Cancer Immunotherapy treatments are having a lot of media coverage at the moment. Some doctors are calling it game-changing approach that works by harnessing a person’s immune system to better target and attack diseases with abnormal cell growth. Cancer Immunotherapy comes in many forms including antibodies, vaccines, cell therapies, or prescription based medications that get delivered through injections, topical ointments, catheters or orally via capsules.
Most recently, former US President Jimmy Carter received a new form of immunotherapy for his melanoma which seemed to work quite well. President Carter called it “the key to my success.” President Carter had immunotherapy along with traditional cancer treatment such as radiation and surgery.
With many of these cutting-edge therapies still in the clinical trial and experimental phase, unanswered questions remain. Some of the more significant issues in cancer immunotherapy research include:
1. Are the results for blood cancer patients getting T-cell therapy durable and repeatable?
Promising results in cancer research are coming from ongoing clinical trials of patients’ that use engineered immune cells programmed with cancer-targeting receptors to kill cancer cells. In a recent clinical trial by researchers at Fred Hutch Cancer center, patients’ T cells were programmed with synthetic CAR receptors to target and kill blood cancer cells with the markers CD19. The results are still preliminarily, but researchers reported a high rate of complete remission in patients with CD19-positive blood cancer even in later stages. Patients with late stage blood cancers have very few treatment options available today, but it’s imperative to try to remember that CAR T-cell clinical trials are still in their infancy and researchers still need to figure out ways they can improve CAR T-cell therapies for more consistent long-term results.
2. Do T-cell immunotherapies work against solid tumors?
With impressive results seen in T-cell therapy, clinical trials for blood cancer patients’ researchers are only beginning to scratch the surface as most cancers that kill in the U.S. are known as solid tumors. According to the American Cancer Society, the leading types of cancers in America are solid tumors and include lung cancer, breast cancer, colorectal cancer, pancreatic cancer and prostate cancers. Solid tumors are particularly challenging for immunotherapies because the tumors cannot be accessed via the bloodstream and are inaccessible to engineered immune cells. In lung cancer tumors, for example, there is often interference from other types of immune cells in the body and T-cells often get blocked by the immunosuppressive signals sent by lung cancer cells. One method to try to overcome this biological challenge is to trick T cells to process the ‘shut down’ biosignals as ‘stay awake’ biosignals thus circumventing the body’s natural response. Researchers are hoping to use engineered surface markets in Immunotherapy for lung cancer to boost survival rates by more than 50 percent which is a vast improvement considering lung cancer typically leads to death less than four years after the initial diagnosis.
New advancements in gene therapy are also getting tested by researchers who hope to sequence the tumor genomes. This technology didn’t exist ten years ago and with genomic sequencing T-cell targets can be used for many other solid tumor types of cancer.
3. Can immunotherapy be used to prevent cancer?
The eventual goal of researchers is to try to use the human immune system to prevent the development of cancer itself. At this stage, it’s not possible; however, there are several Biotechnology companies around the world developing cancer vaccines before they form. Although still early, breast cancer vaccines are in early phase trials for women with high risk of breast cancer. The experimental breast cancer vaccine is the world’s first preventive cancer vaccine that can be trick our immune system against several cancer markers simultaneously. This vaccine is expected to move into clinical use within the next five years and used for women with high risk of developing breast cancer.
4. Which patients respond best to Immunotherapy? Researchers are sifting through millions of biomarkers which can include anything from proteins in tissue and blood to genetic mutations used by checkpoint blockers.
A recent study, in the New England Journal of Medicine, has identified “neo-antigens” which are specific molecules in tumors. Neo-antigens seem to appear when gene mutations cause changes to protein making the altered protein seem “foreign” to the body’s immune system which triggers an immune response. Scientists hope that by better understanding the tumor mutations in DNA they will be better able to identify a more significant number of DNA mutations and map the neo-antigens that occur amongst the participants of checkpoint blockade therapy. These neo-antigens appear to be completely missing in patients who had very little of or no benefit from immunotherapy.
5. How much will cancer immunotherapies cost?
The economic impact of cancer in America is over $90 billion annually. The high cost of developing immunotherapy medications is incredibly high, but like other medical breakthroughs, the associated costs of development are expected to decline as the technology becomes more refined. The current price of T-cell therapies has already plummeted thanks to improvements in gene sequencing which cost over $100 million fifteen years ago but is less than $500 today. Most researchers anticipate that the cost of cellular immunotherapies will drop significantly over the next decade.
For most cutting-edge treatments, it takes many years for clinical research to gather the definitive data on long-term results and associated side effects which are necessary to help define the value equation.
As cancer researchers gain a better understanding of the human body’s immune system, future advances in cancer vaccines and cancer therapies will follow. It may be early, but most oncologists are confident that we are nearing the end of the beginning for cancer immunotherapies.