Prostate cancer study paves the way for 'suicide' gene therapy

Posted: 15/12/2015

Prostate cancer is the most common cancer in men in the UK: around 40,000 men are diagnosed with the disease every year and more than 10,000 men a year die from it. 

A new report from the US, published in the Journal of Radiation Oncology, gives hope that a gene therapy is both safe and effective in treating prostate cancer. The study involved a group of patients who were treated with a combination of radiotherapy and gene therapy. Some patients were also given hormone therapy. These patients were compared and contrasted with historical data of patients with prostate cancer who had been treated with radiotherapy alone. 

Like many cancers, prostate tumours develop because the cancer cells evade the body's normal mechanisms for identifying and destroying rogue cells. The gene therapy used in this study involved introducing a form of herpes virus directly into the prostate cancer cells, causing the infected cells to produce an enzyme. The researchers then treated the patients with an anti-herpes drug. The drug attacks the enzyme-producing cancer cells causing them to self-destruct. In turn, this marks the cells out as being unwanted and triggers the patient's immune system to launch a full scale attack on the cancerous cells. 

The results of phase 2 of this trial compared with the historical data are very encouraging. The treatment benefited men with advanced cancer, as well as those in whom it was confined to the prostate. The five-year survival rates were improved by up to 20% compared with the historical control data, whether with or without hormone therapy. As an added bonus, most trial patients reported few or no adverse side effects and complications from the gene therapy.  

Welcoming the report findings, Andrew Clayton of Penningtons Manches' clinical negligence team comments: "Prostate cancer, particularly in its advanced stages is an awful disease and the treatment is almost as difficult to tolerate as the disease itself. The news of this US study is hugely promising and offers significant hope of a step forward in combatting prostate cancer. 

"The latest data pave the way for a third phase trial that has now started. Patients will now be treated with the gene therapy alongside a clinical control group of patients actively receiving radiotherapy alone. The studies to date have had to rely on historical patient data as the control. The next stage would be to obtain regulatory approval in the US, so we eagerly await the outcome of this final phase of the trial and hope that it reinforces the findings to date."

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