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Efficacy of a Personalized Caplacizumab Regimen Based on ADAMTS13 Activity Monitoring in Adult aTTP

Phase 2
Conditions
Thrombotic Thrombocytopenic Purpura, Acquired
Interventions
Registration Number
NCT04720261
Lead Sponsor
University Hospital, Rouen
Brief Summary

The aim of the study is to evaluate the efficacy of a personalized caplacizumab regimen based on ADAMTS13 activity monitoring in adult acquired thrombotic thrombocytopenic purpura (aTTP): This study is a phase II, prospective, multicenter non-inferiority single-arm study.

Detailed Description

ADAMTS13 activity will be evaluated on day 7 after the end of daily PE and every 7 days until ADAMTS13 activity ≥ 20% is reached. In case of persistent severe ADAMTS13 deficiency (≤ 20%), caplacizumab administration could be extended for a maximum of 58 days after the end of the daily PE period and should be accompanied by an adjusted immunosuppressive therapy as needed. This duration is in accordance with the HERCULES study protocol and its SmPC.

Recruitment & Eligibility

Status
UNKNOWN
Sex
All
Target Recruitment
125
Inclusion Criteria
  • Adult patients ≥ 18 years;

  • Clinical diagnosis of aTTP based on standard clinical and laboratory criteria (French Score ≥ 2): i.e., thrombotic microangiopathy syndrome with platelet count ≤ 30 G/L and serum creatinine ≤ 200 μmol/L; severe ADAMTS13 deficiency is not a requirement for inclusion of patients with a French score of 2 [31];

  • Patient having read and understood the information letter and signed the Informed Consent Form. If the patient is unable to express his consent, the consent will be signed by his representative ((1) the trusted person, or failing that, (2) a family member, or (3) a close relative of the person concerned). In this case, consent to continue the study will subsequently be requested from the patient (article L1122-1-1 of the CSP);

  • Patient affiliated with, or beneficiary of a social security (national health insurance) plan;

  • For women:

    • Women of childbearing potential :

      • Effective contraception according to WHO definition (estrogen-progestin or intrauterine device or tubal ligation) since at least 1 month and;
      • Negative blood pregnancy test;
    • Women surgically sterile (absence of ovaries and/or uterus);

    • Postmenopausal women (non-medically induced amenorrhea for at least 12 months prior to the inclusion visit).

Exclusion Criteria
  • Platelet count > 100 G/L;
  • Patients with a French score < 2 (a serum creatinine level > 200 μmol/L +/- associated with a platelet count > 30 G/L), in order to exclude possible cases of atypical hemolytic uremic syndrome;
  • Known other causes of cytopenias and/or organ failure including but not limited to: uncontrolled cancer, chemotherapy, transplant, drugs, HIV at AIDS stage;
  • Pregnant women (positive result from a blood pregnancy test) or patients with an imminent project of pregnancy; breastfeeding women (due to lack of pharmacological data for caplacizumab during pregnancy and breastfeeding);
  • Congenital TTP;
  • Clinically significant active bleeding or high risk of bleeding (excluding thrombocytopenia);
  • Chronic treatment with anticoagulant that cannot be interrupted safely, including but not limited to: vitamin K antagonists, direct oral anticoagulant, low molecular weight heparin or heparin;
  • Malignant hypertension;
  • Contra-indication to CABLIVI 10 mg powder and solvent for solution for injection: hypersensitivity to caplacizumab or to any of the excipients;
  • Contra-indication to PE treatment;
  • Contra-indication to corticosteroid (= ((methyl)prednisone or (methyl)prednisolone)) or excipients;
  • Contra-indication to rituximab or excipients and to its premedication;
  • Person deprived of liberty by administrative or judicial decision or placed under judicial protection (guardianship or supervision);
  • Participation in another drug interventional clinical trial within 30 days prior to inclusion and during the study.

Study & Design

Study Type
INTERVENTIONAL
Study Design
SINGLE_GROUP
Arm && Interventions
GroupInterventionDescription
CaplacizumabCaplacizumabAll patients in the study are aTTP and needs to be treated by caplacizumab. The duration of this treatment will be evaluated through the ADAMTS 13 activity.
Primary Outcome Measures
NameTimeMethod
To evaluate the feasibility of a personalized caplacizumab regimen in aTTP based on ADAMTS13 activity monitoring assessed by a composite criteria including mortality, refractoriness and/or exacerbation at 30 days post-PE treatment30 days post-PE treatment

composite endpoint defined by the occurrence of at least one the following events during the 30 days post-PE treatment: death, refractoriness or exacerbation.

Secondary Outcome Measures
NameTimeMethod
Response to treatment (platelet count recovery)30 days post-PE treatment

to platelet count recovery (as defined by a platelet count ≥ 150 G/L with a subsequent interruption of daily PE within 5 days)

Durable remission achievement90 days post-PE treatment

Occurrence of durable remission achievement (platelet count ≥ 150 G/L for ≥ 30 consecutive days following PE interruption);

Mortality at D90 post-PE treatment90 days post-PE treatment

Occurrence of death within 90 days post-PE treatment

Refractoriness at D30 post-PE treatmentDay 30 post-PE treatment

Occurrence of refractoriness at D30 post-PE treatment;

Exacerbation at D30 post-PE treatmentDay 30 post-PE treatment

Occurrence of exacerbations at D30 post-PE treatment

Duration of plasma exchange (PE) treatment and the associated plasma volumes30 days

Duration of daily PE with the corresponding plasma volume

Duration of plasma exchange (PE) treatment and the associated plasma30 days

Total number of PE and the corresponding plasma volume during the full study drug treatment period

Occurrence of neurological sequelae treatmentDay 90 post-PE treatment

Neurological assessment based on Rankin score

Evaluate the Quality of lifeDay 90 post-PE treatment

Quality of life based on global post-traumatic score (PCL-S SCALE) at baseline, D90 post-PE treatment

Evaluate the cost of the strategyDay 90 post-PE treatment

Costs of the patients' management (Direct hospital medical expenses, Suppléments, direct costs of home care, caplacizumab injections, rehospitalizations) of patients treated with the regimen according to the study

To perform a safety analysis90 days post-PE treatment

Occurrence of AE and SAE during the study

Occurrence of cognitive sequelae treatmentDay 90 post-PE treatment

Cognitive assessment based on MMS score

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