Health Day reporter
FRIDAY, June 4, 2021 (HealthDay News) – Patients with advanced prostate cancer may have new hope: Researchers have identified a potential new treatment for men with metastatic prostate cancer resistant to castration, which has no cure.
Metastatic castration-resistant prostate cancer means the disease continues to spread despite therapies that deplete male hormones (androgens) such as testosterone, which are believed to “feed” tumors.
Added to standard care, this new targeted radiotherapy has improved the survival of these cancer patients, the researchers report.
The study “offers the possibility of treatment where there was really very little for the most advanced patient, but it opens a door to explore the benefits of this drug in several populations of earlier patients,” said Dr. Michael Morris, Prostate Cancer Section Chief. at Memorial Sloan Kettering Cancer Center in New York.
In about 80% of prostate cancers, there is a protein on the surface of the cancer cell called prostate specific membrane antigen (PSMA). It is also distributed to prostate cancer that has spread to bones, lymph nodes or soft tissues. Still, PSMA is not found on normal tissue, so it was a good target for both diagnosis and therapy, Morris explained.
The new drug has two components, a targeting molecule and a payload that delivers radiation. It is administered intravenously.
“Each of the molecules in the drug seeks to bind to cells containing PSMA, which are usually the prostate cancer cell. As the drug binds to it, the cell brings the drug inside the cell. The radiation, which is attached to the drug, this is the payload of the drug, is also brought inside the cell. And there, it irradiates the cell and kills it and the cells that are close to it ” Morris said.
To be part of the trial, patients had to have disease that had progressed through hypotensive therapy, which has been the norm for decades, Morris said. They also must have progressed through another class of drugs called androgen receptor pathway inhibitors and chemotherapy.
“What happens when you take treatment for prostate cancer is that if you respond, you continue to take that treatment or that regimen until side effects prevent you from continuing the treatment or it doesn’t work anymore because the disease has become resistant to it, “Morris explained.
The trial included 831 participants. Patients were randomized one to one to receive the new treatment, called lutetium-labeled PSMA-617, plus standard care or just standard care between June 2018 and October 2019.
The new treatment increased the median overall survival to 15.3 months compared to 11.3 months for those patients who had very advanced disease. It also increased a measure called radiographic progression-free survival, which reflects disease control during treatment, from a median of 3.4 months to 8.7 months.
The study is presented online at the annual meeting of the American Society of Clinical Oncology, which will be held June 4-8. Results presented at medical meetings are considered preliminary until published in a peer-reviewed journal. Drugmaker Novartis funded the study and plans to submit the data to regulatory authorities for review and potential approval.
Prostate cancer is both the most common cancer in American men and the second leading cause of cancer death. The positive results of the study mean that patients with very advanced disease may have a new treatment option.
“It also means that, generally in prostate cancer as well as other diseases, what you develop and discover as a new therapy for more advanced patients generally benefits earlier patients and we will frequently see these benefits. amplified in less ill patients who have less -resistant disease, ”Morris said.
Ongoing studies are now looking at treatment for patients who have previous illness and have not yet received chemotherapy, as well as those who are just starting treatment for prostate cancer.
Dr Ash Tewari, system director at the Milton and Carroll Petrie department of urology at Mount Sinai Health System in New York City, said the study holds great promise for patients, giving cancer patients new hope. advanced prostate. It also has a reasonable side effect profile, said Tewari, who was not in the study.
“Androgen deprivation is the mainstay of treatment for advanced prostate cancer, but the cure rate is low and patients eventually become resistant to castration,” Tewari said. “There is a need to tailor therapies more closely to individual patient profiles.”
Noting the median results for overall survival that the study found, Tewari said that four additional months of life can be very significant for someone who lives to see a milestone in their family, such as the marriage of a little one. -child.
“This is a good example of when a well-conducted, scientifically-backed clinical trial can impact a patient’s life. And we should always be curious and careful when considering these options,” he said. -he declares.
The National Cancer Institute of the United States offers more on prostate cancer.
SOURCES: Michael Morris, MD, medical oncologist, chief, Prostate Cancer Section, Memorial Sloan Kettering Cancer Center, New York; Ash Tewari, MD, professor and chair of the system, Milton and Carroll Petrie Department of Urology, Mount Sinai Health System, New York; 2021 American Society of Clinical Oncology Annual Meeting, June 4-8, 2021
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