In a study featured at the ESMO Congress 2022, investigators showed that lutetium-177 prostate-specific membrane antigen radioligand therapy (177Lu-PSMA-RLT) exhibited response rates and toxicities comparable with published evidence when administered in a cohort of very old patients with metastatic castration-resistant prostate cancer (mCRPC).
The study’s lead author, Robert Tauber, and colleagues retrospectively enrolled 79 patients with mCRPC aged 80 years or older (median years of age, 82; interquartile range, 81-84) who received 177Lu-PSMA-RLT between March 2016 and September 2021.
Previous treatments included androgen receptor-directed therapy and taxane-based chemotherapy (median number of previous treatment regimens, 2). Fifty (63.3%) patients were chemotherapy-naïve, and 14 (17.7%) had visceral metastases.
Reportedly, all 79 patients demonstrated high uptake of PSMA-ligand at PSMA-PET over a cumulative total of 344 treatment cycles (median number of cycles, 4; range, 1-12). The primary measures of the analyses were best PSA response, progression-free survival (PFS), and overall survival (OS).
According to Tauber, a 90% PSA decline was achieved by 25 (31.6%) patients, and a 50% decline was achieved by 38 (48.1%) patients. The median PFS was 9.5 months, and median OS was 16.5 months.
Notably, chemotherapy-naïve patients had higher PSA response rates compared with patients with prior chemotherapy (50% PSA reduction, 55.1% vs 44.0%, respectively). Moreover, chemotherapy-naïve patients had significantly longer median PFS (11.3 months vs 6.4 months) and OS (20.4 months vs 14.0 months) compared with chemotherapy-treated patients (P<.01).
Grade 3 treatment-related adverse events included 4 cases of anemia, 3 cases of thrombocytopenia, and 6 cases of chronic renal impairment. Tauber noted that no nonhematologic grade 3 and no grade 4 toxicities occurred. Finally, the most common events were grade 1-2 xerostomia, fatigue, and inappetence.
Overall, Tauber suggested that 177Lu-PSMA-RLT demonstrated efficacy and safety profiles consistent with published evidence in a cohort of very old patients with mCRPC.