Oncolytic Virus & Bacteria Therapy: A New Era of Cancer Treatment at Dawn

Cancer is the leading cause of death and illness in humans. However, the advancement of life science and technology, as well as the advancement of medical knowledge, has resulted in significant breakthroughs in cancer therapy. Defeating cancer no longer appears to be impossible.

Immunotherapy, in addition to surgery, radiation, and chemotherapy, has emerged as the fourth pillar of cancer treatment. It comprises novel therapies such as monoclonal antibodies, bispecific-antibodies, PD-1/L1, cell therapies, vaccinations, and oncolytic viruses. This article will introduce more about oncolytic viruses and a new type of oncolytic family, oncolytic bacteria.

Oncolytic virus is a type of natural or genetically engineered virus that may reproduce exclusively in tumor tissue, then infect and destroy tumor cells or induce tumor cell lysis. Oncolytic viral immunotherapies are gaining more and more attention among biotech researchers and the pharmaceutical industry.

The first oncolytic viral treatment, T-VEC (herpes simplex virus), was licensed by the FDA in 2015. Then recently in June 2021, Daiichi Sankyo announced that Delytact (TeserpatureV /G47), an oncolytic viral product, has been authorized in Japan for the treatment of malignant glioma. The potential of this therapy seems to be unlimited.

As more and more large researchers and companies focusing on oncolytic viruses, oncolytic bacteria entered the tumor immunotherapy market, opening a new door for the tumor therapy development.

Actuality, treating tumors with bacteria has been practiced for centuries. A self-healing cancer patient gave American surgeon William B. Corley the idea of employing bacteria to treat cancer in the late 1800s, who pioneered the approach of treating cancer with bacteria and is known as the "Father of Tumor Immunotherapy."

Despite the fact that the concept of using bacteria to treat cancer was initially proposed over a century ago and that bacterial therapy research has never stopped, only a few drugs have made it to clinical trials and have been commercialized. The therapeutic BCG vaccination for bladder cancer is now the only medicine of this type on the market. The discovery of the oncolytic bacterium YB1 signals a new era in tumor immunotherapy.

In 2011, a research team accomplish the highly efficient programming technology of Salmonella Lambda-RED for the first time and established the basis of the synthetic biology transformation of Salmonella. After more than a decade of development, the team created YB1, a tumor-lytic Salmonella Typhimurium.

According to studies, the oncolytic bacterium YB1 can efficiently deliver and carry drugs such as antibodies, mRNA, protein drugs, and oncolytic viruses to precisely target the tumor center, replicate and amplify in massive amounts inside the tumor, and thus increase the concentration of YB1 in solid tumors.

YB1 has unique strengths as the first oncolytic bacterial carrier. To begin with, YB1 can detect tumor locations based on oxygen concentration differences and accomplish targeted colonization of tumor sites. YB1 can also reach the tumor by intravenous injection. Secondly, oncolytic bacteria are independent of host cells, capable of self-proliferation, and sensitive to hypoxic environments. What's more, there is no possibility that YB1 will change the human gene pool by mistake.

Despite the fact that oncolytic bacteria development is still in its early stages, the competitive advantages of oncolytic bacteria immunotherapy offered cannot be overlooked. Preclinical and clinical studies with such smart bacteria will hopefully establish this approach as another powerful weapon in the arsenal in our fight against cancer in the near future.

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