need for caution in designing trials of biotechnology drugs that work through novel mechanisms.