The most frustrating aspect of receiving a mesothelioma diagnosis is that there has been no practical treatment for the disease. The usual course of action is to get one’s affairs in order, and wait for the worst – usually in less than a year.
Thanks to research at the University of Pennsylvania, that may be changing.
A recent article in Science Daily describes real progress being made with a medicine that has been successful with other cancers, that is delivering good results with mesothelioma patients.
The drug is called Pembrolizumab, which goes by the trademark Keytruda.
Pembrolizumab is a cancer immunotherapy drug that has been successful in treating metastatic melanoma in clinical trials. It is one of a new class of drugs called checkpoint inhibitors. This class of drugs works to free the body’s immune system to combat growth of cancer cells.
Success with pembrolizumab has been for treating malignant pleural mesothelioma, a cancer constituting the majority of all mesothelioma cases. Before this new application, the drug has been successful in treating malignant melanoma (skin cancer) and non-small cell lung cancer. It has also been used in treating head and neck cancers.
Releasing the 'immunological brakes’
What are checkpoint inhibitors? The immune system fights off the spread of cells using multiple checkpoints to avoid overactivation of the immune system on healthy cells. Tumors are special cases, having evolved so that they are not detected by the immune system.
The immune system, which is so skillful at identifying and attacking most threats, are fooled by cancer cells. Checkpoint inhibitors have been likened to “immunological brakes” – a checkpoint inhibitor acts to release these brakes so the immune system can do its job.
How pembrolizumab works
For two years the University of Pennsylvania team has been conducting an ongoing trial studying the effectiveness of pembrolizumab on advanced malignancies involving 13 different research sites in six different countries. All 25 of the patients participating in the study either had already been treated with chemotherapy or were unable to receive it.
Doctors administered a dose of pembrolizumab to the 25 patents every two weeks. In 14 of these patients, tumor size was reduced by the drug. The drug effectively created a pause in the tumors’ progress for, on average, six months. Average survival time was about 18 months, with four patients still alive after two years.
This extension amounts to a breakthrough for mesothelioma patients, whose typical survival time from diagnosis on is usually six or seven months.
Reported side effects included fatigue, nausea, loss of appetite and dry mouth. None of the patients in the study had to stop treatment because of side-effects.
Research into the drug’s effectiveness continue, but researchers are encouraged that they have finally found a drug that can lengthen and improve the lives of mesothelioma victims.