Could power to destroy cancer come from within?
Unleashing the body's immune system to fight cancer is generating excitement in the cancer world.
An expert from Memorial Sloan Kettering Cancer Center in New York will be in Louisville next month to talk about advancements in cancer immunotherapy, which is being used or explored for the treatment of various kinds of cancer.
Dr. Michael Postow, a medical oncologist, will be the featured speaker at the annual Gail Klein Garlove lecture, which takes place Nov. 5 at The Olmsted.
Postow conducts immunotherapy research related to melanoma but will speak more broadly on cancer immunotherapy and why it's generating buzz lately at the local talk.
"There have been many different strategies that have been attempted over the years to try to build the patient's own body's immune system against cancer, and some have succeeded to a degree and some have not succeeded at all," Postow said in a phone interview. "What we're seeing now is that one particular strategy is just really, really promising. I think that's what's fueling most of the recent interest."
Postow explains more in this Q&A:
Q: What is cancer immunotherapy?
A:Cancer immunotherapy is a general term for a class of drugs that enhance the immune system's ability to fight tumors.
Q: What's so revolutionary about it?
A:Cancer immunotherapy has been done for over 100 years. However, what's new now is that we are seeing successes better than ever before in a variety of tumor types. The other aspect about it that is new is ... we are seeing greater successes.
Q: How does cancer immunotherapy differ from how the general public thinks of cancer treatment?
A: Standard anti-cancer agents try to destroy the tumor directly, (using) either chemotherapy or radiation or surgery, essentially. Cancer immunotherapy works to target the patient and to boost the patient's own immune system so that the patient themselves can destroy the cancer.
The immune system normally has checks and balances like any system, meaning sometimes the system goes and destroys things and sometimes it needs to restrain itself. Recently, it's been more recognized that why the immune system in general is not more effective at destroying tumors is because it's too restrained. In general, the immune system in a cancer patient is restrained.
Q: It's weakened?
A: Yes, in general.
Q: So how is it strengthened?
A: So there are normally elements of the immune system that are part of that restraining system. It's like a leash that's holding the dog close to the post ... and just no matter how hard it wants to try to get away, the immune system cannot seek and destroy the cancer. So the new strategies that are being used are called "checkpoint blockade," (meaning) you block those restraining mechanisms.
Q: Is this typically done with a pill or an injection?
A: An injection. ... These injections are done to tear down this restraint system and unleash the immune system to fight cancer, meaning cut the cord, if you will, and let things go wild.
Q: What are the currently approved cancer immunotherapy drugs?
A: It depends on what kind of category you're looking at exactly. In this particular category of checkpoint-blocking antibodies you could say that there are two: ipilimumab — that's the CTLA-4 target or the CTLA-4 checkpoint — and ... the drug that targets PD-1 and is now approved by the FDA is called pembrolizumab (Keytruda). Both are approved for melanoma.
Q: What sort of successes have there been?
A: In patients with melanoma, there have been improved outcomes in terms of helping patients live longer with their cancers with these.
Q: How much longer?
A: For melanoma patients with ipilimumab (Yervoy), the agent that was approved by the FDA in 2011, about twice as many people are alive many years after their diagnosis of advanced melanoma compared to the past.
It doesn't mean that everyone, unfortunately, has that long-term survival ... but in the past only about 10 percent of people lived for years with their metastatic melanoma and now it's about 20 percent with ipilimumab.
Q: Could you explain T cells' role?
A: All of the checkpoint-blocking antibodies that we talked about (CTLA-4 and PD-1) target T cells. All of them work by increasing the ability of T cells to destroy tumors.
Q: Have you done research using this checkpoint-blockade method, and where do you see that going in the future.
A: (With ipilimumab) 20 percent of patients have that long-term benefit. We're trying to increase that percentage by giving that drug with other drugs, like combining it with radiation or combining it with other types of treatment like chemotherapy or even combining the two immune therapies together like (the) CTLA-4 and the PD-1 agent together.
Q: Does that seem to work, or are these things that need much, much further study?
A: CTLA-4 and PD-1 blockade has shown some very exciting early results, so far. … Many patients had their melanoma shrink.
Q: I understand that there can be some pretty tough side effects with cancer immunotherapy. Please talk about that.
A: Though it's generally well-tolerated in the majority of patients ... (it) can result in side effects related to the immune system being excessively activated. Symptoms like rash, diarrhea, inflammation of the liver or (inflammation of) hormone glands. That can all happen in these patients and that can require separate treatment in and of itself.
Q: I hear these treatments can be pretty expensive. Might a lot of people be priced out?
A: I'm really hopeful that the price will never prevent people from getting these types of treatments. However, I am recognizing that these are expensive treatments, but insurances generally pay for this.
Q: What types of cancers might someday be treated with immunotherapy?
A: We're already seeing some significant activity beyond melanoma in cases like kidney cancer and lung cancer. It's beyond that now, too. These drugs are being studied in so many others. Hematologic malignancies. Some studies coming soon in breast cancer. GI malignancies. Bladder cancer. I could go on and on, which is good.
Q: I read that you were involved in research combining nivolumab and ipilimumab. Can you discuss that?
A: In an effort to try to increase the number of people that benefit from checkpoint blockade, instead of just giving one or the other of the agents, we just gave them both together to patients, and we found that when you give them both together, many, many patients have great benefits from that.
Q: Is that combination proven to extend life?
A: Not yet, so we are testing whether or not putting them together extends life, compared to sequential therapy, meaning you give one (and) if it doesn't work, then you give the other.
Q: How important is it for people to be willing to participate in clinical trials?
A: I think it's crucially important. No. 1, we would do it just for the patient, but No. 2, we need to learn more about what types of tumors these treatments help, what types that they don't work (on), and what kind of patients are best served with these approaches, and what kind of patients should not, perhaps, be receiving these treatments … The only way to really answer those questions is to conduct the clinical trials."
Reporter Darla Carter can be reached at (502) 582-7068, on Twitter @PrimeDarla and Facebook at DarlaCarterCJ.
CANCER TALK
What: The Gail Klein Garlove Lectureship, featuring Dr. Michael Postow, who will discuss cancer immunotherapy.
When: 6:30 p.m., Nov. 5. (Registration and food at 5:30 p.m.)
Where:The Olmsted, 3701 Frankfort Ave.
How: The event is free, but you must preregister. Call (502) 629-1234, or go online.
Details:www.nortonhealthcare.com/garlove