Prasannan, Nithya;
Thomas, Mari;
Stubbs, Matthew James;
Westwood, John-Paul;
de Groot, Rens;
Singh, Deepak;
Scully, Marie;
(2023)
Delayed normalization of ADAMTS13 activity in acute thrombotic thrombocytopenic purpura in the caplacizumab era.
Blood
, 141
(18)
pp. 2206-2213.
10.1182/blood.2022018847.
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Abstract
The benefits of caplacizumab in acute immune mediated TTP (iTTP) are well established. We identified a delay in normalisation of ADAMTS13 activity (>30%) in a subgroup of caplacizumab treated patients which was not evident in the pre-caplacizumab era. Caplacizumab treated patients (n=64) achieved ADAMTS13 activity >30% at median 31 days post PEX, compared to 11.5 days in the non-caplacizumab group (n=50, p=0.0004). 18/64 (28%) caplacizumab treated patients had an ADAMTS13 activity <10% at the time of stopping caplacizumab with a longer time to ADAMTS13 activity >30% (median 139 days after completing PEX). 18/64 (28%) of patients receiving extended caplacizumab (31-58 days) failed to achieve ADAMTS13 activity >30% at time of stopping caplacizumab compared to 4/47 (8.5%) of historical controls at similar timepoint (30+28 days, p<0.0001). Failure to achieve ADAMTS13 activity >30% within 30+28 days was 6 times more likely in caplacizumab treated patients (OR 6.3, p=0.0006). ADAMTS13 antigen level <30% at caplacizumab cessation was associated with increased iTTP recurrence (4/10 vs 0/9 in patients with ADAMTS13 antigen ≥30%). Admission anti-ADAMTS13 IgG antibody level did not predict recurrence. Anti-ADAMTS13 IgG antibody levels, immunosuppression and ethnicity did not account for differences in ADAMTS13 activity response. ADAMTS13 antigen levels ≥30% may be useful to guide stopping caplacizumab therapy after extended use in patients with ADAMTS13 activity <10%, but patients require close monitoring. The reason for delayed ADAMTS13 normalisation is unclear and requires further investigation.
| Type: | Article |
|---|---|
| Title: | Delayed normalization of ADAMTS13 activity in acute thrombotic thrombocytopenic purpura in the caplacizumab era |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1182/blood.2022018847 |
| Publisher version: | https://doi.org/10.1182/blood.2022018847 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Cardiovascular Science UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Cardiovascular Science > Pre-clinical and Fundamental Science |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10164585 |
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