There are approximately 3,000 new cases of mesothelioma diagnosed every year in the United States, and while mesothelioma rates have reduced slightly in the United States, they continue to increase in other countries.

Most cases of mesothelioma are directly related to work-exposure to asbestos, which is used in a wide range of industries.

While chemotherapy is typically the first—and usually only—type of treatment used for mesothelioma patients, the immunotherapy drug, Pembrolizumab, has recently been used to treat malignant, pleural mesothelioma.

While Pembrolizumab is not a new drug, it appears to be effective in treating this rare type of lung cancer. Many studies have looked at different drugs to treat mesothelioma, with little in the way of positive results.

Checkpoint inhibitors, like Pembrolizumab, appear to be more effective than any other drugs studied for mesothelioma treatment.

How Pembrolizumab Works

Checkpoint inhibitors like Pembrolizumab, help the body fight cancer by halting certain mechanisms used by cancer cells to avoid detection by the immune system.

Pembrolizumab, which sells under the brand name Keytruda, improves the body’s immune response against cancers which are positive for PD-L1, and has already been successfully used to treat melanoma, non-small cell lung cancer, and some types of head and neck cancers as well.

Pembrolizumab Study Showed Promising Results

In one study of 25 patients with malignant pleural mesothelioma, 14 out of the 25 patients showed significant tumor shrinkage after receiving a dose of Pembrolizumab every two weeks for two years. Doctors in charge of the study found the results “very promising,” particularly because none of the patients had to stop taking the drug due to side effects. In other words, the drug appears to be very well-tolerated. The primary side effects noted by the patients in this study were appetite loss, fatigue, dry mouth and nausea.

What Causes Mesothelioma?

Mesothelioma is primarily caused by asbestos exposure, affecting the thin lining of tissue covering the inside of the chest, the abdomen, the heart, and other internal organs.

Patients with malignant pleural mesothelioma typically develop tumors in the pleural lining of the chest and lungs.

Unfortunately, most patients diagnosed with malignant pleural mesothelioma do not have a very good survival rate—usually less than a year. This is due, in part, to the fact that mesothelioma is rarely diagnosed until it is well-advanced.

The risk of developing mesothelioma increases when you are in one of the following areas:

  • at an asbestos processing plant or asbestos mine;
  • in the construction industry;
  • a power plant;
  • a boiler plant;
  • a chemical plant;
  • in the automotive industry;
  • serving on a military ship or in a facility built with asbestos-containing products;

You live in a residential area, near an asbestos mine;

You did a home renovation, and, in the process, disturbed asbestos products

without using proper safety measures;

You have also been exposed to other mineral fibers, such as zeolites, or

You have significant radiation exposure.

Other Risk Factors Associated with Mesothelioma

There is some evidence to suggest that those who received a polio vaccine between the years of 1955 and 1963 could have an increased risk of developing mesothelioma, since polio vaccines during that time span were found to be infected with the simian virus.

Since only a relatively small number of those exposed to asbestos actually develop mesothelioma, researchers believe genetics plays a significant role, and that a mutation in the BAP1 gene can increase the likelihood of developing mesothelioma.

Men are more often diagnosed with mesothelioma than women, and those under the age of 45 are only very rarely diagnosed. Mesothelioma can take decades to develop, and those who work in jobs where asbestos exposure occurs are more likely to develop the disease.

While smoking has not been found to be a risk factor in developing mesothelioma, it can aggravate the disease, as well as weakening the lungs and reducing the body’s ability to dispense of asbestos fibers.