Patients with cancer of the arms and legs often undergo chemotherapy to avoid amputation. Now, researchers from The Institute of Cancer Research in London, UK, say that viruses designed to target and then kill cancer cells could increase the effectiveness of these chemotherapy treatments.
As an alternative to amputation, the type of chemotherapy such cancer patients undergo is called isolated limb perfusion chemotherapy, which is given directly to blood vessels that supply the affected arm or leg.
The technique allows high-dose chemotherapy drugs to target the affected limb without blasting the body with toxic chemicals. To do this, a heart and lung bypass machine is connected to the arm or leg to separate its blood supply from the rest of the body
But the researchers, who publish their findings in the International Journal of Cancer, tested the effectiveness of using a genetically engineered version of the virus used for smallpox vaccination alongside this chemotherapy.
The virus, known as GLV-1h68, was modified to infect and kill cancer cells, the team explains, adding that the virus alongside isolated limb perfusion chemotherapy was more effective in rats than either of the treatments on their own.
Approval for a clinical trial to test the combination treatment in cancer patients has now been approved and will take place at some point soon.
For their study, the researchers tested the combined treatments on rat sarcoma cells in tissue culture and discovered that combining the modified virus and melphalan – a chemotherapy drug – killed more cells than either treatment alone.
After testing the combination in rats with advanced sarcoma, the researchers found it slowed tumor growth and prolonged survival by 50%, compared with standard therapy.
Additionally, rats that were given the combined therapy survived 24 days, compared with 16 days for rats who received standard chemotherapy treatment and 15 days for rats who received the modified virus only. Rats who received no treatment survived a median of 11 days.
The modified virus did not appear to have any negative effects on the rats, which the researchers say ensures the virus has a good safety profile.
They explain that isolated limb perfusion allows drugs to be administered in much higher doses than the whole body could tolerate. Though it is used as a final step in preventing amputation in patients with advanced skin cancer or sarcomas, the technique is not always successful.
“Our research shows that a virus that targets and kills cancer cells could significantly improve an existing treatment for advanced skin cancer and sarcoma in the arms and legs,” says Prof. Kevin Harrington, of The Institute of Cancer Research and Honorary Consultant at The Royal Marsden NHS Foundation Trust in the UK.
Because the combination of the modified virus and isolated limb chemotherapy doubled survival times in the lab, he says it “gives us hope that it might be effective in the clinic.”
Further explaining their work, Prof. Harrington says:
“The beauty of this technique is that the arm or leg is isolated, making it harder for the virus to be destroyed by the immune system – something that has been a stumbling block for virus treatments in the past. The study also showed that the virus didn’t cause any adverse effects, adding to evidence that it should be safe to use as a cancer treatment.”
Cancer Research UK say that the earlier a cancer is identified, the easier it is to treat, which is why identifying symptoms at their early stages is so important.
According to the organization, skin cancers can appear as:
- A sore or spot that does not heal within 4 weeks
- A sore or spot that itches, hurts, scabs, crusts or bleeds for more than 4 weeks
- Skin areas that have broken down or become an ulcer with no reason for change that does not heal within 4 weeks.
Medical News Today recently wrote a feature on UV exposure and why we ignore the health risks.