The same structure in the brain that offers protection and transports nutrients and other essential substances also makes it virtually impossible for medicines to enter and reach their intended targets in the brain.
The blood-brain barrier (BBB) is a complex and intricate system of cells that come together around the blood vessels in the brain. It maintains proper function of the brain, but it also makes it harder to discover and develop new medicines to treat diseases of the brain, such as Alzheimer’s disease, Parkinson’s and others.
“Fewer than 5 percent of small-molecule medicines and virtually no biologic medicines are able to penetrate the blood-brain barrier,” says Alfred Hahn, Ph.D., senior director and head of discovery at AbbVie’s R&D center in Ludwigshafen, Germany. “These numbers do not deter us; we believe we’re onto a number of promising new approaches that may allow us to improve these odds.”
Unmet need drives new approaches
Over the past several decades, significant strides have been made in discovering and developing new medicines for a wide range of conditions, from heart-related diseases and viral infections to certain types of cancer.
The same cannot be said for diseases of the central nervous system (CNS), where significant need for new treatments remains.
Nearly 47 million people are living with dementia1 and there are millions of other people who have Parkinson’s disease, multiple sclerosis and other CNS diseases.2 A number of potential approaches are emerging for finding new ways to cross the BBB without disrupting the brain’s functioning. Here are three of them: