Cancer treatments are becoming more powerful, less toxic and increasingly individualized by patient and by tumor. Researchers are enlisting the immune system in the body's fight against cancer's many forms.
Listen as Dr George Hajaar, oncologist with City of Hope, discusses how years-long research projects are maturing into human clinical trials of new targeted cancer therapies.
Selected Podcast
Targeted Therapies for Cancer: The Latest Advancements
Featured Speaker:
At City of Hope's Santa Clarita and Antelope Valley practices, Dr. Hajjar handles all general medical oncology, with a special interest in gastrointestinal cancer. His research in the field has earned him awards from the American Cancer Society and the Cancer Institute of New Jersey.
George Hajjar, MD
George Hajjar, MD received his medical degree from Aleppo University in Syria and continued his training at Seton Hall University in New Jersey. Before joining City of Hope, he spent a decade serving the community of Porterville, California at the Sierra View Cancer Treatment Center.At City of Hope's Santa Clarita and Antelope Valley practices, Dr. Hajjar handles all general medical oncology, with a special interest in gastrointestinal cancer. His research in the field has earned him awards from the American Cancer Society and the Cancer Institute of New Jersey.
Transcription:
Targeted Therapies for Cancer: The Latest Advancements
Melanie Cole (Host): Cancer treatments are becoming more powerful, less toxic and increasingly individualized by patient and by tumor. Researchers are enlisting the immune system in the body's fight against cancer's many forms. My guest today is Dr. George Hajjar. He's an oncologist with City of Hope. Welcome to the show, Dr. Hajjar. Tell us what targeted cancer therapies are. What does that mean when people hear the words “targeted therapies”?
Dr. George Hajjar (Guest): Thank you very much for having me on your . . . to talk about this very exciting and probably changing way of we approach our treatment of cancer. So, targeted therapies are substances or medications that work by suppressing the growth and spread of cancer. The main idea centers on the fact that there are specific molecules that can be seen mainly in cancer cells or in the cancer tumor environment and these specific molecules are very essential for the survival, growth, or spread of cancer to other organs. So, by identifying these molecules and then developing medications that specifically target them, we are working on blocking the function of these molecules which, as I said, are essential for the survival and growth of these tumors and by doing that, we are suppressing the tumor cells. So, having said that, this is different than what our traditional chemotherapy is which is basically giving medications that kill the cells that divide rapidly, including the cancer cells, but also there are a lot of normal cells in our body that also divide rapidly and will be affected by the chemotherapy. Here, we are trying to identify these areas where we are targeting mainly the tumor and trying to avoid exposure to the normal cells in the body. So, basically, we are turning the cancer treatment from hit and run treatment which was mainly with the chemotherapy, to more turning this disease into chronic disease that we keep giving these medications to suppress the growth of the disease and keep it under control.
Melanie: And, what types of targeted therapies are available as of now?
Dr. Hajjar: There are different molecules and different ways of playing on this modality of treatment. So, there are the hormonal therapies, which some diseases depend mainly on our normal hormones to grow, like our usually dysplastic or breast cancers and by the fact that we identified these tumors that depend mainly on the hormones and suppressing the hormones, we can control them. There is something called “angiogenesis” which is basically, tumors to grow, they need the blood supply. So, they have the capability of making their own blood supply and if we target that capability, the tumors will have not enough blood and they eventually suffocate and die. There's ways of what we call “apoptosis”, which is in using death sentence into the cells so it does not keep growing forever. There are immunotherapy treatments that will also alternate the way how the immune system is handling the cancer because we all know that tumors do suppress our own immune system from attacking them and by reopening our own immune system to attacking the tumor cells, we also use that to kill the tumors. Finally, there is the idea of using something called “monoclonal antibodies” which, again, they are antibodies against these molecules that are presented on the tumor cells, and there's a lot of studies now that if we are able to tag these antibodies with a toxin substance or with even a radioactive isotope, and then inject this molecule, this combined molecule, if you want, into the patient, then the antibody will carry the radioactive isotope or it will carry the toxins very close to the tumor cell where the antigen is, where the substance for this antibody is, and direct deliver the poison, if you want, right into the tumor cells while minimizing exposure to the surrounding tissues. So, there are a lot of ways that are new and also vaccine therapy where we get the patient's tumor and then we create a vaccine that is specific for this patient's tumor and then re-inject it back into the patient's system and depend on that system to do the same and we have one, at least now, approved for the prostate cancer which also was a breakthrough treatment for these patients.
Melanie: That's absolutely fascinating, Dr. Hajjar. What are some of the limitations, as you see it, for targeted cancer therapy?
Dr. Hajjar: So, the main thing, as we said, is to find these targets. So, there's a lot of research being done to identify these molecules that are specific for each disease type and once we get that, then we get the other researchers working on the other hand to develop treatment that targets that specific target, if you want. So, identifying these targets will be one of the limitations in a way. Then, the side effects profile of these medications is somewhat different than what we used to see with the chemotherapies. So, we don't see much the nausea, the vomiting, the hair loss much, but we see more specific type of side effects and, again, these are new medications so we are learning how to deal with that. Like the hormonal therapy medications can increase the risk of osteoporosis, can give the patient hot flashes. Some of these medications can cause skin rashes, we call it “acne-like skin rash”. I tell my patients I'm going to give you acne rash, but I cannot bring you to be a teenager again. Some of these medications can cause clotting, can affect the wound healing, and the latest class of these medications works more on the immune system, so we have seen that the immune system, after it gets off the suppression from that tumors, it's sometimes affecting some other organs, also, like the thyroid. We see people come in with thyroiditis or sometimes diverticulitis or colitis, which is something, again, we are not used to seeing with the traditional chemotherapy medications.
Melanie: In just the last few minutes, how is it determined whether a patient is a candidate for targeted therapy and then, tell us about your what you're doing that's really exciting at City of Hope.
Dr. Hajjar: Yes. So, these days when we get the patient diagnosed with a cancer, we don't just ask the pathologist to tell us if the patient has cancer or not. We ask for a lot of information. We call it “genetic testing”. Let's say a patient comes with a diagnosis with lung cancer, as an example, so we need to know what kind of cancer, and then we ask for some genetic testing, something called EGFR, something called ALK, and the reason why we ask for that, although it's not very commonly seen, it's probably seen between 5 and 10% of patients, the reason we do that is because if a patient with lung cancer comes with, let's say EGFR mutation or possibility, then they are treated with a pill that they take at home and minimum side effects, the mainly is the acne-like skin rash that I talked about before, and I have patients on this pill for more than a couple of years now, just taking the pill every day with no, with the tumor being under . . . It's suppressed, under control. So, there's a lot of information that are needed to identify the specifics for each patient and we at City of Hope have a lot of research being done in the pre-clinical area where a lot of researchers are working to identify more targets, if you want, on specific tumor types and then once we identify this, as we said mainly expressed on the tumor cells, and we have other researchers who are working on developing targets that go right after these molecules and eventually develop new treatment for this disease. It's a very exciting time to be practicing oncology in this era of targeted therapy.
Melanie: Thank you so much for being with us today, Dr. Hajjar. As I said before, it is absolutely fascinating what you're doing. Thank you so much for all of your hard work and thanks for being with us today. You're listening to City of Hope Radio and for more information, you can go to www.cityofhope.org. That's www.cityofhope.org. This is Melanie Cole. Thanks so much for listening.
Targeted Therapies for Cancer: The Latest Advancements
Melanie Cole (Host): Cancer treatments are becoming more powerful, less toxic and increasingly individualized by patient and by tumor. Researchers are enlisting the immune system in the body's fight against cancer's many forms. My guest today is Dr. George Hajjar. He's an oncologist with City of Hope. Welcome to the show, Dr. Hajjar. Tell us what targeted cancer therapies are. What does that mean when people hear the words “targeted therapies”?
Dr. George Hajjar (Guest): Thank you very much for having me on your . . . to talk about this very exciting and probably changing way of we approach our treatment of cancer. So, targeted therapies are substances or medications that work by suppressing the growth and spread of cancer. The main idea centers on the fact that there are specific molecules that can be seen mainly in cancer cells or in the cancer tumor environment and these specific molecules are very essential for the survival, growth, or spread of cancer to other organs. So, by identifying these molecules and then developing medications that specifically target them, we are working on blocking the function of these molecules which, as I said, are essential for the survival and growth of these tumors and by doing that, we are suppressing the tumor cells. So, having said that, this is different than what our traditional chemotherapy is which is basically giving medications that kill the cells that divide rapidly, including the cancer cells, but also there are a lot of normal cells in our body that also divide rapidly and will be affected by the chemotherapy. Here, we are trying to identify these areas where we are targeting mainly the tumor and trying to avoid exposure to the normal cells in the body. So, basically, we are turning the cancer treatment from hit and run treatment which was mainly with the chemotherapy, to more turning this disease into chronic disease that we keep giving these medications to suppress the growth of the disease and keep it under control.
Melanie: And, what types of targeted therapies are available as of now?
