A phase 3 clinical trial has found that adding a targeted radionuclide therapy earlier in the treatment pathway can delay progression in men with PSMA-positive metastatic prostate cancer, according to reporting from Weill Cornell Medicine. The results, published in The Lancet on August 6, suggest the approach may shift care for patients whose disease has just been diagnosed and has not yet become resistant to standard therapy.
The study evaluated the addition of ^177Lu-PSMA-617, also called lutetium PSMA 617 vipivotide tetraxetan, to the usual backbone of androgen deprivation therapy and an androgen receptor pathway inhibitor. Researchers said the triple-drug approach reduced the risk of disease progression or death by 28% compared with the previous standard of care alone. The U.S. Food and Drug Administration approved early use of the drug in late July, following the trial results and ongoing analyses.
Trial results point to earlier use of targeted treatment
The PSMAddition trial enrolled more than 1,100 patients with minimally treated or untreated PSMA-positive metastatic prostate cancer across 169 sites in 20 countries. Half received ^177Lu-PSMA-617 every six weeks alongside androgen deprivation therapy and an androgen receptor pathway inhibitor, while the control group received the standard two-drug backbone only. Patients in the control arm could cross over to triple therapy if their cancer progressed.
According to the report, the treatment did more than slow progression on scans. It also extended the time before patients developed resistance and needed to move to another therapy, and it delayed symptoms linked to spread to the skeleton. Researchers said the benefit is especially notable because about 9 in 10 patients with metastatic prostate cancer have PSMA-positive tumours.
Side effects were higher, but expected
The trial also recorded more adverse events in the group receiving ^177Lu-PSMA-617, which the researchers described as an expected result of adding a third therapy. The most common side effect was dry mouth, reported in 46% of patients. Fatigue was also common, reflecting the combined impact of radiation and hormonal treatment.
Experts involved in the study said the drug’s benefit comes with practical limitations. The treatment must be given by nuclear medicine physicians or radiation oncologists, and patients need specialized imaging to confirm eligibility. That means access may be easier at academic centres than in areas with fewer specialists, where some patients may have to travel for care.
Dr. Scott Tagawa, the lead author, said the findings mean patients may now be able to receive ^177Lu-PSMA-617 at diagnosis rather than waiting until the cancer becomes resistant to backbone therapy. The team is continuing to examine longer-term outcomes, including overall survival and safety with extended use.
For clinicians, the study adds another option to a growing set of biomarker-guided treatments for advanced prostate cancer. For patients, it raises the possibility of more time before disease progression, but also highlights the need for careful selection and specialist delivery of care. Source article | Journal abstract
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