Regensburg (dpa) - In Regensburg, gene therapy against the congenital blood disease beta-thalassemia has shown initial success.
A 20-year-old female patient had been treated worldwide for the first time with the help of the Crispr / Cas9 gene scissors and has had "normal blood values" for nine months, informed the University Hospital Regensburg. Previously, she was dependent on regular blood transfusions.
The first results are positive for the physicians. "For patients who can not be offered a curative alternative, this form of therapy would mean the cure of a terrible disease," said Selim Corbacioglu, head of the Department of Pediatric Hematology, Oncology and Stem Cell Transplantation at the University Hospital Regensburg. The President of the German Society for Gene Therapy, Boris Fehse, expressed his pleasure but also skeptical, because it had been published from a study individual patient data.
Patients suffering from beta thalassemia can only be healed by stem cell transplantation - if a suitable donor is found. "On the positive side, it shows that it works in principle with the Crispr / Cas9 procedure," said Holger Cario from the Department of Pediatric Hematology and Oncology at Ulm University Hospital, who was not involved in the study. Success, however, depends heavily on how much hemoglobin is produced and whether it is sufficient.
In patients with beta-thalassemia, insufficient oxygen is transported through the blood cells into the body, resulting in a lack of oxygen. During the therapy of the University of Regensburg, patients are taken from blood-forming stem cells and processed in a laboratory by the Crispr / Cas9 method. Subsequently, the patient's genetically modified cells are supplied. The new blood stem cells begin to form functioning blood cells. It does not correct genetic defects but activates an alternative gene for hemoglobin production that was already active in the fetus.
As a researcher, he is very happy about these preliminary results, said Fehse, who works at the University Medical Center Hamburg-Eppendorf. As president of the German Society for Gene Therapy, however, he sees it as very critical to publish individual patient data from a study. "You have to have a certain number of patients and a sufficient amount of time to prove that a therapy is working." Simply announce a first success after a relatively short observation period, should not make school.
According to the University of Regensburg, the study will enroll a total of 45 patients with beta-thalassemia in six study centers worldwide, who will then be cared for and followed up for two years. In addition, physicians in the United States had recently used the gene scissors Crispr / Cas, according to the University of Regensburg in a patient for the treatment of sickle cell disease. This leads to clogged blood vessels. Patients suffer from pain and brain and lung infarcts. In the US patient no vascular occlusions have been detected since the start of treatment four months ago. This result also gives cause for hope, says Corbacioglu.
He already believed that the therapy could work on thalassemia and also on sickle cell disease, said Fehse. "These are the first patients to use Crispr / Cas9 to treat thalassemia and sickle cell disease. We do not know yet whether they are healed, "he emphasized. "But the data so far is hopeful."
Whether the conventional gene therapy with viruses as a gene taxis or the Crispr / Cas gene scissors are more efficient and have fewer side effects, one could not say yet. "This will show the future." So far there are more than ten clinical trials with Crispr / Cas9 worldwide to various diseases. In individual cancer immunotherapies the gene-shearing has already shown successes in individual patients.
According to Cario, experimental data with Crispr / Cas show that nonspecific changes in the genetic material can occur in a very small percentage. Although this would occur to a small extent, it should be taken into account with regard to the long-term safety of the process. According to Corbacioglu, the study by the University Hospital of Regensburg focuses first and foremost on the feasibility of the procedure and on acute side effects.
The Medical Director of Hematology at Heidelberg University Hospital, Andreas Kulozik, sees potential in the Crispr / Cas9 procedure to cure affected people. His clinic is also researching beta-thalassemia using the so-called gene addition, in which genes are inserted. So far, according to Kulozik, this procedure has been performed in about 50 patients and was successful at 80 percent. In his opinion, both methods have advantages and disadvantages. "Conceptually, the Crispr / Cas may be more elegant, but the practical benefits need to be demonstrated in a larger number of patients."
Children's blood diseases
Further information about the therapies