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Sickle cell disease (SCD) is the most common inherited blood disorder in the United States. It affects about 100,000 children and adults in the United States—and millions of people worldwide. New treatments are needed to prevent and treat its serious complications. That’s why the U.S. Food and Drug Administration is working with patients and stakeholders, including academics and those from the pharmaceutical industry, to help develop new treatments for SCD.
Sickle cell disease is a group of genetic disorders that most commonly affect people of African descent, says Jonca Bull, M.D., director of FDA’s Office of Minority Health. SCD also can affect Hispanics, Asians, and people of Mediterranean and Middle Eastern descent.
More than 3 million Americans, including one in 12 African Americans, carry the sickle cell trait, the gene that can potentially allow the disease to be passed on to their children. In the United States, screening for sickle cell disease and trait is typically done at birth. A baby born with sickle cell disease inherits a gene for the disorder from both parents.
SCD is chronic and debilitating. People with the disease have “sickled” or abnormally shaped red blood cells that get stuck in small blood vessels and block the flow of blood and oxygen to major organs in the body. These blockages can cause severe pain, organ damage or even stroke. Other complications include susceptibility to infection, fatigue and delayed growth.
The severity of SCD varies from person to person. Most people with the disease will have a shortened lifespan.
Today’s therapies are limited and include a medication called hydroxyurea, which FDA approved in 1998. Bone marrow or stem cell transplants may be a treatment option for younger patients with severe SCD, but serious and potentially life-threatening side effects can accompany these procedures. These transplants, which are expensive, also require the identification of a suitable bone marrow or stem cell donor. Most people cannot receive these transplants. In addition, blood transfusions can be used to treat anemia, which is a common complication of SCD.
“The majority of patients with SCD are treated with hydroxyurea, pain medication and chronic transfusion, and are hospitalized when crises occur,” explains Ann T. Farrell, M.D., director of FDA’s Division of Hematology Products within the Center for Drug Evaluation and Research. Chronic transfusions are given regularly and long-term to prevent complications.
“Unfortunately, although a number of patients will experience a reduction in their crises and hospitalizations with current treatments, some patients will have no reduction of their symptoms and the disease will continue to progress,” she adds. “Better therapies are desperately needed.”
FDA continues to work with stakeholders—including patients, academicians and companies developing treatments—to improve therapeutic options for people with SCD, says Bull. A growing number of new products are in the pipeline, and researchers are exploring new approaches to treating SCD.
“These potential treatments are in different stages of development, including early and late clinical trials,” notes Farrell.
Companies developing sickle cell products can ask FDA to grant them a “fast track” designation, a regulatory status that facilitates consultations between the drug sponsors and the agency. “When we grant that, it allows for early and more frequent interactions with the FDA to discuss any issues that come up during development, such as manufacturing and trial design,” Farrell says. The purpose of these consultations is to bring new products to market faster.
FDA can also facilitate the development of new SCD treatments by designating certain drugs and biological products as “orphan products.” This designation is possible for products intended to treat rare diseases affecting fewer than 200,000 individuals in the United States per year. Sponsors of an orphan designated drug or biological product can qualify for tax credits and marketing exclusivity, among other incentives.
Because SCD is a global issue, FDA encourages the pharmaceutical industry to develop treatments internationally, adds Farrell. Now, companies are conducting clinical trials not only in the United States, but also in Europe and Africa.
FDA has met with patients to learn more about their experiences with SCD and their views on existing treatments. The agency explored these issues at a Patient-Focused Drug Development meeting (its fifth overall) on February 7, 2014, and posted the full meeting report online in October 2014.
“Learning the patient perspective—what symptoms bother them the most and where they would like to see treatments to focus—is important in the development of new therapies,” Farrell explains. “During the meeting, patients stated very clearly that the symptoms that matter most to them in terms of their disease are acute and chronic pain, stroke, fatigue and sleep disturbances. Patients also expressed a willingness to participate in clinical trials to identify new treatments for their disease.”
The 300 meeting participants also confirmed that the health effects of sickle cell disease are wide-ranging, and that the challenges of adequately managing SCD are much greater than the availability of medical treatments, says Farrell. Currently, additional public meetings with consumers, academics and other stakeholders are being planned.
“FDA’s Division of Hematology Products considers the development of new SCD treatments a top priority. We will continue to facilitate problem-solving with sponsors as much as possible in order to help remove roadblocks to new product development,” Farrell says.
“We feel for these patients because they have to live with the devastating consequences of this chronic condition,” she adds. “It’s important for FDA to help as much as we can.”
This article appears on FDA's Consumer Updates page, which features the latest on all FDA-regulated products.
October 14, 2014