Recombinant ADAMTS13 shows no significant difference in acute TTP events versus standard therapy or placebo in phase 2 and 3 trialsNew drug raises enzyme levels but shows no clear benefit over standard care for TTP

OBJECTIVE: Thrombotic thrombocytopenic purpura (TTP) is a rare and potentially fatal blood disorder due to deficiency of the enzyme ADAMTS13. Recombinant ADAMTS13 (rADAMTS13) is a new treatment aimed at restoring enzyme activity. This study aimed to evaluate the efficacy and safety of rADAMTS13 compared to standard therapy or placebo in patients with congenital or acquired TTP using a systematic review and meta-analysis. METHODS: This PRISMA-compliant review searched PubMed, Embase, Cochrane Library, ClinicalTrials.gov, and others up to March 30, 2025. We included randomized controlled trials (RCTs) comparing rADAMTS13 to standard therapy or placebo in patients with TTP. RESULTS: Two RCTs (one phase 3, one phase 2) involving 129 patients (67 rADAMTS13, 62 placebo) met inclusion criteria. No significant differences were observed for the primary clinical outcomes of acute TTP events (risk ratio (RR) = 0.58 [95% CI, 0.20-1.70]) or serious treatment-emergent adverse events (RR = 0.64 [95% CI, 0.31-1.34]). However, rADAMTS13 significantly increased ADAMTS13 activity levels (MD, 0.92 IU/ml [95% CI, 0.59-1.26]; P  < 0.0001). Urticaria was significantly lower in the rADAMTS13 group (RR = 0.25 [95% CI, 0.06-0.96]; P  = 0.04). No significant differences were noted for other adverse events (all P > 0.05). CONCLUSION: rADAMTS13 significantly enhances ADAMTS13 activity but did not demonstrate a significant improvement in key clinical outcomes. These findings, based on two RCTs, are of moderate to low certainty per GRADE assessment. Larger trials are needed to confirm the clinical benefits of rADAMTS13.