New Cancer Treatments Combining Immunotherapy and Oncolytic Virus Vaccines

Every day, we see the impact of advances in genetics and immunology on cancer research. Recently, studies have increasingly shown that immune checkpoint inhibitors , a new generation of cancer immunotherapy, work in many cancer types. In January 2018, Science Translational Medicinepublished two studies suggesting that oncolytic virus vaccines and immunotherapies may be an effective treatment combination in breast and brain cancer.

What Is an Oncolytic Virus Vaccine?

One of the basic principles of cancer vaccines developed for therapeutic purposes is eliminating cancer cells using viruses . The viruses used to develop these vaccines are called oncolytic viruses . Oncolytic means tumor-destroying. For this purpose, these viruses are manipulated using genetic techniques to target only cancer cells.

• The first study was conducted at the University of Leeds and the Institute of Cancer Research in London, United Kingdom. The research investigated patients with aggressive brain tumors in 10 patients, examining oncolytic virus vaccines and immune checkpoint-inhibiting immunotherapies . According to the research results, the oncolytic virus called Reovirus crossed the blood-brain barrier, effectively reached the tumor area and triggered the immune system to attack the tumors. Only flu-like side effects were observed in patients. The promising results will guide the initiation of new, larger clinical trials.
• The second study was conducted at the University of Ottawa in Canada. The researchers investigated triple-negative breast cancerto determine whether oncolytic viruses would be effective. Studies in 3 different mouse models found that all were largely resistant to immune checkpoint inhibitors. However, when immune checkpoint inhibitors were combined with the oncolytic virus Maraba , complete recovery rates of up to 90 percent were observed in mice. When immune checkpoint inhibitors alone were used, the rate remained around 30 percent. In this study, the oncolytic virus was given before surgery and the immune checkpoint inhibitor afterward. The study is particularly strong because it used surgical and metastasis models.

- Related topic: An FDA-approved oncolytic virus vaccine: Lmlygic ( talimogene laherparepvec ) for treating the skin cancer malignant melanoma

What Advantages Do Oncolytic Viruses Offer in Cancer Treatment?

Oncolytic viruses can directly target and destroy cancer cells. The 10 hallmarks of cancer cellsinclude learning to remain invisible to the immune system. In addition to destroying cancer cells, oncolytic viruses have been found to activate the immune system. They enable white blood cells and T cells, the immune system’s fighter cells, to attack the tumor area.

What Does This Study Mean for Us?

• A new treatment combination has been discovered for triple-negative breast cancer and aggressive brain tumors, which can be challenging to treat.
• We are witnessing the dawn of a new era in cancer treatment. Treatments that provide an effective immune response against cancer will replace cancer drugs to which resistance develops quickly, such as chemotherapy.
• For the first time in triple-negative breast cancer, oncolytic viruses and checkpoint inhibitors were shown to be a potentially important treatment option. Clinical research results published in recent months have shown that these approaches may be highly effective in treating the skin cancer malignant melanoma. 
• The ability of oncolytic viruses to cross the blood-brain barrier effectively has enabled a new approach to emerge. For the first time worldwide, a clinical trial has begun examining oncolytic virus treatment alongside standard treatments after surgery. It is important to emphasize that modern medicine is developing effective, next-generation cancer treatments through the contributions of many scientific disciplines.