An HPA-1a-positive platelet-depleting agent for prevention of fetal and neonatal alloimmune thrombocytopenia: a randomized, single-blind, placebo-controlled, single-center, phase 1/2 proof-of-concept study

Background: Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is a rare and potentially life-threatening bleeding disorder of the fetus/newborn. Antibodies against human platelet antigen 1a (HPA-1a) are associated with the most frequent FNAIT cases. There are no approved therapies for FNAIT prevention or treatment. RLYB211 is a polyclonal HPA-1a hyperimmune IgG being developed to prevent FNAIT. Objectives: To investigate whether a single dose of anti–HPA-1a (1000 IU) could markedly accelerate the elimination of HPA-1ab platelets transfused into healthy, HPA1a–negative participants as compared with placebo. Methods: This randomized, single-blind, placebo–controlled, single-center, phase 1/2 proof-of-concept study (EudraCT: 2019-003459-12) included HPA-1a– and HLA-A2– negative healthy men. Cohort 1 received intravenous RLYB211 or placebo 1 hour after transfusion of HPA-1ab platelets. Cohort 1B received RLYB211 or placebo, followed by platelet transfusion 1 week later. Primary endpoint was the half-life of transfused platelets in circulation after administration of RLYB211 or placebo, determined by flow cytometry. Proof of concept was ≥90% reduction of half-life relative to placebo. Results: Twelve participants were allocated to cohort 1 or 1B and randomized to receive RLYB211 (n = 9) or placebo (n = 3). RLYB211 markedly accelerated the elimination of HPA-1ab platelets in all participants vs placebo. In cohort 1B, this effect was observed 7 days after RLYB211 administration. Two treatment–emergent adverse events were possibly related to treatment, both in RLYB211–treated participants. No participants developed HPA-1a antibodies at 12 or 24 weeks. Conclusion: These data support the hypothesis that anti–HPA-1a could be used as prophylaxis in women at risk of having an FNAIT–affected pregnancy

Long-Term Remission of Acquired Von-Willebrand's Disease and Platelet Dysfunction after High-Dose Melphalan in a Patient with Multiple Myeloma

Background: Autologous stem cell transplantation is considered a standard of care treatment in eligible patients with multiple myeloma, but puts the patient at high risk for infections and bleeding complications. Acquired von-Willebrand's disease (AVWD) and acquired platelet dysfunction are rare bleeding disorders that are associated with lymphoproliferative disorders such as multiple myeloma. Patients with acquired bleeding disorders who are planned for ASCT to treat the underlying condition are considered at highest risk for bleeding complications, and optimal treatment strategies are not known. Materials and Methods: We summarized the diagnostic and therapeutic approach to a patient affected by AVWD and acquired platelet disorder related to multiple myeloma. The patient who was planned for ASCT presented with moderate to severe bleeding symptoms. Results: Acute bleeding episodes were successfully controlled and prevented during induction and consolidation therapy with immunoglobulins, whereas replacement of plasma-derived VW factor showed no clinical improvement. High-dose melphalan-based consolidation therapy supported with autologous stem-cell transplantation led to an immediate and sustainable rise of von-Willebrand antigen and activity and a subsequent normalization of platelet aggregation activity. After a follow-up of 40 weeks, the patient maintained normalized VW levels and platelet aggregation capacity. There were no further signs or symptoms of bleeding. Conclusion: This case report highlights the necessity for combined supportive and causal treatment in patients with AVWD and paraproteinemic PD. High-dose melphalan with autologous stem cell support may function as a treatment option in patients with myeloma-related AVWD

Randomised trial of a clinical dosing algorithm to start anticoagulation with phenprocoumon

Prospective validation of two algorithms for the initiation of phenprocoumon treatment

Genetic analysis of sudden unexpected death cases: evaluation of library preparation methods to handle heterogeneous sample material

