Watch: Experimental drug tracks and kills advanced prostate tumours
An experimental drug helps prostate cancer patients live longer, research suggests.
Around one in eight men in the UK will develop the disease at some point in their life, with the tumour generally being non-aggressive and slow growing.
Nevertheless, the disease is the second deadliest form of cancer among men, killing around 11,900 patients in 2018 alone.
Radiotherapy, often a go-to treatment, is generally ineffective when the tumour has spread beyond the prostate.
The pharmaceutical giant Novartis has therefore developed a two-part drug, which tracks malignant cells hiding beyond the prostate, before killing them via radiation.
To test the drug's potential, scientists from the American Society of Clinical Oncology (ASCO) administered it intravenously to around 550 men with advanced prostate cancer, who also underwent standard treatment.
When followed-up two years later, these men had lived four months longer than the (around) 270 patients who just had the standard treatment.
An additional four months of life may not seem significant, however, "these patients don't have many options".
So-called radiopharmaceuticals are an emerging class of medicine that deliver radiation directly into cancer cells.
When the drug is circulating in the bloodstream, trillions of molecules track down tumours.
After latching onto receptors on the outside of the tumour, the drug delivers radiation, with each molecule hitting up to hundreds of cancer cells. DNA damage means some of these malignant cells then die.
The radiation is said to clear quickly from the body.
Under existing treatment guidelines, radiation may be beamed onto a patient's body or implanted into their tumour via pellets, neither of which work well in more advanced cases.
To test the effectiveness of radiopharmaceuticals, the scientists analysed 831 men with advanced prostate cancer, of whom around two thirds were given the experimental drug intravenously every six weeks, for up to six cycles.
Results – which will be presented at the ASCO's upcoming meeting – reveal these men's cancer did not spread for nearly nine months, compared to around three months among those just on the standard treatment.
After receiving the experimental drug, the men generally lived for 15 months, compared to 11 months among the control group patients.
"These patients don't have many options", said Dr Lori Pierce, president of the ASCO.
Serious side effects were more common among the experimental patients, however, with just over half (53%) enduring a severe adverse event, compared to less than one in five (38%) in the control group.
Despite the safety results, Dr Lin hopes the overall findings will pave the way for the experimental drug's widespread use. Novartis plans to seek its approval in the US and Europe later in 2021.
A similar drug, also developed by Novartis, is already used for a rare type of gastrointestinal cancer.
This "would be a first for prostate cancer", said Dr Lin.
Over the next decade, radiopharmaceuticals "will be a major thrust of cancer research", according to Dr Charles Kunos, from the University of Kentucky's Markey Cancer Center.
"It will be the next big wave of therapeutic development," he said.
Similar drugs are also under development for breast, pancreatic and skin cancers, with these having "great potential", according to study author Dr Mary-Ellen Taplin, from the Dana-Farber Cancer Institute.
Watch: Tiger King's Joe Exotic reveals he has prostate cancer