Parachutes and prophylaxis: they both work!

Identification of the Profile of the Patients with Hemophilia B Eligible for Treatment with Nonacog Alfa Once-Weekly

This study aimed to identify the characteristics of patients with hemophilia B eligible for once-weekly treatment with Nonacog alfa. Methods: A survey was conducted in 14 Hemophilia (HCs) of Italy. These centers were given a questionnaire consisting of ten closed multiple-choice questions. The centers were asked: (a) the percentages of their hemophilia B (HB) patients undergoing replacement therapy, “On-demand”, or weekly prophylaxis, (b) the criteria guiding the monitoring of patients, the advantages according to the age of patients, and (c) the obstacles to prophylaxis. The percentage of patients receiving “On-demand” (OD) treatment or continuous prophylaxis (prophy) differed depending on patient age and the severity of the disease. Only 57% of HCs provided “On-demand” therapy to the mild HB patients, about 93% to moderate ones, of whom 43% on prophylaxis. About 78% of patients <6 years old, were on treatment in 9 out of 14 HCs, by prophylaxis 66.7% and 33.3% by On-demand. In the 6–18 age group, 90.1% of HCs treated HB patients with prophylaxis, 42.8% in the 18–30 age range. On-demand treatment was the therapy of choice in 61.5% of HCs for patients aged 30–65 years. In total, 64% of the HCs assigned the maximum score to bleeding frequency, especially in the <6 and 6–18 age groups. Bleeding severity was also taken into significant consideration, particularly in subjects up to 30 years old. The scores regarding venous access were distributed relatively evenly throughout all age groups. The majority of the centers attributed a medium-high score to treatment compliance, especially in the 6–65 age range. In actuality, 55% of HCs attributed pro-thrombotic comorbidity a low score in the 18–30 age group, whereas 81% gave pro-hemorrhagic comorbidity a high rating in patients aged >65 years old. Many centers assigned a medium-high score to the baseline concentration of FIX level at diagnosis in all age groups. Most HCs attributed a medium-high score to type of genetic mutation in the younger age groups. As for socio-cultural barriers and quality of life, the majority of respondents gave a medium-high score in all age groups. For periodic monitoring of patients receiving continuous prophylaxis, 59% of the centers reported using clinical assessment. With regard to prophylaxis administration method, the majority of hemophiliacs were given infusions twice weekly, while as regards to the dose of FIX concentrate delivered, 50% of the centers reported administering prophylaxis once-weekly at a dose ranging from 5–100 IU/kg in 10–50% of HB patients. Thus, 93% of the centers reported using a dose of 25–50 IU/kg for twice-weekly prophylaxis in 6–100% of the patients. The majority of centers (86%) believe that, in a program of early primary prevention, once-weekly treatment with nonacog alfa may represent an alternative strategy to dose escalation. The results show that patients with mild hemophilia, with functional musculoskeletal status and difficulties with venous access, are candidates for once-weekly prophylaxis with nonacog alfa. For such patients, this regimen can improve treatment compliance and quality of life.

Once-weekly prophylactic dosing of recombinant factor IX improves adherence in hemophilia B

Regular prophylactic treatment in severe hemophilia should be considered an optimal treatment. There is no general agreement on the optimal prophylaxis regimen, and adherence to prophylaxis is a main challenge due to medical, psychosocial, and cost controversies. Improved approaches in prophylaxis regimen of hemophilia B are needed to make patients’ lives easier. There is some evidence to support the efficacy of once-weekly prophylaxis. Longer sampling schedules are required for the determination of pharmacokinetic (PK) properties of factor IX (FIX). The half-life of FIX seems to be longer than previously described and is expected to be 34 hours. The clinical significance of maintaining a 1% trough level is widely debated in hemophilia B. The overall relationship between factor concentrate levels and incidence of joint bleeding was found to be very weak. Data also indicate that the distribution of FIX into an extravascular FIX compartment may contribute to hemostasis independently of circulating plasma FIX levels. Clinical assessment of the frequency and severity of bleeds remain an important measure of the efficacy of treatment. Role of PK-guided therapy remains to be established. Two prospective randomized studies had evaluated the efficacy and safety of 100 IU/kg once-weekly prophylaxis with nonacog alfa, and this prophylaxis regimen was found to be associated with lower annual bleeding rate compared with on-demand treatment in adolescents and adults with moderately severe-to-severe hemophilia B. Secondary prophylaxis therapy with 100 IU/kg nonacog alfa once weekly reduced annual bleeding rate by 89.4% relative to on-demand treatment. Residual FIX may be supportive of effectiveness. Once-weekly prophylaxis was well tolerated in the two studies, with a safety profile similar to that reported during the on-demand treatment period. To individually tailor treatment to clinical response and to minimize costs of factor concentrate, it would be of interest to investigate the efficacy of lower doses of the drug administered once a week.

Multicentre, randomized, open-label study of on-demand treatment with two prophylaxis regimens of recombinant coagulation factor IX in haemophilia B subjects

Few randomized studies have reported on the use of factor IX (FIX) for secondary prophylaxis in haemophilia B patients. This study aimed to evaluate the efficacy and safety of two secondary prophylaxis regimens of recombinant coagulation FIX, nonacog alfa, compared with on-demand therapy. Male subjects aged 6-65 years with severe or moderately severe haemophilia B (FIX:C ≤ 2, n = 50) and ≥12 bleeding episodes (including ≥6 haemarthroses episodes) within 12 months of study participation were enrolled in this multicentre, randomized, open-label, four-period crossover trial. The primary measure was the annualized bleeding rate (ABR) of two prophylactic regimens vs. on-demand therapy. In the intent-to-treat group, mean ABR values were 35.1, 2.6 and 4.6 for the first on-demand period, the 50 IU kg(-1) twice-weekly period, and the 100 IU kg(-1) once-weekly period respectively. Differences in ABR between the first on-demand period and both prophylaxis regimens were significant (P < 0.0001); no significant differences were observed between prophylaxis regimens (P = 0.22). Seven serious adverse events occurred in five subjects, none related to study drug. Results demonstrated that secondary prophylaxis therapy with nonacog alfa 50 IU kg(-1) twice weekly or 100 IU kg(-1) once weekly reduced ABR by 89.4% relative to on-demand treatment. Both prophylaxis regimens demonstrated favourable safety profiles in subjects with haemophilia B.

