Game-changing new treatments such as emicizumab feature heavily in the new and expanded World Haemophilia Federation (WHF) guidelines for the management of haemophilia.
For example, the 3rd edition of the WHF guidelines recommends prophylaxis with emicizumab to prevent haemarthrosis, spontaneous, and breakthrough bleeding in patients with severe phenotype haemophilia A without inhibitors.
However the recommendations are tempered by the fact that many people with haemophilia do not yet have access to the bispecific antibody and long-term data on patient outcomes is still lacking.
One of the co-authors, Associate Professor Alison Street from Monash University, told the limbic that there was variable scientific support for some recommendations despite a comprehensive, rigorous methodology for the guidelines development.
A modified Delphi process, including experts and consumers, had contributed to the evidence-informed consensus-based recommendations.
The guidelines have been endorsed by the Asian-Pacific Society on Thrombosis and Hemostasis, European Haemophilia Consortium, and National Hemophilia Foundation (USA). Locally, they will inform the next update of Australian guidelines.
Associate Professor Street, said the guidelines were not all about new and exciting products.
“The big difference that has occurred between the 2nd and 3rd edition is the emphasis on data registries … and meaningful, standardised outcome assessment. Making sure you capture everybody, understanding how the product is used and what the outcomes are.”
“Are people getting better outcomes for the amount of extra product that we are buying? Those are studies that need to be done.”
“The other things they are talking about a lot in the guidelines are the advisability, where possible and culturally appropriate, of getting the genotype done which includes preimplantation genetic diagnosis.”
A new chapter on genetic assessment includes 32 recommendations on indications and techniques for genetic testing, strategies for testing probands, classification of variants, interpretive reporting and more.
Associate Professor Street said gene therapy was the way forward but many more questions remained.
“Are you just trying to convert someone from having severe haemophilia to a less spontaneous bleeding phenotype or do you want to cure them of their haemophilia so they never need product again?”
And more had to be understood about the duration of response.
“At this stage the first licensing submitted to FDA has been deferred until they know more about long-term duration of benefit.”
Other new chapters in the guidelines since the last edition include prophylaxis with hemostatic agents to prevent bleeding; management of inhibitors; and assessment of outcomes.
Associate Professor Street said management of haemophilia required very individualised programs and as yet there were no predictive models.
“The interesting thing is that some people will appear to have the same amount of factors in their blood but some will have severe frequent bleeding and other people won’t.”
And as always there were resourcing issues to be considered in the implementation of guidelines.
“It’s about finding the right product for individual patients that give them maximum bleeding protection at a cost that the country can afford.”