Some of the most common cancers in the US could soon be treated using a common virus, a new breakthrough study suggests.
Scientists in China have developed a modified virus found in birds that causes cancer cells to produce sugars the immune system can easily recognize and attack.
The experimental therapy was tested on 23 patients suffering from eight different cancers — including of the breast, lung and skin — whose disease had not responded to standard treatments.
All but one of the patients saw their tumors shrink or stop growing after receiving infusions once a week for eight to 12 weeks.
Scientists also tested the therapy on five monkeys with liver cancer, and found all lived longer than those that got a placebo.
Experts not involved with the research said it showed promise, especially considering the therapy was used to target such a wide range of cancers.
But they added it would still need to clear rigorous trials before the treatment could be proven safe and made available for Americans — a process that would take years.
The treatment, called NDV-GT, works by tricking the body into unleashing an immune response similar to how it would during an organ transplant rejection.
Liver cancer shown before treatment (left) and one-and-a-half months after the patient received the experimental therapy that uses a virus
Immunologist and surgeon Yongxiang Zhao at Guangxi Medical University in Nanning, got the idea from studying patients who’d received pig organ transplants, which is an emerging and experimental field of medicine.
Human antibodies immediately attach to sugars that stud the surfaces of pig cells, leading to an immense and rapid rejection of the transplanted tissue.
Dr Zhao wondered if this process could be harnessed and used to treat cancer.
His experimental therapy uses a genetically modified Newcastle disease virus, which can be fatal to birds but causes only mild or no disease in humans. It differs from the virus that causes bird flu.
The virus isn’t potent enough to elicit a strong enough immune response, so the team engineered it to carry the genetic instructions for an enzyme called α 1,3-galactotransferase.
This enzyme coats the cancer cells with a sugar found in pig organ tissue.
Antibodies from the immune system bind to this sugar, triggering white blood cells to attack and destroy cancer cells, leaving healthy cells untouched.
The treatment was first tested on ten monkeys suffering from liver cancer.
All five of the monkeys who received a placebo died within four months. The ones who received the therapy survived for more than six months.
In the human trial, scientists recruited patients with eight types of cancer: liver, esophagus, rectum, ovaries, lungs, breast, skin and cervix.
The results were positive.
After two years, two patients saw their tumors shrink, but they had not vanished entirely. Tumor growth halted in five participants.
For some others, tumor growth initially ceased but later resumed. Only two participants experienced no positive effects from the treatment, while two others withdrew from the trial before completing the first year.
An ovarian cancer patient’s scan before treatment (left) and three months after treatment with the experimental therapy
The patients all had stage four cancers or advanced stage three cancers, which patients often survive with for only a few months.
Dr Brian Lichty, an immuno-oncologist at McMaster University in Canada, told Nature that it was still ‘early days’ for the treatment but that the initial results were good.
He also said that it was ‘a little unusual’ for the treatment to show promise across such a wide range of cancers.
‘I hope it stands up to further clinical testing,’ he added.
Researchers said the treatment would now move into phase two and three clinical trials. The treatment was revealed in the journal Cell.
About 2million Americans are diagnosed with cancer every year, and 608,000 die from the disease.
Among the most common are breast cancer, lung cancer and melanoma, which together make up about 608,000 cases per year — or just over 25 percent of cases.
The new therapy is known as oncolytic virus therapy, that uses a virus to destroy cancer cells but leaves healthy cells untouched.
The FDA has approved one of these therapies to date, called T-VEC and which uses a modified herpes virus to treat melanoma.
It was approved in 2015 but only for advanced melanoma that cannot be removed surgically and does not tend to be more effective than other treatments.
Late last year, a scientist revealed she had also reversed her stage three breast cancer using the same method — by combining a measles virus and flu-like pathogen and altering them to attack tumors.
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