Določanje plazemske koncentracije emicizumaba na osnovi prilagojene enostopenjske metode za določanje faktorja VIII

Hrastnik, Eva (author), Preložnik Zupan, Irena (mentor), Fink, Martina (co-mentor)

Hemofilija A je prirojena motnja koagulacije krvi zaradi pomanjkanja oz. zmanjšane aktivnosti faktorja VIII (FVIII). Za bolezen so značilne krvavitve v mišice in sklepe. V primeru neustreznega zdravljenja se bolniki soočajo s krvavitvami, poškodbami hrustanca, vnetjih v kosteh in mišicah. Za ustrezno obravnavo bolnika sta bistvena pravilna diagnoza, ki jo zagotovimo s specifičnimi testi določanja aktivnosti faktorjev strjevanja krvi, in zdravljenje. Razvoj emicizumaba (Hemlibra; Hoffman – La Roche Basel, Švica) je razširil možnosti zdravljenja za bolnike s hemofilijo A, z in brez inhibitorjev proti FVIII, in predstavlja alternativo nadomestnemu zdravljenju s FVIII za bolnike s hudo hemofilijo A. Po strukturi je emicizumab bispecifično protitelo, ki z enim krakom prepozna aktivni FX, z drugim pa aktivni FIX, in tako posnema delovanje FVIII. V Specializiranem hematološkem laboratoriju Kliničnega oddelka za hematologijo Univerzitetnega kliničnega centra v Ljubljani (SHL KOH UKCL) smo v okviru magistrske naloge uvedli novo metodo, R2EMI20, za določitev plazemske koncentracije emicizumaba. Metoda R2EMI20 je prilagojena enostopenjska metoda za določitev aktivnosti FVIII. Meritve koncentracij smo izvedli na koagulacijskem aparatu ACL TOP 500, in sicer je bilo vključenih več arhivskih vzorcih plazme bolnikov, ki bodisi prejemajo bodisi ne prejemajo emicizumaba. Dokazali smo, da je terapevtski interval tistih, ki prejemajo zdravilo, 30–80 µg/ml. Potrdili smo tudi ugotovitve študij, ki pravijo, da je pri bolnikih, ki ne prejemajo emicizumaba, imajo pa v plazmi prisoten rFVIII oz. imajo višjo aktivnost FVIII, rezultat meritev lažno povišana koncentracija emicizumaba. Novo vpeljana metoda R2EMI20 je primerna za klinično uporabo, saj smo poleg že zgoraj naštetih trditev dokazali, da je metoda ponovljiva v in med serijami pri različnih koncentracijah. Metoda bo v pomoč zdravnikom pri lažjem vodenju bolnikov, ki prejemajo to zdravilo. Spremljali bomo lahko, ali je bolnik razvil protitelesa na zdravilo in ali ga redno prejema.

• Language: Slovenian
• Keywords: hemofilija A, emicizumab, metoda R2EMI20, laboratorijska diagnoza
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2022
• PID: 20.500.12556/RUL-143216
• Publication date in RUL: 08.12.2022

Secondary language

• Language: English
• Title: Determination of emicizumab plasma concentration based on the modified one-stage factor VIII assay

Abstract

Haemophilia A is a congenital disorder of blood coagulation due to a deficiency or lack of activity of factor VIII (FVIII). The disease is characterised by bleeding in the muscles and joints. In case of inadequate treatment, patients experience bleeding, cartilage damage, inflammation in bones and muscles. A correct diagnosis, provided by specific tests to determine the activity of blood clotting factors, and treatment are essential for the proper management of the patient. The development of emicizumab (Hemlibra; Hoffman – La Roche Basel, Switzerland) has expanded treatment options for patients with haemophilia A, with and without anti-FVIII inhibitors, and represents an alternative to FVIII replacement therapy for patients with severe haemophilia A. Structurally, emicizumab is a bispecific antibody that recognises active FX with one arm and active FIX with the other, thus mimicking the action of FVIII. In the Specialised Haematology Laboratory of the Clinical Department of Haematology, University Clinical Centre Ljubljana (SHL KOH UKCL), we have introduced a new method, R2EMI20, to determine the plasma concentration of emicizumab as part of the master thesis. The R2EMI20 method is a modified one-step method for the determination of FVIII activity. Concentration measurements were performed on an ACL TOP 500 coagulation device and included several archival plasma samples from patients either receiving or not receiving emicizumab. We have shown that the therapeutic range of those receiving the drug is between 30 - 80 µg/ ml. We have also confirmed the findings of studies suggesting that in patients who do not receive emicizumab but have rFVIII present in their plasma or have higher FVIII activity, the measurements may result in falsely elevated emicizumab concentrations. The newly introduced R2EMI20 method is suitable for clinical use because, in addition to the claims listed above, we have demonstrated that the method is reproducible within and between batches at different concentrations. The method will help physicians to facilitate the management of patients receiving this drug. We will be able to monitor whether the patient has developed antibodies to the drug and also if he/she is receiving it regularly.

• Keywords: haemophilia A, emicizumab, R2EMI20 method, laboratory diagnosis