Joint WFH-ISTH session: issues in clinical trial design

Haemophilia therapy is experiencing an unprecedented expansion in the number and novelty of clotting factor concentrates. Every product must be licensed by regulatory authorities, primarily on the basis of its safety and efficacy profiles. The low prevalence of haemophilia, and other inherited bleeding disorders, presents a significant challenge to patient recruitment for preauthorization clinical trials, especially given the low frequency of inhibitory antibodies, the major adverse event related to clotting factor exposure. Other challenges include a lack of harmonization between the major regulatory authorities in certain key areas, the selection of laboratory monitoring methodologies and the difficulty in obtaining high-quality phase IV safety data following authorization. These aspects will be reviewed in this session, which will also highlight the roles played by the World Federation of Hemophilia and International Society on Thrombosis and Haemostasis in the promotion of these discussions.

Relative survival benefit and morbidity with fluids in severe sepsis - a network meta-analysis of alternative therapies

BACKGROUND

Fluid resuscitation is widely practiced in intensive care units for the treatment of sepsis. A comparison of the evidence base of different fluids may inform therapeutic choice.

METHODS

The risks of mortality and morbidity (the need for renal replacement therapies (RRT)) were assessed in patients with severe sepsis. A network meta-analysis compared trials for crystalloids, albumin and hydroxyethyl starch (HES). A literature search of human randomized clinical trials was conducted in databases, the bibliographies of other recent relevant systematic reviews and data reported at recent conferences. Mortality outcomes and RRT data with the longest follow up period were compared. A Bayesian network meta-analysis assessed the risk of mortality and a pair-wise metaanalysis assessed RRT using crystalloids as the reference treatment.

RESULTS

13 studies were identified. A fixed-effects meta-analysis of mortality data in the trials demonstrated an odds-ratio (OR) of 0.90 between crystalloids and albumin, 1.25 between crystalloids and HES and 1.40 between albumin and HES. The probability that albumin is associated with the highest survival was 96.4% followed by crystalloid at 3.6%, with a negligible probability for HES. Sub-group analyses demonstrated the robustness of this result to variations in fluid composition, study source and origin of septic shock. A random-effects pairwise comparison for the risk of RRT provided an OR of 1.52 favoring crystalloid over HES.

CONCLUSION

Fluid therapy with albumin was associated with the highest survival benefit. The higher morbidity with HES may affect mortality and requires consideration by prescribers.

Health technology assessment and haemophilia

Although the funding of rare diseases such as haemophilia in developing countries remains a low priority, pressures on the funding of haemophilia treatment are also emerging in developed economies affected by the global economic downturn and the other demands on health care budgets. This is leading advisory bodies and payers alike to explore the tools of Health Technology Assessment (HTAs) in deriving recommendations for reimbursement policies. In particular, the use of cost utility analysis (CUA) in deriving costs per quality adjusted life year (QALY) for different interventions is being used to rank interventions in order of priorities relative to a threshold cost per QALY. In these exercises, rare chronic disorders such as haemophilia emerge as particularly unattractive propositions for reimbursement, as the accepted methodology of deriving a CUA. For e.g. the use of prophylaxis in haemophilia leads to a range of costs/QALY which exceed the willingness to pay thresholds of most payers. In this commentary, we review the principles utilized in a recent systematic review of the use of haemophilia products carried out in Sweden as part of an HTA. We suggest that ranking haemophilia related interventions with the standard interventions of therapeutics and public health in CUA comparisons is inappropriate. Given that haemophilia treatment is a form of blood replacement therapy, we propose that such comparisons should be made with the interventions of mainstream blood transfusion. We suggest that unequivocally effective treatments such as haemophilia therapies should be assessed differently from mainstream interventions, that new methodologies are required for these kinds of diseases and that evidence of a societal willingness to support people with rare disorders needs to be recognized when reimbursement policies are developed.

