“This therapy could have the potential to improve the follow-up of hemophilia patients.” An innovative treatment for hemophilia, developed by the French giant Sanofi, shows high efficacy against the symptoms of this disease, according to a study published in the Lancet which evaluates the therapeutic interest of fitusiran.
This molecule, for which Sanofi has held the rights since 2018, is one of the main innovative avenues for treating hemophilia, a genetic disease that mainly affects men and results in excessive bleeding due to lack of adequate coagulation.
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In order to prevent this bleeding, hemophilia patients are generally treated preventively by directly administering the coagulant proteins they lack due to defective genes. But a significant number of patients develop “inhibitory” antibodies against these proteins, which prevents them from being given preventive treatments. They are therefore reduced to being treated punctually during their bleeding episodes.
preventive treatments
For several years, research has focused on another therapeutic avenue: preventive treatments which, instead of directly replacing coagulant proteins, seek to obtain the same result by reducing the anticoagulant action of certain cells.
This is the case of fitusiran from Sanofi as well as another molecule, developed by Roche, emicizumab, which is already approved in the United States and in the European Union (EU) against the main form of haemophilia, known as type A.
But another form of hemophilia, type B, still lacks preventive treatment for patients who have developed inhibitory antibodies.
Risk of side effects
According to the study of Lancetcarried out on around forty patients compared to around twenty without any preventive treatment, fitusiran drastically reduced bleeding episodes for both types of haemophilia.
This treatment is therefore able to change the situation but still has “many unknowns”, underlined in the same issue of the Lancet independent study researchers, including hematologist Flora Peyvandi. They especially wonder about the side effects of fitusiran. Of the forty patients treated, about ten observed an abnormal concentration of an enzyme characteristic of serious liver problems.
Above all, two patients experienced thromboembolic episodes, ie the formation of clots that impede blood circulation. “The potential risk of thrombosis (…) must be clarified,” warned Flora Peyvandi and her colleagues.
