Recombinant ADAMTS13 shows no significant difference in acute TTP events versus standard therapy or placebo in phase 2 and 3 trials

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Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis Published June 1, 2026 Medically reviewed June 1, 2026 Study authors: Samad Anaya Abdul, Qureshi Safwat Irshad, Khan Akif Shahid, Khan Bilal, Tufail Muhammad, Bakry Nourh… PubMed ↗ DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Note that recombinant ADAMTS13 shows no significant difference in acute TTP events versus standard therapy or placebo in current evidence.

This systematic review and meta-analysis assesses the efficacy and safety of recombinant ADAMTS13 compared to standard therapy or placebo in patients with congenital or acquired thrombotic thrombocytopenic purpura. The analysis included data from two randomized controlled trials with a total sample size of 129 patients. The setting was not reported for these trials.

Regarding the primary outcome of acute TTP events, the meta-analysis showed no significant difference between recombinant ADAMTS13 and the comparator (RR = 0.58, 95% CI 0.20-1.70). Similarly, serious treatment-emergent adverse events showed no significant difference (RR = 0.64, 95% CI 0.31-1.34). Other adverse events also showed no significant differences with all P values greater than 0.05.

Secondary outcomes revealed that ADAMTS13 activity levels were significantly increased (MD = 0.92 IU/ml, P < 0.0001). Urticaria rates were significantly lower with recombinant ADAMTS13 (RR = 0.25, P = 0.04). The authors note that findings are of moderate to low certainty per GRADE assessment. Discontinuations and overall tolerability were not reported. The authors conclude that larger trials are needed to confirm the clinical benefits of recombinant ADAMTS13.

Study Details

Study typeMeta analysis

Sample sizen = 129

EvidenceLevel 1

PublishedJun 2026

PMID41934124

View Original Abstract ↓

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.