What if we can extend the lives of countless patients living with prostate cancer by targeting the proteins on the malignant cells to induce self-destruction? Prostate cancer is one of the most common cancers in the United States; the American Cancer Society estimates that in the year 2022, there will be approximately 268,490 cases of prostate cancer and 34,500 deaths [1]. One of the most deadly forms of prostate cancer is metastatic castration-resistant prostate cancer, which is a malignant growth that cannot be removed with surgery. One key indicator of metastatic castration-resistant prostate cancer is an increase in prostate-specific antigen level, which is a protein that is produced in both healthy and cancerous prostate cells [2]. The traditional treatments include hormone therapy, chemotherapy, and targeted radiation. However, since the fatality rate of the cancer is so high, these methods are usually only effective in prolonging the patient’s lifespan by a few months.
Recently, a new drug named Lutetium-177–PSMA-617 was developed and tested to treat patients with this form of cancer. The heart of this treatment centered on its ability to target the prostate-specific membrane antigen (PSMA), a biomarker that is exclusively expressed on the surface of prostate cancer cells. Essentially, Lutetium-177–PSMA-61 is able to identify the cancerous cells that express the PSMA biomarker and deliver to them a dose of lethal radiation that encourages apoptosis, or programmed cell death.
A “prospective, open-label, randomized, international, phase 3 trial” called VISION was conducted by prostate-cancer researchers across 84 sites in North America and Europe to test the efficacy of Lutetium-177–PSMA-617 [3]. Patients eligible to participate in the trial had to have at least one PSMA-positive metastatic lesion detected via a CT, MRI, or bone-scan.
According to the results of the study, Lutetium-177–PSMA-617 was able to double progression-free survival (the length of time that the cancer does not grow) and added an average of four more months of survival for patients with metastatic castration-resistant prostate cancer. In the treatment group, there was a median of 8.7 months of progression-free survival and 15.3 month overall survival rate, as opposed to 3.4 months and 11.3 months respectively in the control group. These statistics show that the treatment halted the growth of the disease by 5 months and prolonged their lives by 4 months. In addition, decreases in prostate-specific antigens was 50% to 80% higher in the treatment group than the control group. In other words, Lutetium-177–PSMA-617 was effective in killing the cancerous prostate cells. The results of this trial show the effectiveness of Lutetium-177–PSMA-617 as a treatment option for metastatic castration-resistant prostate cancer.
The safety of Lutetium-177–PSMA-617 was highly monitored alongside its efficacy. Adverse side effects such as fatigue, dry mouth, and nausea were higher in the treatment group than the control group. In addition, more than 30% of Lutetium-177–PSMA-617 patients had decreased lymphocytes, hemoglobin, leukocytes, platelet, calcium, and sodium levels. However, these side effects were not threatening enough to the patients to reduce or terminate treatment using this drug.
Overall, Lutetium-177–PSMA-617 safely extended the disease-free progression and survival of the patients taking these treatments by a few months over traditional treatments. After the VISION trial ended, the researchers submitted the drug for FDA approval, and it was recently approved as a treatment option for those diagnosed with metastatic castration-resistant prostate cancer in March of 2022. Now, patients are able to get life-extending treatment with just one medical scan, which is crucial in saving the time it takes to diagnose the disease, allowing them to start the treatment as soon as possible. Though Lutetium-177–PSMA-617 may not cure the cancer, it does give the patients a few more precious months to spend with their loved ones.
References
Key statistics for prostate cancer: Prostate cancer facts. American Cancer Society. (n.d.). https://www.cancer.org/cancer/prostate-cancer/about/key-statistics.html
Prostate-Specific Antigen (PSA) Test. (2022, March 11). National Cancer Institute. https://www.cancer.gov/types/prostate/psa-fact-sheet
Sartor, O., Al., E., Investigators*, for the V. I. S. I. O. N., Author AffiliationsFrom the School of Medicine, Others, J. F. G. and, Others, R. A. G. and, Others, N. D. G. and, Others, G. W. and, Basso, C., & E. J. Anderson and Others. (2021, December 23). Lutetium-177–PSMA-617 for metastatic castration-resistant prostate cancer: Nejm. New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/NEJMoa2107322
Fischer, L. (2022, March 24). FDA approves 177lu-PSMA-617 for metastatic castration-resistant prostate cancer. Oncology Nursing News. https://www.oncnursingnews.com/view/fda-approves-177lu-psma-617-for-metastatic-castration-resistant-prostate-cancer
Lee, S. (n.d.). Treatments for castration-resistant prostate cancer. Canadian Cancer Society. https://cancer.ca/en/cancer-information/cancer-types/prostate/treatment/castration-resistant-prostate-cancer#:~:text=Metastatic%20castration%2Dresistant%20prostate%20cancer%20has%20spread%20to%20lymph%20nodes,your%20testosterone%20level%20is%20low