Study of I-131-1095 Radiation Therapy in Combination With Enzalutamide in Patients With Metastatic Castration-resistant Prostate Cancer Who Are Chemotherapy Naive and Have Progressed on Abiraterone

Official Title

A Multicentre, Randomized, Controlled Phase 2 Study: Efficacy and Safety of I-131-1095 Radiation Therapy in Combination With Enzalutamide in Metastatic Castration-resistant Prostate Cancer (mCRPC) Patients Who Are 18F-DCFPyL Prostate-specific Membrane Antigen (PSMA)-Avid, Chemotherapy-naive, and Progressed on Abiraterone


This is a multicentre, randomized, controlled, phase 2 clinical trial designed to evaluate the safety and efficacy of I-131-1095 radiation therapy in combination with enzalutamide compared to enzalutamide alone in participants with prostate-specific membrane antigen (PSMA)-avid metastatic castration resistant prostate cancer (mCRPC) who have progressed on abiraterone. Participants must be chemotherapy-naive and must be ineligible or refuse to receive taxane-based chemotherapy at time of study entry. PSMA-avidity will be determined by central imaging review based on assessment of 18F-DCFPyL PET/CT imaging during screening. Eligible participants meeting the PSMA-avidity criteria will be randomized in a 2:1 ratio to receive either I-131-1095 in combination with enzalutamide (80 participants) or enzalutamide alone (40 participants). An interim analysis for efficacy will be performed after a minimum of 48 evaluable participants have PSA data for at least three months following the first dose of randomized treatment. All participants will be followed for efficacy, safety assessments, survival status, adverse events of special interest, and new anti-cancer therapy for at least one year or to the end of the study (whichever is later) following the first dose of randomized treatment. Safety data will be monitored by an independent Data Monitoring Committee and the sponsor.

Trial Description

Primary Outcome:

  • PSA Response Rate
Secondary Outcome:
  • Objective Response Rate (ORR)
  • Radiographic Progression Free Survival (rPFS)
  • Overall Survival (OS)
  • PSA Progression
  • Duration Of Response
  • Time To Initiation Of Next Treatment For Prostate Cancer
  • Incidences Of Treatment-Emergent Adverse Events (TEAEs) and Serious Adverse Events As Assessed by CTCAE v5.0 (Safety Outcome Measure)
  • Adverse Events Resulting In Discontinuation Of Study Drug (Safety Outcome Measure)
  • Physical Examination Findings (Safety Outcome Measure)
  • Changes In Blood Pressure (Safety Outcome Measure)
  • Changes In Heart Rate (Safety Outcome Measure)
  • Changes In Temperature (Safety Outcome Measure)
  • Shift From Baseline In Selected Clinical Chemistry Laboratory Values At Follow-up (Safety Outcome Measure)
  • Shift From Baseline In Selected Hematology Laboratory Values At Follow-up (Safety Outcome Measure)
  • Changes From Baseline In Overall Electrocardiogram (ECG) Assessment At Follow-up (Safety Outcome Measure)
  • Summary Of Concomitant Medications (Safety Outcome Measure)

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