Gene therapy demonstrates efficacy in the treatment of hemophilia

Hemophilia A is an inherited bleeding disorder caused by a lack of blood clotting factor VIII. It occurs due to an error in a gene located on the X chromosome (therefore, it is more frequent in males since they only have one copy of this chromosome), which codes for the coagulation factor, translating into a lack of it, decreasing the ability to form blood clots showing inability to stop bleeding.

Recently the prestigious New England Journal of Medicine published the results of a Phase III study, in which the gene therapy called “Valoctogene roxaparvovec” was tested based on a vector in a type of adenovirus that contains the DNA fraction of the factor VIII gene.

This therapy has already been tested in Phase I and II studies, showing promising results. At the time of Phase III, 134 patients received the drug through an infusion (single dose). The results showed a significant increase in the production of endogenous factor VIII and a reduction in bleeding 52 weeks after receiving the treatment.

To date, treatment for hemophilia consists of supplementing recombinant clotting factors (synthesized in the laboratory) periodically, as well as using other chemicals that stimulate the release of the factor or prevent clots from breaking down. Gene therapy could represent an effective treatment alternative in the very long term, thus avoiding the need for exogenous replacement treatments. We will have to wait to know the limitations of this drug in terms of activity time in the body.

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Sources:

1. CDC. Hemofilia. HHSGov – Dep Salud y Serv Humanos GobiernoUSAGov 2020.

2. Ozelo M, Mahlangu J, Pasi J, Giermasz A, Leavitt A, Laffan M, et al. Valoctocogene Roxaparvovec Gene Therapy for Hemophilia A. N Engl J Med 2022;386:1013–25. https://doi.org/DOI: 10.1056/NEJMoa2113708.