Low-factor consumption for major surgery in haemophilia B with long-acting recombinant glycoPEGylated factor IX.

INTRODUCTION: Surgery in patients with haemophilia B carries a high risk of excessive bleeding and requires adequate haemostatic control until wound healing. Nonacog beta pegol, a long-acting recombinant glycoPEGylated factor IX (FIX), was used in the perioperative management of patients undergoing major surgery. AIM: To evaluate the efficacy and safety of nonacog beta pegol in patients with haemophilia B who undergo major surgery. METHODS: This was an open-label, multicentre, non-controlled surgery trial aimed at assessing peri- and postoperative efficacy and safety of nonacog beta pegol in 13 previously treated patients with haemophilia B. All patients received a preoperative nonacog beta pegol bolus injection of 80 IU kg-1 . Postoperatively, the patients received fixed nonacog beta pegol doses of 40 IU kg-1 , repeated at the investigator's discretion. Safety assessments included monitoring of immunogenicity and adverse events. RESULTS: Intraoperative haemostatic effect was rated 'excellent' or 'good' in all 13 cases. Apart from the preoperative injection, none of the patients needed additional doses of nonacog beta pegol on the day of surgery. The median number of postoperative doses of nonacog beta pegol was 2.0 from days 1 to 6 and 1.5 from days 7 to 13. No unexpected intra- or postoperative complications were observed including deaths or thromboembolic events. No patients developed inhibitors. CONCLUSIONS: These results indicated that nonacog beta pegol was safe and effective in the perioperative setting, allowing major surgical interventions in patients with haemophilia B with minimal peri- and postoperative concentrate consumption and infrequent injections as reported with standard FIX products.

Pharmacokinetics of recombinant factor XIII at steady state in patients with congenital factor XIII A-subunit deficiency.

BACKGROUND: The use of monthly recombinant factor XIII (rFXIII) recently demonstrated favorable safety and efficacy for congenital FXIII A-subunit deficiency patients aged ≥ 6 years (mentor(™) 1 trial), although the pharmacokinetics (PK) were not fully evaluated. OBJECTIVES: To comprehensively evaluate the steady-state PK of rFXIII in patients aged ≥ 6 years with congenital FXIII A-subunit deficiency. PATIENTS/METHODS: mentor(™) 2 is an ongoing, multinational safety and efficacy trial in which patients are receiving monthly rFXIII (35 IU kg(-1) ) for ≥ 52 weeks. For this 28-day PK analysis, blood samples were collected immediately predosing, and 1 h, 2 h, 3, 7, 14, 21, and 28 days postdosing. FXIII activity was measured and PK parameters were calculated using non-compartmental analysis, without prior baseline adjustment. Information regarding adverse events and bleeding was collected at each visit. Antibody assessments were performed predosing and at day 28. RESULTS: PK analysis in 23 patients revealed first-order elimination of rFXIII with a geometric mean half-life of 13.6 days. Mean FXIII activity was > 0.1 IU mL(-1) throughout the 28-day period, with a geometric mean peak activity of 0.87 IU mL(-1) and trough of 0.16 IU mL(-1) . The geometric mean clearance was 0.15 mL h(-1) kg(-1) . No bleeding episodes occurred during the PK session, and no anti-rFXIII antibodies were detected. Peak and trough FXIII activities were constant over time, compared with previous activities (≥ 10 rFXIII doses) in the same patients. CONCLUSIONS: Clearance of rFXIII is unaffected over time, and monthly prophylaxis with 35 IU kg(-1) rFXIII provides FXIII activity > 0.1 IU mL(-1) throughout the dosing interval in patients with congenital FXIII A-subunit deficiency.

Pharmacokinetics of recombinant factor XIII in young children with congenital FXIII deficiency and comparison with older patients.

Congenital factor XIII (FXIII) deficiency is a rare bleeding disorder, which in its severe form is associated with a significant bleeding phenotype, requiring regular prophylactic therapy. A recently developed recombinant FXIII (rFXIII) has demonstrated safety and efficacy in children aged ≥6 years and adults (mentor1 trial). This article describes the mentor4 trial, which has assessed the pharmacokinetics (PK) and safety of rFXIII in younger children (1 to <6 years) with congenital FXIII deficiency, and compares extrapolated PK parameters with the mentor1 trial. Six children with congenital FXIII A-subunit deficiency received a single, 35 IU kg(-1) rFXIII dose. PK properties were similar in all the children, with a mean area under the concentration vs. 30-day time curve of 248.6 IU h(-1) mL(-1) , maximal FXIII activity (30 min) of 0.67 IU mL(-1) , and mean 30-day trough of 0.21 IU mL(-1) . All patients maintained FXIII activity above the lower target level (0.1 IU mL(-1) ). rFXIII half-life was 15.1 days (range, 10-25). No safety findings of clinical concern were observed. PK properties of rFXIII were similar in patients from both trials. The study demonstrated that a single dose of 35 IU kg(-1) rFXIII maintained plasma FXIII levels above 0.1 IU mL(-1) over a 30-day period in young children with congenital FXIII deficiency, and is, therefore, likely to provide adequate prophylaxis in this age group. The study extends the previous findings of the mentor1 trial and confirms that no dose adjustment is required for different age groups with congenital FXIII deficiency.

Impact of growth factors in the regulation of apoptosis in low-risk myelodysplastic syndromes.

Increased apoptosis of hematopoietic progenitors is a hallmark of myelodysplastic syndromes (MDS) and results in ineffective hematopoiesis. Erythroid apoptosis is thought to be the main mechanism underlying the severe anemia observed in the low-risk subgroups, refractory anemia (RA) and RA with ringed sideroblasts (RARS). Treatment with erythropoietin (Epo) alone or in combination with granulocyte colony-stimulating factor (G-CSF) may significantly improve anemia and reduce bone marrow apoptosis. A synergistic effect between Epo and G-CSF has been observed in the clinic, in particular in RARS. However, the molecular mechanisms beyond the anti-apoptotic effect of these growth factors have not been fully understood. This paper outlines the potential mechanisms underlying the augmented apoptosis during the erythroid differentiation in low-risk MDS as well as the anti-apoptotic effect of the growth factors.

Granulocyte colony-stimulating factor inhibits Fas-triggered apoptosis in bone marrow cells isolated from patients with refractory anemia with ringed sideroblasts.

Treatment with granulocyte colony-stimulating factor (G-CSF) plus erythropoietin may synergistically improve hemoglobin levels and reduce bone marrow apoptosis in patients with refractory anemia with ringed sideroblasts (RARS). Fas-induced caspase activity is increased in RARS bone marrow cells. We showed that G-CSF significantly reduced Fas-mediated caspase-8 and caspase-3-like activity and the degree of nuclear apoptotic changes in bone marrow from nine RARS patients. A decrease in mitochondrial membrane potential and an increase in intracellular reactive oxygen species occurred in Fas-treated cells, but became significant only 24 h after changes in caspase activity and decrease in proliferation. G-CSF also reduced the magnitude of these late apoptotic changes. In CD34-selected normal cells, G-CSF induced myeloid colony growth, and an overall small decrease in the number of erythroid colonies. By contrast, G-CSF induced a 33-263% increase of erythroid colony formation in CD34+ cells from four of five RARS patients with severely reduced erythroid growth, while the normal or slightly reduced erythroid growth of three other patients was not influenced by G-CSF. This study suggests that G-CSF may reduce the pathologically increased caspase activity and concomitant apoptotic changes, and promote erythroid growth and differentiation of stem cells from RARS patients. Our data support the clinical benefit of G-CSF in this subgroup of myelodysplastic syndromes.