Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in Combination With Standard of Care Treatment in Patients With Metastatic Castration Sensitive Prostate Cancer
Phase: PHASE1
Conditions: Castration-Sensitive Prostate Carcinoma, Metastatic Prostate Adenocarcinoma, Stage IVB Prostate Cancer AJCC v8
Sponsor: Emory University

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 1 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
PROTOCOL TITLE: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of 
XmAb20717 in Combination with Standard of Care Treatment in Patients with Metastatic Castration 
Sensitive Prostate Cancer
WINSHIP PROTOCOL #: WINSHIP5741-22
COORDINATING CENTER: Winship Cancer Institute at Emory University
CO-PRINCIPAL INVESTIGATORS:
Name: Bassel Nazha, MD, MPH
Institution: Winship Cancer Institute of Emory University
Address: 36 Linden Avenue, Office 330, Atlanta, Georgia, 30345
Phone: 404-778-1900
Fax: 404-778-8573
Email: bassel.nazha@emory.edu
Name: Mehmet Asim Bilen, MD
Institution: Winship Cancer Institute of Emory University
Address: 1365 Clifton Road NE, B4301
Phone: 404-778-3693
Fax: 404-778-3366
Email: mbilen@emory.edu
CO-INVESTIGATORS:
Jacqueline T Brown, MD
Assistant Professor, Department of Hematology and Medical Oncology
Winship Cancer Institute of Emory University
Bradley Carthon, MD, PhD
Associate Professor, Department of Hematology and Medical Oncology
Winship Cancer Institute of Emory University

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 2 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
Omer Kucuk, MD
Professor, Department of Hematology and Medical Oncology
Winship Cancer Institute of Emory University
Haydn T. Kissick, PhD
Assistant Professor, Department of Microbiology and Immunology
Winship Cancer Institute of Emory University 
David M. Schuster, MD
Professor, Department of Radiology and Imaging Sciences
Emory University School of Medicine
STATISTICIAN:
Name: Yuan Liu, PhD
Institution: Emory University
Address: 1534 Clifton Rd, Atlanta, GA 30322
Phone: 404-778-1989 
Email: yliu31@emory.edu
VERSION:  4, 8/1/2024
FUNDING SOURCE: Xencor
INVESTIGATIONAL PRODUCT (IP): XmAb20717
OTHER AGENT(S):  abiraterone, enzalutamide, docetaxel, Androgen Deprivation Therapy (ADT)
SPONSOR -INVESTIGATOR (IND HOLDER): Bassel Nazha, MD
IND #: 164246

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 3 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
REVISION HISTORY
Revision #
Version 
Date
Summary of Changes
4
8/1/24
Xmab20717 dose was changed to 750mg IV every 3 weeks. 
Enrollment sequence was clarified to start and complete 
Cohort B first. Safety stopping rule was updated to include 
Grade 3 or Grade 4 toxicities. 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 4 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
Table of Contents
1.
Study Summary ..............................................................................................................................................5
2.
Objectives (and Endpoints) ...........................................................................................................................13
3.
Background...................................................................................................................................................15
4.
Study Intervention/Investigational Agent .....................................................................................................17
5.
Procedures Involved .....................................................................................................................................19
6.
Data and Specimen Banking..........................................................................................................................34
7.
Statistical Analysis Plan.................................................................................................................................19
8.
Sharing of Results with Participants ..............................................................................................................36
9.
Study Timelines ............................................................................................................................................36
10.
Inclusion and Exclusion Criteria.....................................................................................................................37
11.
Local Number of Participants ........................................................................................................................39
12.
Recruitment Methods...................................................................................................................................40
13.
Withdrawal of Participants ...........................................................................................................................40
14.
Risks to Participants......................................................................................................................................41
15.
Potential Benefits to Participants..................................................................................................................42
16.
Data Management and Confidentiality .........................................................................................................42
17.
Provisions to Monitor the Data to Ensure the Safety of Participants .............................................................43
18.
Provisions to Protect the Privacy Interests of Participants.............................................................................52
19.
Economic Burden to Participants ..................................................................................................................53
20.
Consent Process............................................................................................................................................53
21.
Setting ..........................................................................................................................................................54
22.
Resources Available ......................................................................................................................................54
23.
References....................................................................................................................................................55
APPENDIX A
PERFORMANCE STATUS CRITERIA ..............................................................................................57
APPENDIX B 
Drug Diary..................................................................................................................................58
APPENDIX C         Abbreviations and definition of terms.........................................................................................60

