Factor XI

Why factor XI deficiency is a clinical concern

“…In many parts of the world, including the United States, plasma is used for replacement because fXI concentrates are not readily available. Two plasma-derived concentrates, Hemoleven (a high purity product from LFB Biomedicaments, Les Ulis, France) and FXI Concentrate (a partially purified product from Bioproducts Laboratory, Elstree, UK) have shown efficacy, but have yet to be widely used [8,60,61]. A three-year post-marketing analysis of Hemoleven indicated it was effective as prophylaxis for surgery, invasive procedures and pregnancy, and for treating active bleeding [62].…”

“…A three-year post-marketing analysis of Hemoleven indicated it was effective as prophylaxis for surgery, invasive procedures and pregnancy, and for treating active bleeding [62]. However, safety concerns have led to recommendations to use it sparingly [8, 60,61]. The first fXI concentrates appeared to be responsible for cases of thrombosis and DIC, mostly in older patients with cardiovascular disease receiving doses >30 units/kg [4,60,63].…”

“…The first fXI concentrates appeared to be responsible for cases of thrombosis and DIC, mostly in older patients with cardiovascular disease receiving doses >30 units/kg [4,60,63]. Traces of fXIa in the concentrates were thought to be responsible, and current preparations contain serine protease inhibitors (antithrombin, C1-inhibitor) and heparin to blunt this effect [60,61]. Recent analyses indicate that patients receiving lower doses (20 to 30 units/kg) are still at risk for thrombosis, and it has been suggested that initial doses should not exceed 10 to 15 U/kg, and that they should be avoided in patients with a history of thrombosis, or with thrombotic risk factors [60,62].…”

Safety and efficacy of factor XI (FXI) concentrate use in patients with FXI deficiency: a single‐centre experience of 19 years.

“…Since 1993, BPL FXI contains a small amount of heparin (10 U mL ‐1 ) and antithrombin (64–155 U mL −1 ). Hemoleven contains antithrombin (2.5–5.5 U mL −1 ), heparin (3–6 U mL −1 ) and C1 esterase inhibitor (1.5–3.5 U mL −1 ), the latter agent added in 1993 . FXI concentrate administration has been shown to increase thrombin–antithrombin complex formation and levels of fibrinopeptides and D‐dimer .…”

“…FXI concentrate administration has been shown to increase thrombin–antithrombin complex formation and levels of fibrinopeptides and D‐dimer . Both BPL FXI and Hemoleven contain heparin and antithrombin for reducing the rate of VTEs . Since the change in BPL FXI preparation in 1993, data collated by BPL on their concentrate from multiple centres show no thrombotic events .…”