Safety and Tolerability of Atezolizumab (ATZ) in Combination With Radium-223 Dichloride (R-223-D) in Metastatic Castrate-Resistant Prostate Cancer (CRPC) Progressed Following Treatment With an Androgen Pathway Inhibitor
Castrate-Resistant Prostate Cancer

About this trial
This is an interventional treatment trial for Castrate-Resistant Prostate Cancer
Eligibility Criteria
Inclusion Criteria:
- Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
- Life expectancy greater than or equal to (>/=) 12 weeks
- Histologically confirmed, castrate-resistant adenocarcinoma of the prostate
- Measurable disease according to RECIST v1.1
- Multiple bone metastases within 12 weeks prior to study drug
- Participants receiving bisphosphonate or denosumab therapy must have been on a stable dose for at least 4 weeks
- Visceral metastasis and/or lymphadenopathy
- Tumors that are amenable to serial biopsy
- Disease progression according to Prostate Cancer Working Group 2 (PCWG2) criteria during or following treatment with at least one second generation androgen pathway inhibitor (for example, enzalutamide, abiraterone) for metastatic prostate cancer
- Adequate hematologic and end-organ function
- One prior taxane-containing regimen for mCRPC, or refusal or ineligibility of a taxane-containing regimen
Exclusion Criteria:
- History of small-cell or neuroendocrine prostate carcinoma
- Treatment with approved anti-cancer therapy (with the exception of abiraterone) within 3 weeks of study drug. Abiraterone must not be administered within 2 weeks prior to initiation of study treatment
- Participation in another clinical trial/investigation within 28 days prior to study drug
- Brain metastases or active leptomeningeal disease (with the exception of participants with treated epidural disease and no other epidural progression)
- Uncontrolled tumor-related pain
- Uncontrolled hypercalcemia
- Significant cardiovascular disease
- History of autoimmune disease except controlled/treated hypothyroidism, type 1 diabetes mellitus, or certain skin disorders
- Prior allogeneic stem cell or solid organ transplant
- History of pulmonary fibrosis/inflammation, including active tuberculosis
- Human immunodeficiency virus (HIV) or hepatitis B or C
- Prior treatment with cluster of differentiation (CD) 137 agonist, anti-programmed death (PD) 1, or anti-programmed death ligand (PD-L) 1 therapeutic antibody or pathway-targeting agents
- Immunostimulants within 4 weeks or immunosuppressants within 14 days prior to study drug
- Prior radium-223 dichloride or hemibody external radiotherapy
- Systemic strontium-89, samarium-153, rhenium-186, or rhenium-188 for bone metastases within 24 weeks prior to initiation of study treatment
- Spinal compression or structurally unstable bone lesions suggesting impending pathologic fractures based on clinical findings and/or magnetic resonance imaging (MRI)
- Bone marrow dysplasia
- Unmanageable fecal incontinence
Sites / Locations
- City of Hope
- University of California, San Francisco, Helen Diller Family Comprehensive Cancer Center
- Yale School of Medicine
- Georgetown University Medical Center
- Mayo Clinic Hospital - Florida
- Indiana University Health Melvin & Bren Simon Cancer Center
- Tulane University School of Medicine
- University of Michigan Comprehensive Cancer Center
- Karmanos Cancer Institute
- Mayo Clinic - Minnesota
- Comprehensive Cancer Centers of Nevada (CCCN) - Central Valley
- Memorial Sloan-Kettering Cancer Center
- Duke University Hospital
- Thomas Jefferson University Hospital
- University of Pittsburgh - Hillman Cancer Center
- Vanderbilt University Medical Center
- University of Washington
Arms of the Study
Arm 1
Arm 2
Arm 3
Arm 4
Arm 5
Arm 6
Experimental
Experimental
Experimental
Experimental
Experimental
Experimental
Cohort 1: ATZ + R-223-D (Concurrent)
RT Arm A: ATZ + R-223-D (Concurrent)
RT Arm B: ATZ + R-223-D (Staggered, 28-Day R-223-D Run-In)
RT Arm C: ATZ + R-223-D (Staggered, 28-Day ATZ Run-In)
Cohort 2: ATZ + R-223-D (Staggered, 28-Day R-223-D Run-In)
Cohort 3: ATZ + R-223-D (Staggered, 56-Day R-223-D Run-In)
Participants will receive concurrent radium-223 dichloride and atezolizumab for a single-cycle, 28-day dose limiting toxicity (DLT) assessment. If the combination is initially found to be safe and tolerable, additional participants will be randomized to Arms A, B, and C.
If Cohort 1 regimen is found to be safe, additional participants will be randomized to this arm (randomized treatment [RT]) to receive concurrent radium-223 dichloride and atezolizumab.
If Cohort 1 regimen is found to be safe, additional participants will be randomized to this arm to receive radium-223 dichloride in Cycle 1 and radium-223 dichloride and atezolizumab from Cycle 2 onward.
If Cohort 1 regimen is found to be safe, additional participants will be randomized to this arm to receive atezolizumab in Cycle 1 and radium-223 dichloride and atezolizumab from Cycle 2 onward.
If Cohort 1 regimen is not tolerable, Arms A, B, and C will not be introduced and additional participants will be enrolled in this cohort to receive radium-223 dichloride in Cycle 1 and radium-223 dichloride and atezolizumab in Cycle 2. If the regimen is found to be safe, additional participants will be enrolled to receive this same treatment (radium-223 dichloride in Cycle 1 and radium-223 dichloride and atezolizumab from Cycle 2 onward). If, at Cycle 2, Cohort 2 regiment is not tolerable, additional participants will be enrolled in Cohort 3.
If Cohort 2 regimen is not tolerable, additional participants will be enrolled in this cohort to receive radium-223 dichloride in Cycles 1, 2 and radium-223 dichloride and atezolizumab in Cycle 3. If the regimen is found to be safe, additional participants will be enrolled to receive this same treatment (radium-223 dichloride in Cycles 1, 2 and radium-223 dichloride and atezolizumab from Cycle 3 onward). If, at Cycle 3, Cohort 3 regiment is not tolerable, no additional participants will be enrolled in this study.