May 31, 2015 | by Denise Heady
Cancer researchers have long explored the potential of modified viruses, such as pox, parvo and coxsackie, in treating the disease. Now headlines are suggesting that this potential may have been realized.
Initial findings published in the Journal of Oncology on May 26 show that a genetically engineered herpes virus, known as T-VEC, could be especially beneficial for patients with melanoma, the deadliest form of skin cancer. Specifically, the virus is showing the ability to kill cancer cells and stop tumors from growing.
This power comes from the fact that viruses, unlike chemotherapy, have the ability to target the cancer cells directly, activating the immune system to fight cancer without collateral damage to healthy cells.
In the latest study, researchers from The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust found that out of 436 patients with aggressive Stage 3 or Stage 4 malignant melanoma included in the trial, 16 percent had a response rate that lasted for more than six months.
The findings have been widely heralded. Said the Washington Post: "In a few months time, those suffering from skin cancer may find an unlikely hero in their treatment regimen: herpes. A modified version of the Herpes Simplex 1 virus (known for causing cold sores and some cases of genital herpes) called T-Vec has successfully been used to treat melanoma in a phase III clinical trial. That means it's just waiting for a final okay from the FDA before the Amgen product can hit the market."
Amid the enthusiasm, much of it warranted, Jae Jung, M.D., Ph.D., assistant professor in dermatology at City of Hope, urges perspective.
The research focused on a unique method of treating melanoma, she said, and it has many limitations. Further, the treatment is not suitable for all patients diagnosed with melanoma.
“It is a proof of concept that oncolytic viruses can be used to treat cancer, but the response rate was low (16 percent) and I am not convinced that all of the safety concerns have been addressed,” Jung said.
Other therapies to treat melanoma, such as neoadjuvant therapies (that is, therapy that occurs before the primary treatment), have shown to have a much higher response rate — up to 60 percent, she added.
“The patients that will benefit [from T-VEC] need to have injectable lesions. It cannot be used in patients who have recurrent or chronic HSV infections [herpes simplex virus], or those with mucosal melanoma,” Jung said.
A new clinical trial that uses T-VEC in combination with a checkpoint inhibitor will be starting soon, which Jung believes will "have more favorable results.”
City of Hope is currently participating in two multicenter clinical trials using oncolytic viruses to treat melanoma, with one of them involving T-VEC. Other City of Hope research is specifically looking at the pox virus as a way to treat melanoma.
Learn more about skin cancer treatment and research at City of Hope.
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