PB0668 - Emicizumab treatment regimen based on vial size along with quantification of emicizumab plasma concentration. Real-world experience from a single pediatric center in Argentina.

Monday, June 26, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

GS

Gabriela B. Sciuccati, MD (she/her/hers)

Pediatric Hematologist
Hospital de Pediatría "Prof. Dr. J.P.Garrahan"
CABA, Ciudad Autonoma de Buenos Aires, Argentina

Co-Author(s)

RS

Rodolfo E. Sueldo, PhD

Biochemist
Laboratorio de Hematología y Hemostasia. Hospital César Milstein Laboratorio de Hemostasia. Servicio de Hematología y Oncología Hospital de Pediatría Prof. Dr. Juan P. Garrahan
Buenos Aires, Ciudad Autonoma de Buenos Aires, Argentina
Carolina Cervio, MD (she/her/hers)

staff Pediatric Hematologist
Hospital de Pediatría "Prof. Dr. Juan P. Garrahan"
Buenos Aires, Buenos Aires, Argentina
MB

Maria B. Bianco

Pediatric Hematologyst
Hospital de Pediatria Porf Dr Juan P Garrahan
CABA, Ciudad Autonoma de Buenos Aires, Argentina
Juan P. Frontroth, Biochemist (he/him/his)

Biochemist staff
Hospital de Pediatría "Prof. Dr. J.P.Garrahan"
CABA, Ciudad Autonoma de Buenos Aires, Argentina
SA

Silvina E. Annetta

Biochemist
Hospital de Pediatria Porf Dr Juan P Garrahan
CABA, Ciudad Autonoma de Buenos Aires, Argentina
MH

Mirta D. Hepner

biochemist staff
Hospital de Pediatría "Prof. Dr. J.P.Garrahan"
CABA, Ciudad Autonoma de Buenos Aires, Argentina

Background: Emicizumab is used for nonfactor replacement in patients with Haemophilia A(HA). Discrepancies between Emicizumab dosed according to label and the vials content may drive waste or lead to subtherapeutic or supratherapeutic doses. Few reports about emicizumab dosing adjusted to vial content and monitoring in the real-world scenario have been published.

Aims: To report clinical and laboratory results of a pediatric cohort with congenital severe hemophilia A treated with emicizumab doses based on vial size along with quantification of emicizumab plasma concentration(Epc).

Methods: Since 2011, 105 patients with Hemophilia have been diagnosed in our center, 62 of them with severe HA(sHA). From sept/2019-dec/2022, patients with sHA and poor venous access and/or inhibitors(sHAi) started emicizumab according to the following protocol: 4 weekly loading doses and maintenance doses adjusted to use whole vials. Bleeding, adverse events, and surgeries were recorded on a standardized data form.
Epc sampling times: after 4 weekly loading doses(week 5), at early steady state based on its half-life(15-25 weeks) and every 6 months thereafter(long-term steady state). Validated modified one-step FVIII coagulation (Stago reagents and STA Compact Max2 coagulometer,DiagnosticaStago) with in-house calibrator and controls. FVIII inhibitor(ChromogenixCoamatic®Factor VIII-bovine reagent).

Results: 12 males were included, median age at emicizumab onset was 5.3years(range 0.5-8.7). Tables 1 and 2 describe patients´ characteristics and laboratory result.
During a median follow-up of 86.4 weeks(range 10-170,1), the median AJBR in patients with inhibitor dropped from 2 (range 0-7) to 0 (0-2).Only one patient presented with a joint bleed during the study period despite being within the therapeutic range. FVIII Inhibitor reappearance was observed in 2 sHAi patients partially tolerized. No adverse events were observed.

Conclusion(s): This pediatric cohort was successfully managed with doses adjusted to whole vials along with emicizumab levels monitoring. This dosing regimen allowed individualized treatment keeping the recommended therapeutic range and may be cost-effective.