Gene therapy is making a difference in the lives of patients. A phase
I/II clinical study run by researchers at Harvard Medical School and
the University of Paris has added a new gene into a man’s cells and
freed him from a lifetime of blood transfusions. The patient has beta-thalassaemia,
a kind of genetically inherited blood disease that keeps his body from
producing the right hemoglobin chains for his red blood cells. Like many
with beta-thalassaemia, the man has been dependent on blood
transfusions since childhood. After his experimental gene therapy he has
not needed a transfusion for 21 months! The new genetic material was
added to his body’s own bone marrow stem cells in an autologous
transfusion via bluebird bio’s experimental new LentiGlobin therapy. The study was recently published in the journal Nature.
Though these results are very preliminary they speak to a wide range of
new treatments that will be made possible through gene therapy.
According to bluebird bio, 60,000 children are diagnosed each year with
beta-thalassaemia. About half of those kids end up needing a lifetime of
blood transfusions. Bone marrow transplants can help treat the disease
but about 75% of patients won’t be able to find a compatible donor. This
is just one of several types of haemoglobinopathies
that can have troubling effects on those who inherit the wrong genes –
sickle cell anemia is a better known example. It’s estimated that around
7% of the world’s population are carriers for these types of illnesses.
Gene therapy provides a promising solution. Take the patient’s own bone
marrow, isolate stem cells, change the genes in those cells using a lentivirus,
and reinsert them into the patient. The altered stem cells will be
accepted by the patient and propagate, giving the patient a correct way
to produce the hemoglobin he or she needs. It’s a technologically
brilliant solution.
In the case of beta-thalassaemia, there’s still a lot of work to be
done. This preliminary phase I/II study showed that the procedure was
safe and had some positive effects. 33 months after receiving the
transfusion, the male patient mentioned above had gone 21 months without
need of transfusion. (Clearly there was a warm up time during which the
altered cells had to propagate before being effective).
Yet there was another patient (a woman) in the study who received the
same therapy and did not benefit. The authors of the study explain that
her transplant cells were compromised during the process. Back up
procedures were unable to produce a steady population of genetically
modified cells in her body. She had no adverse results, but her
condition obviously did not improve.
It’s also unclear if the man who did see positive benefits is an
ideal example of success. Roughly one third of his blood has the
hemoglobin chains produced by the genetically modified cells. That seems
to be enough to relieve him of needing transfusions, but this is
probably not the optimal level of transformed globin production.
Furthermore, there was some concern about the over-expression of a HMGA2 gene
that could have been responsible for the some of the LentiGlobin
therapy’s success. That’s a concern because elevated HMGA2 levels have
been associated with cancers. bluebird bio’s press release, however, says that these HMGA2 levels have been declining in the patient and continue to do so.
At this stage, there’s no guarantee that LentiGlobin itself will be a
viable solution for beta-thalassaemia. The study was very small, and I
don’t really know if we should call it 50% successful or 100% successful
if performed correctly… we’re going to need a lot more tests before we
know if this is a successful gene therapy.
Yet the promise of gene therapy continues to grow. We’ve seen other trials ramping up recently, and bluebird bio itself has plans for therapies for Sickle Cell (perhaps through the LentiGlobin platform) and for a neurological disorder.
There are a host of genetically inheritable diseases which could be
treated with the right forms of autologous transplants and gene
modifications. Of course, there are many conditions which one wouldn’t
normally consider to be a disease that might also be ‘cured’ through the
applications of gene therapies. We may be able to extend life expectancy, grant increased muscle mass, or even raise intelligence
through these sorts of manipulations. While gene therapies begin with
aiding with tragic illnesses, their ultimate potential could lie in
reshaping the human body to match our desires.
