A clinical trial at the University of Cincinnati has found that adding a newly developed immunotherapy drug to standard treatment methods could improve survival rates for head and neck cancer patients. The trial was led by Trisha Wise-Draper, MD, and published in the American Association for Cancer Research’s journal Clinical Cancer Research.
The drug, pembrolizumab, is sold under the brand name Keytruda. It is already in use as a treatment for several other types of cancer. Let’s look closer at this study and what it could mean for the future of cancer treatment.
How Does Pembrolizumab Work?
Pembrolizumab is an antibody cancer immunotherapy drug that is used to treat a wide range of cancer types, including head and neck cancers. The antibody targets two receptors that disable the immune system after the system has protected the body from a foreign substance. These receptors essentially tell the body to relax its immune response after the virus or infection has been eliminated.
While the receptors serve an important function to the immune system, tumor cells have found a way to manipulate these receptors, causing them to overreact. This prevents the immune cells from identifying the tumor cells as dangerous foreign objects that the immune system should attack. Pembrolizumab blocks tumor cells from interacting with the receptors in this way, allowing the immune cells to continue functioning. When this happens, the immune cells can attack cancer cells as they were designed to do.
Pembrolizumab was developed to treat multiple cancers and has already shown promise as a treatment for head and neck cancers that have metastasized or have returned after the first round of treatment. According to Dr. Wise-Draper, early studies have shown that approximately 20 percent of patients treated with the drug have responded well to the treatment.
The Hypothesis of the Clinical Trial
The University of Cincinnati researchers sought to determine if pembrolizumab could be used as an initial treatment method for the prevention of cancer recurrence. Statistics show that head and neck cancer patients who receive treatments like surgery, radiation, and chemotherapy usually see their cancers return between 30 percent and 50 percent of the time.
Recurring cancers are much more difficult to treat. The team of researchers decided to test whether they could reduce the risk of cancer returning by adding pembrolizumab to the standard treatment regimen. Additionally, the trial was designed to determine why not all patients respond to pembrolizumab. Researchers gathered tissue and blood samples before and after administering the immunotherapy drug so that they could analyze what factors could influence responses to the drug.
Methodology and Findings
In the clinical trial, patients were given one dose of pembrolizumab before surgery. Researchers evaluated each patient for their risk status and grouped the participants into intermediate or high-risk groups following surgery. Patients were considered high risk if part of the tumor remained after surgery or if the tumor was not contained within a lymph node.
All of the participants continued to be treated with the appropriate standard of care for their risk status. Those in the intermediate group received radiation, while high-risk patients received a combination treatment of radiation and chemotherapy. Each patient received six additional doses of the drug after surgery.
The researchers found that for about half of the patients, pembrolizumab caused their tumors to start dying before surgery. This was a much better rate than the results for metastatic or recurrent head and neck cancer patients who received the drug. Of the half, all were cancer-free one year after surgery. Dr. Wise-Draper notes that this was a much more encouraging result than the researchers expected.
In the intermediate group, less than 70 percent of participants who were treated with radiation alone following surgery were found to be cancer-free a year after treatment. However, over 95 percent of patients in the trial were cancer-free one year after treatment when they received both radiation and pembrolizumab.
Building Off the Findings of This Study
For patients whose tumors began to die after taking pembrolizumab before surgery, this effect seems to be a strong indicator of patients who would respond well to the combination treatment. Researchers can use these findings to design future trials that will allow them to gain a better understanding of what types of patients will respond to this type of treatment. Researchers can then adjust the treatments for patients who do not respond well to the combination of surgery, pembrolizumab, chemotherapy, and radiation.
Dr. Wise-Draper says that the University of Cincinnati researchers plan to conduct additional research into biomarkers and how new and better-targeted therapy methods can be developed based on these biomarkers.
The University of Cincinnati is not the only institution conducting research into this promising new treatment method. Harvard University has conducted a similar study that showed similar results. Additionally, pharmaceutical company Merck is currently conducting a randomized trial that compares results for patients who receive pembrolizumab in combination with their standard of care treatments against patients who only receive the standard of care.