ONE of the great challenges in curing cancer is that the disease may return after being contained or apparently cured. This is often due to the way that some cancer cells “learn” to evade or defeat a therapy. But medicine is now responding with innovative drugs and strategies to ensure that the disease is attacked from all angles.

While the first generation of cancer therapies, radiation and chemotherapy, attacked cancer using external weapons, scientists are increasingly recruiting the body’s own defences. One of the latest approaches creates cancer vaccines that educate the body’s immune system to attack tumours — an approach that doctors call immunotherapy or biological therapy.

This month a new treatment for the most common lung cancer type, developed from work by Cancer Research UK scientists at Guy’s Hospital, entered phase III clinical trials that will involve more than 1,300 patients. The drug, Stimuvax, stimulates the body’s immune cells to target MUC1, a protein in non-small cell lung cancer cells.

Doctors at the Royal Marsden Hospital and Southampton University Hospitals, are beginning early trials for a vaccine for recurrent prostate cancer. It aims to teach the body’s immune cells to spot a substance made by some prostate cancer cells, called prostate-specific membrane antigen. Meanwhile scientists at the University Hospital Birmingham NHS Foundation Trust are completing a phase 1 trial on a vaccine for advanced melanoma — skin cancer that has spread around the body.

The most high-profile new cancer vaccine, though, is of the old-style preventive type, against the human papilloma virus, a big cause of cervical cancer. The Department of Health is said to be launching a nationwide programme this year to get school nurses to administer the Gardasil jab to children and young teenagers before they become infected.

Another route for using our own immune systems against cancer involves two natural substances, interferon alpha and interleukin. Our bodies produce both as part of our immune response, but now they can be made in the laboratory and used in much larger quantities as treatments.

Interferon alpha was one of the first immunotherapies used on cancer, mostly on melanoma, myeloma and kidney cancer. It can help to stop cancer cells growing and may also boost the immune system. Interleukin-2 is most often used to treat kidney cancer. They are not cures, though clinical trials have shown that interferon-based treatments can help patients with advanced kidney cancer to live longer.

Another class of cancer-cell killer is monoclonal antibody proteins (MABs) . Made in the lab from a single copy of a human antibody, they find and kill foreign matter. They are designed to recognise abnormal proteins outside cancer cells. Different antibodies recognise different cancers. Rituximab recognises the CD20 protein on non-Hodgkin’s lymphoma cells, while Adept is an antibody-directed enzyme pro-drug therapy that recognises bowel cancer. Most MABs are experimental and development may take years.

Another strategy is to attempt to strangle the tumours, using anti-angiogenesis treatment. Cancers need to grow their own blood vessels as they get bigger, a process called angiogenesis. These new drugs halt the process, thus preventing the tumour from growing.

Drugs in this class include Thalidomide, which is mainly used for treating multiple myeloma, a form of blood cancer. Professor Herbie Newell says: “Thalidomide is very important. But one of the problems is that it causes abnormalities to babies in the womb. Our groups are looking to create an analogue of thalidomide, with all its anti-cancer effects but none of the dangers to babies.”

There is also the Trojan Horse approach, typified by a new form of gene therapy, called Vdept — virus directed enzyme prodrug therapy. A modified harmless virus is used to carry an enzyme into the cancer cells. Once the enzyme has found its way to the cancer cells, an inactive form of a chemotherapy drug, called a prodrug, is administered.

When the inactive prodrug reaches the cancer cells, the enzyme converts it into the active chemotherapy drug, so that it can kill the cancer cell. This treatment is becoming more common, although it is still only in clinical trials. Vdept also exemplifies another popular approach — targeted therapy — where only cancer cells are attacked by drugs, leaving normal body cells unaffected.

In December, London investigators announced a breakthrough in another area of targeted cancer medicine — gene therapy. Scientists at the Institute of Cancer Research, a college of the University of London, found that one in ten breast cancers is linked to an overactive gene called FGFR1.

Lab tests using a compound targeted at FGFR1 indicated that by blocking the gene that fuels cancer cells, tumour growth can be significantly cut. The research echoes the work that led to the development of the breast cancer drug Herceptin, a treatment that targets the HER2 protein found on about one in four breast cancers.

Explore Related Features

• Young Photographer