Earlier use of a targeted radionuclide therapy delays metastatic prostate cancer progression when administered as part of a trio of drugs, according to a phase 3 clinical trial led by Weill Cornell Medicine, NewYork-Presbyterian, Memorial Sloan Kettering Cancer Center and investigators at several other institutions worldwide, according to an Aug. 6 publication in The Lancet.
The study found that adding the targeted radionuclide therapy drug 177Lu-PSMA-617 to standard backbone therapy reduced the risk of disease progression or death by 28% for patients with PSMA-positive metastatic prostate cancer. The standard backbone treatment has been an androgen receptor pathway inhibitor paired with androgen deprivation therapy. The U.S. Food and Drug Administration approved early use of the drug for this patient group in late July following these results.
"About 9 out of 10 patients with metastatic prostate cancer have tumors that are positive for PSMA," said lead author Dr. Scott Tagawa, the Gebroe Family Professor of Hematology-Oncology at Weill Cornell Medicine and director of the Genitourinary Oncology Program at NewYork-Presbyterian/Weill Cornell Medical Center. "Now, we have a new therapy that, when added to the backbone therapy, extended radiographic progression-free survival for almost all patients with metastatic prostate cancer."
The PSMAddition trial enrolled more than 1,100 patients across 169 sites in 20 countries. Half received intravenous 177Lu-PSMA-617 every six weeks along with ADT and ARPI; half received only ADT and ARPI. Patients in the control arm could cross over to triple therapy if their disease progressed.
Dr. Tagawa said more adverse events occurred among those receiving triple therapy—an expected result—including dry mouth (46% incidence) and fatigue. In addition to delayed progression, the drug increased time until resistance developed and delayed symptoms related to spread into bone tissue.
Tagawa noted that while this new option is now available earlier in treatment pathways for eligible patients, it may not be suitable for everyone due to requirements such as specialized imaging scans and administration by nuclear medicine physicians or radiation oncologists—resources often concentrated at academic medical centers rather than community hospitals or rural areas.
