Sickle Cell Disease: The Importance of Amplifying Patient Voices
Having a one in four chance of developing sickle cell disease (SCD) is uniquely, and overwhelmingly, familiar to the African American population. Considered a rare disease, research in finding better therapies – and possibly even a cure – for SCD may be competing for funding with conditions impacting broader populations. SCD’s significant impact on African Americans also means it predominantly impacts a minority community historically underserved by clinical research. Due to these factors, there is a wide-reaching impact on patients with SCD.
According to the Centers for Disease Control and Prevention (CDC), SCD, also known as sickle cell anemia, is “a group of inherited red blood cell disorders. Red blood cells contain hemoglobin, a protein that carries oxygen. In someone who has SCD, the hemoglobin is abnormal, which causes the red blood cells to become hard and sticky and look like a C-shaped farm tool called a ‘sickle.’ The sickle cells die early, which causes a constant shortage of red blood cells.”
SCD is defined as a rare disease, a disease affecting fewer than 200,000 people in the United States. While the exact number is unknown, SCD affects approximately 100,000 Americans. This disease primarily affects the African American population. In Africa, malaria is prevalent across the continent, and scientists hypothesize SCD evolved as a way to protect people from malaria.
When Tiffani Moss, Senior Manager for Advarra Consulting, was born, her parents – both sickle cell trait carriers – knew the odds greatly favored Moss’s chances of developing the disease and so had her tested. Results confirmed their daughter would have to live with this disease.
CDC also states SCD occurs in one out of every 365 African American births. Additionally, approximately one in 13 African American babies are born with the sickle cell trait, which means they have a higher propensity for passing the condition to their offspring. The CDC also reports the U.S. Hispanic population is also affected by the disease, with one out of every 16,300 births resulting in the disease.
To add even more complexity to this rare disease, there are different types:
- Hemoglobin SS
- Hemoglobin SC
- Hemoglobin SB+(beta) thalassemia
- Hemoglobin SB 0 (Beta-zero) thalassemia
Currently, the only cure for SCD is accomplished through a bone marrow transplant. This cure comes with a huge caveat – only the sickest of the sick are eligible for this curative treatment. Moss, on the surface, is fairly healthy. This however, means the only cure for this disease is not available to her.
“Sickle cell disease can trigger crises, and it looks different for everyone,” she said. “For me, pneumonia is an example of something that will trigger a crisis.”
Acute vaso-occlusive episodes (VOEs, also known as pain crises, pain episodes, or vaso-occlusive crises) are acute episodes of intense pain and are underpinned by a complex pathophysiology. VOEs are multifactorial and may stem from a variety of causes, and a high rate of VOEs is typically associated with early mortality from multi-organ damage.
Reducing the frequency of “crises” and managing the symptoms is a consuming task. Moss said she’s currently using hydroxyurea, a chemotherapy drug also approved to treat SCD, in an effort to increase her hemoglobin levels.
Another common treatment is blood transfusions to boost hemoglobin – but that can get very complicated due to blood typing issues. A patient who has received many blood transfusions throughout their life may find future transfusions are more and more dangerous, as the antibodies in the blood change.
Facing Obstacles of a Rare Disease
Since SCD is classified as a rare disease, patients face the added challenge of finding health care providers who truly understand the disease and the people it impacts. In Moss’s case, finding sickle cell specialists in the U.S. has been abysmal at best.
“I’ve only seen two dedicated sickle cell specialists in my life,” she said. “Otherwise, I get sent to a hematologist or oncologist. And typically, these specialists are not very familiar with SCD.”
It’s not just a lack of specialists in the U.S. hindering progress on SCD – there is also a lack of clinical trials and research. As of March 2023, clinicaltrials.gov listed 192 recruiting drug studies on sickle cell. In comparison, there were 1,904 studies recruiting for COVID-19 in March 2023.
Even more, most of those 192 trials actually target a pediatric population. This is not surprising to Moss, who said as a child, she got “decent care” from care providers specializing in pediatric SCD. But once she turned 18, she found it nearly impossible to find someone to help her manage her rare disease as an adult.
Diversity in Clinical Trials and SCD
As many clinical trials in the U.S. face ongoing recruitment challenges, Moss believes trials targeting SCD is plagued by diversity recruitment obstacles, as well as less prioritization for curative therapies. One reason for recruitment obstacles is generational fear of clinical trials due to their history. As seen in the data above, there is a lower priority and number of clinical trials for SCD. Moss is hopeful a renewed focus on diversity in clinical trials will improve current asset pipelines for SCD cures.
Additionally, Moss noted recent headlines have indicated the pipeline of medicines in development for sickle cell disease are shrinking. Additionally, Phase III trials in early human testing for SCD have been discontinued due to lack of efficacy. These are reasons for biotech organizations to renew a focus on improving diversity in clinical research while bringing more sickle cell gene therapies to market.
FDA Draft Guidance Regarding Diversity, Equity, and Inclusion in Clinical Trials
In April 2022, the Food and Drug Administration released its draft guidance Diversity Plan to Improve Enrollment of Participants in Clinical Trial. This guidance provides a framework for sponsors who are developing medical products on developing a Race and Ethnicity Diversity Plan for engaging underrepresented racial and ethnic populations in the U.S.
Moss has had many instances where she had to educate her health care providers on her disease. Once, she developed a painful, raised lesion on her heel. A visit to a podiatrist and family doctor yielded less than satisfactory diagnoses. One surgery later, Moss spoke with a second doctor who immediately identified it as a sickle cell ulcer, and it would’ve gone away on its own. The only reason he knew what it was, though, was from his residency in an area with a large African American population, and he hadn’t encountered similar situations since.
Situations like this link Moss, and other African Americans with this disease, to the current lack of diversity of clinical trials in research. Moss noted if there were more research studies regarding SCD, perhaps her first doctor would’ve been able to correctly identify what was on her heel. The lack of focus on studies for this disease in an adult and aging population contributes to the limited health care options available.
Even with the heightened need for diversity in clinical trials, there are very few rare diseases primarily impacting a minority population in the way SCD impacts the African American population in the U.S. By beginning to prioritize clinical research, developing assets leading to curative treatments, and improving diversity recruitment in trials for patients with SCD, can allow for more medical professionals to become familiar with this disease and significantly impact lifespan rates.