Flebogamma(®) DIF (intravenous immunoglobulin) purification process effectively eliminates procoagulant activities

Background: Studies have demonstrated that traces of activated factor XI (FXIa) present in specific brands of intravenous immunoglobulin (IVIG) concentrates may pose a thrombogenic risk.

Aim: To characterize procoagulant activity during fractionation and the elimination capacity of the Flebogamma(®) DIF (Grifols' IVIG) manufacturing process.

Methods: Flebogamma(®) DIF fractionation steps included cryoprecipitate supernatant (Cryo/S), Fraction (Fr) I supernatant, and Fr II + III suspension. Purification steps included ultrafiltrate I, acid treatment, and pasteurization. Samples were assessed for total protein, IgG, and procoagulant activation markers.

Results: Cryo/S showed no procoagulant activity for prekallikrein activator (PKA), kallikrein-like, and non-activated partial thromboplastin time (NaPTT) with normal (-PPP) or FXI-deficient (-FXI) platelet poor plasma. Thrombin generation test (TGT)-PPP and TGT-FXI were <83-148 and <53-197 nM thrombin, respectively. Shortened NaPTTs (100-296 s), high PKA (51-119 IU/mL), kallikrein-like activities (0.043-0.075 ΔAU/min), positive TGTs (98-298 nM), and FXIa (9.5-14.0 ng/mL) were detected in Fr II + III. After pasteurization, no residual evidence of any procoagulant activity marker was observed, including the final IVIG concentrate at 5% or 10% protein. Results were similar in Fr II + III from different IVIG manufacturing facilities.

Conclusions: The Flebogamma(®) DIF production process is capable of eliminating procoagulant activity because of its purification steps.