Exciting results from a new clinical study showed that a personalized vaccine combined with an immunotherapy drug had a promising response rate in patients with advanced incurable head and neck cancer.
Dr. Julie Bauman, chief of Hematology and Oncology at the University of Arizona College of Medicine — Tucson, led a phase one clinical trial with the pharmaceutical company, Moderna, to test the combined use of personalized vaccines created from tumor DNA with the immunotherapy drug pembrolizumab.
Of the 10 patients involved in the study, five of the them responded to the treatment, meaning 30% of the cancer mass had decreased. Furthermore, two of the patients completely responded, meaning that cancer could not be detected.
Molly Cassidy is one of those two patients. What was initially determined to be a stress-related ear-ache turned out to be an aggressive case of squamous cell carcinoma, a form of head and neck cancer.
Head and neck cancers impact the linings of the mouth and throat. Risk factors for this disease include alcohol consumption, smoking and other environmental carcinogens that we are all exposed to. It can also be caused by human papillomavirus (HPV).
Cassidy did not fit this profile at all.
“I’m HPV-negative. I didn't drink. I didn't smoke. I’m a woman. I was the first person in my family to have cancer. I was 35 when I got my diagnosis,” Cassidy said. “I was also in really good health … To hear that I had cancer was really surprising."
With an initial prognosis that the cancer was curable, Cassidy underwent a standard but invasive surgery followed by a grueling series of radiation and chemotherapy sessions over the next few months.
Just a week after completing Cassidy's initial treatment plan, the cancer returned aggressively. She had several tumors in her neck and they were spreading to her lungs. Her prognosis became bleaker.
“Having such a quick recurrence was not a good sign … they put me on a palliative plan and I was told I need to get my affairs in order,” Cassidy said. “I wasn't expected to live for more than a year.”
Cassidy now had advanced incurable head and neck cancer which occurs when an initial cancer treatment fails and the cancer returns. This combined with the fact that she was HPV negative made her eligible for Bauman’s clinical study.
One of the recent frontiers of cancer research has been immunotherapy — harnessing our immune systems to fight cancer. Our immune system is able to detect and attack foreign invaders in our bodies, including cancer cells. However, these cells develop ways to hide from the immune system.
Immunotherapy can involve using medication to activate and train the immune system to recognize and eliminate these cancer cells. When this treatment is effective, the response can be long-lived.
“I can give you chemo and drive you to a complete response, but as soon as chemo is not there, the cells that are left become resistant and grow back,” Bauman said. "Immunotherapy leaves behind an army of T-cells that if the cancer rears its ugly head again, will presumably kill it."
According to Bauman, the current U.S. Food and Drug Administration-approved therapies are non-specific. These therapies generally activate the T-cells of the immune system which recognize foreign invaders. This method means that T-cells that recognize cancer cells would be activated. This method of therapy however has a low effectiveness rate.
“In head and neck cancer, this class of therapy is successful 10-15%of the time … We want that to be more often," Bauman added.
Furthermore, there can be auto-immune side effects because T-cells that recognize our own healthy tissues may start attacking those very tissues.
This is where new and fascinating technology comes into the picture: personalized vaccines. This approach is a specific approach, where T-cells are activated based on the mutations of the patient’s cancer.
After taking a sample of cancer cells from the patient, those cells’ DNA is sequenced. Using a computational algorithm, the cancer DNA is compared to the patient's healthy DNA to find the specific mutations present in that patient’s cancer. From all those mutations, Moderna is able to synthesize a messenger RNA vaccine, which can be used to train the appropriate T-cells to recognize abnormal proteins from these cancer cells.
A helpful video about the process can be found at the UA Health Sciences website. The clinical trial consisted of using both this personalized vaccine approach with the FDA approved T-cell activator pembrolizumab.
“The trial is the combination of using those mutations almost like a trojan horse … educating the immune system to see those mutated proteins at the same time as we give the unbridled T-cell activator,” Bauman said. “We’re awakening T-cells, but we’re saying this is the particular class of T-cells that we are calling.”
For the trial, each patient was given two doses of pembrolizumab over six weeks. During this time, the vaccine was developed by Moderna. After the vaccines were created, the patients received one dose of their vaccine every three weeks for nine weeks along with the pembrolizumab, and the cancer was monitored using a CAT scan.
And the results show that the vaccines are safe. This seems really promising and exciting to pursue.
“Although it is only 10 patients, and we have to not only overpromise … it is a really strong signal to expand the study and to see if we continue to see what we saw with these 10 patients,” Bauman said.
“When I was going into treatment, I was really ill and the treatments themselves were pretty hard on me. Cancer treatment is no walk in the park," Cassidy said. "But once I got through the treatment’s initial side effects, I started to notice an increase in my energy and I wasn’t in as much pain.”
Having completely responded to her treatment, Cassidy is now able to live a normal life. She has spoken with various dentists and used her platform to help educate people about the prevalence and signs of oral cancers and the importance of understanding what the inside of our mouths are supposed to look like.
“It also brought forth what are the most important things for me — my son and husband and the importance of slowing down and enjoying my time with my family,” Cassidy said.
There are many new things that Bauman is looking into researching further. As they expand the trial to 40 participants for the next phase of trials, she is exploring how to optimize the vaccine.
“If we can selectively educate the immune system … we can have a therapy that is active, could drive a permanent response and not be toxic or harsh on the rest of the body,” Bauman said.
Bauman also mentioned that this optimization might mean potentially experimenting with a different drug than pembrolizumab for treatment, although this is a great start. They have also taken samples of the T-cells from the patients to see which types of mutations the T-cells respond best to.
“People who have advanced in cancer … have extraordinary suffering because cancer is uncontrolled in this area where things are critical to our humanity, like talking and breathing and eating and kissing and smiling. To be able to reverse that suffering and offer that hope is uniquely gratifying,” Bauman said.
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