Payment, compensation and replacement--the ethics and motivation of blood and plasma donation

The supply of blood and plasma to produce haemotherapies varies around the world, but all environments need donors to furnish the raw material. Many countries still lack adequate supply, and the question of what amounts of blood and plasma are required for optimal treatment is still unresolved. The issue of compensating donors has been a controversial and emotive one in blood transfusion for many decades. Donors are conventionally classified as paid, voluntary or replacement, and a level of stigma, based on safety and ethical considerations, has been attached to paid donation. This review points to evidence which renders many of these concerns redundant. Purist arguments against compensated donation have little basis in evidence and would lead to many of today's voluntary donors being designated as paid, because of the large range of incentives used to recruit and retain them. Misplaced application of 'Titmussian' volunteerism has precipitated its own safety and supply problems. Current systems of compensation and replacement are needed to maintain supplies of essential products and lead to safe products in controlled environments. We propose that a plurality of routes towards donation is an appropriate paradigm in the heterogeneous landscape of blood and plasma product supply.

A study of reported factor VIII use around the world

The effect of replacement therapy has significantly improved the morbidity and mortality of people with haemophilia A in high income countries, a recent socio-economic development as the availability of safe concentrates has been matched by a willingness for their provision through reimbursement. In the developing world, however, this state has not been achieved, primarily because of the low visibility of haemophilia coupled with its expense, leading to inadequate treatment with its sequelae of severe pain, joint deformities, arthropathy, disabilities, and even death in childhood or early adult life. The objective of this paper was to study the reported factor VIII (FVIII) use on a country-by-country basis. Data on the reported FVIII use for 104 countries were obtained from the Marketing Research Bureau, Inc. and the World Federation of Hemophilia. The results show that FVIII use varies considerably among countries, even among the wealthiest of countries. The use of FVIII concentrate increases as economic capacity increases; in addition, consumption of FVIII has been increasing at a greater rate in high income countries. Given these trends, there probably will be a global increase in FVIII concentrates usage. Such information is critical for national healthcare agencies to determine realistic budget priorities in planning for an increased allocation of resources required to improve the treatment of patients with haemophilia A. This information is also important for pharmaceutical manufacturers to adequately plan for increased production of FVIII concentrates.

Efficiency evaluation of a DNA extraction and purification protocol on archival formalin-fixed and paraffin-embedded tissue

Formalin-fixed and paraffin-embedded tissue (FF-PET) is an invaluable resource for retrospective molecular genetic studies, but the extraction of high-quality genomic DNA from FF-PET is still a problematic issue. Despite the range of DNA extraction methods currently in use, the association of phenol-chloroform extraction and silica-based purification protocols, reported in ancient DNA studies on archaeological bones, has, to our knowledge, not been used for DNA extraction from FF-PET yet. The present study compared the efficiency of three DNA extraction and purification protocols from two different FF-PET substrates, heart and liver, by using quantitative PCR and multiplex amplification. We showed that the method, using phenol-chloroform and the QIAamp DNA mini Kit (Qiagen), was the most effective DNA extraction and purification method and that the DNA quantity extracted from liver is statistically more important than that extracted from heart. Autosomal STR typing by multiplex amplifications gave partial allelic profiles with only small size products (less than 300 bases) amplified, suggesting that DNA extracted from FF-PET was degraded. In conclusion, the protocol presented here, previously described in studies on ancient bones, should find application in different molecular studies involving FF-PET material.

Measured and simulated nitrogen fluxes after field application of food-processing and municipal organic wastes

The aims of this study were to (i) assess N fluxes (mineralization, volatilization, denitrification, leaching) caused by spreading various organic wastes from food-processing industries during a field experiment, and (ii) to identify the main factors affecting N transformation processes after field spreading. Experimental treatments including the spreading of six types of waste and a control soil were set up in August 2000 and studied for 22 mo under bare soil conditions. Ammonia and nitrous oxide emissions, and nitrogen mineralization were measured in experimental devices and extrapolated to field conditions or computed in calculation models. The ammonia emissions varied from 80 to 580 g kg(-1) NH4+-N applied, representing 0 to 90 g N kg(-1) total N applied. Under these meteorologically favorable conditions (dry and warm weather), waste pH was the main factor affecting volatilization rates. Cumulated N2O-N fluxes were estimated at 2 to 5 g kg(-1) total N applied, which was quite low due to the low soil water content during the experimental period; water-filled pore space (WFPS) was confirmed as the main factor affecting N2O fluxes. Nitrogen mineralization from wastes represented 126 to 723 g N kg(-1) organic N added from the incorporation date to 14 May 2001 and was not related to the organic C to organic N ratio of wastes. Nitrogen lost by leaching during the equivalent period ranged from 30 to 890 g kg(-1) total N applied. The highest values were obtained for wastes having the highest inorganic N content and mineralization rates.