Over the past years, next-generation sequencing (NGS) technologies revolutionized the possibilities in a broad range of application areas. Also in the field of forensic genetics, NGS continuously gained in importance and attentiveness. A significant number of sudden cardiac deaths (SCD) in the young is due to heritable arrhythmia syndromes emphasizing the need of examining the genetic basis in these cases also with regard to the identification of relatives and/or patients being at risk. As a result, high-throughput methods became of increasing value in molecular autopsy investigations enabling the analysis of a broad spectrum of genes. Most standard protocols are optimized for high-quality samples and frequently not directly applicable to challenging forensic sample material. In the present study, we intended to examine a comprehensive gene panel associated with SCD and inherited arrhythmogenic disorders. We compared three different hybridization-based library preparation technologies in order to implement a suitable NGS workflow for heterogeneous, forensic as well as diagnostic sample material. The results obtained indicated, that the Illumina technologies Nextera DNA Flex and TruSeq were compatible with samples exhibiting varying levels of degradation. In comparison, the TruSight method also resulted in good sequencing data, but seemed to be more dependent on DNA integrity. The preparation protocols evaluated in our study are not restricted to molecular autopsy investigations and might be helpful for and transferrable to further forensic research applications

Prospective evaluation of the pre-, intra-, and postoperative kinetics of ADAMTS-13, von Willebrand factor, and interleukin-6 in vascular surgery

Postoperative thrombotic thrombocytopenic purpura (TTP) shows clinical presentation similar to classical TTP, whereas exact pathophysiological contexts remain unexplained. In this study, we investigated intraoperative and postoperative changes in ADAMTS-13 (a disintegrin and metalloprotease with thrombospondin type 1 motifs, member 13), von Willebrand factor (VWF), large VWF multimers, and interleukin-6 (IL-6) in vascular surgery patients. The objective was to compare the impact of endovascular, peripheral, and aortic surgery on target parameters which are supposed to play a role in surgery-associated TTP. A total of 93 vascular surgery patients were included and divided into 4 groups according to the specific type of intervention they underwent. Blood samples were taken preoperatively, intraoperatively, and postoperatively on days 2 and 4. The ADAMTS-13 activity decreased significantly in 3 of the 4 groups during surgery (from median 81% to 49%, P < .001, in the group undergoing aortoiliacal interventions), whereas the percentage of large VWF multimers increased in all groups of patients. von Willebrand factor antigen increased significantly in all groups on postoperative day 2 and IL-6 increased significantly in the intraoperative and early postoperative period. There was no significant correlation between the intraoperative decrease in ADAMTS-13 and the increase in VWF or IL-6. No patient in this study showed clinical picture of TTP; the precise cause and clinical significance of moderately reduced ADAMTS-13 activity in the perioperative setting have not yet been definitely determined

Current pharmacogenetic developments in oral anticoagulation therapy: The influence of variant VKORC1 and CYP2C9 alleles

For decades coumarins have been the most commonly prescribed drugs for therapy and prophylaxis of thromboembolic conditions. Despite the limitation of their narrow therapeutic dosage window, the broad variation of intra- and inter-individual drug requirement, and the relatively high incidence of bleeding complications, prescriptions for coumarins are increasing due to the aging populations in industrialised countries. The identification of the molecular target of coumarins, VKORC1, has greatly improved the understanding of coumarin treatment and illuminated new perspectives for a safer and more individualized oral anticoagulation therapy. Mutations and SNPs within the translated and non-translated regions of the VKORC1 gene have been shown to cause coumarin resistance and sensitivity, respectively. Besides the known CYP2C9 variants that affect coumarin metabolism, the haplotype VKORC1*2 representing a frequent SNP within the VKORC1 promoter has been identified as a major determinant of coumarin sensitivity, reducing VKORC1 enzyme activity to 50% of wild type. Homozygous carriers of the VKORC1*2 allele are strongly predisposed to coumarin sensitivity. Using individualized dose adaptation, a significant reduction of bleeding complications can be expected, especially in the initial drug saturation phase. Furthermore, concomitant application of low dose vitamin K may significantly reduce intra-individual coumarin dose variation and, thus, may stabilize oral anticoagulation therapy. The use of new pharmacogenetics-based dosing schemes and the concomitant application of low-dose vitamin K with coumarins will decidedly influence the current practice of oral anticoagulation and greatly improve coumarin drug safety