Author: Dr. Oliver Sartor (on-camera comments) - Courtesy of ESMO.org
At ESMO 2023, an opportunity arose to present new data from the [177Lu]Lu-PSMA-617 trial, which focused on metastatic KR-resistant prostate cancer in treatment-naive patients. The study compared two agents from different classes: IS lithium and a secondary hormone (either abiraterone or insulin). Eligibility for the study was determined through PSMA PET scans, which revealed that 92% of patients were qualified. A total of 468 patients were randomized, with the primary endpoint being radiographic progression-free survival (rpfs).
The data presented at ESMO showed a significantly positive outcome, with an rpfs Hazard ratio of 0.43. The control arm with hormonal treatment had an rpfs of 5.59 months, while the PIS lithium arm had an rpfs of 12.02 months, more than double that of the control arm. Various secondary endpoints were also considered, including PSA decline and objective response rate. Importantly, crossover-adjusted overall survival indicated that over 80% of eligible patients who progressed while on hormonal treatment discontinued hormones and crossed over to PIS lithium.
Overall, the study demonstrated that IS lithium is highly active in this treatment-naive metastatic prostate cancer space and is well-tolerated, with lower adverse events and discontinuation rates compared to the hormonal arm. This suggests a promising new therapy for patients in this space, pending regulatory approval.