Treating rare diseases

People with a rare inherited disease resulting in severe swelling of soft tissues, particularly around the eyes, lips, nose, and tongue, that in the most severe cases can lead sufferers to choke to death, could soon be treated with new and more effective treatments, according to Cardiff University's Dean of Medicine.

Writing in the New England Journal of Medicine (NEJM) Professor Paul Morgan, a leading research specialist in Clinical Immunology and Dean of Medicine, considers the effectiveness of three new treatments, currently under trial, for hereditary angioedema.

Hereditary angioedema is a rare disease, estimated to affect between one and five thousand people in England and Wales. Sufferers present with painless, recurrent swelling, usually of the hands, feet, arms, legs or face, and sometimes involving the throat.

Current treatment works by restoring levels of C1 inhibitor – low in the patient's body. C1 inhibitor is made from blood plasma, and concerns have been raised about the safety of this treatment because of the possible transmission of viruses like hepatitis C, and also because of difficulties with administering the treatment, especially in emergency cases.

"The preferred treatment for hereditary angioedema should restore normal C1-inhibitor levels in sufferers" writes Professor Morgan.

"However, because of concerns about the possibility of the transmission of viruses, and the fact that C1 inhibitor is not an ideal treatment for patients to administer, there is a desperate need to find alternative approaches."

In his article, Professor Morgan considers the effectiveness of three new treatments which could help provide more effective options for the routine and emergency treatment of the disease.

The first is the creation of a new formulation of C1 inhibitor called Cinryze, which is treated to eliminate the risk of the spread of viruses. The second is Rhucin, a small molecule enzyme inhibitor that replaces some of the functions of C1 inhibitor, and the third is Ecallantide a small protein that also mimics C1 inhibitor.

In trials, each of these has proved effective in acute attacks.

Professor Morgan adds: "The availability of three new drugs suggest that new ways of treating hereditary angioedema could soon be on their way.

"Each of the three new agents helps reduce the duration of attacks as well as the risk of laryngeal obstruction – which will save lives.

"These trials provide an important step forward; however, more work is needed to confirm the safety and stability of the drugs and ease of administration. These trials move us closer to creating better treatments for a small but vulnerable group of patients."

(Source: Cardiff University: New England Journal of Medicine)