Scientists have the first proof that a “brand new” way of combating cancer, using genetically modified viruses to attack tumour cells, can benefit patients, paving the way for a “wave” of new potential treatments over the next decade. Specialists at the NHS Royal Marsden Hospital and the Institute of Cancer Research (ICR) confirmed that melanoma skin cancer patients treated with a modified herpes virus (the virus that causes cold sores) had improved survival – a world first. In some patients, the improvements were striking. Although all had aggressive, inoperable malignant melanoma, those treated with the virus therapy – known as T-VEC – at an earlier stage survived on average 20 months longer than patients given an alternative. In other patients results were more modest, but the study represents a landmark: it is the first, large, randomised trial of a so-called oncolytic virus to show success.
The method – known as viral immunotherapy – works by launching a “two-pronged attack” on cancer cells. The virus is genetically modified so that it can’t replicate in healthy cells – meaning it homes in on cancer cells. It multiplies inside the cancer cells, bursting them from within. At the same time, other genetic modifications to the virus mean it stimulates the body’s own immune response to attack and destroy tumours. Other forms of immunotherapy – the stimulation of the body’s own immune system to fight cancer – using antibodies rather than viruses, have been developed into successful drugs. It is hoped that T-VEC could be used in combination with these. Findings from trials of T-VEC, which is manufactured by the American pharmaceutical company Amgen, have already been submitted to drugs regulators in Europe and the USA.
Viral immunotherapies are also being investigated for use against advanced head and neck cancers, bladder cancers and liver cancers. Kevin Harrington, UK trial leader and professor of biological cancer therapies at the ICR and an honorary consultant at the Royal Marsden, said he hoped the treatment could be available for routine use within a year in many countries, although it would need to pass the UK’s own regulatory approval before it could be prescribed here. Professor Paul Workman, chief executive of the ICR said: “We may normally think of viruses as the enemies of mankind, but it’s their very ability to specifically infect and kill human cells that can make them such promising cancer treatments.”
Melanoma is the fifth most common cancer in the UK, and is becoming more widespread as a result of increased exposure to the sun in younger generations who have benefitted from easier access to sunnier climates on holiday. Survival chances are good if the cancer – indicated by the appearance of a new mole on the skin – is caught early.
Charlie Cooper, The Independent
27 May 2015