A radioactive drug against prostate cancer has been launched in the UK. Marketed as Xofigo, it contains polonium-210, the very same substance that killed Alexander Litvinenko, former KGB agent and Kremlin critic, in 2006 in London.

Xofigo selectively zones on places where cancer has already affected the bone. Tumour cells are killed by its alpha particles by smashing through their DNA. The new injectable drug however can only be bought and used on patients who are in the advanced "castration resistant" stage, when the cancer no longer responds to conventional hormone treatments.

Administering alpha particles in high doses essentially destroys a body's tissues and organs. But when administered in a careful, controlled and targeted manner, they can help wipe out and cure a man's prostate cancer.

"The majority of men who develop castration-resistant prostate cancer will develop bone metastases which can be painful and even life-threatening," Dr Christopher Parker, from the Royal Marsden NHS Foundation Trust and Institute of Cancer Research in London, said.

"There are many men with this disease who could benefit from the availability of radium-223 (marketed as Xofigo)."

In the UK, around 41,000 men are diagnosed with prostate cancer annually; around 11,000 die from the disease.

Xofigo however has yet to be approved by the National Institute for health and Clinical Excellence, the agency that sets guidance on a treatment's cost effectiveness in England and Wales.

"The launch and availability of Xofigo in the UK should be welcome news for physicians and patients, who have been looking for new treatment options," Jon Hemphill from Bayer, the pharmaceutical company that manufactured Xofigo, said.

Most treatments for prostate cancer either cut off the supply of the male hormone testosterone or block its effect on tumours.