A new prostate cancer treatment is set to become a new “mainstay” of cancer care, alongside surgery, chemotherapy and radiation therapy. But for now, only patients participating in a clinical trial have access to it.
The radioligand therapy, or RLT, clinical trial involves precise targeting of cancer cells with radiation delivered intravenously. “We’re able to deliver this very specific therapy to specific cells in the body,” says Dr.r David Laidley, a nuclear oncologist at Western University and London Health Sciences Centre.
“We are able to deliver lethal radiation therapy that is specifically targeted to cancer cells while generally sparing normal tissue,” adds Dr.r Laidley, principal investigator in London, Ontario, where the pan-Canadian clinical trial comparing RLT to chemotherapy is taking place.
Dale Cousins was thrilled when he saw before and after images of the new therapy, having been diagnosed with prostate cancer in 2010 and undergone numerous treatments, including surgery. After being stable for several years, tests last year revealed his cancer had spread and he was enrolled in the trial.
With the last of his six RLT infusions on July 10, the 79-year-old from Petrolia, Ont., has already had a “dramatic reduction” in cancer lesions and his prostate-specific antigen levels have dropped significantly, suggesting an “excellent response” to treatment, Laidley said.
Previous clinical trials have already demonstrated the effectiveness of RLT, leading Health Canada to approve Pluvicto — the radioactive drug that kills targeted cancer cells — in August 2022 for patients whose prostate cancer has spread and whose chemotherapy has failed.
But nearly two years later, patients with advanced prostate cancer still cannot access radioligand treatment as negotiations continue over the cost of the technology to government health systems.
Better access requested
According to David Ladiley, while waiting for this decision, some men with prostate cancer need treatment to improve their quality of life and live longer.
“Oncologists are asking, ‘Can we refer patients or is that an option?’ And unfortunately, we have to say that it’s not available.”
Currently, radioligand cancer treatment is publicly available only for patients with neuroendocrine tumors, an uncommon but not rare cancer that begins in neuroendocrine cells in the gastrointestinal tract or pancreas, Dr.r Simron Singh, a medical oncologist at Sunnybrook Health Sciences Centre in Toronto.
The latter was the principal investigator of a recent international clinical trial that found that another radioactive drug administered by RLT, called Lutathera, reduced the progression of neuroendocrine tumors and the risk of death by 72% when given early after a patient’s diagnosis.
Like Pluvicto, Lutathera has already been approved in Canada as a last-line cancer treatment, but the trial results, published in The Lancet last month, were the first to show that RLT could be used as an “initial treatment,” says Dr.r Singh, who is the co-founder of the Susan Leslie Neuroendocrine Tumour Clinic at Sunnybrook.
In addition to neuroendocrine cancer and prostate cancer, radioligand treatment using different radioactive drugs is currently in clinical trials for other types of cancer, he adds.
“This is a new pillar (in cancer care) that we are developing,” the researcher said. “It will completely revolutionize the way we treat cancer in the years to come.”
Dingh explains that RLT works by finding a target, which is usually a receptor on the surface of cancer cells that doesn’t exist in healthy tissue.
The Canadian Cancer Society calls radioligand therapy a “remarkable breakthrough” that began with Lutathera for neuroendocrine cancer around 2018.
“We’ve seen patients who have metastases all over their body and then, with one or two treatments, are completely cured. It’s incredible,” says Stuart Edmonds, a pharmacology expert and vice-president of mission, research and public interest advocacy at the Canadian Cancer Society.
According to Stuart Edmonds, RLT also has fewer side effects compared to traditional radiation because it minimizes damage to healthy cells.
Now that RLT has been proven to be effective in prolonging the lives of patients with metastatic prostate cancer who have run out of other treatment options, the Cancer Society is funding clinical trials across Canada to determine whether Pluvicto can be used in patients with prostate cancer at much earlier stages of the disease.
In the meantime, Mr Edmonds says it is “extremely important” to make Pluvicto publicly available for patients with advanced prostate cancer.
“I just want it to be available in Canada as soon as possible,” he says.
Long negotiations
Global pharmaceutical company Novartis manufactures both Pluvicto and Lutathera.
Both the company and the agency responsible for negotiating drug prices confirmed to The Canadian Press that they had not yet reached an agreement on the price of Pluvicto.
Negotiations began in August last year but then encountered “an unforeseen delay,” Dominic Tan, interim CEO of the pan-Canadian Pharmaceutical Alliance (pCPA), said in an emailed statement.
“(The APP) is still striving to complete the process as quickly as circumstances allow,” Mr Tan said.
“However, the negotiations are going both ways and we are not able to provide a specific timeline as to when the process will be completed.”
Novartis said it recognizes the unmet needs of patients with advanced prostate cancer.
“It is with these patients in mind that we continue to actively collaborate with the APP to achieve rapid and responsible access to this therapeutic advance,” Novartis Canada spokesperson Rosa D’Acunti said in an emailed statement.
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