Karina Meijer

In 2018, Refacto AF R , a B-domain-deleted third-generation FVIII concentrate, became our preferential product. After the introduction, the development of inhibitors was prospectively monitored; retrospectively, we sought for risk factors in the patients who developed a de-novo inhibitor. Over a period of 15 months, 4/19 adult patients with non-severe haemophilia who were treated on demand for surgery, developed high titer antibodies to FVIII after administration of Refacto AF R ; 5/52 mostly severe patients on prophylaxis, developed an inhibitor (3 ≥ 0.1 BU; 1 > 0.6 BU, 1 high titre) after they switched to Refacto AF R ; all were children <14 years of age and with >100 exposure days, none related to surgery or intensive treatment; all received Kovaltry R before. In conclusion: inhibitors were encountered in on demand patients and previously treated prophylaxis patients; this observation might be a coincidental finding, but also risk factors like genotype and surgery and/or that Refacto AF R is more immunogenic should be considered. For the patients on prophylaxis we hypothesize that loss of tolerance by preceding Kovaltry R might have contributed to inhibitor development.

Trends of coagulation parameters during long-term treatment with combination antiretroviral therapy (cART) are unclear. We followed 40 male subjects living with human immunodeficiency virus (HIV). Plasma levels of procoagulant parameters, factor VIII, von Willebrand factor and D-dimer, and anticoagulant parameter Protein S (PS), were measured before start and 3 months, 1 year, and 9 years after. Analyses were adjusted for cardiovascular risk factors (age, smoking, and hypertension) at baseline. At baseline, procoagulant parameters were markedly elevated and PS was in the lower range of normal. CD4/CD8-ratio improved during the complete follow-up period. In the first year, procoagulant parameters were decreasing, but at year 9 an increase was observed. After correction for cardiovascular risk factors, this increase was no longer present. PS remained stable during the first year and slightly increased from one to 9 years. This study indicates that decreasing immune activation by cART reverses the procoagulant state in HIV partially during the first year. These parameters increase in the long term despite an on-going decrease in immune activation. This increase might be related to established cardiovascular risk factors.