Immune Drugs Show Increasing Promise Against Some Cancers
Researchers are positive about the ability of immune drugs to help people with cancer, as a number of trials continue to show their effectiveness in extending the lives of people with certain forms of the disease.
Immunotherapy Research Paying Off
Immune drugs, or immunotherapy, are used to encourage the immune system to attack tumour cells in the way that it typically fights off other diseases and infections. One of the major hurdles to overcome in immunotherapy research has been difficulties in getting the drugs to work against only cancerous cells, while leaving healthy tissue alone.
However, oncologists are finally finding ways to deal with this problem. More recently approved immune drugs have been labelled “checkpoint inhibitors”, as they work by blocking immune cell molecules called “checkpoint proteins”. Checkpoint proteins prevent the immune system from going overboard and attacking normal tissue. The problem with this is that tumours can fool checkpoint proteins into thinking they are normal tissue, allowing them to fly under the immune system’s radar. Checkpoint inhibitors, therefore, prevent the immune system from overlooking these tumour cells by blocking the checkpoint proteins which would otherwise protect them, allowing the immune system to recognise them as foreign.
“The immune system was designed by nature to recognise foreign things in the body,” says Dr Richard Schilsky, chief medical officer at the American Society of Clinical Oncology. “Every cancer is a foreign object. It’s only a question of how foreign it appears to be so that the immune system can recognise it.”
Recently Approved Immune Drugs
A drug called Keytruda (pembrolizumab) was approved last September for advanced melanoma and has helped people with advanced head and neck cancer.
Another drug, called Opdivo (nivolumab), was also approved for the treatment of advanced melanoma in December, and for squamous, non-small-cell lung cancer in March. This type of lung cancer represents around 25% of all lung cancers, and the drug has been found to extend survival for people with this particular condition. Opdivo has also showed promise in the treatment of advanced liver cancer in studies so far.
The Research Continues
While researchers have much more to learn about immunotherapy, there is no denying that this form of treatment has had a positive impact on a number of cancer patients already. When Keytruda was approved, the FDA said it helped shrink tumours in 24% of patients, while Opdivo helped shrink melanoma tumours in 32% of patients.
“It’s looking like there’s no type of cancer in which some patient won’t benefit from these immune approaches,” says Dr Schilsky.
As scientists learn more about enhancing the immune system’s defences against cancer, it is hoped that increasingly effect immune drugs will become available. Amongst researchers, immune checkpoint inhibitors have reignited enthusiasm for the development of immunotherapy drugs for cancer.