ADAMTS13 and thrombotic thrombocytopenic purpura: Subsequently, a phase III, randomized, controlled trial assessing the efficacy and safety of rADAMTS13 in comparison to standard treatment found that patients receiving rADAMTS13 for prophylaxis experienced no acute TTP events, had a minimal number of TTP symptoms, and achieved nearly 100% of normal ADAMTS13 activity levels [72].