December 6, 2018
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Over the past three decades, I have consistently spoken about the enormous potential of biomedical breakthroughs that could solve many of our pressing public challenges. Because of this potential, I have advocated for increased public funding of basic scientific research and reforms at the Food and Drug Administration to speed up the process by which new treatments are available to patients.
One of the most exciting areas of biomedical science today is in genetic medicine, where we are just now seeing the public investment into sequencing the human genome bear fruit in the form of treatments to help patients overcome hereditary disorders.
On Tuesday, I had the pleasure of seeing first-hand just how extraordinary these new treatments are, when I attended the Sanford Lorraine Cross Award ceremony in Sioux Falls, South Dakota.
The award is different than most prizes for medical achievements. Rather than simply rewarding research which led – or could one day lead – to treatments, the Lorraine Cross Award honors doctors who take their research beyond the lab and take the risks to develop cutting edge cures that actually help patients today.
This focus on cures is a trademark of the philanthropic efforts of Denny Sanford, who has pledged almost $1 billion over the past 16 years to transform a small rural health system in South Dakota into a global health system of hospitals, research centers, and clinics. This system is helping transform the way health care is practiced around the world. In his honor, the health system adopted his name, Sanford Health.
In this inaugural year of the Sanford Lorraine Cross Award, all three of the finalists for the $1 million prize have developed gene therapy techniques which are being used to treat patients today.
As I learned about the incredible things these doctors were doing in this bold new field of medicine, it occurred to me that lack of funding and unnecessary bureaucracy are not the only things that can slow down the progress of developing new treatments. Unnecessary fear caused by confusion over what gene therapy is can also slow progress.
For example, last week, a researcher in China, He Jiankui, claimed that he had used a gene editing technique to confer HIV immunity on twin girl embryos, who were then successfully brought to term. The announcement was met with near universal global criticism, and the Chinese government responded by closing the doctor’s lab and opening an investigation that could result in criminal charges.
So, you see a $1 million prize and acclaim for gene therapy – versus criminal charges and outrage for gene editing. But what is the difference?
In the coming years, we will be hearing a lot more about genetic medicine. We will hear a lot of hope and optimism but also a lot of fear and calls for caution. To understand the awesome promise and peril of this extraordinary new field of medicine, it is worth examining the differences between the work which was honored yesterday in Sioux Falls and the work which was rightly condemned in China.
The technique – gene therapy vs. genome editing
First, there is a big difference between gene therapy and genome editing.
Gene therapy is treating an existing disease in an individual patient who is sick. As one of the Sanford Award nominees, Dr. Jim Wilson, who directs the Gene Therapy Program at the University of Pennsylvania – and whose work refining a gene therapy delivery system is the foundation upon which much of today’s gene therapy treatment is built – explained, “Gene therapy is really the ultimate treatment for patients that have disease due to single gene defects.”
Gene therapy only impacts somatic cells, which are non-reproductive. This means that changes in somatic cells will not be passed on to offspring. So, the treatment only impacts individual patients who give their consent to being treated. In the case of patients who are children, their parents give consent – a practice around which there is a long-established ethical consensus.
By contrast, the work done by the Chinese biologist involved manipulation of the genetic code of human embryos – a technique referred to as “embryo genome editing” (sometimes “germline cell editing.”) Germline cell editing alters reproductive cells. This means the changes will be passed on to future generations.
There is no ethical consensus in place that fully understands the implications of a set of parents giving ethical consent to treatment that will impact all future generations of a patient.
In addition, there is the huge ethical and scientific challenge of how to advance the science of genome editing without the destruction of human embryos.
We may very well see germline editing used in the future to cure disease. But that should only be done after much study and a consensus around these and other ethical issues is reached, which will take time.
In the meantime, we should continue to move forward with gene therapy of somatic cells.
The diseases being treated
Even within the field of somatic cell gene therapy, there are necessary guardrails in place.
Because the field is so new, gene therapy is currently only allowed for diseases which have no other cure or effective treatment.
For instance, one of the Sanford Lorraine Cross Award nominees, Dr. Brian Kaspar, is using gene therapy to change the course of type 1 spinal muscular atrophy, a devastating disease that destroys basic muscle function in babies and usually results in death by age 2. His treatment results in dramatic improvements in muscle function and survival.
Another pair of nominees, Drs. Jean Bennett and Katherine High, are using gene therapy to reverse an inherited form of blindness, which typically begins with a severe visual impairment during infancy that can continue to worsen over time. Their drug, Luxturna, was the first FDA approved gene therapy and has paved the way for many more breakthroughs.
Contrast these two intractable diseases being treated with gene therapy with what was done in China to make the children immune to HIV.
First, authorized gene therapy techniques are for conditions that already exist in a patient. The children treated at the embryonic stage in China were not HIV positive.
Second, avoiding HIV infection is relatively easy. And even if one contracts the virus, there are already a wide variety of effective treatments. An extraordinary combination of public and private research since the 1980s has turned being HIV positive from a death sentence into a manageable condition – if treatments are available.
There was simply no reason to use a technique as new, experimental, and fraught with ethical and medical peril as gene editing to prevent HIV infection. The risks greatly outweigh the reward.
With gene therapy on defective cells, we have a high degree of certainty about the medical impact of successful treatment – namely, normal function.
The work of the Chinese researcher was very different. He used a gene editing technique called CRISPR-Cas9 to shut down a gene called CCR5, which creates a protein necessary for HIV to enter cells. In other words, he shut down a gene that was functioning normally for humans in order to create an “artificial” resistance to the disease. However, while shutting down CCR5 may make one immune to HIV, we don’t know what other health impacts this will have. These two girls will need to be monitored for the rest of their lives to see how they develop.
Fixing a defect vs. human enhancement
Finally, the most fundamental difference between the type of work in genetic medicine honored by the Sanford Lorraine Cross Award and the work in China condemned around the world is that the former is treatment for genetic defects while the latter is the enhancement of human beings.
The prospect of human enhancement poses enormous ethical questions which strike at the core of how we think about equality – particularly in America.
The American ideal is not just equality under the law, it is also equal opportunity. Namely, that America should strive to be an open society, where people can achieve success through hard work and applying their God-given talents.
But what if talent was no longer exclusively God-given – and could be purchased? Human enhancement that can carry on through the generations could rapidly create a permanent and intractable divide between the wealthy and the rest of humanity because the rich would have both material advantages – and they would literally be born smarter, stronger, and healthier.
There may very well be a future in which genome editing is used medically, such as an effort to permanently eliminate certain recessive genetic disorders from humans. But that day should only come after we have figured out how to make the treatments available to all so that we advance together as a species – as we have with vaccinations for many diseases. Furthermore, we need to find a way to advance the science with the proper respect for human life in all its stages – including embryonic.
In the meantime, we should press forward with the kind of promising gene therapy techniques that were honored Tuesday in Sioux Falls. While these early stage gene therapies were for relatively rare conditions, they are setting the stage for gene therapy treatments for other inherited diseases, such as hemophilia and sickle cell anemia – diseases that impact many people. This is important foremost because of the number of patients it will help but also because of the public costs that are associated with these diseases.
We should all be excited and optimistic about the potential of gene therapy to save lives and make our world a better place.
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