Session: MP11: Prostate Cancer: Advanced (including Drug Therapy) I
MP11-07: Radioligand Therapy with 177Lu-PSMA-I&T in Patients with Metastatic Castration-Resistant Prostate Cancer: Oncological Outcomes and Toxicity Profile
Introduction: Prostate-specific membrane antigen (PSMA) targeted radioligand therapy (RLT) with 177Lu-PSMA-617 is associated with prolonged overall survival in patients with metastatic castration-resistant prostate cancer (mCRPC). Data regarding the oncological efficacy and toxicity profile of 177Lu-PSMA-I&T is limited. Herein, we aimed to investigate the oncological outcomes and toxicity profile of 177Lu-PSMA-I&T RLT in patients with mCRPC. Methods: A total of 33 consecutive patients with mCRPC were treated with a total of 88 cycles (median 2 cycles, range 1-7) of 177Lu-PSMA-I&T RLT. The 177Lu-PSMA-I&T was given with a median activity of 7.5 GBq (IQR: 6.7 – 8.1) per cycle. Response to RLT were assessed according to prostate-specific antigen (PSA) changes and imaging response. Oncological outcomes were reported using clinical progression-free survival (cPFS), and overall survival (OS). Time interval from the first RLT cycle to any radiological or biochemical progression was considered clinical progression-free survival (cPFS). Common Toxicity Criteria for Adverse Events (CTCAE) criteria were utilized to assess toxicity. Results: The mean patient age at the time of the first RLT cycle was 71.6 ± 10.7 years. Any PSA decline was detected in 22 (69%) cases after RLT. The number of patients achieving PSA declines of =30% and =50% were 18 (56%) and 11 (34%), respectively (Figure 1). The cPFS and OS after first cycle of RLT was 6.3 and 21.4 months, respectively. During RLT, nephrotoxicity occurred in 4 cases (12.1%); CTCAE grade according to estimated glomerular filtration rate worsening from I to II (n=2), II to III (n=1), III to IV (n=1). Six patients (18.2%) experienced a grade I/II myelotoxicity and 3 cases (9.1%) had grade III/IV myelotoxicity. Conclusions: 177Lu-PSMA-I&T RLT achieved a good PSA response (=30%) in more than half of the patients with mCRPC with an acceptable toxicity profile. Further studies are required to assess the role of 177Lu-PSMA-I&T RLT in mCRPC. SOURCE OF Funding: Baris Esen is supported by European Urological Scholarship Programme through a 1-year research scholarship.
