2019 GU Symposium: Novel Radiolabeled Therapy for Resistant Prostate Cancer
Posted: Tuesday, February 19, 2019
Metastatic castrate-resistant prostate cancer that has progressed despite therapy with standard regimens appears to respond to treatment with a novel, targeted radiation therapy. Lutetium-177 (177Lu)-PSMA-617 (LuPSMA) is a radiolabeled small molecule that binds with high affinity to prostate-specific membrane antigen, enabling targeted delivery of beta-radiation. The results of the phase II, single-arm trial were presented at the 2019 Genitourinary Cancers Symposium in San Francisco (Abstract 228).
“For men in our trial, with cancer cells spread throughout the body, LuPSMA provides a new approach to a form of the disease that has been difficult to treat,” stated Michael Hofman, MBBS, of the Peter MacCallum Cancer Centre, Melbourne, Australia, in a related press release. “It’s exciting to see that LuPSMA can potentially offer benefits for many men with these very aggressive cancers, with few side effects and significant improvements in quality of life.”
A total of 50 men with prostate-specific membrane antigen–positive metastatic, castration-resistant prostate cancer received up to 4 cycles of LuPSMA every 6 weeks. The majority of patients experienced disease progression after therapy with docetaxel (84%), cabazitaxel (48%), and abiraterone and/or enzalutamide (90%).
A decrease in prostate-specific antigen (PSA) level of at least 50% was achieved in 32 men (64%), including 22 men with a decline in PSA level of 80% or more (44%). The median overall survival was 13.3 months, longer than the average 9-month survival time for men with this stage of disease. The most common side effects were nausea, fatigue, and dry mouth; grade 3 and 4 anemia and thrombocytopenia were seen in 10% of treated patients.
When LuPSMA was administered to 14 patients who subsequently experienced disease progression, 64% had a decline in PSA level of at least 50%. “Importantly, we saw continued benefits with LuPSMA retreatment,” noted Dr. Hofman. Based on these early-phase study results, two randomized trials are currently underway to further evaluate LuPSMA.
Disclosure: The study authors’ disclosure information may be found at coi.asco.org.