The risk of HIV, HBV, HCV and HTLV infection among musculoskeletal tissue donors in Australia

In Australia, there are no current national estimates of the risks of transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) or human T-lymphotrophic virus (HTLV) by musculoskeletal tissue transplantation. We determined the prevalence rates of antibodies against HIV (anti-HIV), HCV (anti-HCV) and HTLV (anti-HTLV) and Hepatitis B surface antigen (HBsAg) for 12,415 musculoskeletal tissue donors from three major bone tissue banks across Australia for the period 1993-2004. The prevalence (per 100,000 persons) was 64.44 for anti-HIV, 407.13 for HBsAg, 534.63 for anti-HCV and 121.88 for anti-HTLV. The estimated probability of viremia at the time of donation was 1 in 128,000, 1 in 189,000, 1 in 55,000 and 1 in 118,000, respectively. With the addition of nucleic acid amplification testing (NAT), the probability of donor viremia would be reduced to 1 in 315,000 for HIV, 1 in 385,000 for HBV and 1 in 500,000 for HCV. The prevalence of HIV, HBV, HCV and HTLV although low, are higher among musculoskeletal tissue donors than among first-time blood donors. The risks associated with musculoskeletal donation will be reduced with NAT, though further cost analysis is required prior to its implementation.

Iron and blood donation- an under-recognised safety issue

A growing body of evidence suggests that iron status is frequently affected by blood donation. Iron deficiency may be assessed through iron storage depletion measured by serum ferritin. These measurements indicate a high incidence of iron deficiency in repeat donors. This is not ameliorated through increasing pre-donation haemoglobin cut-offs. Depletion of tissue--rather then storage--iron, may be assessed by measurement of the serum transferrin receptor; such measurements in repeat donors indicate tissue iron depletion, but to a much lesser extent than storage iron depletion. A fuller understanding on how repeat donation affects donor health will allow better haematological criteria for donor selection to be developed. Blood agencies and standard-setting authorities need to accord the issue of donor iron and donation status as high a priority as that of any blood safety issue involving patient safety, if the safety and supply of the blood system is to be maintained.

Globalization and blood safety

Globalization may be viewed as the growing interdependence of countries worldwide through the increasing volume and variety of cross‐border transactions in goods and services, and also through the more rapid and widespread diffusion of technology. Globalization is not just an economic phenomenon, although it is frequently described as such, but includes commerce, disease and travel, and immigration, and as such it affects blood safety and supply in various ways. The relatively short travel times offered by modern aviation can result in the rapid spread of blood‐borne pathogens before measures to counteract transmission can be put in place; this would have happened with SARS if the basic life cycle of the SARS virus did not include an asymptomatic viraemia. This risk can be amplified by ecological factors which effect the spread of these pathogens once they are transferred to a naïve ecosystem, as happened with West Nile virus (WNV) in North America. The rationalization and contraction of the plasma products industry may be viewed as one aspect of globalization imposed by the remorseless inevitability of the market; the effect of this development on the safety and supply of products has yet to be seen, but the oversight and assurance of a shrinking number of players will present particular challenges. Similarly, the monopolization of technology, through patent enforcement which puts access beyond the reach of developing countries, can have an effect on blood safety. The challenges presented to blood safety by globalization are heightening the tensions between the traditional focus on the product safety – zero‐risk paradigm and the need to view the delivery of safe blood as an integrated process. As an illustration of this tension, donor deferral measures imposed by globalization‐induced risks such as vCJD and WNV have resulted in the loss of the safest and most committed portion of the blood donor population in many Western countries, leading to an increased risk to safety and supply. It is only through an appreciation of the basic needs of transfusion medicine, including the enunciation of appropriate principles to manage, rather than eliminate, risks, that the challenges imposed by globalization may be overcome.

