The Promise of Immunotherapy
A Q&A on the newest weapon against cancer
Recently, the American Association for Cancer Research (AACR) partnered with Time magazine, the Mayo Clinic Cancer Center and the Cancer Research Institute for a Twitter chat on “The Promise of Immunotherapy.” VCU Massey Cancer Center oncologists and researchers, John McCarty, M.D., and Andrew Poklepovic, M.D., provided expert commentary as the moderators posed a series of questions and discussion topics.
Below is a recap of the chat. Some of the responses have been slightly altered to provide context that could not fit into the original 140-character tweets. Be sure to follow @VCUMassey on Twitter to keep up with Massey’s latest groundbreaking research and clinical trials, learn about patient and caregiver resources and learn about volunteer and philanthropic opportunities while connecting with others who share similar interests and life experiences in fighting cancer.
Q: When we talk about cancer immunotherapy, are we talking about using the immune system like we do to fight bacteria and viruses?
McCarty: Yes, it’s the same concept. The many facets of immunity include traditional infectious disease defense, such as bacteria and viruses, as well as tumor surveillance.
Poklepovic: And some forms of immunotherapy mimic the way that the immune system works. The goal is to get the body to reject the tumor.
Q: How effective are immune cells at recognizing tumors as foreign?
Poklepovic: In advanced cancer, they are largely ineffective on their own, which is one of the ways that cancers survive. But with modification of the immune system, we can overcome this evasion in some cases. This concept is currently being explored in clinical trials.
McCarty: It varies. Tumors can occur either from: stealth (invisible or indistinguishable from normal cells); defense (blinding the immune system); concealment (shedding recognizable targets); or speed (growing faster than immune response).
Q: Are some tumors more vulnerable to immune attack than others?
McCarty: Often the less differentiated or "grown up" the tumor cell might be, the less vulnerable it might be to immune attack.
Poklepovic: Also, historically, melanoma and kidney cancer have been more vulnerable to immune attack than others, but that is changing due to advances in research. Lung, bladder, head and neck, cervical and other cancers are all demonstrating response to immune therapies as well.
Q: Would immunotherapies work alongside chemotherapy or instead of chemotherapy?
Poklepovic: Chemotherapy modifies the immune system in different ways. In the future, there will likely be a combination or sequence approach of chemotherapy and immunotherapy in some cancers.
McCarty: In addition, chemotherapy can slow cancer growth and allow for better immune response.
Q: How lasting are immune-based treatments against tumors?
McCarty: Many are not permanent solutions, but serve as a bridge to more definitive therapies. Bone marrow transplant is an example of permanent immunotherapy, because through that treatment the immune system is being replaced.
Poklepovic: Some appear to be curative. Interleukin 2 has the longest survival data and can lead to cures in melanoma and kidney cancer.
Q: What does typical cancer immunotherapy treatment look like? For example, is it regular injections, cell therapy procedures, and for how long do the treatments last?
Poklepovic: Immunotherapy treatments are widely variable. Some are infusions on intermittent schedules, while others are more intensive and can be similar to bone marrow transplant preparation regimens.
McCarty: Other examples include vaccinations, vaccination cell infusions, engineered cell transfusions, medications which "release" the immune system to work, and bone marrow transplantation. They are all different in method and duration of treatment.
Q: If the immune system is trained to target one type of cancer, can it also protect against others?
McCarty: Unless two cancers share the same unique immunotarget, there is usually not much overlap. Thus, there is not one immunotherapeutic "magic bullet" for cancer, but likely several of differing caliber and type.
Q: Should every cancer patient be asking their doctor about cancer immunotherapy trials?
McCarty: Patients should always ask about standards and trials, including immunotherapy, and should ask when these are most appropriately timed in their treatment course. Doing their own research, using info such as the Massey website, will also inform patients and families about available trials and treatments. Many of these trials are performed at major university medical centers or their affiliates. Patients who learn the most about their disease and treatment are best able to partner with their doctors in accomplishing their successful recovery back to health!
Q: What are your final thoughts on immunotherapy?
McCarty: We will advance in immunotherapy as we better understand the biology of not just each and every cancer and how it evolves under treatment, but also in what is the difference between a normal and malignant cell so that we maximize the treatment benefit and minimize the treatment side effects. Ultimately, effective immunotherapy will likely be individualized not just to the cancer cell, but to the cancer cell in the individual who has the cancer.
Poklepovic: It is a rapidly changing field with immense potential. New studies are being developed all over the world. We still don’t know who these therapies will work best for, but we are working to figure that out.