Initial Management of Thrombotic Thrombocytopenic Purpura (TTP) in Adults in BGH with Caplacizumab

NHS Borders clinical guidelines
NHS Borders

Objectives

To describe the prescribing and administration of a single dose of caplacizumab for adult patients diagnosed with thrombotic thrombocytopenic purpua (TTP) to be given prior to transfer for therapeutic plasma exchange at another centre.

Scope

To be used by trained nursing, medical, and pharmacy staff in the initial management of adults with a confirmed diagnosis of TTP.

Audience

Adult haematologists, Emergency Department Doctors and Nurses, Acute Medicine Doctors and Nurses, Clinical Pharmacists

TTP is a rare condition (annual incidence approximately 2.3 per million per year) that generally presents as an acute, life-threatening emergency. The pathogenesis of TTP is profoundly low activity of ADAMTS13, which results in widespread formation of microthrombi in small vessels with associated consumption of platelets resulting in thrombocytopenia. The classical presentation is with laboratory features of TMA with associated clinical features such as fever, neurological involvement, cardiac involvement, renal involvement and GI involvement. However, there may be no clinical manifestations at the time of initial presentation.

Most cases are thought to be iTTP, where autoantibodies against ADAMTS13 develop, resulting in a rapid onset of an acutely life-threatening presentation. Inherited ADAMTS13 deficiency results in cTTP, which is thought to account for <5% of all cases. However, it is more common in certain patient groups such as children and pregnant women.

Historically, mortality of an acute presentation of iTTP was approximately 90%. With modern management, this is now <10%. Key to this improved outcome is the rapid recognition of possible iTTP with initiation of TPE within 8 hours (ideally 4) of diagnosis. Despite this, there is still significant morbidity associated with TTP.

Initial management following confirmed diagnosis of TTP is with caplacizumab as a single dose before transfer to the Royal Infirmary of Edinburgh (RIE), NHS Lothian, for plasma exchange and ongoing treatment. Caplacizumab is given only once diagnosis has been confirmed by the Haematology team in NHS Lothian.

Prescribing

  1. Diagnosis of TTP must be confirmed by the Haematology Team in NHS Lothian and direction will be given to prescribe and administer a single dose of caplacizumab 10mg injection prior to transferring the patient to RIE for therapeutic plasma exchange and ongoing treatment.
  2. Caplacizumab is licensed for use in people 12 years old or over and weighing >40kg. Please note it is NOT licensed for use in pregnancy and must only be given in this circumstance with local MDT agreement.
  • Caplacizumab is contra-indicated in active bleeding
  • Primary side-effect of caplacizumab is bleeding

     3.Prescribe caplacizumab as a “once only” dose at 10mg to be administered by intravenous (IV) injection.

Supply

  1. ONE vial of Caplacizumab 10mg for injection is kept in the emergency cupboard fridge in the BGH Pharmacy waiting area which can be accessed during Pharmacy opening times or out of hours.
  • In-hours: Please contact Pharmacy and advise that the vial of caplacizumab will be needed, complete a stock request order for a single vial of caplacizumab 10mg for injection and take to Pharmacy to obtain the supply
  • Out-of-hours: Contact the Hospital at Night team and advise them that the vial of caplacizumab 10mg for injection is needed for immediate treatment from the emergency cupboard fridge and follow usual procedure.
  1. If no supply is available in the emergency cupboard fridge then discuss the urgency of treatment with the NHS Lothian oncall Haematology team (in-hours or out-of-hours) as sourcing further supply from RIE may take some time.

     3.If stock is used as described above then BGH Pharmacy will order further stock to replace this and put            it in the emergency cupboard fridge.

Administration

  1. Reconstitute the powder contained in the vial using the vial adapter and all solvent (1ml water for injection) in the pre-filled syringe.
  2. The solvent should be added slowly and mixed gently to avoid foaming of the solution.
  3. Allow the vial with the connected syringe to stand on a surface for 5 minutes at room temperature.
  4. The reconstituted solution should be clear, colourless, or slightly yellowish. It must be visually inspected for particulate matter. Do not use a solution where particulates can be seen.
  5. Transfer the entire volume of the reconstituted solution back to the glass syringe and immediately administer the entire volume of the syringe.
  6. Once administered, sign off the “once only” prescription as per local policy.

 

Caplacizumab, once reconstituted, is for single use only. Any unused product or waste material must be disposed of as per local policy. If caplacizumab is NOT administered immediately, it is known to be stable for 4 hours at 25oC.

Stock Maintenance

An agreement is in place with NHS Lothian Royal Infirmary of Edinburgh (RIE) Pharmacy to support stock rotation of caplacizumab vials when they are nearing expiry. This is in place due to the high cost of the product and the low prevalence of the indication, usage of caplacizumab in NHS Borders will likely be very low, to avoid medicines waste.

NHS Borders Pharmacy Procurement will contact RIE Pharmacy Procurement to exchange a vial of caplacizumab when it is within 6 months of its expiry date as agreed with RIE Pharmacy Procurement and RIE Haematology Teams.

Editorial Information

Next review date: 29/03/2029

Author(s): Richardson-Read, S.

Version: 1.0

Approved By: NHS Borders Area Drug & Therapeutics Committee

Reviewer name(s): Richardson-Read, S.

References

NHS Lothian, Guideline on the Diagnosis and Management of TTP in Adults (2022)

Summary of Product Characteristics, Caplacizumab, available at: Cablivi 10 mg powder and solvent for solution for injection - Summary of Product Characteristics (SmPC) - (emc) | 10347 [accessed 25/02/2026]

British National Formulary, Medicines Complete, available at: MedicinesComplete — CONTENT > BNF > Drug: Caplacizumab [accessed 25/02/2026]
Evidence method

Content and guidance sourced from NHS Lothian guideline (as referenced) as well as BNF dosing information and manufacturer’s information.