Variant Creutzfeldt-Jakob disease transmission by plasma products: assessing and communicating risk in an era of scientific uncertainty

A substantial body of animal data indicates that transmissible spongiform encephalopathies (TSEs) are transmitted through blood. These data have been augmented in the past year by reports that two recipients of red cells from donors with variant Creutzfeldt-Jakob disease (vCJD) in the United Kingdom have acquired this infection. Most of the blood donations collected in countries affected by bovine spongiform encephalopathy (BSE) and vCJD also contribute plasma to fractionation pools. Thus, a number of batches of fractionated products have included plasma from donors who developed vCJD. On the basis of public health strategies influenced, in part, by risk assessments, the UK and the French authorities have instituted measures for recalling products and informing patients of the estimated risks. It is therefore relevant to review the principles used by authorities in generating risk assessments for the transmission of TSEs by blood and blood products. While the general principles are fairly straightforward, the final assessments are very dependent on the magnitude of several key parameters, which are, largely, still unknown. A critical determinant of final product risk is the extent to which the plasma fractionation process will contribute to eliminating the infectious prion agent. Therefore, regulatory and industry measures to characterize fractionation processes for their capacity to eliminate prions are to be strongly encouraged. In the interim, an understanding of the principles used to generate risk assessments should contribute to an enhanced ability to address this threat to patient safety. Authorities should recognize that adequate communication is an integral part of good risk-management practices.

Osteoprotegerin (OPG) is localized to the Weibel-Palade bodies of human vascular endothelial cells and is physically associated with von Willebrand factor

Recent studies demonstrate roles for osteoprotegerin (OPG) in both skeletal and extra-skeletal tissues. Although its role in preventing osteoclast (OC) formation and activity is well documented, emerging evidence suggests a role of OPG in endothelial cell survival and the prevention of arterial calcification. In this communication, we show that vascular endothelial cells in situ, and human umbilical vein endothelial cells (HUVEC) in vitro, express abundant OPG. In HUVEC, OPG co-localizes with P-selectin and von Willebrand factor (vWF), within the Weibel-Palade bodies (WPB). Treatment of HUVEC with the pro-inflammatory cytokines, tumor necrosis factor (TNF)-alpha and IL-1beta, resulted in mobilization from the WPBs and subsequent secretion of OPG protein into the culture supernatant. Furthermore, TNF-alpha treatment of HUVEC resulted in a sustained increase in OPG mRNA levels and protein secretion over the 24-h treatment period. Reciprocal immunoprecipitation experiments revealed that while not associated with P-Selectin, OPG is physically complexed with vWF both within the WPB and following secretion from endothelial cells. Interestingly, this association was also identified in human peripheral blood plasma. In addition to its interaction with vWF, we show that OPG also binds with high avidity to the vWF reductase, thrombospondin (TSP-1), raising the intriguing possibility that OPG may provide a link between TSP-1 and vWF. In summary, the intracellular localization of OPG in HUVEC, in association with vWF, together with its rapid and sustained secretory response to inflammatory stimuli, strongly support a modulatory role in vascular injury, inflammation and hemostasis.

International movement of plasma and plasma contracting

Plasma fractionation is a global business characterised by technological stability, increasing consolidation and a high level of regulatory oversight. All these factors affect the ease with which plasma derivatives can be accessed in the world market. As domestic regulatory measures in the first world blood economies become increasingly resonant to the precautionary approach, the availability of plasma as a raw material, as well as its cost, become an increasingly significant component in the cost of the final product. This decreases the amount of plasma which fractionators are able to allocate for export activities. Also, regulatory standards in the country of manufacture will reflect priorities in that country which may not be similar to those in export markets, but which will affect entry to those markets. While many countries possess a fractionation capacity, the limiting factor in supply worldwide is the amount of plasma available, and nationalistic drivers for each country to have its own plant are inimical to product safety and supply. Rather, the provision of sufficient supplies of domestic plasma should be the focus of resource allocation, with a choice of an appropriate contract fractionator. However, contract fractionation too may be affected by domestic considerations unrelated to the needs of the country of plasma origin. This chapter will review the global plasma market and the influences on plasma and plasma product movement across national borders. Problems in ensuring adequate safety and supply will be identified, and some tentative approaches to the amelioration of current barriers to the provision of plasma derivatives will be outlined.

Regulatory challenges to global harmonization and expanded access to concentrates: how will regulators balance the increasing cost of new safety requirements with the desire to increase the availability of affordable product?