Dr. Hajjar: There are different molecules and different ways of playing on this modality of treatment. So, there are the hormonal therapies, which some diseases depend mainly on our normal hormones to grow, like our usually dysplastic or breast cancers and by the fact that we identified these tumors that depend mainly on the hormones and suppressing the hormones, we can control them. There is something called “angiogenesis” which is basically, tumors to grow, they need the blood supply. So, they have the capability of making their own blood supply and if we target that capability, the tumors will have not enough blood and they eventually suffocate and die. There's ways of what we call “apoptosis”, which is in using death sentence into the cells so it does not keep growing forever. There are immunotherapy treatments that will also alternate the way how the immune system is handling the cancer because we all know that tumors do suppress our own immune system from attacking them and by reopening our own immune system to attacking the tumor cells, we also use that to kill the tumors. Finally, there is the idea of using something called “monoclonal antibodies” which, again, they are antibodies against these molecules that are presented on the tumor cells, and there's a lot of studies now that if we are able to tag these antibodies with a toxin substance or with even a radioactive isotope, and then inject this molecule, this combined molecule, if you want, into the patient, then the antibody will carry the radioactive isotope or it will carry the toxins very close to the tumor cell where the antigen is, where the substance for this antibody is, and direct deliver the poison, if you want, right into the tumor cells while minimizing exposure to the surrounding tissues. So, there are a lot of ways that are new and also vaccine therapy where we get the patient's tumor and then we create a vaccine that is specific for this patient's tumor and then re-inject it back into the patient's system and depend on that system to do the same and we have one, at least now, approved for the prostate cancer which also was a breakthrough treatment for these patients.
Melanie: That's absolutely fascinating, Dr. Hajjar. What are some of the limitations, as you see it, for targeted cancer therapy?
Dr. Hajjar: So, the main thing, as we said, is to find these targets. So, there's a lot of research being done to identify these molecules that are specific for each disease type and once we get that, then we get the other researchers working on the other hand to develop treatment that targets that specific target, if you want. So, identifying these targets will be one of the limitations in a way. Then, the side effects profile of these medications is somewhat different than what we used to see with the chemotherapies. So, we don't see much the nausea, the vomiting, the hair loss much, but we see more specific type of side effects and, again, these are new medications so we are learning how to deal with that. Like the hormonal therapy medications can increase the risk of osteoporosis, can give the patient hot flashes. Some of these medications can cause skin rashes, we call it “acne-like skin rash”. I tell my patients I'm going to give you acne rash, but I cannot bring you to be a teenager again. Some of these medications can cause clotting, can affect the wound healing, and the latest class of these medications works more on the immune system, so we have seen that the immune system, after it gets off the suppression from that tumors, it's sometimes affecting some other organs, also, like the thyroid. We see people come in with thyroiditis or sometimes diverticulitis or colitis, which is something, again, we are not used to seeing with the traditional chemotherapy medications.
Melanie: In just the last few minutes, how is it determined whether a patient is a candidate for targeted therapy and then, tell us about your what you're doing that's really exciting at City of Hope.
Dr. Hajjar: Yes. So, these days when we get the patient diagnosed with a cancer, we don't just ask the pathologist to tell us if the patient has cancer or not. We ask for a lot of information. We call it “genetic testing”. Let's say a patient comes with a diagnosis with lung cancer, as an example, so we need to know what kind of cancer, and then we ask for some genetic testing, something called EGFR, something called ALK, and the reason why we ask for that, although it's not very commonly seen, it's probably seen between 5 and 10% of patients, the reason we do that is because if a patient with lung cancer comes with, let's say EGFR mutation or possibility, then they are treated with a pill that they take at home and minimum side effects, the mainly is the acne-like skin rash that I talked about before, and I have patients on this pill for more than a couple of years now, just taking the pill every day with no, with the tumor being under . . . It's suppressed, under control. So, there's a lot of information that are needed to identify the specifics for each patient and we at City of Hope have a lot of research being done in the pre-clinical area where a lot of researchers are working to identify more targets, if you want, on specific tumor types and then once we identify this, as we said mainly expressed on the tumor cells, and we have other researchers who are working on developing targets that go right after these molecules and eventually develop new treatment for this disease. It's a very exciting time to be practicing oncology in this era of targeted therapy.
Melanie: Thank you so much for being with us today, Dr. Hajjar. As I said before, it is absolutely fascinating what you're doing. Thank you so much for all of your hard work and thanks for being with us today. You're listening to City of Hope Radio and for more information, you can go to www.cityofhope.org. That's www.cityofhope.org. This is Melanie Cole. Thanks so much for listening.