Clinical trial NCT05876221: Platelet Response to Caplacizumab in the Treatment of Acquired Thrombotic Thrombocytopenic Purpura
Official title: Platelet Response to Caplacizumab in the Treatment of Acquired Thrombotic Thrombocytopenic Purpura
Study type: OBSERVATIONAL
Overall status: RECRUITING
Conditions: Acquired Thrombotic Thrombocytopenic Purpura
Keywords: caplacizumab
platelet responses
aTTP
iTTP
Lead sponsor: University of Cologne
Sponsor class: OTHER
First posted: 2023-05-25
Enrollment: 160
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: In this trial will be enclosed iTTP patients treated with caplacizumab from:

* the German real-world cohort of iTTP patients treated with caplacizumab in the years 2018 to 2020 , and
* the respective TITAN and HERCULES trial cohorts.

Brief summary: The interpretation of platelet counts has to be revaluated in the light of caplacizumab. By effectively blocking platelet binding sites on VWF-multimers, the nanobody leads to a rapid normalization of the platelet count within 3 to 4 days. Most importantly, caplacizumab uncouples platelet counts from ADAMTS13 activity and thereby launches unprecedented thrombocyte dynamics, with potential pitfalls for over- and undertreatment.

A relevant number of patients responds to caplacizumab with a brisk increase in platelet count, followed by a marked dip of platelets (patient on the left). This may mislead treating physicians into re-intensifying therapy, with a respective risk for adverse side-effects and complications. Taken together, these observations call for reliable descriptions and the identification of predictive parameters to predict the platelet response upon administration of caplacizumab in a large patient cohort. Here, PREDICT-2020 is designed as a retrospective study to specifically address the following aspects:

* Identifying and describing clusters of platelet responses to caplacizumab
* Identifying potential pitfalls for treating physicians
* Predicting the individual thrombocyte response
* Correlating platelet responses with individual patient outcome


Eligibility criteria: Inclusion Criteria:

* Confirmed diagnosis of autoimmune thrombotic thrombocytopenic purpura
* Treatment with at least a single dose of caplacizumab, either i.v. or s.c.
* Male or female patients older than 18 years of age

Exclusion Criteria:

* Hereditary thrombotic thrombocytopenic purpura

Primary outcomes:
measure: Reliable description and prediction of platelet responses to caplacizumab
timeFrame: Enrollment
Secondary outcomes:
measure: Determination of different clusters of platelet responses to caplacizumab
timeFrame: Enrollment
measure: Correlation of platelet responses to caplacizumab with patient outcome
timeFrame: Enrollment
measure: Risk stratification of iTTP patients based on their platelet response to caplacizumab
timeFrame: Enrollment
Other outcomes:
Locations:
city: Cologne
country: Germany
facility: University Hospital of Cologne
Study officials:
affiliation: Department II of Internal Medicine, University Hospital of Cologne
name: Lucas Kühne, MD
role: PRINCIPAL_INVESTIGATOR
References: