Treatment for Inoperable Mesothelioma Greatly Improves Survival

On May 18, Dr. Lee Krug announced via Twitter that a phase III clinical trial found that a novel drug improves survival rates in mesothelioma patients. The drug bevacizumab proved to be effective when combined with standard chemotherapy for pleural mesothelioma.

Adding bevacizumab to standard chemotherapy for #mesothelioma improves survival in phase 3 trial! @asco @curemeso: http://t.co/NMWKBeBKzB

— Dr. Lee Krug (@KrugMD) May 18, 2015

The authors of the study said that bevacizumab in addition to standard chemotherapy “provides a significantly longer survival” in patients with pleural mesothelioma.

Patients in the trial were not eligible for surgery nor had they been treated with chemotherapy prior to the clinical trial. The median survival time among 448 participants in the study was 18.8 months, which in many cases is double the survival time of a patient with inoperable mesothelioma.

The phase III trial was sponsored by the Intergroupe Francophone de Cancerologie Thoracique, a French mesothelioma cancer center. Researchers from the cancer center will present their study on May 30 at the 2015 American Society of Clinical Oncologists Annual Meeting.

What Is Bevacizumab?

Bevacizumab (trade name: Avastin) is a special type of chemotherapy that prevents blood vessels from growing in mesothelioma tumors. The process of inhibiting the growth of tumor blood vessels is known as anti-angiogenesis.

Mesothelioma tumors form when carcinogenic asbestos fibers cause mutations in healthy mesothelial cells. These cells make up the lining of the lungs, chest, heart and abdomen. But when they are mutated, they divide faster and form tumors. These tumors, however, need nutrients to survive and spread. The number one source of nutrients comes from the bloodstream.

Bevacizumab blocks the vascular endothelial growth factor (VEGF) pathway. Through this pathway, cells send signals to other cells responsible for blood vessel growth. If the cells can’t send the message, new blood vessels aren’t created. This slows, and may even stop, mesothelioma from spreading. It also helps prevent metastasis to other organs since mesothelioma cells also spread through the bloodstream.

Preventing Metastasis

Angiogenesis inhibiting drugs like bevacizumab have been at the brink of success over the past several years, as phase I and II trials were conducted with promising results. The reason mesothelioma doctors have been interested in angiogenesis inhibiting drugs is partially a result of changing philosophies.

It is unlikely that angiogenesis inhibiting drugs could eradicate a patient’s mesothelioma. However, it can help patients manage their disease comfortably for a much longer time.

Essentially, the goal of drugs like bevacizumab is to manage mesothelioma over the long term by preventing metastasis. In this way, patients can live much longer than the average survival rates, as seen in the recently completed phase III trial.

What Happens After Phase III?

The completion of the phase III trial is a big deal because very few mesothelioma drugs pass this stage. Phase III is when a drug deemed relatively safe is given to a large population of patients. This phase ultimately determines if the drug is effective enough to prescribe outside of clinical trials. As bevacizumab successfully passed phase III, it shouldn’t be long before the drug is marketed for use in mesothelioma.

Progress Through International Collaboration

Because mesothelioma is such a rare disease, international collaboration helps move research forward much faster. Different cancer centers across the world can run different clinical trials, and they can compare results to choose the next logical course of action. Therefore, any mesothelioma clinical trial in any country could reveal a treatment useful for any patient.

In the case of the French clinical trial of bevacizumab, mesothelioma specialists in the United States now have scientific evidence to justify using the drug more extensively amongst their patients. For now, it’s a matter of time before more bevacizumab trials emerge in the U.S. or the drug is full-on marketed to patients and doctors.

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