A nuclear payload to prostate cancer
Anovel and ‘‘exciting’’ treatment for prostate cancer is being trialled by a private radiology group in Auckland. The study of six men with advanced metastatic prostate cancer aims to replicate studies underway or completed in Germany and Australia and ahead of a large phase three trial in the United States next year.
The therapy, called ‘‘lutetium 177 PSMA radioligand therapy’’, is complex and costly, and the Auckland group is also trialling new forms of patient care and comparing conventional diagnostics with artificial intelligence.
Lutetium-177 is a molecule that emits small radiation doses distances of less than 2 millimetres, said Dr Lloyd McCann, chief executive of Mercy Radiology and Clinics.
If doctors can get the substance alongside cancer cells, the radiation can kill the cancer without damaging other nearby cells or subjecting body regions to radiation.
It turns out that PSMA, an amino acid, is present with almost all types of prostate cancers. Indeed it is ‘‘overexpressed’’ in many cases.
PSMA is a receptor that is an ‘‘ideal target’’ for lutetium-177, according to a 2017 research paper out of the University of New South Wales.
So it’s possible to deliver an experimentally effective ‘‘payload’’ to the cancer and have it bind there while the radiation does its work.
Within hours of the injection, the lutetium is flushed out in urine. It has a half-life of 6.73 days and is considered in Australia to be safe enough for outpatient treatment.
The therapy is not a cure, said Mercy medical director Dr Remy Lim. When it works, it may potentially extend a patient’s life and improve quality of life, he said.
Prostate cancer is the most diagnosed cancer among men in the Western world. A small proportion are relatively indolent and patients will eventually die of other causes. Other types are more aggressive and when they metastasise, often to the lymph nodes and bones, they are usually controlled with hormones or chemotherapy.
Lutetium 177 PSMA therapy is ‘‘showing exciting treatment responses … and almost certainly has an important future role in the treatment of prostate cancer’’, concluded the Australian paper.
The Auckland proof of concept trial is being half funded by the Prostate Cancer Foundation NZ and half by Mercy.
It’s rare in New Zealand for private groups to undertake human healthcare research, although it is commonplace in the United States.
The preliminary results of the study will be released on Friday at a Health Informatics New Zealand Conference in Wellington.
McCann and Lim hoped their proof-of-concept study – plus the larger international studies – would lead to acceptance of the therapy in this country.
‘‘Although not all patients would be suitable for this treatment, those who are may benefit from the therapy for palliation of their disease’’ said McCann.
The therapy is not currently funded in New Zealand, but should be one day, he said. Some New Zealanders had travelled abroad for the treatment.
The Mercy study is also using ‘‘digital tools to understand how this therapy is impacting on patients’ quality of life’’, a statement said. Patients answered online questionnaires when first enrolled in the study and answered more questions as they progressed through treatment cycles. The digital tools ‘‘provide real-time feedback’’ and may enhance patient care, McCann said.
The group is also testing whether artificial intelligence ‘‘can assist’’ in the diagnostic process for prostate cancer patients. ‘‘Our radiologists will continue to report scans in the usual manner and we’ll use an algorithm to assess the same scans to see how accurate it is,’’ McCann said.
When it works, the therapy may potentially extend a patient’s life and improve quality of life.