A Common Virus Used in the Fight to Treat Lung Cancer

A common virus that can cause coughing and mild diarrhea appears to have a major redemptive quality: the ability to kill cancer. Harnessing that power, researchers are conducting a clinical trial to see if the virus can target and destroy specific tumor types.

By the age of five, most people have been exposed to the virus called reovirus. For some, it can trigger brief episodes of coughing or diarrhea while many other do not develop any symptoms. The body merely overpowers the virus. But what scientists have discovered is that the virus grows profusely inside tumor cells with a specific malfunction that leads to tumor growth. That finding led researchers to ask whether it is possible to use the virus as a treatment.

Researchers are looking for an answer by conducting a phase II clinical trial for individuals with advanced or recurrent non-small-cell lung cancer with a specific tumor profile. "With reovirus, we're able to accentuate the positive and attenuate the negative," said the study's lead investigator at Lombardi, Deepa Subramaniam, M.D., interim-chief of the Thoracic Medical Oncology Program at Georgetown Lombardi Comprehensive Cancer Center, part of Georgetown University Medical Center (Washington, DC, USA). In other words, researchers have genetically modified the virus so that it will not replicate in a healthy cell, which is what makes an individual ill. "What's left is a virus in search of a host, and reovirus loves the environment inside a specific kind of cancer cell," explained Dr. Subramaniam.

That specific kind of cancer cell is one with malfunctioning machinery called KRAS (V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) or epidermal growth factor receptor (EGFR) mutation. "These mutations leave the cancer vulnerable to a viral take-over. Once it's in, the reovirus exploits the cell's machinery to drive its own replication. As a result, the cell is filled with virus particles causing it to literally explode."

Volunteers in the clinical trial will receive reovirus (Reolysin) in addition to paclitaxel and carboplatin. The physicians will watch to see if the tumors shrink while also seeing if this combination of drugs causes serious side effects. "This is a subset of cancer where we haven't had many successes in terms of finding drugs that extend life after diagnosis," concluded Dr. Subramaniam. "This trial represents an attempt to seek and destroy cancer by choosing a treatment based on specific tumor characteristics. Preliminary data from the study should come quickly."

Researchers are also studying the effect of reovirus in other cancer types. The study is sponsored by Oncolytics Biotech, Inc. (Calgary, Canada), maker of Reolysin.

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