A dual gene therapy approach was employed for the first time in delivering key components of a CRISPR/Cas-9 mediated gene targeting system that would help treat hemophilia B. The research was conducted on mice, and it addressed the disease that is also called factor IX deficiency.
The study, conducted by scientists at the Perelman School of Medicine at the University of Pennsylvania, tried to treat the illness triggered by a missing or defective clotting protein.
Pioneering Hemophilia Research
"Basically, we cured the mice," noted Lili Wang, Ph.D., research associate professor in the Penn Gene Therapy Program.
The researchers experimented on a mouse model where the clotting factor IX was knocked out in order to cure hemophilia. The team employed a two-vector method. Vector 1 expressed the SaCas9 gene for the gene-editing system to home to the liver, thus producing the clotting factor IX.
Vector 2 is where this study is different from previous ones conducted as part of the same program; it contains an RNA sequence which targets a specific region, making the approach more accurate in curing hemophilia.
The researchers injected the two vectors with progressively increasing doses in newborn and adult knockout mice. The results were a stable factor IX activity. Eight weeks after administrating the treatment, the researchers created a subgroup of the mice category, who were also administered a partial liver removal.
All the mice survived the medical procedure, and no complications followed this medical approach.
Hemophilia Treatment — Scientific Approaches
While the current research brings a new approach that could help treat this rare genetic disorder, other steps have been made in this direction in the recent years, in order for patients who suffer from this disease to lead better lives. Back in 2014, the Food and Drug Administration approved a treatment that was considered the first recombinant, DNA-derived therapy for the rare disorder.
"The approval of this product provides another therapeutic option for the treatment and prevention of bleeding in patients with Hemophilia B," noted Dr. Karen Midthun, FDA's Center for Biologics Evaluation and Research director, when the treatment was approved.
Due to the fact that people who suffer from this affection lack factor IX, the most common symptom is prolonged oozing after injuries, as well as tooth extractions or surgery. The delayed or recurrent bleeding is also a symptom associated with this disease; depending on the stage of the disease, the symptoms can be more severe or scarce.
"In any individual with hemophilia B, bleeding episodes may be more frequent in childhood and adolescence than in adulthood," according to the National Center of Biotechnology Information.