Sickle Cell Disease (SCD) was first described in medical literature more than 100 years ago. Despite this, according to the New England Journal of Medicine (NEJM), the development of effective treatments, and ultimately a cure, has stagnated because of inadequate research funding due, at least in part, to structural racism. This has changed recently with several treatment breakthroughs, but there is still a lot of work to be done.
In honor of Sickle Cell Awareness month last month, let’s take a deeper dive into the history of SCD, the societal issues impacting patients, and the latest treatment advancements.
What is SCD and who does it affect?
SCD is a life-threatening, inherited blood disorder affecting more than 100,000 Americans. In someone with SCD, as their red blood cells deliver their oxygen to the tissues, they become hard, sticky and take on a C-shape, making them look like a “sickle” farm tool. As these “sickled” red blood cells travel through small blood vessels, they get stuck and begin to clog blood flow in a process called “vaso-occlusion”. They also break down early causing a constant shortage of red blood cells called “anemia”.
Without adequate treatment, SCD can affect virtually all the organs and is associated with decreased quality of life and a shortened life span. Among the dozens of conditions that are screened for in state newborn-screening programs, SCD is the most commonly detected condition, regardless of ethnicity. Although the disease is more common in certain ethnic groups - including people of African descent, Hispanic Americans from Central and South America, and people of Middle Eastern, South Asian, and Mediterranean descent - it is important to recognize SCD as a common and important medical condition among all Americans.
“Although sickle cell can be an acutely life-threatening condition, it's mostly a life-limiting or life-shortening condition,” Dr. Matthew Heeney, Associate Chief of Hematology and Director of the Sickle Cell Program at Boston Children’s Hospital said. “With diagnosis by universal newborn screening, we can prevent many of the deaths that historically occurred in childhood, in particular by protecting them from the life-threatening bacterial infections that they are susceptible to.”
Because SCD affects fewer than 200,000 people nationwide, it’s considered an orphan disease by the FDA. Yet, SCD does not receive the research funding and pharmaceutical investment directed to other orphan diseases with significantly smaller numbers of affected individuals. Cystic fibrosis, for example, is comparable to SCD, but it primarily affects White Americans. The research on the Comparison of US Federal and Foundation Funding of Research for Sickle Cell Disease and Cystic Fibrosis and Factors Associated With Research Productivity found that although Cystic fibrosis affects one third fewer Americans than SCD, it receives 7 to 11 times the research funding per patient, resulting in disparate rates of development of medications. Currently, the Food and Drug Administration has approved 4 medications for SCD and 15 for cystic fibrosis.
One of the main symptoms of SCD is repeated episodes of acute pain related to vaso-occlusion that can lead to chronic pain, which, according to Dr. Heeney, makes it very difficult to manage.
“Patients have recurring painful crises, which often require opioid medications. Given the opioid crisis there is a lot more oversight and there can be challenges in access to these medications,” Dr. Heeney said. “In terms of the management of pain, it can be a very challenging symptom to manage chronically, so many adult doctors are deterred to care for this population. Therefore, adult patients tend to fall to academic medical centers, of which there are many in Boston, but not so represented around the rest of the country, so patients often have a hard time finding continuity of care in a ‘medical home’.”
Dr. Heeney added that the time of transition from pediatric to adult care is a very high-risk period for these patients. Searching for a new medical provider - while also completing education, seeking employment and independent living, and falling off their parent’s insurance - they can often get lost in the system, which can lead to higher mortality rates.
Combating Bias and Systemic Issues
In addition to struggling to find care and manage symptoms, SCD patients often struggle with bias associated both with race and seeking out opioids to manage their pain. “Outside of their medical home, patients too frequently have the overwhelming sense that they’re seen as drug seekers when they seek care in an unfamiliar emergency department,” Dr. Heeney said.
One study found that too often patients with SCD simultaneously combat unbearable pain and racist attitudes expressed by health care workers in our hospitals. Despite inexorable pain, patients reported getting dressed nicely before presenting to the emergency department in an attempt to avoid judgment and receive better care.
According to Dr. Heeney, SCD specialists spend a lot of time educating their patients on their pain management so they can be self-sufficient, but this can back-fire. If a patient is on vacation shows up at an emergency department they’ve never been to before and says to the provider, ‘I need 10 milligrams of morphine. I will probably need it again in 30 minutes if the first dose doesn’t work, and I’d like you to keep going until I tell you to stop….’ the doctor unfamiliar with the patient or the disease is likely to deny or restrict their treatment, Dr. Heeney said.
“We empower patients to know what medications and doses work for them, but of course, that can come across as being too knowledgeable” Dr. Heeney added. “So, some of that probably works against them.”
Another challenge for patients and families affected by SCD is that the disease doesn’t fit within most common definitions of disability, but it can still have debilitating effects on a person’s life.
“A patient with sickle cell disease is 100% able bodied 95% of the time, but then 5% of the time, when they are having a painful crisis, they are 100% disabled,” Dr. Heeney said. “A patient may be admitted frequently enough to fail a grade of school, but yet not enough to meet the threshold to get academic extra help. Similarly, an adult could miss enough work to be fired from a stable job that has health insurance, but yet not meet the definition of disability to get SSI [Supplemental Security Income] benefits.”
Hope on the Horizon
According to Dr. Heeney, in the last 2 years, there have been 3 approved disease-modifying drugs for SCD. This, he said, is in large part due to policy changes that look to develop better medications and implement clinical trials for Americans with orphan diseases. Because of this, the pharmaceutical industry can now get FDA benefits from developing a treatment for the US population that they could potentially sell across the world. “So, we’ve seen a lot more investment and a lot more interest in sickle cell disease,” Dr. Heeney said. “It’s a very exciting time in the sickle cell for patients and providers.”
There’s been a curative option for SCD for many decades – a hematopoietic stem cell transplant (sometimes referred to as bone marrow transplant). The problem, according to Dr. Heeney, is that the best outcomes are if you have a fully matched full sibling for a stem cell donor, but the chances of this happening, and that sibling also being sickle negative, are about 1 in 6 with each sibling. Therefore, many patients don’t have an optimal stem cell donor.
In addition, the preparation treatment for this (known as “conditioning”) is chemotherapy to remove the existing bone marrow before replacing it with the stem cells from the donor. “That chemotherapy can cause you to lose your hair, result in near certain sterility, and have about a 5% chance of dying,” Dr. Heeney said. “There are very challenging questions for parents to confront with their care team on behalf of their children, and so many patients, even if they have a fully matched sibling donor, will choose not to go through it.”
Now, researchers are looking for ways for patients to be their own donors. With this process, the patient would still undergo conditioning chemotherapy, but then their own stem cells can be genetically altered (“gene therapy”) and would be given back to them, thus reducing the risk that their body will reject them. There are currently several different methods of gene therapy under investigation in SCD, Dr. Heeney said.
“The truth about these curative therapies with gene therapy is that they are going to be tremendously expensive,” Dr. Heeney said. “They're talking maybe $1,000,000 a hit, which from an actuarial scientist’s perspective probably makes sense if the procedure prevents the next 30 years of vaso-occlusive painful crises, reduces medical bills, all while the patient is more able contribute to the workforce, it's probably worth it. But then who pays for it?”
RubiconMD is proud to partner with Boston Children’s to support clinicians and patients. For more information on their Sickle Cell Disease program, visit http://www.childrenshospital.org/centers-and-services/programs/o-_-z/sickle-cell-disease-program#.