Bevacizumab (Avastin) is commonly viewed as chemotherapy treatment because when administered intravenously, it is particularly effective in controlling such illnesses such as lung cancer and colon cancer. However, it is a bit different than traditional chemotherapy treatments, which directly attack cancer cells. Bevacizumab fights cancer cells by cutting off oxygen and other nutrients the cells need to grow and survive, and prohibit new blood vessels from forming (angiogenesis). Without angiogenesis, cancer growth slows down, and the cancer cells eventually die.
For those suffering from mesothelioma, the prognosis is grim. The survival rate after diagnosis is generally around 12 months as the cancer spreads rapidly. One of the main components to this asbestos-caused diseased is the vascular endothelial growth factor (VEGR) and its receptor. This protein aids in the formation of new blood vessels and when it is over-produced, it can contribute to disease. The more blood that is able to be supplied, the larger cancer cells are able to grow. Bevacizumab is a monoclonal antibody, meaning it is able to find specific cancer proteins – like VEGR – on cancer cells and control them.
When treating mesothelioma, combination therapies have yielded better overall results, rather than single-agent chemotherapy which have had a disappointing response rate of less than 20 percent. In 2004, the first chemotherapy treatment combination of cisplatin and pemetrexed was approved for mesothelioma patients and today, is still the first line treatment. Overall survival improved on average three months.
With the discovery of bevacizumab’s effectiveness on controlling the VEGR and the positive results from the combination cisplatin-pemetrexed treatment, clinical trials for a cisplatin-pemetrexed-bevacizumab chemotherapy treatment began in hopes to decrease tumor size even more, and increase overall survival time. A 2016 Phase III clinical trial in France saw an improvement in survival time by 2.7 months when compared to mesothelioma patients who were only given cisplatin-pemetrexed. However, some side-effects have been noted when bevacizumab is administered and more serious side-effects have been discovered specifically when bevacizumab is used in a combination therapy. Hemorrhaging, blood clots in the lungs, low white blood cells count, and gastrointestinal issues are deadly complications that have been found when bevacizumab was used with other chemotherapy treatments and in some cases, patients are more likely to die.
Despite the risk of life-threatening side effects, more Phase III trial results from the combination cisplatin-pemetrexed- bevacizumab treatment in France have been promising, and the National Comprehensive Cancer Network had included this combination treatment as a viable option for standard front-line therapy for those suffering from malignant pleural mesothelioma.
Sources
Brosseau S, et. al., “A Review of Bevacizumab in the Treatment of Malignant Pleural Mesothelioma,” Future Oncology (2017 September). [Link]
Pavel A. Levin & Jonathan E. Dowell, “Spotlight on Bevacizumab and its Potential in the Treatment of Malignant Pleural Mesothelioma: The Evidence to Date,” Oncotargets (2017 April). [Link]
