A new therapy option for late-stage prostate cancer has been approved.
The FDA approved a new treatment option for advanced prostate cancer that has metastasized, or spread throughout the body, in late March. When called Pluvicto (and called lutetium-177-PSMA-617), and administered by intravenous infusion, the medication can search out and eradicate tumors that are still too small to see with standard kinds of medical imaging.
Pluvicto has been approved for men who have already received other anticancer medicines, such as chemotherapy and hormonal therapies that inhibit the tumour-promoting hormone testosterone. The drug has two parts: one that binds to a protein on prostate cancer cell surfaces called PSMA, and the other is a radioactive particle that kills the cancer cells. Most normal cells do not contain PSMA, or do only in very low quantities. This permits Pluvicto to attack tumors while protecting healthy tissues.
To check whether a guy is eligible for the medicine, doctors first inject a radioactive tracer that travels through the bloodstream, hunting for and then sticking to PSMA proteins. Cancer cells indicated by the tracer will show up on a specialist scanning tool called positron-emission tomography. Around 80% of patients with prostate cancer have PSMA-positive tumours; those who do not are treated ineffectively.
831 men were randomly assigned to one of two groups during the clinical trial that resulted in Pluvicto's clearance. Men in one group received Pluvicto in addition to standard-of-care therapies, while men in the control group received only standard-of-care treatments. Each man had metastatic, castration-resistant prostate cancer, which means their tumors had progressed and were no longer responding to hormonal therapy.
Conclusions and implications
After 21 months, the results indicated that Pluvicto was more successful at delaying the progression of cancer. It took an average of 8.7 months for men who received the medicine for their tumors to begin growing again, compared to 3.4 months for men who received normal care. Pluvicto was also associated with a significantly higher overall survival rate of 15.3 months compared to 11.3 months. While the medication was usually well taken, it did cause fatigue, nausea, kidney issues, and bone marrow suppression.
Pluvicto is a novel and fascinating technology, according to Dr. David Einstein, a medical oncologist at Beth Israel Deaconess Medical Center in Boston and an assistant professor at Harvard Medical School. He emphasized, however, that while the medicine represents a significant step forward for men with advanced prostate cancer, it is not a cure. "Some patients may believe that Pluvicto is a panacea for all other existing medications, which is most emphatically not the case," he explains.
Meanwhile, further questions about who may be able to obtain the medicine remain. "How about males who have never received treatment for metastatic prostate cancer?" Dr. Einstein inquires. Previous chemotherapy is required if the label is followed strictly. However, some men are either too ill or unwilling to undergo chemotherapy due to probable negative effects. Pluvicto is currently being studied to establish whether it is effective in the early stages of prostate cancer and whether it can be combined with other medicines to increase its effects.
The availability of this new treatment is critical for a variety of reasons, said Dr. Marc Garnick, Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, editor of Harvard Health Publishing's Annual Report on Prostate Diseases, and editor in chief of HarvardProstateKnowledge.org. To begin with, it improves survival in men who have already received extensive treatment and have few therapeutic alternatives remaining. Second, it demonstrates a novel approach to the use of radioactive chemicals that complements conventional treatment. Finally, it is based on a diagnostic scan that pinpoints the males most likely to benefit from treatment.
