Cancer is one of the most dreaded diseases of our time. It is estimated that over 9 million people worldwide will die from various types of cancer this year alone. However, there is some good news. Over the years, research in cancer treatment has advanced by leaps and bounds, offering new hope for saving countless lives. In particular, the development of cancer immunotherapy and targeted therapy has shown tremendous potential in fighting cancer, and the combination of the two may even be more effective.
What is Cancer Immunotherapy?
Cancer immunotherapy is a type of cancer treatment that uses the body’s immune system to fight cancer. It is based on the understanding that cancer cells can use different mechanisms to evade the immune system. Immunotherapy works by boosting or helping the immune system to recognize and attack cancer cells.
There are different types of immunotherapy. One approach is to use antibodies to block checkpoint molecules that suppress immune responses. Immune checkpoint inhibitors are currently used to treat different types of cancer, and they work by blocking the checkpoint molecules (such as PD-1 and CTLA-4) that prevent T cells from attacking cancer cells. Another approach is to use adoptive cell therapy (ACT) to engineer T cells to target cancer cells. ACT involves removing T cells from the patient, modifying them in the laboratory to recognize cancer cells, and then infusing them back into the patient.
Immunotherapy has shown remarkable success in some cancers, such as melanoma and lung cancer. However, not all patients respond to immunotherapy, and some cancers are still resistant to the treatment. Additionally, immunotherapy can cause side effects such as inflammation of organs and tissues.
What is Targeted Therapy?
Targeted therapy is another form of cancer treatment that aims at specific molecules that are essential for the growth and survival of cancer cells. Unlike chemotherapy, which indiscriminately kills rapidly dividing cells, targeted therapy only affects cancer cells and spares healthy cells.
Targeted therapy works by using small molecules or antibodies to block the activity of specific proteins that are necessary for cancer cell survival. For example, some targeted therapies target the HER2 protein that promotes the growth of certain breast cancers. Others target the BRAF protein that drives the growth of melanoma.
Targeted therapy has shown significant success in some cancers such as breast cancer and leukemia. However, like immunotherapy, not all patients respond to targeted therapy, and some cancers develop resistance to the treatment.
Combining Immunotherapy and Targeted Therapy
The idea of combining immunotherapy and targeted therapy is to enhance the effectiveness of both treatments and overcome some of their limitations. The rationale is that by combining the two treatments, we can enhance the immune response against cancer cells, target cancer cells more specifically, and overcome resistance.
There are several ways in which immunotherapy and targeted therapy can be combined. Here are some examples:
1. Immunotherapy and Targeted Therapy Sequentially
One approach is to use one treatment first, followed by the other. For example, patients could receive targeted therapy to reduce the tumor burden and then receive immunotherapy to boost the immune response against cancer cells. This approach may be beneficial because targeted therapy can decrease the number of cancer cells that the immune system needs to attack, and immunotherapy can prevent the surviving cancer cells from evading the immune system.
2. Immunotherapy and Targeted Therapy Simultaneously
Another approach is to use both treatments at the same time. For example, patients could receive a combination of immune checkpoint inhibitors and targeted therapy to enhance the immune response and target specific molecules on cancer cells. This approach may be beneficial because it can enhance the immune response and overcome the resistance to targeted therapy.
3. Immunotherapy and Targeted Therapy Designed to Enhance Each Other
Finally, another approach is to design immunotherapy and targeted therapy to enhance each other’s effectiveness. For example, targeted therapy could be used to upregulate the expression of molecules that attract immune cells to tumors, while immunotherapy could be used to activate those immune cells and enhance their killing of cancer cells.
Recent Advances in Combining Immunotherapy and Targeted Therapy
Over the past years, there have been several breakthroughs in combining immunotherapy and targeted therapy. Here are a few examples:
1. Combining Immune Checkpoint Inhibitors and Targeted Therapy in Lung Cancer
In a clinical trial, patients with non-small cell lung cancer who received a combination of immune checkpoint inhibitors and targeted therapy had better outcomes than those who received only one of the treatments. The study showed that the combination treatment increased progression-free survival and objective response rates compared to targeted therapy alone.
2. Applying CAR T Cells and Tyrosine Kinase Inhibitors in Leukemia
In another study, researchers demonstrated that combining CAR T cells (a type of ACT) and tyrosine kinase inhibitors (TKIs, a type of targeted therapy) can overcome resistance to TKIs in chronic myeloid leukemia. The study showed that the combination treatment reduced the number of leukemic cells and extended the survival of mice with leukemia.
3. Harnessing Antibody-Drug Conjugates (ADCs) and Immunotherapy in Breast Cancer
Researchers have also explored combining ADCs (an antibody conjugated with a chemotherapy drug) and immunotherapy in breast cancer. In a preclinical study, a combination of ADCs and immune checkpoint inhibitors showed superior antitumor activity compared to each treatment alone. The study showed that the combination treatment increased the infiltration of T cells into tumors, enhanced the immune response, and improved the survival of mice with breast cancer.
The combination of immunotherapy and targeted therapy has shown remarkable promise in cancer treatment. It offers a way to enhance the effectiveness of both treatments and overcome some of their limitations. However, more research is needed to optimize the combination regimens, identify biomarkers that predict response, and develop strategies to prevent or manage side effects. With continued research, we may be able to develop more effective treatments for cancer and offer new hope to patients and their families.