How has the use of animals in research contributed to medical research/science?
The following examples relate to MRC research. Additional case-studies can be found on Understanding Animal Research’s website.
Mice and melanoma
Yervoy (Ipilimumab) is a cancer drug that has dramatically prolonged the lives of a small number of patients with advanced metastatic melanoma since it was licensed for use in 2011. It was basic research on the mouse immune system function which led scientists to this exciting treatment. Traditional cancer treatments like chemotherapy attack the cancer itself. Yervoy works in a more complex way, interacting with the immune system so that the patient’s own cells are able to attack and destroy the cancer.
In 1995, scientists discovered that tumours in CTLA-4 knockout mice were completely destroyed by the T-cells in their immune systems. By developing a monoclonal antibody which interacted with the CTLA-4 molecule, they were able to treat cancers in normal mice and later in humans. The treatment seems to work only in 10—15% of patients, but those who do respond exhibit dramatic responses.
Skipping muscular dystrophy
Duchenne muscular dystrophy (DMD) is an inherited muscle wasting disease affecting young boys. About 100 boys with Duchenne muscular dystrophy are born in the UK each year. At around the age of 10, sufferers are likely to need a wheelchair. However, with high standards of medical care and support, many young men with the condition live into their 30s.
The disease is caused by mutations in the very large dystrophin gene, which contains 79 exons or coding regions. A new type of gene treatment called “exon skipping” involves small pieces of antisense DNA (molecular patches) which mask an exon where there is a mistake or mutation. Various exon skipping drugs have been developed using mice with a form of DMD. These treatments are currently at different stages of testing in animal and human trials. Completed human trials show “proof of principle” of the treatment, which is safe and mirrors results found in the mouse model of DMD.
Further case-studies and recent publications will be added in due course.