Patients were included if they had previous treatment with abiraterone or enzalutamide, or previous taxane-based chemotherapy or determined to be taxane ineligible. Patients also needed to have a positive Galium 68 PSMA tracer uptake in metastasis on a baseline PET scan. Intravenous administration of 177Lu-PSMA was given at 6- to 8- weekly with an activity of 7.4 GBq. Up to 6 cycles were administered in patients without clinical or radiographic expression.
Median age was 72 years with a median PSA of 165 ng/ml. 82 of the patients had received previous docetaxel therapy with over half having greater than 3 previous systemic therapies. Metastatic sites included: 87 patients with nodal disease, 96 patients with bone disease, and 35 with visceral metastasis.
Most common adverse events were grade 1-2 and they included anemia, dry mouth, and fatigue. Most common grade 3-4 toxicities were anemia and neutropenia. PSA decline >30% was seen in approximately half of the patients and >50% in 38 patients. Median clinical progression-free and overall survival was 4.1 months and 12.9 months, respectively. Multivariate subgroup analysis demonstrated a progression-free survival in patients without visceral metastasis of 5.9 months compared to 3.1 months in patients with visceral metastasis (p=0.007). Additionally, overall survival in these cohorts were 14.0 months versus 8.0 months (p=0.03).
In conclusion, 177 Lu-PSMA appears to be safe and active in patients with previous systemic treatments and metastatic castration-resistant prostate cancer. It has a low and acceptable toxicity profile with PSA response. Future prospective trials are needed to evaluate this novel therapy.
Presented by: Matthias Heck, MD, Technical University of Munich, Germany
Co-Authors: Sebastian Schwaiger, Karina Knorr, Margitta Retz, Tobias Maurer, Friederike Janssen, Calogero D`Alessandria, Munich, Germany, Hans-Jürgen Wester, Gauting, Germany, Jürgen Gschwend, Markus Schwaiger, Robert Tauber, Matthias Eiber, Munich, Germany
Written by: David B. Cahn, DO, MBS Fox Chase Cancer Center Philadelphia, PA, @dbcahn at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA