Potential breakthrough trial for rare disease Hunter syndrome

Actigen has initiated a clinical development programme for GNR-055, a potentially breakthrough treatment for the debilitating, life-limiting, rare disease mucopolysaccharidosis II (MPS II), also known as Hunter Syndrome.

The disease occurs in around 1 in 100,000-170,000 births, and presents almost exclusively in males. MPS II has a major impact on the physical and neurological health of those living with the disease. It is caused by a deficiency of the enzyme responsible for breaking down sulphated sugar molecules, which are known as glycosaminoglycans (GAGs), throughout the body. Left untreated, the disease leads to a progressive deterioration of organ systems across the body, including the heart, lungs, brain, bone, and cartilage.

Brain deterioration then leads to cognitive and behavioural issues including disturbed sleep, disruptive behaviour, and poor temper control.

GNR-055 uses an innovative combination of the missing enzyme, and an antibody fragment, to access brain cells. The antibody has a particularly important function, binding to the human insulin receptor on capillary cells, to cross the blood-brain barrier. Once in the brain, GNR-055 is then expected to break down the GAGs that cause neurological issues.

Michael Braunagel commented: “MPS II is very debilitating condition for those affected and we are hopeful that the trial will establish the treatment’s efficacy. GNR-055 is the first therapeutic in our innovative development pipeline and we are thrilled to be working with Generium, who is a major player in the industry.”

Current treatment options available for MPS II, such as enzyme replacement therapy, offer only a partial solution: they can help improve the functioning of internal organs and improve patient quality of life. However, their inability to cross the blood-brain barrier means that GAGs continue to build up in the brain, leading to ongoing neurological issues.

Ana Ovey