Prostate cancer patients to benefit from targeted radiation delivery

Some men with aggressive prostate cancer will benefit from targeted radiation therapy. The new therapy, utilising radioactive material sourced from Australia’s Lucas Heights nuclear reactor, has produced dramatic responses in some men with aggressive prostate cancer and who have failed current therapies.

The treatment, LuPSMA (Lutetium-177 PSMA-617), involves a radioactive molecule that is purpose made to bind to prostate cancer cells, enabling the targeted delivery of radiation to kill these tumours.

LuPSMA was also seen to reduce bone pain and improve quality of life in the proof-of-concept clinical trial which involved 30 patients – a world-first on this scale. Results of the Peter Mac-sponsored Phase II, single-arm study have been published online by Lancet Oncology.

Professor Michael Hofman, who led the trial at Peter Mac, said the responses were remarkable and supported starting a larger, randomised and multi-site trial of LuPSMA.

“Our small proof-of-concept trial shows that LuPSMA is highly active in men with aggressive prostate cancers, and it can trigger striking responses in some men,” said Prof Hofman.

“That LuPSMA was able to achieve this in men who have exhausted conventional treatment options is remarkable, and we now look forward with great interest and optimism to results of our Australia-wide TheraP trial now underway.”

The TheraP trial (ANZUP 1603) – which commenced once the positive results of Peter Mac’s proof-of-concept trial were known – is a partnership between ANZUP Cancer Trials Group Limited (ANZUP) and Prostate Cancer Foundation of Australia (PCFA).

The primary goal of Peter Mac’s proof-of-concept trial was whether LuPSMA could reduce PSA (Prostate Specific Antigen) levels by more than 50%. PSA is a blood biomarker for prostate cancer, so lowering PSA levels in men with advanced disease indicates a reduction in cancer activity.

After LuPSMA, all but one of the men saw a decline in PSA levels. More than half (57%, 17 of 30) showed at least a halving of their PSA levels – meeting the goal. Notably, in six of the men (20%) exceptional responses were seen with PSA levels becoming close to undetectable. Full body scans also confirmed dramatic changes in men before and after receiving LuPSMA (see below).

“Some men also reported LuPSMA gave them rapid relief from otherwise severe bone pain and they had more energy for daily tasks and to enjoy their family time,” Prof Hofman said, noting the treatment was well tolerated with no immediate adverse effects and no treatment-related deaths.

LuPSMA is a personalised treatment using a concept called “theranostics”. This combines a diagnostic test and targeted therapy. First patients undergo a PSMA PET scan to see if the tumours “light up” reflecting adequate expression of the target. Only if suitable do they proceed with treatment. Peter Mac has a long history of expertise in theranostic therapies which enabled the team to perform this world-first study.

Recruitment for the larger ANZUP/PCFA TheraP trial (ANZUP 1603) is underway with trial sites now open in Victoria, NSW and Queensland and soon to open in WA and SA.

ANZUP Chair, Professor Ian Davis, says ANZUP was delighted to work with Prof Hofman to launch this important study in partnership with PCFA and: “Clinical trials like this are the only way we can find out how well new treatments work, whether they are safe, and whether they should become the new gold standard for treatment in the future.”

The news was first published on the Peter Mac Website. Image courtesy of Peter Mac, from left to right: Shaun Jenkinson (ANSTO), AProf Anthony Lowe (PCFA), AProf Michael Hofman (Study Chair) and Marg McJannett (ANZUP) at the Lucas Heights reactor.

The Australian Cancer Research Foundation has supported Peter MacCallum Cancer Centre by providing four grants, totalling AUD $7million, towards cutting edge cancer research equipment and technology.