According to a recent study, an antibody drug which makes a wide range of cancers more vulnerable to the body’s immune system is “exciting” and may mark a new era.
The new drug strips cancer cells of the “camouflage” they use to evade attack by the immune system.
In the most detailed study, published in Nature, some patients completely recovered from terminal bladder cancer.
The immune system is in delicate balance with some chemicals in the body encouraging a strong vigorous response, while others try to dampen it down.
Tumors can hijack this system to hide from the immune system.
One trick which tumors use is a protein called PD-L1 which is normally used to prevent autoimmune diseases.
An international team of scientists has been trialing a drug to block PD-L1, produced by the company Roche, on 68 people with advanced bladder cancer.
All the patients had tried chemotherapy and had been given six-to-eight months to live.
More than half the patients, whose tumors were using PD-L1 to hide from the immune system, showed signs of recovery.
In two patients there were no signs of cancer after the treatment.
One in ten patients responded to the experimental therapy even if PD-L1 was not present in the tumor.
Dr. Tom Powles, an oncologist at the Barts Cancer Institute at Queen Mary University of London and part of the research team, said: “There have been no new drugs for bladder cancer for 30 years.
“The tumors have developed a camouflage layer, PD-L1, and by removing the camouflage the tumor becomes identifiable.
“A subgroup of patients seems to do exceptionally well.”
Dr. Tom Powles is funded by the UK’s National Health Service (NHS) and receives no money from Roche.
The drug has been given “breakthrough therapy” status in the US and could be used widely by patients there at the end of 2015, if a larger trial shows the same results.
Much larger randomized clinical trials would be needed in order for the experimental therapy to be used in Europe.
A similar set of trials to boost the immune attack revealed at the American Society of Clinical Oncology conference in Chicago in June, showed similar therapies could improve survival in advanced skin cancer.
In a trial of 411 patients evaluating a drug, pembrolizumab – 69% of patients survived at least a year.
Those results were described as having the “potential to be a paradigm shift for cancer therapy”.
A separate study of 175 patients, led by Yale University in the US, showed responses to the drug in patients with non-small cell lung cancer, melanoma, renal cell carcinoma and other cancers.