Equipoise should be amended, not abandoned

BACKGROUND

Benjamin Freedman has argued in 1987 that before a controlled trial is started, there should be 'genuine uncertainty in the expert medical community about the preferred treatment'. Freedman's definition of the concept is widespread in clinical research, but has been controversial since its start. Over the past decade, the equipoise controversy has become increasingly complex.

PURPOSE

This article aims: (1) to identify and clarify the main points of contention in the equipoise controversy, and (2) to reconcile the opposing views by pointing at areas of overlap between proponents and opponents in the equipoise debate.

METHODS

We analyze the positions of the leading authors in the equipoise debate in the past decade.

RESULTS

There is substantial overlap between the opponents and proponents of equipoise. Both should be able to accept the following answers to points of contention in the debate: (1) the therapeutic obligation can remain the basis for equipoise as long as it is conceived as an obligation to provide participants with competent care, (2) equipoise is grounded in a competent care and an epistemological dilemma, (3) equipoise does not as a rule prohibit placebo-controlled trials when proven effective treatment exists, (4) patient equipoise and individual physician equipoise are irrelevant, and (5) having to stop a trial is not always equivalent to disturbing equipoise. Clarification of these points of contention leads to a sharpened definition of equipoise: 'a state of genuine agnosticism or conflict in the expert medical community about the net preferred medically established procedure for the condition under study'. This definition asks of physician-researchers and members of IRBs to meet two conditions: (1) to genuinely evaluate to what extent a proposed randomized clinical trial solves a state of agnosticism or a knowledge conflict in the expert medical community and (2) to respect the standard of competent care, meaning that they consider whether the regular clinical standard from an all-things considered perspective is also the preferred standard in the research context. Equipoise is a specification of two general ethical principles for clinical research: scientific validity and a favorable risk benefit ratio. As a specification equipoise adds substance to these principles since they do not explicitly ask for the two conditions. Equipoise is a prima facie obligation rather than a morally authoritative principle for determining the acceptability of clinical trials. It needs to be balanced against other norms for clinical research. Violation of equipoise is therefore not always unethical.

LIMITATIONS

This study is limited to the context of randomized clinical trials.

CONCLUSIONS

There is no decisive reason to give up on the equipoise requirement.

Clinical experience with Optivate®, high-purity factor VIII (FVIII) product with von Willebrand factor (VWF) in young children with haemophilia A

Optivate® is a high-purity FVIII/VWF product. Its safety, tolerability and efficacy in subjects ≥ 12 years have been demonstrated. This study was undertaken to assess Optivate® in children with haemophilia A. Twenty-five children, including one PUP (previously untreated patient), aged 1-6 years (mean 4.67 years) were treated with Optivate® for 26 weeks. Inhibitors were assessed every 3 months and viral status at the study start and end. Prophylaxis was used by five boys and on demand by twenty. The mean number of bleeds in the study was lower compared to the same period pre-study (12.0/child vs. 16.2/child), with fewer bleeds (P < 0.05) in the prophylactic subgroup (8.0/child) compared with the on-demand sub-group (13.4/child). Fourteen major bleeds were reported, all by the on-demand sub-group. Children on prophylaxis were administered a mean of 59.4 infusions; on-demand group 35.1 infusions. A total of 998 infusions were used with a mean dose of 29.1 IU kg⁻¹, and a mean of 38.6 exposure days (ED). Children < 4 years used higher doses, and reported fewer bleeds than older children. Children's Parents/Guardians rated Optivate® as helpful or very helpful in controlling 97.5% of bleeds by the prophylactic group, and in 98.5% of the bleeds in the on-demand group. Only 5 of 101 ADRs were treatment-related events (5%), all were mild and non-serious. There were no clinically significant changes in vital signs, viral transmissions or inhibitors. In young children Optivate® was well tolerated, safe and efficacious.

RCTs and observational studies to determine the effect of prophylaxis in severe haemophilia

It has been suggested that more RCTs should be conducted in the evaluation of haemophilia treatment, including prophylaxis. To draw valid conclusions from experimental or observational studies, internal validity should be ensured. In particular, similarity of prognosis between treatment groups compared in a particular study is needed. Because the use of prophylaxis in observational studies is nonrandomized by definition, special efforts should be made to achieve comparability of prognosis, that is, to avoid 'confounding by indication'; in RCTs this is ensured by randomized allocation of treatment. However, the high costs of an RCT results in a limitation of both patient numbers and length of follow up. Observational studies tend to be more generalizable and cheaper, as they may include a wider spectrum of morbidities, use treatment protocols in agreement with routine care, and use available data. Therefore, observational studies can be much larger and of longer duration than RCTs; and are the preferred design for the evaluation of long term treatment effects. Several valid observational studies comparing prophylaxis and on demand treatment have reported both a short term reduction of 75-90% in bleeding frequency, and significant improvement in arthropathy, quality of life, and socioeconomic parameters after more than 20 years of prophylactic treatment. RCTs provide the most powerful tool for the evaluation of short term effects of any treatment, but are infeasible for the evaluation of long term effects. The definitive assessment of the long-term benefits of prophylaxis requires observational studies that should be performed according to rigorous standards.