NEJM: Gene therapy enables "super strong" clotting factor, expected to "one-time" treatment of hemophilia
Release date: 2017-12-15
Image source: iStock.com/somersault18:24
hemophilia
I believe many people know about hemophilia. As an X-linked genetic disease, because of the congenital lack of coagulation factors, even small wounds can cause dangerous symptoms of blood flow, and even severe cases of "spontaneous" bleeding. Many patients require one or more hemostasis treatments per week.
The current main treatment for hemophilia is to regularly supplement blood clotting factors. Although this therapy can greatly extend the life expectancy of patients, patients face a large medical burden and inconvenience.
Therefore, scientists hope to find a "one-size-fits-all" approach to fundamentally solve problems, and gene therapy is the hope. Although animal testing has confirmed the enthusiasm of this strategy, previous gene therapy trials for hemophilia did not go well because the patient's immune system easily attacked modified cells or liver cells could not secrete enough clotting factors.
New results in gene therapy
Now, the research teams from Spark Therapeutics and Pfizer have confirmed the feasibility of gene therapy for hemophilia for the first time in the world through technological research and innovation!
The SPK-9001 product they developed is designed to treat hemophilia B (lack of factor IX). In the latest clinical phase 1/2 trial, 10 patients were treated with a virus carrying the IX factor gene for 18 months, and the average level of clotting factor produced by the liver tissue reached 34% of normal people.
Among them, 9 patients did not have bleeding symptoms again, and 8 patients no longer need regular injection of factor IX. This means that SPK-9001 gene therapy is expected to address their dependence on regular injections of clotting factors.
"We hope that gene therapy can solve all problems at once, which is the ideal treatment goal for hemophilia patients," said Dr. Lindsey George, a lead researcher and a hematologist at the Children's Hospital of Philadelphia.
"Super version" coagulation factor
Unlike previous gene therapy attempts, Spark Therapeutics chose a superior version of the Factor IX-Padua (FIX-Padua) and reduced the immune response by reducing the dose of the virus.
In 2009, scientists discovered this “super-strong†coagulation factor in an Italian family, confirming that its function is 8-10 times that of normal coagulation factors!
The team engineered genetically engineered adeno-associated viruses (which do not cause disease) to carry genes that express the FIX-Padua factor. The virus is delivered to the patient's liver cells by injection. The latest clinical data show that 10 patients with hemophilia B who are treated can independently express enough high-activity clotting factors.
Bill Konduros (58, right) and Jay Konduros (53) are brothers and hemophilia patients involved in clinical trials of gene therapy. Before the treatment in August 2016, even a slight exercise can cause muscle strain and require clotting factor treatment. Now, they no longer need to receive clotting factor treatment.
Bill Konduros (58, right) and Jay Konduros (53) are brothers and hemophilia patients involved in clinical trials of gene therapy. Before the treatment in August 2016, even a slight exercise can cause muscle strain and require clotting factor treatment. Now, they no longer need to receive clotting factor treatment.
"One time and for all" treatment
The road to R&D of SPK-9001 began at the end of 2014. In June 2016, it achieved initial success in the treatment of hemophilia, and in July it received the FDA's breakthrough new treatment.
In the latest clinical data, patients had an average monthly bleeding before treatment, and after treatment, they had not experienced bleeding symptoms for at least a year without serious side effects.
Considering that some liver cells do not pass on new genes during the process of division, scientists are concerned that the effects of gene therapy will diminish over time. However, other clinical trials of gene therapy for hemophilia have been going on for 8 years (12 years in the dog model) and the treatment is still very good.
Dr. Matthew Porteus of Stanford University wrote a comment for this. He believes that this new achievement is "amazing" and it indicates that we are on the road to "achieve a cure."
Of course, this result is phased and experimental, and the final result still needs time to “speakâ€.
Other research projects and plans
In addition to Spark Therapeutics, BioMarin pharmaceutical companies are conducting gene therapy research on another type of hemophilia, and have achieved some results - 13 patients have been treated, they are treated with bleeding frequency and clotting factor-dependent treatment A very good improvement.
It is reported that BioMarin will report the latest results at the upcoming American Hematology Conference. In addition, Sangamo Therapeutics is validating the potential of traditional gene therapy and gene editing for hemophilia.
Lindsey George hopes that in the next three clinical trials, SPK-9001 will still be able to give a good answer. He believes that this study is a new beginning to change the paradigm of hemophilia treatment.
Reference materials:
Gene therapy dose bleeding episodes in hemophilia trial
Gene therapy shows promise against blood-clotting disease
One-dose gene therapy produces clotting factor, safely decreased bleeding in hemophilia B patients
Source: Bio-Exploration
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