Could this be the end of the misery of chemo?

As British scientists use viruses to kill cancer cells . . .

We can turn bugs into a mutant army It’s a powerful new defence against cancer

ENeMy agents that have been ‘turned’, betrayal from the inside and multiple disguises — it sounds like the stuff of a John le Carre spy novel. But this game of deception is far more deadly. It is the life-or-death fight against cancer.

In a British breakthrough, scientists this week announced they have turned one of our smartest and oldest enemies — the herpes virus — into a double agent that exposes skin cancer cells as the enemy within for our defences to attack. the virus then works as a trojan horse to destroy the malignant melanoma tumours from inside.

this development is the latest advance in an exciting field of cancer medicine called immunotherapy — a new weapon in the scientific fight against the dreaded disease.

the first drug technique that modern science created, chemotherapy, was developed in the Forties. Using it to treat cancer is like carpet-bombing an enemy.

Chemotherapy targets all the fast-replicating cells in the body, with the aim of knocking out cancer cells, which multiply rapidly. But it also kills prolific cells in the stomach and hair roots — hence the terrible sideeffects, including sickness and hair loss, we associate with it.

After treatment, patients may find they have a lower resistance to infection for a time.

Other side- effects may not appear until months or years after chemo has finished, i ncluding early menopause, infertility, changes to feeling in the hands and feet (peripheral neuropathy) and, with some drugs, heart and lung problems.

some types of chemotherapy contribute to loss of bone mass, risking osteoporosis; men can suffer from sexual dysfunction; and there is sometimes a risk of a second cancer.

Make no mistake, chemotherapy has saved countless lives. But it is a treatment that can be brutal.

In military terms, this would be called collateral damage. to minimise it, scientists have invented targeted drugs, such as the breast cancer therapy tamoxifen. think of them as smart bombs for cancer. But they don’t always hit the target and can have distressing side-effects.

Immunotherapy, in contrast, uses viruses to identify cancer cells with lethal delicacy, then destroys them from within.

the latest breakthrough has been led by the Institute of Cancer Research and the Royal Marsden Nhs Foundation trust, both i n London. It involves injecting malignant melanoma patients with a herpes virus that has been altered genetically so it does no damage to healthy cells.

Instead, it acts as a precisely targeted weapon inside the body. Invading cancer cells, the modified virus releases a chemical that alerts the patient’s immune system to a tumorous threat, so the body’s own defences attack the cancer.

this is a crucial element of immunotherapy. Often tumour cells can be sufficiently similar to normal, healthy ones that they sneak under the radar of our immune systems.

By recruiting our natural immune system to the fight, the risk of unwanted sideeffects is reduced significantly.

the new skin cancer therapy, called t-VeC, has another weapon in its arsenal. Once the virus is inside a cancerous cell, it multiplies before bursting out, killing the cell in the process.

so, by hijacking the herpes virus, scientists are effectively employing the counterespionage tactic of ‘turning’ an enemy agent to work for you.

herpes has been plaguing us since before we even became human. Last year, researchers in the U.s. revealed that our ancestors were infected with the virus before they evolved away from apes six million years ago.

the Ancient Greeks named it herpes, meaning ‘to creep or crawl’, because it can cause skin sores to spread inexorably.

Viruses in the herpes family — there are many strains — cause chicken pox, the nervous system disease shingles, cold sores and serious eye problems, such as the cornea infection herpes simplex keratitis, as well as the notorious sexually transmitted infection.

Once we contract a herpes virus, it can lurk as a ‘sleeper’ in our bodies for the rest of our lives, re-emerging in the case of shingles and cold sores when our resistance to viruses is low.

Ironically — given the latest developments — herpes can cause cancer of the nose and is l i nked with some cases of stomach cancer, as well as hodgkin lymphoma. It can also accelerate cervical cancer.

But because scientists have studied the virus’s invasive capabilities in labs for decades, they can modify its genes so those destructive powers are used for our benefit.

the new cl i nical tr i als, published in the Journal of Clinical Oncology, involved 436 patients with inoperable malignant melanoma — the most deadly form of skin cancer — which is seen in about 13,000 cases a year and results in more than 2,000 deaths.

For some patients, being injected with the modified virus has already worked in terms of combating their cancer for more than three years — a feat that comes tantalisingly close to being classed as a cure.

In those cases where t-VeC worked, the tumours vanished i n almost 40 per cent and shrank by more than half in the others.

some commentators warn that a good deal more trial work is needed. But Kevin harrington, the t-VeC trial leader from the Royal Marsden, hopes it could be available for routine use within a year.

‘We hope this is the first of a wave of these sorts of agent we will see coming through in the next decade or so,’ he says.

Indeed, other viral immunotherapy drugs are already being developed for use against cancers of the head and neck, bladder and liver.

Researchers i n Italy and the U.s. are recruiting the food poisoning bugs salmonella and listeria to provoke tumour-killing i mmune responses, with backing from Cancer Research UK.

strangely, the idea of harnessing our immune systems to fight cancer first arose 150 years ago, but was neglected. such theories were pushed aside by the arrival of powerful chemotherapy drugs.

Now, with the advent of genetic medicine, we have the potential to turn infectious bugs into a mutant army of tumour fighters.

this is not to say that the advent of modern immunotherapy will signal an end to the use of chemotherapy and conventional cancer- drug therapies. We need all the weapons at our disposal.

But it does raise the prospect of the treatment of cancer becoming less debilitating.

With luck, immunotherapy drugs will prove a powerful new means of defence.

the problem is that cancer is often notoriously difficult to beat with a single therapy because of its very nature.

tumour cells multiply so rapidly and mutate so wildly that combating the disease is like fighting an enemy that is constantly evolving.

We know cancer cells quickly ‘learn’ to disguise themselves from attack by drugs and hide deep in the body so effectively that patients can seem cured before, almost inexplicably, the cancer reappears.

A big threat to new immunotherapy drugs is lack of funding. It costs about £1.7 billion to develop a drug and prove its safety and effectiveness — and drug company shareholders want to see profits, too.

the maker of the new t-VeC skin cancer drug, Amgen, says it has applied to market it in europe. But even if it is approved by drugs regulators, it could still be judged too costly for the Nhs.

In the continuing battle against cancer, we have to ask: can we afford the price of human misery if we skimp on our medical defence budgets?