PB0220 - Evaluation of four different reagents on the coagulation analyzers STAR MAX® and ATELLICA® COAG 360 for Emicizumab concentration measurement in severe hemophilia A patients

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Co-Author(s)

AL

Amélie Launois, Dr

Hematologist
Laboratoire de Biologie Médicale, Hôpital André Mignot
Le Chesnay, Ile-de-France, France
Ed

Emmanuelle de Raucourt

Hematologist
Centre de ressources et compétences des Maladies Hémorragiques Constitutionnelles rares, centre hospitalier de Versailles (André Mignot)
Le chesnay, Ile-de-France, France
IM

Isabelle Martin-Toutain

Hematologist
Laboratoire de Biologie Médicale, Hôpital André Mignot
Le Chesnay, Ile-de-France, France
FS

Farahna SAMDJEE

Pharmacist
Hôpital André Mignot
Le Chesnay, Ile-de-France, France
SL

Sophie LE DORE

Psychologist
Hôpital André Mignot
Le Chesnay, Ile-de-France, France
EF

Emmanuelle FERRE

Nurse
Hôpital André Mignot
Le Chesnay, Ile-de-France, France

Presenting Author(s)

Claire Flaujac

Hematologist
laboratoire de biologie médicale- secteur hémostase - André Mignot hospital, Versailles
Le Chesnay, Ile-de-France, France

Background: Emicizumab is a bispecific antibody restoring part of coagulation and indicated in prophylaxis in severe hemophilia A patients. Biological monitoring is a challenge because emicizumab interferes with coagulation tests.

Aims: The objective of this study is to evaluate the reliability of the CK-Prest®, Cephasceen® and STA-PTT Automate® reagent (Stago) on the analyzer STAR MAX® (Stago) and Actin FS® (Siemens) on the analyzer ATELLICA® COAG 360 (Siemens) for emicizumab dosing in real life conditions.

Methods: 21 patients (mean age=33 years [7-55]), had a dosage before emicizumab treatment, and at day 7, 14 and 21. 83 samples were analyzed with APPT (CK-Prest®) and FVIII:C dosage with one stage chronometric assay. Emicizumab dosage were calibrated with r2 diagnostics reagents, on a FVIII derived methodology using CK-Prest®, Cephascreen®, STA-PTT Automate® or Actin FS®. Inter-assay variability was evaluated by normal and pathologic controls (CN;CP).

Results: At baseline, emicizumab was < 2 µg/mL, except for 4 patients with FVIII:C >0.15 IU/mL. APTT normalizes at day 7 with a FVIII:C mean concentration at 1.80 IU/mL [1.10-3.00]. The mean emicizumab concentration was around 21 µg/mL at day 7, 37 µg/mL at day 14 and 50 µg/mL at day 21, with a mean FVIII:C >4.0 IU/mL for all patients except one (3.11 IU/mL) which had the lowest emicizumab concentration. Inter-assay variabilities were, respectively for CP and CN, 7.0% and 7.2% with CK-Prest®, 6.6% and 6.4% with Cephascreen®, 5.9% and 5.0% with STA-PTT Automate® and 1.9% and 5.0% with Actin FS®. Emicizumab assays showed a good correlation and a mean bias under 10% for the four reagents [2.7%;-8.4%] compared to CK-Prest®.

Conclusion(s): In real life conditions, our evaluations show that the four techniques seem to be acceptable for the measurement of emicizumab on the coagulation analyzers STAR MAX® and ATELLICA® COAG 360. This must be confirmed by further evaluation.