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Recent developments on the horizon regarding treatment for mesothelioma hold promise for future patients. There could soon be another medication introduced as a first-line treatment chemtherapy option. Rather than reinvent the treatment wheel, this particular drug would compound the effects of current chemotherapy treatments, to the benefit of many mesothelioma patients.
Cisplastin and Pemtrexed: The Chemotherapy Gold Standard
Until now, cisplastin and pemetrexed (Almita) have been regarded as the gold standard for first-line chemotherapy treatment. Chemotherapy works by preventing cell divison, interrupting the cell cycle to prevent new cancer cells from forming. Chemotherapy drugs accomplish this by killing off cells that rapidly divide. It is where the treatment is most effective.
Cisplastin and pemetrexed are often chosen because they work very well together. Cisplastin is a cell cycle non-specific alkylating agent – put simply, it keeps cells from rapidly dividing during the resting phase of cell division. Pemetrexed, on the other hand, is a cell cycle specific antimetabolite, meaning that if it is introduced during and active phase of cellular metabolism during an active phase, the cells will not divide.
The cooperation of the two drugs is the primary reason they have been used as the gold standard for treatment. They effectively work together to eliminate cancer cells during both the active and resting phases of mitosis. Using both drugs covers both sides of the mitosis equation, which can lead to remission for many mesothelioma patients.
The Problem with Chemotherapy
However, as with all chemotherapy treatment, the infusion drugs cannot differentiate between cells that are cancerous and those that are normal. It aggressively targets any cell in the body that divides rapidly.
This is why chemotherapy side effects such as nausea, diarrhea, hair loss, mouth sores, and low blood counts are common. Healthy areas of the body such as bone marrow, the lining of the intestines and mouth, and hair follicles produce cells that divide quickly too. Once chemotherapy begins, it is indiscriminate, killing both the cancerous and non-cancerous cells that rapidly divide.
The side effects mentioned above usually stop once treatment is finished. With cancerous cells gone, healthy processes can continue unaffected by chemotherapy – and the body can begin to heal.
Research is constantly underway to improve first line chemotherapy treatment in regards to patient care. This is where bevacizumab (Avastin) could play a role.
Classified as an angiogenesis inhibitor, bevacizumab inhibits the growth of new blood vessels. These are blood vessels that could be used to feed certain cancerous cell production cycles, or worse, cancerous tumors.
The promise of bevacizamub lies in its operation. It is very specific and works similarly to a lock and key. Your body constantly creates antibodies to respond to germs that enter the body. These antibodies will attach themselves to the protein found in a germ (called antigens), and “mark” them for destruction by your body's immune system. Cancer researchers have identified certain antigens in cancer cells and developed special antibodies from animal and human proteins to target them. Since they are specific to particular types of cancer cells, the toxicity potential for healthy cells is diminished.
Bevacizamub works by targeting human vascular endothelial growth factor (HVEG). This is a small protein that is responsible for new blood vessel formation when it interacts with certain receptors found in the body. The blood vessels that form could be used to feed the cancerous cell production cycles and tumors mentioned previously.
Currently, bevacizumab is most often used to treat metastatic colon/rectal cancer, certain types of lung cancer, breast cancer, glioblastoma, and renal cell carcinoma.
How Bevacizumab Can Make a Difference
A recent study funded by Intergroupe Francophone de Cancerologie Thoracique holds some findings worth noting. In the study, a Phase 3 trial was conducted using bevacizumab with patients between the ages of 18 and 75. All patients were diagnosed with unresectable malignant pleural mesothelioma, had not received any prior chemotherapy, and had a life expectancy of less than 12 weeks prior to entering treatment.
The results of the study are pretty incredible. After the combined treatment of bevacizumab, cisplatin, and pemetrexed, the average survival rate was 18.8 months – an increase of more than 15 months over the pretrial prognosis! The study also noted some potentially negative effects, including an increase in the chemical creatinine (a byproduct of the process that supplies muscles with energy), increased proteinuria levels (high levels of protein in the urine, a potential sign of kidney problems), and a somewhat higher incidence of hemorrhage. However, the overall increase in survival rate seems to outweigh any of these other problems.
So what does this mean for future first-line chemotherapy treatment for mesothelioma? The horizon appears bright. If survival rates were increased from less than 12 weeks to almost 19 months with individuals in advanced stages of malignant mesothelioma, it is possible that introducing bevacizumab earlier during the treatment process could yield even better results.
The investigators of the study concluded the following: "addition of Bevacizumab to Pemetrexed plus Cisplatin significantly improved [overall survival] in malignant pleural mesothelioma at the cost of expected manageable toxic effects; therefore it should be considered as a suitable treatment for the disease."
Only time will bear the findings out in full, but the study seems to suggest that adding bevacizumab to an existing first-line chemotherapy treatment regimen helps. It is one addition that could revolutionize chemotherapy treatment for mesothelioma by both extending life and providing a better quality of life for those who survive.