Pharmacokinetic study of minipooled solvent/detergent-filtered cryoprecipitate factor VIII

Stepwise options for preparing therapeutic plasma proteins from domestic plasma in low- and middle-income countries

Industrial plasma fractionation, a complex and highly regulated technology, remains largely inaccessible to many low- and middle-income countries (LMICs). This, combined with the limited availability and high cost of plasma-derived medicinal products (PDMPs), creates deficiency of access to adequate treatment for patients in resource-limited countries, and leads to their suffering. Meanwhile, an increasing number of LMICs produce surplus plasma, as a by-product of red blood cell preparation from whole blood, that is discarded because of the lack of suitability for fractionation. This article reviews pragmatic technological options for processing plasma collected from LMICs into therapies and supports a realistic stepwise approach aligned with recent World Health Organization guidance and initiatives launched by the Working Party for Global Blood Safety of the International Society of Blood Transfusion. When industrial options based on contract or toll plasma fractionation programme and, even more, domestic fractionation facilities require larger volumes of quality plasma than is produced, alternative methods should be considered. In-bag minipool or small-scale production procedures implementable in blood establishments or national service centres are the only realistic options available to gradually reduce plasma wastage, provide safer treatments for patients currently treated with non-pathogen-reduced blood products and concurrently improve Good Manufacturing Practice (GMP) levels with minimum capital investment. As a next step, when the available volume of quality-assured plasma reaches the necessary thresholds, LMICs could consider engaging with an established fractionator in a fractionation agreement or a contract in support of a domestic fractionation facility to improve the domestic PDMP supply and patients' treatment.

National strategic advocacy to manage patients with inherited bleeding disorders in low and lower-middle income countries

INTRODUCTION

Inherited bleeding disorders (IBDs) including hemophilia, von Willebrand disease, platelet disorders, mucocutaneous bleeding disorders and coagulation factor deficiencies are rarely found and under-recognized in low and lower-middle-income countries. Some patients succumbed to serious bleeding without diagnosis and treatment during childhood.

AREA COVERED

Diagnosis, management, and prevention should be integrated into the existing health care system. Although some countries have not implemented appropriate health care infrastructure, an initiative plan should be set up by cooperation of experienced experts and health care providers. Identification of patients with IBDs should be started in the antenatal setting to search for females at risk of carrier state. The investigations include bleeding assessment, mixing venous clotting time, coagulogram, coagulation factor assay and mutation detection. Genotypic analysis is helpful for confirming the definite diagnosis, carrier detection as well as prenatal diagnosis for females at risk of bearing an offspring with severe bleeding manifestations. Management involves replacement therapy ranging from blood component to virus-inactivated factor concentrate. Appropriate research is an essential backbone for improving patients' care.

EXPERT OPINION

Effective national strategic advocacy to manage patients with IBDs requires intensive collaboration among policy makers, health care providers, patients, and family members.

Use of Cryoprecipitate in Newborn Infants

Cryoprecipitate is a transfusion blood product derived from fresh-frozen plasma (FFP), comprised mainly of the insoluble precipitate that gravitates to the bottom of the container when plasma is thawed and refrozen. It is highly enriched in coagulation factors I (fibrinogen), VIII, and XIII; von Willebrand factor (vWF); and fibronectin. In this article, we have reviewed currently available information on the preparation, properties, and clinical importance of cryoprecipitate in treating critically ill neonates. We have searched extensively in the databases PubMed, Embase, and Scopus after short-listing keywords to describe the current relevance of cryoprecipitate.

Low-dose immune tolerance induction therapy in children of Arab descent with severe haemophilia A, high inhibitor titres and poor prognostic factors for immune tolerance induction treatment success

INTRODUCTION

Immune Tolerance Induction (ITI) is the first-choice therapy to eradicate Factor VIII (FVIII) neutralizing antibodies in patients with haemophilia A (HA). There is limited published data on ITI from East Mediterranean countries.

AIM

To assess the effectiveness of a low-dose ITI regimen to eradicate FVIII neutralizing antibodies in children with severe HA and high-titre inhibitors.

METHODS

A prospective, single-arm study was conducted in children with HA (FVIII < 1 IU/dl), high-titre inhibitors and poor prognostic factors for successful ITI. Patients were treated with ∼50 IU/kg plasma-derived FVIII containing von Willebrand factor (pdFVIII/VWF) concentrate (Koate-DVI, Grifols) three times a week. Time to achieve tolerance, total and partial success were analysed after ITI. Annual bleeding rate (ABR), number of target joints, FVIII recovery and school absence were compared before and after ITI.

RESULTS

Twenty patients with median (range) age of 6.2 (3-12) years and pre-ITI inhibitor titre of 36.5 (12-169) BU were enrolled. ITI lasted ≤12 months (early tolerization) in 45% of patients. Median follow-up was 12 months (3-22) and total response rate was 80% (60% total success; 20% partial success). Patients with two and three poor prognosis factors achieved overall success rate of 60% and 50%, respectively. ABR, target joints and school absence were reduced after ITI by 60%, 50% and 44.1%, respectively. In successful ITI tolerized patients, FVIII recovery was 90 (60-100)%.

CONCLUSION

A low-dose ITI therapy using a pdFVIII/VWF concentrate achieved at least partial tolerance in 80% of patients, and reduced annual bleeds in children with high inhibitor titres and at least one poor prognosis factor for ITI treatment success.

Allometry of factor VIII and informed scaling of next-generation therapeutic proteins

Allometric scaling has been applied to the pharmacokinetics (PK) of factor VIII (FVIII), but published relationships are based on relatively small subsets of available data. Numerous next-generation forms of FVIII are being developed (e.g., Fc fusion, PEGylated, and liposomal formulations) and traditional PK scaling of these products would not incorporate the wealth of existing knowledge for current FVIII therapy in humans. We conducted a meta-analysis and developed allometric relationships of FVIII from over 100 PK studies collected from literature. Normalized Wajima curves were used to relate mean FVIII profiles between species. An "informed scaling" approach was derived for predicting first-in-human PK parameters and demonstrated with a case study for an Fc fusion FVIII. NCA values for FVIII PK were well described by the allometric equations CL = 6.59 W(0.85) and V(ss) = 65.0 W(0.97). A subset of studies characterized by two-compartment modeling showed strong linearity in scaling of total clearance (CL) and central volume, but more variability in distributional CL and peripheral volume. Wajima curves for FVIII superimposed across species and the disposition of Fc fusion FVIII in humans was well predicted by "informed scaling." This approach might be generally applicable for predicting human PK of next-generational therapeutics.