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Location: Marriott Marquis
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PQA 08 - PQA 08 Genitourinary Cancer, Patient Safety, and Nursing/Supportive Care Poster Q&A

3205 - Psmaddition: Phase 3 Trial of [177lu]Lu-PSMA-617 Plus Standard of Care (SoC) vs. Soc Alone in Patients with Metastatic Hormone-Sensitive Prostate Cancer

Tuesday, October 1, 2024
2:30 PM – 3:45 PM ET
Location: Hall C

Screen: 13

    Presenter(s)

  • Hyun Kim, MD

    Washington University School of Medicine in St. Louis
    St. Louis, Missouri

H. Kim1, S. T. Tagawa2, A. O. Sartor3, F. Saad4, A. Reid5, O. Sakharova6, F. Y. Feng7, K. Fizazi8, and M. Morris9; 1Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO, 2Division of Hematology & Medical Oncology, Weill Cornell Medical College, New York, NY, 3Mayo Clinic, Rochester, MN, 4Urology Department, University of Montreal Hospital Centre, Montreal, QC, Canada, 5Uro-oncology Unit, The Royal Marsden NHS Foundation Trust, Surrey, United Kingdom, 6Development, Novartis Pharmaceuticals AG, Basel, Switzerland, 7Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, 8Cancer Medicine Department, Gustave Roussy Institute, University of Paris-Saclay,, Villejuif, France, 9Genitourinary Oncology Service, Memorial Sloan Kettering Cancer Center, New York, NY

Purpose/Objective(s): Lutetium (177Lu) vipivotide tetraxetan ([177Lu]Lu-PSMA-617) plus protocol-permitted standard of care (SoC) significantly improved radiographic progression-free survival (rPFS) and overall survival (OS) in patients with previously treated, prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer (mCRPC). Androgen deprivation therapy (ADT) and androgen receptor pathway inhibitors (ARPIs) may alter PSMA expression and radiosensitivity. PSMAddition will assess the efficacy and safety of [177Lu]Lu-PSMA-617 plus SoC vs SoC alone in metastatic hormone-sensitive prostate cancer (mHSPC). Materials/

Methods: PSMAddition (NCT04720157) is an international, prospective, open-label, randomized, phase 3 trial in mHSPC. Eligible patients are treatment-naive or minimally treated candidates for hormonal therapy who have PSMA-positive disease (per [68Ga]Ga-PSMA-11 positron emission tomography/computed tomography), an Eastern Cooperative Oncology Group performance status of 0–2, and adequate major organ function. Patients with rapidly progressing tumors requiring chemotherapy are excluded. Eligible p</span>atients are randomized 1:1 to [177Lu]Lu-PSMA-617 (7.4 GBq Q6W; max 6 cycles) plus SoC or SoC alone (ARPI + ADT). Stratification factors are tumor volume (high/low), age (= 70/< 70 years), and previous/planned prostatectomy or radiation treatment of the primary prostate tumor (yes/no). The primary endpoint is rPFS, per Blinded Independent Review Committee. Upon centrally confirmed radiographic progression (rPD), patients receiving SoC alone can crossover to receive [177Lu]Lu-PSMA-617. The planned sample size (n=1126) provides 95% power to detect a hazard ratio of 0.7 for rPFS after 418 events (overall one-sided significance level of 0.025). The key secondary endpoint is OS; other endpoints include the proportion of patients with a prostate-specific antigen (PSA) decline of = 90% from baseline, time to development of mCRPC, composite progression-free survival (radiographic, clinical, or PSA progression), safety and tolerability, and health-related quality of life. Imaging and biospecimen (tissue and blood) collection is embedded for correlative analysis. A second [68Ga]Ga-PSMA-11 scan will be performed in both arms at time of rPD for imaging biomarkers. [177Lu]Lu-PSMA-617-treated patients can enroll in a separate long-term safety follow-up study. Enrollment is complete; 1144 patients have been randomized.
Results: TBO
Conclusion: TBO