Retention of hemostatic and immunological properties of frozen plasma and COVID-19 convalescent apheresis fresh-frozen plasma produced and freeze-dried in Canada

Background Randomized clinical trial data show that early plasma transfusion may save lives among trauma patients. Supplying plasma in remote environments is logistically challenging. Freeze-dried plasma (FDP) offers a possible solution. Study Design and Methods A Terumo BCT plasma freeze-drying system was evaluated. We compared pooled frozen plasma (FP) units with derived Terumo BCT FDP (TFDP) units and pooled COVID-19 convalescent apheresis fresh-frozen plasma (CC-AFFP) with derived CC-TFDP units. Parameters measured were: coagulation factors (F) II; V; VII; VIII; IX; XI; XIII; fibrinogen; Proteins C (PC) and S (PS); antithrombin (AT); alpha(2)-antiplasmin (alpha(2)AP); ADAMTS13; von Willebrand Factor (vWF); thrombin-antithrombin (TAT); D-dimer; activated complement factors 3 (C3a) and 5 (C5a); pH; osmolality; prothrombin time (PT); and activated partial thromboplastin time (aPTT). Antibodies to SARS-CoV-2 in CC-AFFP and CC-TFDP units were compared by plaque reduction assays and viral protein immunoassays. Results Most parameters were unchanged in TFDP versus FP or differed <= 15%. Mean aPTT, PT, C3a, and pH were elevated 5.9%, 6.9%, 64%, and 0.28 units, respectively, versus FP. CC-TFDP showed no loss of SARS-CoV-2 neutralization titer versus CC-AFFP and no mean signal loss in most pools by viral protein immunoassays. Conclusion Changes in protein activities or clotting times arising from freeze-drying were <15%. Although C3a levels in TFDP were elevated, they were less than literature values for transfusable plasma. SARS-CoV-2-neutralizing antibody titers and viral protein binding levels were largely unaffected by freeze-drying. In vitro characteristics of TFDP or CC-TFDP were comparable to their originating plasma, making future clinical studies appropriate.

Automated summary

The study compared traditional frozen plasma with freeze-dried plasma, as well as fresh-frozen plasma with freeze-dried plasma, showing that most parameters did not differ significantly between the two types of plasma. Changes in protein activities and clotting times due to freeze-drying were less than 15%, and the in vitro characteristics of freeze-dried plasma were comparable to their originating plasma.