Selected Podcast

Cancer Vaccine: Taking The Double-Pronged Approach

Although chemotherapy can be effective in treating cancer, it can also exact a heavy toll on a patient’s health. One impressive alternative researchers have found is in the form of a vaccine. A type of immunotherapy, one part of the vaccine primes the body to react strongly against a tumor; the second part directly attacks the tumor itself.

This double-pronged approach could be both more powerful against cancer and far less toxic to the body than traditional chemotherapy.

Don J. Diamond, Ph.D. is here to explain the cancer vaccine.
Cancer Vaccine: Taking The Double-Pronged Approach
Featured Speaker:
Don J. Diamond, Ph.D.
Don J. Diamond, Ph.D., chairs the Department of Experimental Therapeutics, which develops vaccines to combat hematologic malignancies, solid tumors, and infectious pathogens such as the herpesvirus, cytomegalovirus (CMV) HIV. The prospect of an effective CMV vaccine means significant benefits for immunocompromised patients such as those with AIDS, or stem cell and solid organ transplant recipients. A therapeutic CMV peptide vaccine developed in the department is undergoing phase II human efficacy testing in City of Hope stem cell transplant recipients, while a second generation CMV vaccine based on the attenuated poxvirus MVA, or modified vaccinia Ankara, is currently undergoing phase I human safety testing.

Learn more about Don J. Diamond, Ph.D
Transcription:
Cancer Vaccine: Taking The Double-Pronged Approach

Melanie Cole (Host):  The immune system is a complex network of cells, tissues and organs and the substances that they make help the body to fight infections and other diseases. The immune system's role in defending against diseases has long been recognized. My guest today is Dr. Don Diamond. He's the Chair and Professor in the Department of Experimental Therapeutics at City of Hope.  Welcome to the show, Dr. Diamond. So, are cancer cells specifically recognized by the immune system?

Dr. Don Diamond (Guest):  It’s a very interesting question because that is one of the great problems that we face. Cancer cells are minimally recognized by the immune system. When they are capable of propagating and forming a tumor or, later on, a metastasis, it is very much the case that they evade the immune system. Cancers that are not developed into eventual tumors may be recognized by the immune system. We don’t know if they are or how they are but we do know that we escape the ravages of a progressive tumor.

Melanie:  So then, what are cancer vaccines? Are there certain types of them?

Dr. Diamond:  There have been many different types of cancer vaccines over the history of this field, which is quite long—about 50 years old as a field of endeavor. It has suffered a tremendous number of failures over the years. The first immunologic-based therapy was approved by the FDA several years ago for prostate cancer called “Provenge”. Unfortunately, it did not provide a substantial increase in survival. So, the next stage of immunologic development for treatment has been what are known as “checkpoint inhibitor” molecules. They’re actually antibodies. They are now becoming quite prominent in the field of oncology and one can see their commercials describing them by various big pharma. So, they’ve hit the popular press and the popular forms of entertainment because they extend survival. Actual cancer vaccines are still a work in progress. There are a number of different strategies but it’s a very difficult problem to solve; whereas, vaccines for infections that are lifesaving have been a part of our pharmacopeia for many years, dating all the way back to the smallpox vaccine. The one that, of course, many of us who are a bit older recall—the Salk vaccine against polio and then the oral Sabin. So, vaccines for infectious disease have been very successful and that leads, really, to what can be called a “transitional vaccine” which is a vaccine against HPV. That has now, over the last several years, received FDA approval. While that guards against an infection, it also, eventually, guards against development of cervical carcinoma. So, a vaccine against an infectious disease becomes a cancer vaccine. The same is true of the hepatitis vaccine which was developed for an infectious disease but, in fact, it protects against hepatocellular carcinoma. So, infectious disease vaccines are very successful. Interestingly enough, in some cases, they can protect against cancer.

Melanie:  So, those preventive or prophylactic vaccines for HPV, for example, are getting much more prominence. What about a treatment vaccine? Something that goes along with whatever the patient is going through. Are there those?

Dr. Diamond:  The concept of a therapeutic vaccine for cancer is, of course, very attractive because once a patient comes to the clinic with a disease, they hope—they expect—that there would be a treatment available.  The challenges of a therapeutic vaccine are many fold and, unfortunately, a therapeutic vaccine for cervical carcinoma still remains to be developed. It, unfortunately, is in the same bag as the other cancer vaccines which are still in development. But, the good news is that there is a preventative vaccine and it is available to the public and it can be demonstrated objectively that it prevents a near fatal condition if left untreated, namely cervical carcinoma.

Melanie:  If there are patients with immunocompromised situations, is there something that’s added to the vaccines to help with their immune system and immune response or to go along as an adjunct to the treatment?

Dr. Diamond:  In parallel to the development of vaccines, drug companies and academic institutions like the City of Hope, have also been working on adjunct—they’re called adjuvant—to make vaccines more effective. So, in my work with transplant patients, we have developed two different approaches for addressing a herpes virus condition that normally does not cause symptoms in a healthy adult, but in the transplant population can be quite deadly. So, we have developed two different types of vaccines that have these, what we would call “Immune stimulators”,  that make them more effective. One of the vaccines, we published a small study, carried out at the City of Hope with 36 patients in the prestigious journal, Lancet Hematology, where we showed that there was an advantage to the patient receiving the vaccine and, therefore, we have been extending the development of this vaccine into a larger clinical trial to demonstrate that it truly has protective qualities.

Melanie:  Can they go along with other types  of cancer therapy? Chemotherapy? Radiation?

Dr. Diamond:  This is also an exciting area which investigators are pursuing because it is likely the case that no one agent will be sufficient to successfully combat cancer. So, the new regime—the new paradigm—is multimodal therapy in which various agents are combined together. One of the most fascinating aspects of the science behind chemotherapy is that what was once thought to be simply the destruction of cancer cells by drugs turns out to be much more complicated and interesting in that these drugs actually affect the immune system. There are many studies being carried out by pharmaceutical companies as well as academic centers, including our center, in which vaccines are combined with standard chemotherapy. We have a clinical trial in advanced ovarian cancer in which we are combining a common chemotherapy drug with our experimental oncology vaccine to see whether we can improve the survival of advanced ovarian cancer patients who have few alternatives at that stage of their disease.

Melanie:  Dr. Diamond, where do you see—in just the last few minutes, here—cancer vaccines going in the world of research? To give hope to people out there listening, what do you see happening in the future? What’s on the horizon?

Dr. Diamond:  I think the explosion in technological advances really makes the future much brighter. We’re having to catch up with all of the other scientific disciplines in which they have made striking advances. With the moon shot, there is, of course, the necessary  funding by the U.S. government to propel forward the exciting research. There is definitely hope. There are, of course, complications but there is hope that the new technology will allow a more developed and personalized medicine in which each patient can be treated as an individual and a regimen of therapy which possibly could include various types of cancer vaccines would be structured for each individual. City of Hope is the perfect institution to carry out both that research and its clinical development for the benefit of the patient.

Melanie:  That’s wonderful! It’s so fascinating and great information that you’re doing there at City of Hope. We applaud all the great work that you’re doing. Thank you so much, Dr. Diamond, for being with us today. You’re listening to City of Hope Radio. For more information, you can go to CityofHope.org. That’s CityofHope.org. This is Melanie Cole. Thanks so much for listening.