A retrospective, observational study organized by the European Association of Urology’s Young Academic Urologists group examined the performance of lutetium-177 prostate-specific membrane antigen-617 (177Lu PSMA) for the treatment of metastatic castration-resistant prostate cancer (mCRPC).
The real-world study included 233 patients with mCRPC who received 177Lu PSMA from 1 of 8 high-volume European treatment centers. Baseline characteristics and clinical parameters during and after treatment were documented.
A prostate-specific antigen (PSA) decrease of ≥30% was seen in 41.7%, 63.5%, and 77.8% of patients after the first, second, and third treatment cycles, respectively. Restaging performed via PSMA positron emission tomography-computed tomography showed that 33.7% of patients had an imaging-based response, including 2 patients with a complete response. Stable disease was observed in 13.4% of patients.
The median time to progression was 5.0 months, and the median time to the start of a consecutive antineoplastic therapy was 8.5 months.
A PSA decrease ≥30% after the first 2 cycles of 177Lu PSMA (1 cycle: P=.0003; 2 cycles: P=.004), absolute PSA after the first 3 cycles (1 cycle: P=.011; 2 cycles: P=.0005; 3 cycles: P=.002), and a PSA doubling time greater than 6 months (P=.009) were significantly correlated to treatment response.
In patients without visceral metastases (P=.046), gamma-glutamyl transferase ≤31 U/L at the start of 177Lu PSMA therapy was associated with a 1.5 times higher risk of progression.
A PSA decrease ≥30% after the first 2 cycles of 177Lu PSMA can serve as an early marker of response that is easily replicated in clinical practice, demonstrating that 177Lu PSMA can be an effective treatment for patients with mCRPC.