Use of pharmacokinetic modelling to individualize FFP dosing in factor V deficiency

Therapy with fresh frozen plasma (FFP) confers serious risks, such as contraction of blood-borne viruses, allergic reaction, volume overload and development of alloantibodies. The aim of this study was to apply principles of pharmacokinetic (PK) modelling to individual factor content of FFP to optimize individualized dosing, while minimizing potential risks of therapy. We used PK modelling to successfully target individual factor replacement in an 8-month-old patient receiving FFP for treatment of a severe congenital factor V (FV) deficiency. The model fit for the FV activity vs. time data was excellent (r = 0.98) and the model accurately predicted FV activity during the intraoperative and postoperative period. Accurate PK modelling of individual factor activity in FFP has the potential to provide better targeted therapy, enabling clinicians to more precisely dose patients requiring coagulation products, while avoiding wasteful and expensive product overtreatment, minimizing potentially life-threatening complications due to undertreatment and limiting harmful product-associated risks.

The use of a single von Willebrand factor-containing, plasma-derived FVIII product in hemophilia A immune tolerance induction: the US experience

BACKGROUND

Inhibitors are a serious complication for patients with severe hemophilia A. Immune tolerance induction (ITI) is the primary method for eradicating these inhibitors. The role of type of concentrate and in particular the use of von Willebrand factor-containing, plasma-derived factor VIII (VWF/pd-FVIII) concentrate in primary or rescue ITI remains unclear.

OBJECTIVES

To report retrospective collection of data on the use of a single VWF/pd-FVIII concentrate in primary and rescue ITI.

METHODS

Retrospective chart review of hemophilia A inhibitor patients at 11 US institutions who received VWF/pd-FVIII concentrate in primary or rescue ITI.

RESULTS

Primary ITI was carried out in eight inhibitor patients with a 75% complete and partial success. Secondary ITI was carried out in 25 inhibitor patients, with 52% attaining complete or partial success.

CONCLUSIONS

This report represents the largest group of primarily pediatric, high-titer inhibitor patients treated with a single VWF/pd-FVIII concentrate. It adds retrospective data to the use of VWF-containing plasma-derived factor VIII concentrate in primary and rescue ITI, particularly in those patients with characteristics of poor response to ITI.

Suppressive antibiotic therapy in chronic prosthetic joint infections

Thirteen patients with chronic total joint infections (eight knees, five hips) were treated with suppressive antibiotic therapy and retention of the prosthesis following surgical debridement and 4 to 6 weeks of intravenous antibiotic therapy. These patients faced poor functional outcome after prosthesis removal. After a mean follow up of 37.6 months (range: 24 to 55), only three patients have retained their prostheses. Ten patients required prosthesis removal for recurrent infection a mean of 21.6 months (range: 6 to 48) after starting suppressive therapy. In addition, 38% of patients experienced adverse effects which led to changes in the antibiotic regimen. Suppressive antibiotic therapy in the treatment of chronic prosthesis infections has limited clinical efficacy and is associated with a substantial risk of adverse effects.

Measurement of prothrombin mRNA during gestation and early neonatal development

Prothrombin levels in the fetal and newborn lamb follow a gestational age-related pattern of development. The changes in activity are reflected by similar changes in prothrombin antigen concentration. Our investigations indicate that these changes in prothrombin antigen and activity levels are paralleled by changes in the levels of prothrombin messenger RNA present in liver samples from fetuses of various gestational ages.

The effect of anaerobiosis on antistaphylococcal antibiotics

The activity of eight antimicrobial agents which might be used in the treatment of staphylococcal osteomyelitis was tested under anaerobic conditions similar to those found in chronically infected bone. An agar-dilution method was employed to determine the minimum inhibitory concentrations of tobramycin, vancomycin, teicoplanin, ciprofloxacin, clindamycin, ceftriaxone, ticarcillin-clavulanic acid, and amoxicillin-clavulanic acid against 25 coagulase-positive and 25 coagulase-negative staphylococcal strains. The activity of tobramycin against coagulase-positive staphylococci, and of amoxicillin-clavulanic acid and ticarcillin-clavulanic acid against coagulase-negative staphylococci was markedly decreased with anaerobiosis. Vancomycin, teicoplanin, and ciprofloxacin were active against coagulase-positive and coagulase-negative staphylococci under both aerobic and anaerobic conditions. It was also found that antibiotic concentrations comparable to the high levels which might be achieved with local antibiotic therapy of osteomyelitis were not sufficient to overcome the level of resistance (100 micrograms/ml) of staphylococci which were not susceptible to tobramycin, clindamycin, ceftriaxone, and ticarcillin-clavulanic acid.

Embolization therapy in the management of infantile hemangioma with Kasabach Merritt syndrome

A case is presented in which a giant infantile hemangioma with thrombocytopenia is managed successfully by serial transcatheter embolization.