If you have sickle cell disease (SCD), you are aware of the effect it can have on your life. SCD can trigger periods of intense pain (known as “pain crises”) and other problems and sometimes send you to the emergency room or the hospital.
Well, there’s good news: the medicine called hydroxyurea (“hi-drox-ee-ure-EE-a”) helps adults and children with SCD.
What is Hydroxyurea?
It is an oral therapy first approved for numerous types of cancer and later developed for use in the treatment of SCD.
Some background info on Hydroxyurea approval
The therapy put on the market as Droxia by Squibb was approved by the U.S. Food and Drug Administration back in 1998 to help decrease the regularity of vaso-occlusive crises (VOCs) and the necessity for blood transfusions in adults living with SCD.
In June 2007, hydroxyurea was approved by the European Commission and was sold under the brand name Siklos, for the same indication, however covering adult and pediatric patients from 2 years old and older.
In December 2017, ten years later, the FDA approved Siklos to decrease VOCs and reduce the necessity for blood transfusions in 2-year-old children and above with SCD and recurrent, mild-to-severe VOCs. The therapy’s use got extended to adult patients in February 2022.
How does hydroxyurea work?
People living with SCD produce an abnormal form of hemoglobin which is the protein inside red blood cells responsible for transporting oxygen. This defective protein bunches together into long, rigid rods, forming deform red blood cells that appear like a sickle or crescent-like shape.
Also, these sickled cells are targeted for destruction, causing anemia. They often stick to the walls of the blood vessel, blocking or slowing down the flow of blood and triggering VOCs (blocking blood flow enough to deprive tissues of oxygen) This usually provokes sudden episodes of pain or pain crisis.
Hydroxyurea is a small molecule that is orally available in the medical world. It works by increasing the levels of fetal hemoglobin. It is a form of hemoglobin that is produced during fetal development and transports oxygen more effectively throughout the human body than its adult counterpart.
When Hydroxyurea increases fetal hemoglobin, the therapy expectedly reduces red blood cell sickling and damage and improves the circulation of oxygen all over the body. This, therefore, lowers the frequency of VOCs and the necessity for transfusing blood.
Additionally, it reduces the number of neutrophils as well. Neutrophils are a type of immune cell which interacts with sickled red blood cells in order to clog blood vessels, leading to VOCs.
Hydroxyurea in clinical trials
Numerous clinical trials tested hydroxyurea as an SCD treatment, and adequate evidence suggests the therapy benefits those with Sickle Cell Disease.