SPPADE symptom burden and ePRO-based outcome prediction in patients with mCRPC treated with 177 Lu-PSMA-617 (LuPSMA).

142 Background: LuPSMA is a life-prolonging radioligand therapy that is widely considered to have favorable tolerability. SPPADE symptoms (Sleep disturbance, Pain, Physical dysfunction, Anxiety, Depression, low Energy) are common in prostate cancer, yet data on patient-reported outcomes with LuPSMA in real-world settings remain limited. Methods: The E2C2 study (NCT03892967) evaluates the impact of a collaborative care intervention on patient-centered outcomes and healthcare utilization. This analysis includes mCRPC patients who initiated LuPSMA at Mayo Clinic (June 2022-July 2023) and completed at least one symptom survey within 6 weeks before or 2 weeks after the first LuPSMA treatment (baseline survey). SPPADE symptoms were rated on 0-10 scales; scores of 4-6 indicate moderate and 7-10 severe burden. A composite z-score was derived by standardizing each SPPADE domain to the cohort mean and averaging z-scores across domains per patient. Patients were stratified by composite symptom burden using cohort median and upper-tertile cutoffs. Associations with PSA50 response and overall survival (OS, from start of LuPSMA) were assessed using chi-square and Kaplan-Meier methods. In a longitudinal subgroup of patients completing a baseline survey plus at least one additional PRO survey while receiving LuPSMA (≥2 surveys), scores were compared from baseline to best during-treatment using Wilcoxon and Mann-Whitney U tests. Results: Of 373 patients starting LuPSMA, 51 patients met inclusion criteria. Median age was 71 years, 31% had visceral metastases, and median baseline PSA was 42.1 ng/mL. Overall, 85% of patients reported at least one moderate symptom and 46% at least one severe symptom. The most common moderate-to-severe symptoms were low energy (58%), pain (52%), and sleep disturbance (49%). Using an upper-tertile cutoff of the composite SPPADE score, 17 patients had high and 34 had low/moderate symptom burden prior to LuPSMA. PSA50 response was achieved in 17.6% of patients with high vs 47.1% with low/moderate composite symptom scores (p = 0.08). Median OS was 9.2 vs 16.7 months for high vs low symptom groups (p = 0.15, median split). The longitudinal subgroup included 24 patients with serial ePRO assessments while on LuPSMA. Composite SPPADE scores improved from baseline to the best during-treatment assessment in both PSA50 responders (n=10) and non-responders (n=14), with median composite z-score Δ of 0.35 vs 0.20, respectively (p = 0.68). Conclusions: Among patients with mCRPC receiving LuPSMA, baseline SPPADE symptom burden was high. Though not statistically significant in this underpowered cohort, PSA response and OS were numerically inferior in those with higher baseline burden. These findings suggest that ePRO-captured symptom burden may provide prognostic and patient-centered insights beyond traditional clinical variables. Clinical trial information: NCT03892967 .