Additive solutions are used to limit changes that red blood cells (RBCs) undergo during storage. Several studies have shown better preservation of glucose and redox metabolism using the alkaline additive solution PAGGGM (phosphate-adenine-glucose-guanosine-gluconate-mannitol). In this randomized open label intervention trial in 20 healthy volunteers, the effect of storage, PAGGGM versus SAGM (saline-adenine-glucose-mannitol), on post transfusion recovery (PTR) and metabolic restoration after transfusion was assessed. Subjects received an autologous biotinylated RBC concentrate stored for 35 days in SAGM or in PAGGGM. As a reference for the PTR, a 2-days stored autologous biotinylated RBC concentrate stored in SAGM was simultaneously transfused. RBC phenotype and PTR were assessed after transfusion. Biotinylated RBCs were isolated from the circulation for metabolomics analysis up to 24 hours after transfusion. The PTR was significantly higher in 2 days stored RBCs than in 35 days stored RBCs after 2 and 7 days after transfusion: 96% [90-99] versus 72% [66-89] and 96% [90-99] versus 72% [66-89] respectively. PTR of SAGM and PAGGGM stored RBCs did not differ significantly. Glucose and redox metabolism were better preserved in PAGGGM stored RBCs. Thedifferences measured in the blood bag remained present after transfusion only until one day after transfusion. No differences in RBC phenotype were found besides an increased complement C3 deposition on 35 days RBCs stored in PAGGGM. Our data indicate that despite better metabolic preservation, PAGGGM is not a suitable alternative for SAGM since storage in PAGGGM did not result in an increased PTR. Finally, RBCs that were recovered from circulation after transfusion showed reversal of the metabolic storage lesion in vivo within a day. This study is registered in the Dutch trial register (NTR6492).

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Background Vilobelimab, a complement 5a (C5a)-specific monoclonal antibody, reduced mortality in critically ill COVID-19 patients in a phase 3 multicentre, randomized, double-blind, placebo-controlled study. As part of the study, vilobelimab concentrations and C5a levels as well as antidrug antibodies (ADAs) to vilobelimab were analysed. Results From Oct 1, 2020 to Oct 4, 2021, 368 invasively mechanically ventilated COVID-19 patients were randomized: 177 patients were randomly assigned to receive vilobelimab while 191 patients received placebo. Pharmacokinetic sampling was only performed at sites in Western Europe. Blood samples for vilobelimab measurements were available for 93 of 177 (53%) patients in the vilobelimab group and 99 of 191 (52%) patients in the placebo group. On day 8, after three infusions, mean vilobelimab (trough) concentrations ranged from 21,799.3 to 302,972.1 ng/mL (geometric mean 137,881.3 ng/mL). Blood samples for C5a measurements were available for 94 of 177 (53%) patients in the vilobelimab group and 99 of 191 (52%) patients in the placebo group. At screening, C5a levels were highly elevated and comparable between groups. In the vilobelimab group, median C5a levels were 118.3 ng/mL [IQR 71.2–168.2 ng/mL] and in the placebo group, median C5a levels were 104.6 ng/mL [IQR 77.5–156.6 ng/mL]. By day 8, median C5a levels were reduced by 87% in the vilobelimab group (median 14.5 ng/mL [IQR 9.5–21.0 ng/mL], p < 0.001) versus an 11% increase in the placebo group (median 119.2 ng/mL [IQR 85.9–152.1 ng/mL]). Beyond day 8, though plasma sampling was sparse, C5a levels did not reach screening levels in the vilobelimab group while C5a levels remained elevated in the placebo group. Treatment-emergent ADAs were observed in one patient in the vilobelimab group at hospital discharge on day 40 and in one patient in the placebo group at hospital discharge on day 25. Conclusions This analysis shows that vilobelimab efficiently inhibits C5a in critically ill COVID-19 patients. There was no evidence of immunogenicity associated with vilobelimab treatment. Trialregistration ClinicalTrials.gov, NCT04333420. Registered 3 April 2020, https://clinicaltrials.gov/ct2/show/NCT04333420