Caplacizumab Treatment for Acquired Thrombotic Thrombocytopenic Purpura: Comparative Real-world Multicenter Study

E. Gavriilaki¹, E. Koravou², S. Besikli², T. Chatziconstantinou², E. Nikolousis³, A. Mpanti⁴, C. Pontikoglou⁵, C. Kalpadaki⁵, A. Bitsani⁶, I. Tassi⁷, T. Touloumenidou², M. Papathanasiou², A. Syrigou², G. Kaiafa⁸, E. Kapsali⁷, E. Papadaki⁵, A. Anagnostopoulos², C. Lalayanni², I. Sakellari²

¹G Papanicolaou Hospital, Thessaloniki, Greece, Thessaloniki, Thessaloniki, Greece, ²G Papanicolaou Hospital, Thessaloniki, Thessaloniki, Greece, ³Athens Medical Center, Athens, Attiki, Greece, ⁴Papageorgiou Hospital, Thessaloniki, Thessaloniki, Greece, ⁵University of Crete, Heraklion, Iraklion, Greece, ⁶Laiko University Hospital, Athens, Attiki, Greece, ⁷University Hospital of Ioannina, Ioannina, Ioannina, Greece, ⁸Aristotle University of Thessaloniki, Thessaloniki, Thessaloniki, Greece

Abstract Number: PB0302

Meeting: ISTH 2022 Congress

Theme: Platelet Disorders, von Willebrand Disease and Thrombotic Microangiopathies » ADAMTS13 and TTP

Background: Caplacizumab is the first approved targeted therapy of acquired thrombotic thrombocytopenic porphyra (aTTP).

Aims: We designed this multicenter real-world study to assess safety and efficacy of caplacizumab compared to historic controls.

Methods: We recorded clinico-biological data from consecutive adult aTTP patients that were treated with corticosteroids and plasma exchange over the last decade (2011-2021) according to international guidelines. Diagnosis was confirmed with ADAMTS13 activity. Results are presented as median (range).

Results: We studied 63 patients [aged 48 (19-75) years]: 16 in the caplacizumab and 47 in the historic control group. The latter had a higher rate of neurological involvement (p=0.017). Rituximab was given in the majority of patients for refractory disease (2/3 patients with refractory disease in the caplacizumab group versus 15/16 in controls, p=0.161) or as pre-emptive treatment (12/13 in caplacizumab versus 15/29 in controls, p=0.011). No other significant differences were observed in patient or disease characteristics between groups.

Caplacizumab was given at a median day 4 (1-32) from diagnosis of acute phase (10 mg daily) for 31 (6-40) doses. There were no major hemorrhages or other complications. Plasma exchange sessions were 12 (9-21) in caplacizumab versus 14 (6-32) in controls. ADAMTS13 activity normalized after treatment in all caplacizumab patients and no relapses have been observed. Control patients presented a median of 1 (0-14) relapse. With 15.4 (2.2-320) months from disease diagnosis, there were 4 deaths (only from the control group, p-0.310, Figure).

Conclusion(s): Given the limited international experience, our study confirms safety and efficacy of caplacizumab in aTTP. Modifications of dosing compared to the clinical trial setting seem to have non-inferior outcomes in the real-world setting. Since ADAMTS13 remission has emerged as an important marker of long-term results, further studies in large real-world populations with longer follow-up are needed to highlight the value of caplacizumab.

Figure

Overall Survival in aTTP patients receiving caplacizumab -black line- compared to historic control -dotted line-

To cite this abstract in AMA style:

Gavriilaki E, Koravou E, Besikli S, Chatziconstantinou T, Nikolousis E, Mpanti A, Pontikoglou C, Kalpadaki C, Bitsani A, Tassi I, Touloumenidou T, Papathanasiou M, Syrigou A, Kaiafa G, Kapsali E, Papadaki E, Anagnostopoulos A, Lalayanni C, Sakellari I. Caplacizumab Treatment for Acquired Thrombotic Thrombocytopenic Purpura: Comparative Real-world Multicenter Study [abstract]. https://abstracts.isth.org/abstract/caplacizumab-treatment-for-acquired-thrombotic-thrombocytopenic-purpura-comparative-real-world-multicenter-study/. Accessed October 1, 2023.

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