{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T05:16:05Z","timestamp":1782364565626,"version":"3.54.5"},"reference-count":0,"publisher":"American Society of Hematology","content-domain":{"domain":["ashpublications.org"],"crossmark-restriction":true},"short-container-title":[],"abstract":"The benefits of caplacizumab in acute immune mediated TTP (iTTP) are well established. We identified a delay in normalisation of ADAMTS13 activity (&gt;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 &gt;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 &lt;10% at the time of stopping caplacizumab with a longer time to ADAMTS13 activity &gt;30% (median 139 days after completing PEX). 18\/64 (28%) of patients receiving extended caplacizumab (31-58 days) failed to achieve ADAMTS13 activity &gt;30% at time of stopping caplacizumab compared to 4\/47 (8.5%) of historical controls at similar timepoint (30+28 days, p&lt;0.0001). Failure to achieve ADAMTS13 activity &gt;30% within 30+28 days was 6 times more likely in caplacizumab treated patients (OR 6.3, p=0.0006). ADAMTS13 antigen level &lt;30% at caplacizumab cessation was associated with increased iTTP recurrence (4\/10 vs 0\/9 in patients with ADAMTS13 antigen \u226530%). 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 \u226530% may be useful to guide stopping caplacizumab therapy after extended use in patients with ADAMTS13 activity &lt;10%, but patients require close monitoring. The reason for delayed ADAMTS13 normalisation is unclear and requires further investigation.<\/jats:p>","DOI":"10.1182\/blood.2022018847","type":"journal-article","created":{"date-parts":[[2023,1,31]],"date-time":"2023-01-31T21:04:41Z","timestamp":1675199081000},"update-policy":"https:\/\/doi.org\/10.1182\/blood.2019cm0000","source":"Crossref","is-referenced-by-count":11,"title":["Delayed normalisation of ADAMTS13 activity in acute Thrombotic Thrombocytopenic Purpura in the caplacizumab era"],"prefix":"10.1182","author":[{"given":"Nithya","family":"Prasannan","sequence":"first","affiliation":[{"name":"University College London Hospital, London, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mari","family":"Thomas","sequence":"additional","affiliation":[{"name":"University College London Hospitals, London, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew James","family":"Stubbs","sequence":"additional","affiliation":[{"name":"University College London Hospitals NHS Foundation Trust, London, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John-Paul","family":"Westwood","sequence":"additional","affiliation":[{"name":"Department of Haematology, University College London Hospital, London, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1044-9499","authenticated-orcid":false,"given":"Rens","family":"de Groot","sequence":"additional","affiliation":[{"name":"University College London, London, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Deepak","family":"Singh","sequence":"additional","affiliation":[{"name":"Health Services Laboratories, United Kingdom, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marie","family":"Scully","sequence":"additional","affiliation":[{"name":"Department of Haematology, University College London Hospital, London, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"234","published-online":{"date-parts":[[2023,1,30]]},"container-title":["Blood"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/ashpublications.org\/blood\/article-pdf\/doi\/10.1182\/blood.2022018847\/2031648\/blood.2022018847.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/ashpublications.org\/blood\/article-pdf\/doi\/10.1182\/blood.2022018847\/2031648\/blood.2022018847.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,1,31]],"date-time":"2023-01-31T21:04:43Z","timestamp":1675199083000},"score":1,"resource":{"primary":{"URL":"https:\/\/ashpublications.org\/blood\/article\/doi\/10.1182\/blood.2022018847\/494285\/Delayed-normalisation-of-ADAMTS13-activity-in"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,1,30]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1182\/blood.2022018847","relation":{},"ISSN":["0006-4971","1528-0020"],"issn-type":[{"value":"0006-4971","type":"print"},{"value":"1528-0020","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,1,30]]},"article-number":"blood.2022018847"}}