[image credit: adultstemcellawareness]
[source: bluebird bio Press Release (PDF), Cavazzana-Calvo et al 2010 Nature]
--
http://grou.ps/africanatheistsdotorg/blogs/1106968
I/II clinical study run by researchers at Harvard Medical School and
the University of Paris has added a new gene into a man’s cells and
freed him from a lifetime of blood transfusions. The patient has beta-thalassaemia,
a kind of genetically inherited blood disease that keeps his body from
producing the right hemoglobin chains for his red blood cells. Like many
with beta-thalassaemia, the man has been dependent on blood
transfusions since childhood. After his experimental gene therapy he has
not needed a transfusion for 21 months! The new genetic material was
added to his body’s own bone marrow stem cells in an autologous
transfusion via bluebird bio’s experimental new LentiGlobin therapy. The study was recently published in the journal Nature.
Though these results are very preliminary they speak to a wide range of
new treatments that will be made possible through gene therapy.
According to bluebird bio, 60,000 children are diagnosed each year with
beta-thalassaemia. About half of those kids end up needing a lifetime of
blood transfusions. Bone marrow transplants can help treat the disease
but about 75% of patients won’t be able to find a compatible donor. This
is just one of several types of haemoglobinopathies
that can have troubling effects on those who inherit the wrong genes –
sickle cell anemia is a better known example. It’s estimated that around
7% of the world’s population are carriers for these types of illnesses.
Gene therapy provides a promising solution. Take the patient’s own bone
marrow, isolate stem cells, change the genes in those cells using a lentivirus,
and reinsert them into the patient. The altered stem cells will be
accepted by the patient and propagate, giving the patient a correct way
to produce the hemoglobin he or she needs. It’s a technologically
brilliant solution.
In the case of beta-thalassaemia, there’s still a lot of work to be
done. This preliminary phase I/II study showed that the procedure was
safe and had some positive effects. 33 months after receiving the
transfusion, the male patient mentioned above had gone 21 months without
need of transfusion. (Clearly there was a warm up time during which the
altered cells had to propagate before being effective).
Yet there was another patient (a woman) in the study who received the
same therapy and did not benefit. The authors of the study explain that
her transplant cells were compromised during the process. Back up
procedures were unable to produce a steady population of genetically
modified cells in her body. She had no adverse results, but her
condition obviously did not improve.
It’s also unclear if the man who did see positive benefits is an
ideal example of success. Roughly one third of his blood has the
hemoglobin chains produced by the genetically modified cells. That seems
to be enough to relieve him of needing transfusions, but this is
probably not the optimal level of transformed globin production.
Furthermore, there was some concern about the over-expression of a HMGA2 gene
that could have been responsible for the some of the LentiGlobin
therapy’s success. That’s a concern because elevated HMGA2 levels have
been associated with cancers. bluebird bio’s press release, however, says that these HMGA2 levels have been declining in the patient and continue to do so.
At this stage, there’s no guarantee that LentiGlobin itself will be a
viable solution for beta-thalassaemia. The study was very small, and I
don’t really know if we should call it 50% successful or 100% successful
if performed correctly… we’re going to need a lot more tests before we
know if this is a successful gene therapy.
Yet the promise of gene therapy continues to grow. We’ve seen other trials ramping up recently, and bluebird bio itself has plans for therapies for Sickle Cell (perhaps through the LentiGlobin platform) and for a neurological disorder.
There are a host of genetically inheritable diseases which could be
treated with the right forms of autologous transplants and gene
modifications. Of course, there are many conditions which one wouldn’t
normally consider to be a disease that might also be ‘cured’ through the
applications of gene therapies. We may be able to extend life expectancy, grant increased muscle mass, or even raise intelligence
through these sorts of manipulations. While gene therapies begin with
aiding with tragic illnesses, their ultimate potential could lie in
reshaping the human body to match our desires.
[image credit: adultstemcellawareness]
[source: bluebird bio Press Release (PDF), Cavazzana-Calvo et al 2010 Nature]
--
http://grou.ps/africanatheistsdotorg/blogs/1106968
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