Low-dose factor VIII infusion in Chinese adult haemophilia A patients: pharmacokinetics evidence that daily infusion results in higher trough level than with every-other-day infusion with similar factor VIII consumption

Pharmacokinetic profile of children with haemophilia A receiving low-dose FVIII prophylaxis in Indonesia: A single centre experience

BACKGROUND

Pharmacokinetic (PK) studies of low-dose prophylaxis (LDP) of coagulation factor VIII (FVIII) in children with severe haemophilia A (SHA) are scarce.

OBJECTIVE

This study aims to investigate the PK profile of children with SHA receiving LDP of FVIII.

METHODS

Paediatric patients receiving FVIII infusions (10 IU/kg twice weekly) were included. PK profiles were estimated using the Web Accessible Population Pharmacokinetic Service for Haemophilia (WAPPS-Haemo). The primary outcomes were the terminal half-life (t_1/2 ), concentration-time profile, and time to reach an FVIII level of < 1%. The secondary outcome was the suggested dosing interval of FVIII prophylaxis based on the individual PK profile.

RESULTS

Twenty-five patients were recruited; their mean age was 12.3 ± 3.0 years. The t_1/2 differed among patients receiving LDP of FVIII twice weekly, with a median of t_1/2 was 14.8 h (IQR 12.6-16). The median time to reach an FVIII level of < 1% was 73.8 h (IQR 58.8-80.3). Most patients could maintain a trough level of FVIII > 1% longer than 48 h. At 72-96 h, patients needed a second dose of FVIII infusion because the FVIII level was < 1%. The suggested dosing interval of FVIII prophylaxis ranged from daily to every 96 h, depending on the individual PK profile.

CONCLUSION

Our study identified inter-individual differences in the PK parameters using LDP of FVIII twice weekly. The inter-individual results in different dosing intervals advise the timing of LDP. Estimating individual PK parameters enables the identification of the optimal prophylaxis frequency to prevent bleedings.

Low-dose prophylaxis and its impact on the health of haemophilia patients

BACKGROUND AND OBJECTIVES

There is convincing evidence to show that low-dose prophylaxis (LDP) results in reduction in annualized bleeding rate (ABR) and better health-related quality of life (HRQoL) compared with on-demand or episodic treatment (ET) in haemophilia patients. The aim is to review various LDP protocols practised for the treatment of haemophilia, specifically in resource-limited countries.

METHODS

A literature survey was made of articles published in English language in PubMed and EMBASE without any time limit using keywords 'low dose', 'prophylaxis' and 'haemophilia' in different combinations.

RESULTS

A total of 19 reports involving LDP in patients with haemophilia were included in this review. Almost all studies reported reduction in ABR, improvement in joint function, pain and HRQoL compared with ET, but this did not fully translate into significant improvement in structural arthropathy already caused by earlier bleeds, suggesting that LDP may be less or ineffective in either stopping or reversing the damage. Individualized dose escalation protocols based on pharmacokinetic (PK) or clinical parameters were found to be superior to fixed LDP protocols and cost-effective compared with standard dose protocols.

CONCLUSION

The developing countries can initiate LDP as the first step of prophylaxis, but certainly this should not be the final goal of the health care system in any country. Due to the complex pathophysiological mechanisms underlying haemophilic arthropathy, long-term data on LDP in haemophilia patients are warranted.

Extended half-life recombinant products in haemophilia clinical practice - Expectations, opportunities and challenges

Extended half-life (EHL) products have shown robust efficacy in clinical trials, whilst allowing for less intense treatment regimens when compared with standard half-life products. Regimen optimisation with EHL products could lead to further improvements in bleeding rates, quality of life and reductions in treatment burden. Patients now expect good efficacy, a lower treatment burden and equivalent safety when compared with standard half-life products. As our knowledge base grows these expectations have evolved and targeting an annualised bleeding rate of zero has become a more realistic clinical goal. Personalised prophylaxis can help patients achieve these goals. However, a number of challenges still remain, including cost, challenges in predicting outcomes for patients and differences in patients' and clinicians' expectations. When switching a patient, comprehensive patient care can reduce the impact of these issues. This review presents in brief the protein therapeutics with an extended half-life, including key trial results, challenges of chronic care that impact on patients' outcomes and how the modified proteins might help address some of these issues. In addition, practical steps for managing the switch to EHL products are presented.

[Population pharmacokinetics of two recombinant human coagulation factor Ⅷ preparations in patients with hemophilia A]

Objective: To compare the differences in population pharmacokinetic (PK) parameters between two recombinant coagulation factor Ⅷ (FⅧ) preparations, Kogenate FS and Advate, in patients with hemophilia A, and to provide the theoretical basis of precise individualized treatment for those patients. Methods: Patients with moderate or severe hemophilia A who had at least one injection of Kogenate FS or Advate at 41 international hemophilia centers were enrolled as subjects from the WAPPS-Hemo project since January 2015 to December 2017. The half-lives of the two drugs and the time of FⅧ activity reaching 2% (TAT 2%) were calculated, and the differences of PK between the two drugs among different age and dose subgroups were further analyzed. Results: ①The mean age of patients in the Kogenate FS (n=117) and Advate groups (n=120) were (27.6±17.7) and (23.4±16.2) years old, respectively. All patients in the two groups were males. ②The administration doses in the Kogenate FS and Advate groups were (31.5±13.1) IU/kg and (38.17±14.83) IU/kg, respectively; the half-lives of the two drugs were (12.3±3.5) h and (10.8±2.9) h, respectively; and the TAT 2% were (65.2±21.7) h and (57.0±17.9) h, respectively. ③In the Kogenate FS group, the drug half-lives in patients aged ≥12 and <12 years old were (12.7±3.7) h and (11.1±2.5) h, respectively; the TAT 2% were (68.6±22.9) h and (55.8±14.6) h, respectively. In the Advate group, the drug half-lives in patients aged ≥12 and <12 years old were (11.4±3.1) h and (9.4±1.8) h, respectively; and the TAT 2% were (61.1±18.0) h and (45.2±11.3) h, respectively. ④In the Kogenate FS group, the drug half-lives in <20 IU/kg, (20-29) IU/kg, (30-39) IU/kg and ≥40 IU/kg groups were (13.3±4.0) h, (12.3±3.6) h, (12.2±3.5) h and (11.6±2.6) h, respectively; and the TAT 2% were (61.5±21.4) h, (63.9±22.4) h, (67.0±24.3) h and (68.0±19.5) h, respectively. In the Advate group, the drug half-lives in <20 IU/kg, (20-29) IU/kg, (30-39) IU/kg and <40 IU/kg groups were (11.5±3.8) h, (11.4±3.7) h, (11.0±2.9) h and (10.4±2.3) h, respectively; and the TAT 2% were (50.8±19.2) h, (56.7±21.0) h, (58.2±18.8) h and (58.1±15.8) h, respectively. Conclusion: The PK parameters of Kogenate FS are superior to those of Advate among different age and dose subgroups.