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Researchers from the Abramson Cancer Center of the University of Pennsylvania tested the immunotherapy approach in two groups of patients with advanced head and neck squamous cell carcinoma (HNSCCa) and found 86 percent showed elevated T cell activity. It is also the first study to show that the vaccine can help immune cells infiltrate tumors.
The study describes one patient who received the vaccine on the trial, developed metastatic disease seven months later, then was treated with anti-PD-1 immunotherapy and has been in remission for more than two years.
HNSCCa is a cancer that develops in the mucous membranes of the mouth and throat. Smoking and using tobacco are known causes, but the number of cases related to HPV infection-a sexually transmitted infection that is so common, almost all sexually active adults will contract it at some point in their lifetimes—is among the fastest growing cancer types.
There are many types of HPV, the HPV 16 and 18 subtypes are most commonly associated with cancer. Many of patients with this type of HNSCCa have good outcomes from treatment that includes surgery or chemotherapy and radiation. For patients who don’t respond to treatment or who develop metastatic disease , anti-PD-1 therapy is approved, but only helps about 15 percent of patients.
The vaccine in this study- MEDI0457, is a DNA vaccine that can have a therapeutic benefit. Researchers gave four doses of MEDI0457 to 21 patients separated into two different groups. One group received a dose before surgery, followed by three doses after surgery. The second group received four doses following chemotherapy and radiation.
Eighteen out of the twenty one patients showed elevated T cell activity that lasted at least three months after the final vaccine dose, meaning the immune effect persisted for at least six months from the start of immunotherapy. Five tumors were biopsied both before and after one dose of the vaccine, and there was evidence of T cells reacting with antigens contained in the vaccine in all five “after” samples.
One of the patients developed a metastatic recurrence seven months after treatment, at which point he received the PD-1 inhibitor Nivolumab and went on to have a complete response. Two years later, he still shows no signs of disease. This shows that vaccine may, in some manner, prime the immune system, potentially boosting the effects of subsequent anti-PD-1 therapy. A therapeutic vaccine can boost antibodies and T cells, helping them infiltrate tumors and fight off human papillomavirus (HPV)-related head and neck cancer.