Prophylaxis for adults with haemophilia: towards a personalised approach?

Intermediate Dose Prophylaxis in Adults with Haemophilia: A Clinical Audit from a Resource Limited Setting

To address the scarcity of real world data on adult prophylaxis from developing world, a short term intermediate dose prophylaxis in adult haemophilia A patients was initiated. A total of eight patients aged > 18 years with moderate/severe haemophilia A were given an average dose of 23 IU/kg recombinant factor VIII (rFVIII) concentrate twice weekly for 2 months. A clinical audit was done on completion of four months. The mean age of the participants was 31.63 (± 6.98) years. The mean bleed rate during two months of episodic versus prophylactic regimen was 5.13 versus 0.63 (p = 0.01) and that of work days lost, hospital visits for hemophilia care were 30.63 (± 24.69) versus zero days, 20.63 (± 16.19) versus zero days respectively. The mean of factor VIII consumed during prophylaxis was 13,500 IU/month (i.e., 23 IU/kg/dose).The median time gap between prophylactic infusion to trough level was 67.50 h (60-74 h) and the median trough level observed was 2.50% (range 1-5%). The results of our clinical audit show that Intermediate dose prophylaxis with rFVIII concentrates in young adult patients with moderate/severe haemophilia A appears to be effective in reducing the frequency of bleeds.

Understanding patient preferences and willingness to pay for hemophilia therapies

BACKGROUND

Despite clearly improved clinical outcomes for prophylaxis compared to on-demand therapy, on average only 56% of patients diagnosed with severe hemophilia receive prophylactic factor replacement therapy in the US. Prophylaxis rates generally drop as patients transition from childhood to adulthood, partly due to patients becoming less adherent when they reach adulthood. Assessment of patient preferences is important because these are likely to translate into increased treatment satisfaction and adherence. In this study, we assessed preferences and willingness to pay (WTP) for on-demand, prophylaxis, and longer acting prophylaxis therapies in a sample of US hemophilia patients.

METHODS

Adult US hemophilia patients and caregivers (N=79) completed a discrete-choice survey that presented a series of trade-off questions, each including a pair of hypothetical treatment profiles. Using a mixed logit model for analysis, we compared the relative importance of five treatment characteristics: 1) out-of-pocket treatment costs (paid by patients), 2) factor dose adjustment, 3) treatment side effects, 4) availability of premixed factor, and 5) treatment effectiveness and dosing frequency. Based on these attribute estimates, we calculated patients' WTP.

RESULTS

Out-of-pocket treatment costs (P<0.001), side effects (P<0.001), and treatment effectiveness and dosing frequency (P<0.001) were found to be statistically significant in the model. Patients were willing to pay US $410 (95% confidence interval: $164-$656) out of pocket per month for thrice-weekly prophylaxis therapy compared to on-demand therapy and $360 (95% confidence interval: $145-$575) for a switch from thrice-weekly to once-weekly prophylaxis therapy.

CONCLUSION

Improvements in treatment effectiveness and dosing frequency, treatment side effects, and out-of-pocket costs per month were the greatest determinants of hemophilia treatment choice and WTP. The positive preferences and WTP for longer acting prophylactic therapies suggest that the uptake is likely to increase adherence, improving treatment outcomes. These preferences should also inform the Food and Drug Administration's assessment of new longer acting hemophilia therapies.

Humanistic and economic aspects of haemophilia treatment in Bulgaria. Comparison between two therapeutic approaches: prophylactic vs. on-demand treatment

The aim of the present study was to calculate the cost-effectiveness of on-demand and prophylactic treatments of severe haemophilia A for Bulgarian patients. The point of view is that of all patients suffering from severe haemophilia A. An epidemiological model was created, which includes data regarding the number of patients divided into age groups up to 74 years. In the model, the transition age from prophylactic to on-demand treatment was gradually increased to up to 40 years. Costs of blood clotting factor, hospitalization, major surgery and indirect costs were considered; incremental cost-effectiveness ratio was calculated. The results showed that despite the increase in the costs for factor VIII with 20 million BGN, the saving obtained from other health services and indirect expenses reduce the overall expenses with 5.3 million BGN. If there is a gradual increase in the age when patients are transferred from a prophylactic to an on-demand regimen, the costs for factor VIII would increase from 10.4 million to 19.7 million BGN, but due to a decrease in indirect costs as well as other health service costs, the total costs would decrease. The sensitivity analysis showed that the costs for clotting factor VIII are what influences the cost-effectiveness in both regimes. This indicates that decreases in the factor VIII cost will increase the overall efficiency in both regimes. In conclusion, the application of the prophylactic regime for patients up to 40 years of age will provide better treatment, increase the quality of life and decrease the incremental costs.

Advancing personalized care in hemophilia A: ten years' experience with an advanced category antihemophilic factor prepared using a plasma/albumin-free method

Detailed analysis of data from studies of recombinant antihemophilic factor produced using a plasma/albumin-free method (rAHF-PFM) in previously treated patients showed a substantial level of interpatient variation in pharmacokinetics (PKs), factor VIII dosing, and annualized bleed rate (ABR), suggesting that individual patient characteristics contributed to outcome. For example, plasma half-life (t_1/2), recovery, and clearance appeared to differ between patients aged <6 years and 10–65 years. Prophylaxis resulted in lower ABRs than episodic treatment in both age groups; better adherence to the prophylactic regimen resulted in a lower ABR in patients aged 10–65 years. The weekly frequency of dosing and adherence to dosing were both significantly and inversely related to the rate of bleeding (young children, P<0.0001 for both all bleeds and joint bleeds; older patients, P<0.0001 for all bleeds and P<0.05 for joint bleeds), as was adherence to dosing frequency (P<0.0001 for all comparisons). A post-marketing randomized study of prophylaxis demonstrated that a PK-guided dosing regimen, based on an individual patient’s rAHF-PFM PK (infusion interval, estimated t_1/2, and recovery), was as effective as standard prophylaxis and that both prophylactic regimens were superior to episodic treatment with respect to ABR and quality of life measures. Thus, compared with standard prophylaxis, the PK-guided regimen achieved comparable efficacy with fewer weekly infusions. A two-compartment population PK model describes the PK data across the entire age range and forms the basis for future PK-guided therapy with rAHF-PFM. The model confirmed a shorter t_1/2 and faster clearance of rAHF-PFM in children <6 years of age versus patients ≥10 years and predicted similar PK parameters with either a full or reduced blood sampling schedule, offering the potential for the use of PK-guided, individualized treatment in the routine clinical care setting.