Emerging and receding risks of therapeutic regimens for haemophilia

Continuous infusion of coagulation factors: current opinion

PURPOSE OF REVIEW

To review the most recent reports on continuous infusion of coagulation factors, focusing on the current issues relating to this mode of therapy.

RECENT FINDINGS

Continuous infusion has been extensively used as an alternative to intermittent bolus factor replacement since the 1990s. To date, more than 100 reports comprising more than 800 continuous infusion treatments in various clinical situations have been published, with an increase in the current utilization of recombinant coagulation factors. An excellent hemostatic efficacy of continuous infusion has been reported. Continuous infusion protocols, however, still vary widely in terms of the different hemostatic levels targeted, dosage regimens, modes of continuous infusion and duration of therapy, which obviously result in variations in the cost-effectiveness reported by different centers.

SUMMARY

Continuous infusion has been shown to be a safe and cost-effective mode of replacement for treatment of hemophilia. The lack of evidence-based information on the hemostatic levels to be maintained in specific clinical situations, and recent concerns regarding the development of inhibitors, particularly in patients with mild hemophilia treated with continuous infusion, need to be addressed by prospective, randomized studies that compare traditional intermittent injections and the continuous infusion mode of factor replacement.

The natural evolution of haemophilia care: developing and sustaining comprehensive care globally

Comprehensive care is vital for patients with haemophilia to prevent early death and free patients from the complications that inhibit living normal lives. Experience has shown that once introduced in a country, there is a progressive restoration of normal healthy lives to the haemophilia community. Accompanying this progress is a gradual decreased dependency on the haemophilia comprehensive centre - except during brief periods when expertise contained within the comprehensive centre is mandatory for life-saving clinical management or to prevent severe morbidity. During each stage of the natural evolution of comprehensive haemophilia care in a country, challenges to the existence of the centre occur, which threaten the comprehensive treatment concept. The haemophilia community must understand this natural evolution and be prepared to work collaboratively with governments, physicians and other patients to ensure that centres retain the expertise to meet the emergent needs when they arise.

Plasma protein therapies: current and future perspectives

Although early developments in immunology and haemostasis indicated the potential therapeutic application of plasma fractions, it was not until Cohn's development of a stable plasma protein solution for the treatment of battlefield injuries in the Second World War that the manufacture of plasma derivatives became part of industrial pharmaceutics. The resulting albumin product remained the mainstay of the plasma fractionation industry for the next 40 years but the sequential removal of 'unwanted' fractions en route to the final albumin product lent itself to the characterization and use of other products. By the 1970s, the harvesting of cryoprecipitate before the initiation of the Cohn fractionation scheme allowed access to products for treating the haemophilias, using simple precipitation and, from the 1970s, chromatographic methods to concentrate the coagulation factors. Further minor modifications allowed the administration of the immunoglobulin in high intravenous dosages, significantly extending the usage and indications of immunoglobulin products. By the 1980s, the needs for haemophilia A had made factor VIII, rather than albumin, the driver for plasma fractionation, and the advent of recombinant coagulation factors in the 1990s contributed to immunoglobulin assuming the position of the plasma procurement driver. In recent years, the plasma industry has developed a relatively large range of products but has also entered a period of consolidation as various pressures, such as technological innovations, infectious and other risks and quality requirements-all of which are discussed in this review-decreased the demand of at least two of the three products that underpin the industry's current financial basis. At the same time, modern principles of evidence-based therapeutics are coming into play in the traditionally empirical base for most of the usage for plasma derivatives. The future use of plasma derivatives, at least in the developed world, will probably follow a different path to the one seen so far, and a sound understanding for the pathophysiology of the medical indications for plasma therapies should contribute to a continuing role for these medicines in modern therapeutics.

Optimal haemophilia care versus the reality

Haemophilia A and B are inherited bleeding disorders whose diagnosis and management is generally well established and best provided by specialists in a comprehensive care setting. Patients may be put at unnecessary risk if appropriate expertise is not sought for the management of accidents and surgery. The delivery of a high quality comprehensive service to patients with bleeding disorders depends upon defined standards and a network of haemophilia centres in the UK with similar models in other countries. In developing countries, despite a shortage or absence of treatment products, development of local expertise results in an improved outlook and reduction in mortality. Optimal care for severe haemophilia includes accurate diagnosis, early and adequate factor replacement for bleeding episodes and the provision of prophylaxis from an early age to prevent joint bleeding and the consequent arthropathy. Haemophilia treatment is expensive resulting in considerable inequity in provision of care across the world. Despite decades of experience, optimal treatment levels are not robustly defined. Transfusion-transmitted infections continue to have a significant impact on patient management. The development of inhibitory antibodies seriously complicates the management both in morbidity and cost. While gene therapy has not yet produced the hoped-for cure, new technologies will produce improved products.