Dr. Hobaugh’s Health Headlines:
A Cure for Sickle Cell Anemia?
Over the last 70 years, the medical advances made possible by improvements in materials science, molecular biology and manufacturing have revolutionized healthcare for both patients and physicians. Antibiotics, mechanical ventilation, intravenous nutrition, effective medicines for cancer, high blood pressure, depression… you name it. It has all happened in the last 75 years.
It is amazing that for our great-grandparents, an ear infection would have been treated by popping the ear drum in order to drain the infection, hopefully preventing its spread into the brain. Penicillin first appeared as an experimental drug for our GIs during WWII. Even with all these amazing advances, there have continued to be many diseases for which there are only limited treatment options and too often, children born with these conditions face a life of chronic ill health.
For patients and families with a loved one who suffers from a chronic illness, the excitement of a promising new medical discovery is palpable. So, too, is the excitement for scientists and physicians when we hear about a potential medical advance in the news. While we always strive to offer compassionate care to the sick, we like offering effective care even more.
Sickle cell disease is caused by a mutation in the DNA sequence for hemoglobin. When only one copy of the gene is affected (either the one from the child’s mother or the one from the father) the child will have some sickle hemoglobin; and that is protective against malaria. However, when the mutation is inherited from both parents’ chromosomes, the child is born with a lifelong illness that substantially decreases life expectancy and carries ongoing risks of bacterial sepsis, stroke and cardiopulmonary collapse. Sickle cell disease also causes frequent, debilitating episodes of severe pain sometimes requiring hospitalization for intravenous narcotic analgesics. During my time as a pediatrician for hospitalized children, I cared for hundreds of children with this debilitating illness.
One recent health news story has raised hopes for millions across the globe and hundreds of thousands in the US who suffer from SCD. The bone marrow — our “factory” for blood cells — was extracted from a French teenager with sickle cell disease and infected with an engineered virus carrying the correct DNA sequence for hemoglobin. This new set of instructions for making hemoglobin correctly inserted in the harvested bone marrow progenitor cells and began making the correctly folded hemoglobin, curing his disease (http://www.bbc.com/news/health-39142971). This kind of technique is called “gene therapy” and so far, only severe combined immunodeficiency (the “bubble boy” disease) had been successfully cured with this technique.
The news of a cure for Sickle Cell Anemia has fueled hopes that the pain and terrible complications of this previously incurable illness will soon be a thing of the past. However, one thing we should all be better about is maintaining a little skepticism when we learn of purportedly “revolutionary” medical advances. One case report does not make a cure.
Even when the evidence for medical discoveries looks promising, there are bumps in the road or dead ends. One analysis of 101 promising medical discoveries published in prestigious scientific journals over a five year period found that only one ultimately yielded an effective new medicine. When it comes to the “revolutionary discoveries” trumpeted in popular science journalism, you can bet the odds are even worse.
There is no substitute for randomized, blinded, controlled clinical trials of new treatments for medical problems. We would all be wise to maintain a healthy skepticism for new medicines and surgical techniques that have not been evaluated through such studies. As a pediatrician in northern Colorado, one of my roles is to help educate families about the scientific complexities of illnesses and their medical therapies using the best available evidence from the medical literature.
In the case of the sickle cell report, I am hopeful that this will be the revolutionary breakthrough these kids deserve. Over the next couple of years, the researchers in Paris who performed this first successful gene therapy intervention for sickle cell disease will try the technique on dozens of others. Other research teams at medical centers across the world will try to replicate the Paris group’s technique. If they, too, are successful, that’s when we’ll know that we can move sickle cell disease out of the chronic, untreatable group of illnesses patients and physicians both dread and into that serious but curable category that usually comes with a happy ending.
Here’s to the thousands of scientists across the world who have led the unbelievable technical advances of the past half-century! Many thanks.