19 May 2022

Aussie researchers begin ‘world-first’ clinical trial

Prostate cancer

Australian researchers have started what they say is a “world-first” clinical trial to evaluate the effectiveness of experimental therapy combined with immunotherapy in patients with prostate cancer – and they are looking for more recruits.

If the phase II clinical trial proves effective, it could establish a new global standard of care and give men access to a new form of treatment that will extend their lives by keeping the deadliest forms of prostate cancer in remission.

Prostate Cancer Foundation of Australia CEO Anne Savage said the organisation had invested $1.6 million in funding for the EVOLUTION Phase II Clinical Trial to evaluate Lutetium-177-PSMA (Lu-PSMA) and immunotherapy for treatment of advanced forms of prostate cancer that have stopped responding to other treatments.

“We are on the verge of a complete transformation in prostate cancer treatment, giving men with the most aggressive and deadly forms of this disease a greater hope of survival,” she said.

“This trial will go beyond where any other trial has gone before, exploring the next frontier in precision nuclear medicine for prostate cancer, combining Lu-PSMA with immunotherapy, which we think will be a game-changer in the treatment of advanced prostate cancer.”

Lu-PSMA therapy, also known as Lutetium177 Prostate Specific Membrane Antigen therapy, is a treatment for men with prostate cancer that has spread outside the prostate to other parts of the body. On its own, the drug Lutetium binds to the cancer cells while not affecting the surrounding tissue, like radiation and chemotherapy do. It is currently considered experimental in Australia and is typically only used when other treatments have failed, Ms Savage said.

“The EVOLUTION trial goes one step further than Lutetium on its own, pairing it with immunotherapy,” she said.

“This new class of precision medicine treatments is called Theranostics which combines therapy and diagnostics to improve our understanding of each man’s prostate cancer, and how it can be most effectively treated.” Ms Savage said.

Prostate cancer is the most common cancer among Australian men and the second most common cause of cancer-related death. About 15 per cent of those newly diagnosed have advanced prostate cancers, which have spread beyond the prostate to other areas of the body.

Ms Savage said the ProPSMA study and TheraP clinical trials, previously co-funded by PCFA, have already vastly improved the standard of care available to men, most recently by resulting in the listing of PSMA PET/CT scanning on Medicare. The foundation advocated strongly to the federal government for the listing, which will happen from 1 July.

“PSMA PET/CT scanning can help to identify whether a man’s prostate cancer has spread beyond the prostate to other parts of the body, using nuclear medicine to pinpoint the prostate cancer cells, while the CT scan uses x-rays to create a 3D image of the body that can be used by specialists to get a more complete picture of each man’s situation,” she said.

The trial found this method of imaging to be 92% accurate in detecting deadly tumours, compared to only 65% accuracy for CT and bone scans combined.

“If the cancer has spread to other parts of the body, doctors use a special nuclear medicine radiotracer that attaches itself to the PSMA and deploys a form of targeted radiation to find and destroy the killer cancer cells,” she said.

This isn’t new treatment – the Peter Mac centre in Melbourne performed the first PSMA PET scan in 2014.

Professor Michael Hofman, director of the Peter Mac’s Prostate Cancer Theranostics and Imaging Centre of Excellence (ProsTIC), said the MBS listing would was a major step forward, with out-of-pocket expenses for the scan close to $1000 currently.

“This is truly practise changing for the management of men with prostate cancer in Australia,” he said. “This funding provides important equitable access for patients with the most commonly diagnosed cancer in Australia.”

The primary data in the funding application for this MBS addition came from Peter Mac’s ProPSMA study, published in The Lancet in 2020. The study found that PSMA PET/CT scans provide better accuracy, more definitive results, lower radiation exposure, and enables more effective management of disease. It also included a health economics assessment, demonstrating that PSMA PET/CT is more cost effective than standard imaging.

Professor Declan Murphy, ProPSMA senior author and director of genito-urinary oncology at Peter Mac said better detection of cancer spread was critical to direct curative treatments whilst also avoiding additional treatments that may be harmful.

“PSMA PET/CT is a game changer, detecting disease that previous medical scanning technology failed to detect,” he said.

Meanwhile, as part of the EVOLUTION trial, Lu-PSMA will be given in conjunction with commonly used immunotherapy drugs ipilimumab and nivolumab.

The foundation has partnered with the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP) for the 12-month trial of 100 men across Australia, who are now being recruited. ANZUP Chairman Professor Ian Davis, said that while cancer immunotherapy was already used to combat many different types of cancer, it has so far not proven successful in helping treat prostate cancer.

“The reasons for this are not known, but we believe it could be made more effective if we think creatively about how it is given,” he said. “Radiotherapy has been shown to help boost the immune response in other settings so it is possible that combining radiotherapy with immunotherapy might lead to more and better responses in prostate cancer.”

The foundation is advocating for Lu-PSMA treatment to be made available to all men who need it, with no out-of-pocket costs. It typically costs $10,000 per round.

The Lancet 2020, online 22 March