A recent study conducted on cancer vaccines in animal models has shown serious potential in treating mesothelioma. The study was led by Mark Poznansky, MD, Director of the Massachusetts General Hospital Vaccine and Immunotherapy Center.
While more common cancers are readily treated with a more personalized approach due to the heap of funding directed at research, mesothelioma still has limited treatment options and receives much less funding than other cancers. The lack of treatment options relative to other diseases has spurred many mesothelioma doctors to research novel approaches such as immunotherapy.
In a recent mesothelioma conference held in the country’s capital, mesothelioma specialists spent a significant amount of time discussing the advancement of novel immunotherapy treatments. The vaccine being studied at MGH is a perfect example of the type of drug they believe may revolutionize mesothelioma treatment.
How Do Cancer Vaccines Work?
Cancer vaccines are different than vaccines used to prevent disease in that they aren’t preventative. Cancer vaccines act by initiating the immune system to fight and kill cancer cells. That is, antibodies are injected into the patient in order to stimulate their immune system to fight the cancer.
This does work in a similar manner to common vaccines used to prevent chickenpox or measles. Immune cells also have the capacity for memory. Therefore, in theory, the patient’s immune system will attack any mesothelioma cells that grow back. This is why people only get chicken pox once; the immune system remembers the virus and attacks if it comes backs.
Making Cancer Vaccines More Practical
The development of cancer vaccines has been slow. Only in recent years was the first cancer vaccine approved by the Food and Drug Administration because there are hurdles that make developing cancer vaccines difficult. However, Dr. Poznansky is attempting to change this.
“Some approaches to creating cancer vaccines begin by extracting a patient’s own immune cells, priming them with tumor antigens and returning them to the patient, a process that is complex and expensive,” said Dr. Poznansky.
Unfortunately, not all cancer centers are equipped to handle this process.
“Many patients with advanced cancers don’t have enough functioning immune cells to be harvested to make a vaccine,” Dr. Jeffrey Gelfand, co-author of the study, points out as another potential problem. He also believes this treatment “could dramatically enhance cancer immunotherapy.”
In order to solve this problem, MGH combines an engineered protein with a protein found in tuberculosis bacteria. This man-made antibody specifically targets a protein found on mesothelioma and ovarian cancer tumors called mesothelin. In animal models, MGH’s protein slowed tumor growth and increased survival in both types of cancer.
Dr. Poznansky and the team at MGH is on track to develop a more cost-effective way to deliver immunotherapy treatment.
He described MGH’s study as a “very practical, potentially broadly applicable and low-cost approach that could be used by oncologists everywhere.”
Working Toward a Cure With Novel Treatments
Many mesothelioma doctors argue that working toward better treatment for mesothelioma involves the research of novel treatment methods. Although it has improved substantially in the past decade, standard chemotherapy for mesothelioma is nowhere near as successful as it is for other cancers.
Dr. Julian Molina of the Mayo Clinic has expressed optimism in replacing traditional chemotherapy with novel treatments being researched as the new standard of care for patients. His reasoning is that novel treatment can be more effective than chemotherapy without too many side effects, while still improving survival rates.
Dr. Molina has conducted a study of an angiogenesis drug known as Pazopanib. Angiogenesis drugs work by hindering the growth of blood vessels at tumor sites and preventing metastasis.
The small, phase II study was conducted with 34 patients who experienced survival times ranging from six months to over 18 months. The average survival time for mesothelioma is 9 to 12 months. These survival times are encouraging because the sample of patients used was relatively small. Dr. Molina is currently moving forward with a Pazopanib study that could include over 500 patients across the globe. Pazopanib is already FDA-approved for treatment in kidney cancer.
Dr. Poznansky also supports alternative treatments with fewer side effects than traditional methods.
“Immunotherapy is generally nontoxic, so this vaccine has the potential of safely extending survival and reducing the effects of these tumors, possibly even cutting the risk of recurrence,” he said.
Cancer vaccines have had curative potential for decades. However, they haven’t been as easy, or as affordable, to administer as chemotherapy. It seems the team at MGH may be overcoming this issue, however, and may be instrumental in ushering in a new standard of care for mesothelioma patients. For now, only continued research efforts and clinical trials will reveal the viability of mesothelioma vaccines as an acceptable alternative.
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