Sickle cell anemia is an inherited condition that affects the red blood cells, which transport oxygen throughout the body.

The disease is caused by a mutation in the HBB gene, resulting in the production of an abnormal hemoglobin protein, called HbS.

Hemoglobin is the protein that oxygen binds to inside the red blood cells. Unlike normal hemoglobin, HbS proteins stick together or polymerize, forming rigid structures inside the red blood cell. This forces the red blood cells to adopt an abnormal and inflexible “sickle” shape, causing them to become trapped inside small blood vessels. This results in a lack of oxygen reaching tissues, as well as inflammation and pain.

There are several approved treatments to help manage the symptoms of sickle cell anemia. Some of these can reverse the symptoms of the disease in some people. Research is still ongoing to find a more robust cure and to discover more effective ways of reducing the symptoms of the disease.

Approved treatments

Currently, the only treatment that offers a potential cure for sickle cell anemia is stem cell transplantation. This aims to replace the source of new red blood cells, the stem cells in the bone marrow, with healthy stem cells from a matching donor. This treatment is not available to everyone because it can be very difficult to find a suitable donor.

In addition, there are several approved medications to improve the symptoms of sickle cell anemia. These include hydroxyurea and Endari (L-glutamine).

Patients may also benefit from a transfusion of healthy red blood cells, especially if they are at high risk of complications such as a stroke.

Because pain is a common and debilitating symptom in sickle cell anemia patients, their clinicians may recommend painkillers such as acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and diclofenac. Opioids such as codeine or morphine may also be prescribed for more severe or chronic pain.

Children may be prescribed daily penicillin from as young as 2 months to prevent infections. This is called penicillin prophylaxis and should be complemented by vaccinations and antibiotics in case of infection.

Experimental treatments

A number of new therapies are in clinical trials to evaluate their safety and effect on sickle cell anemia patients.

For example, gene therapy could be promising as a potential cure for sickle cell anemia. Scientists are considering ways to deliver a functioning copy of the HBB gene to the patient’s cells, and many clinical trials are ongoing or have been completed to investigate this.

If this approach is successful, it should enable the patient to produce their own healthy red blood cells. One example of gene therapy to treat sickle cell anemia is CTX001, by CRISPR Therapeutics.

There are other experimental therapies that aim to more effectively treat the symptoms of the disease.

For example, Voxelotor (GBT440), by Global Blood Therapeutics, targets the underlying cause of sickle cell anemia, the abnormal hemoglobin. It aims to prevent hemoglobin from sticking together, which should allow the red blood cells to maintain a partially normal and flexible shape.

Some experimental therapies are aimed at finding ways to improve blood flow and reduce the numbers of red blood cells that get trapped inside the blood vessels. These include:

Experimental therapies to reduce pain are also being investigated, for example, by targeting inflammatory pathways in the body, that can be the cause of pain in sickle cell anemia. Two examples include Novartis’ ACZ885 (canakinumab) and NKTT120 by NKT Therapeutics.

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Sickle Cell Anemia News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.