The provision of concentrates of the deficient coagulation factors is an essential component of the provision of comprehensive haemophilia care. Their safety, quality and efficacy need to be assured independently of the measures dictated by the market and the individual manufacturers. Over the past 20 years, this assurance has become the role of regulatory authorities, which in the developed world have generated a framework that assesses haemophilia products as medicines in the highest category of risk relative to other therapeutic agents. Systems of official regulation mandating standards and other measures are now coupled with voluntary standards adopted by industry bodies as additional features of a comprehensive nexus of arrangements contributing to product quality and risk minimization. Currently, the regulation of products for haemophilia in less developed economies relies on reference to decisions in the first-world authorities. This may not always result in optimal outcomes as most of the haemophilia care in the developing world is through local plasma and cryoprecipitate, which are not subject to the oversight of mainstream regulators. Furthermore, the emergence of companies based outside the developed world and seeking to supply the emerging economies of the developing world with haemophilia concentrates has necessitated new strategies for regulation that are independent of the established frameworks. Overall, the principles used by mainstream agencies may be applied in all environments seeking to assure the quality of haemophilia care. Applied properly, they can contribute to maintaining the delivery of a form of therapy that is nowadays amongst the safest in therapeutic practice. A rigid interpretation can seriously impede access to treatment, and therefore the development of independent expertise and appropriate strategies in assuring product safety and quality in the developing world is essential if patient safety and access to products can be assured.

Plasma for fractionation: safety and quality issues

Plasma may be procured for use as a therapeutic product or as a raw material for manufacture of other products, and may be collected as a by-product of whole blood, or as a plasma donation from aphaeresis. When collected for fractionation, the quality and safety of the plasma are intimately linked to the quality and safety of the manufactured plasma derivatives. High quality plasma can be obtained either from whole blood or from plasmapheresis; quality can, however, be adversely affected by poor storage conditions after collection. Quality standards for plasma for fractionation are necessarily different than for plasma for transfusion and, with modern fractionation methods, certain quality aspects become less relevant. Similarly, the relevance of certain recent technological advances, such as nucleic acid testing (NAT), for maximizing the safety of plasma for fractionation are questionable, although their introduction through the linkage of recovered plasma to whole blood collection can improve the safety of fresh blood components. Viruses that are not screened for at blood banks may also be excluded from the plasma pool they are more clinically relevant when multiple products made from a pool may infect a large number of recipients, in contrast to components given to one or a small number of patients.

Product delivery in the developing world: options, opportunities and threats

While many developed countries are moving to recombinant coagulation factors as their preferred modality for delivering haemophilia care, the cost of these products currently impedes their access by developing countries. A number of options are available to these countries for the provision of plasma-derived therapeutic products. The decreasing market for plasma-derived coagulation factors in the developed world is leading to the generation of a surplus of these products and an ability to offer them outside their traditional markets if prices are affordable. Current indications are that the commercial fractionation industry of the developed world has an excess capacity in both available plasma and fractionation plants. It would seem that accessing this capacity might have attractions for the developing world. Countries wedded to achieving self-sufficiency in haemophilia products may elect to develop a strategy for fractionating domestically sourced plasma. This may be achieved by the generation of a capacity to fractionate within the country or by contracting the fractionation to an external agency overseas. However, reliance on domestic plasma should not be allowed to impede access to sufficient and safe coagulation products. Irrespective of the route chosen, products need to attain satisfactory compliance to standards for safety, quality and efficacy. This is best done through alignment of the products with the requirements of credible regulatory agencies. While the approval of the mainstream regulators of the developed world affords considerable assurance regarding product quality, the increasing efforts made by fractionation agencies in the developing world to attain best practice is commendable and augurs well for the enhancement of haemophilia care in these countries.

Emerging and receding risks of therapeutic regimens for haemophilia

During the past two decades, the improvement of therapeutic agents for the management of haemophilia has created the opportunity for individuals with haemophilia to live normal lives. However, in some instances, the progress made has been accompanied by emergence of unexpected risks and other new complications. A number of viruses have either emerged, or become greater risks to people with haemophilia. In addition, the drive of many countries towards self-sufficiency in blood products may in fact be endangering people with haemophilia by restricting blood donation to a pool of donors with high infection risk, discouraging commercial interests from developing safer products, and discouraging use of 'foreign' products even where that may be the safer option. Gene therapy for haemophilia, although an encouraging new treatment, has brought with it a number of adverse events, including risk of virus infection and development of carcinomas. The risk of inhibitors is still the most important problem for people with haemophilia, and a recent report showed that the type of factor concentrate does not impact significantly on this risk. Despite the advent of new and promising treatments for haemophilia, heathcare providers must be alert to new risks posed by them.