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 5 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
1. Study Summary
1.1 Synopsis
Title:
Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of 
XmAb20717 in Combination with Standard of Care Treatment in Patients with Metastatic 
Castration Sensitive Prostate Cancer
Study 
Description:
This research study is an open label, multiple-arm, Phase I-Ib study, designed to evaluate 
the safety, tolerability, and preliminary efficacy of XmAb20717 in combination with 
standard of care treatment in patients with metastatic castration-sensitive prostate 
cancer.
Objectives:
Primary Objective:
To determine the safety and tolerability of XmAb20717 in combination with standard of 
care treatment in subjects with metastatic castration-sensitive prostate cancer (mCSPC) as 
assessed by frequency and intensity of adverse events.
Secondary Objectives:
i) To assess preliminary antitumor activity of XmAb20717 with standard of care treatment 
by:
•
Radiographic progression-free survival (rPFS) per PCWG-modified RECIST 1.1 as 
outlined in PCWG31 (soft tissue to be assessed by RECIST 1.1, and bone disease to be 
assessed by PCWG3)
•
Time to: initiation of the first subsequent therapy or death, PSA progression, 
radiographic soft tissue progression, bone progression, first symptomatic skeletal-related 
event
•
PSA response rate (PSA decline 50% from baseline up to 24 weeks from treatment 
initiation) and PSA undetectable rate (PSA < 0.2 ng/mL up to 24 weeks from treatment 
initiation)
•
Overall response rate (ORR) and duration of response (DOR) per PCWG-modified 
RECIST 1.1
(ii) Exploratory: To identify factors that may be indicative of response to XmAb20717 in 
combination with standard of care treatments.
•   Baseline tumor tissue: molecular signatures, immune and tumor cell expression of 
immune checkpoint markers such as PD-L1, and immune cell density.

Peripheral blood: correlative changes in peripheral T-cell subsets, T-cell activation and 
exhaustion, and myeloid derived suppressor cells (MDSC). 

Baseline PSMA PET and FDG-PET role in mCSPC

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 6 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
Endpoints:
Primary Endpoints:
Safety and tolerability:
•
Frequency and intensity of adverse events
•
Vital signs measurement
•
Physical examination
•
Clinical laboratory tests
Secondary Endpoints:
i) To assess the preliminary antitumor activity of XmAb20717 with standard of care 
treatment by:

Radiographic progression-free survival (rPFS) per PCWG-modified RECIST 1.1 
as outlined in PCWG31 (soft tissue to be assessed by RECIST 1.1, and bone 
disease to be assessed by PCWG3)

Time to: initiation of the first subsequent therapy or death, PSA progression, 
radiographic soft tissue progression, bone progression, first symptomatic 
skeletal-related event

PSA response rate: PSA decline 50% from baseline up to 24 weeks from 
treatment initiation

PSA undetectable rate: PSA < 0.2 ng/mL up to 24 weeks from treatment 
initiation)

Overall response rate (ORR) and duration of response (DOR) per PCWG-
modified RECIST 1.1
ii) Exploratory: To identify factors that may be indicative of response to XmAb20717 in 
combination with standard of care treatments. 

Correlate baseline tumor tissue characteristics with response:

Expression profile of tumor cells and surrounding immune cells by 
immunohistochemistry and immunofluorescence

Genomic molecular signatures

Assessment of peripheral blood by flow cytometry for expression of T-cell 
subsets, T-cell activation and exhaustion, and myeloid derived suppressor 
cells (MDSC).

Assess the role of PSMA PET and FDG-PET in mCSPC by categorization 
according to PSMA-dominant, FDG-dominant, similar FDG and PSMA total 
activity, or negative PSMA and FDG statuses. 
Study 
Population:
The patient population consists of subjects ≥18 years of age with advanced or metastatic 
hormone-sensitive prostate adenocarcinoma
Phase:
Phase I-Ib

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 7 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
1.2 Schedule of Assessments
Description of 
Sites/Facilities 
Enrolling 
Participants:
Winship Cancer Institute of Emory University (Atlanta, GA). 
Description of 
Study 
Intervention:
Subjects meeting inclusion criteria will be enrolled into one of the three cohorts, starting 
with Cohort B first. After Cohort B has completed enrollment with no safety concerns 
leading to pausing the trial as defined by the safety stopping rule, the principal investigator 
and Xencor will both review the safety data from Cohort B. Once approved by the principal 
investigator and Xencor, enrollment in Cohort A and C can start.  
a. Cohort A: 
XmAb2071 (750mg IV every 3 weeks, up to 1 year) plus
Abiraterone (1000 mg PO daily) with prednisone 5mg PO daily 
plus 
ADT
b. Cohort B: 
XmAb20717 (750mg IV every 3 weeks, up to 1 year) plus
Enzalutamide (160 mg PO daily)
plus
ADT
c. Cohort C: 
XmAb20717 (750mg IV every 3 weeks, up to 1 year) plus 
Docetaxel (75 mg/m2 for 6 doses only every 3 weeks) plus 
Abiraterone (1000 mg PO daily) with prednisone 5mg PO daily plus 
ADT
ADT may include LHRH agonist or antagonist. Subjects can enroll to this trial within 3 
months of start of ADT. Participant must maintain continuous ADT during study 
treatment or have a history of bilateral orchiectomy.
Study Duration:
Patients will be treated until unacceptable toxicity, death, or disease progression per 
Response Evaluation Criteria In Solid Tumors version 1.1 (RECIST 1.1).

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 8 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
Table 1A: Cohort A Schedule of Assessments (XmAb20717 plus abiraterone plus ADT) † ǂ
(Cycle=21 days)
Pre-
treat
ment
Cycle 1
Cycle 2
Cycle 3
Cycle 
4
Cycle 
5
Cycle 
6 +
Day
Screen 
(Days 
-28 to 
-1)
Day 
1
Day 
8
Day 
1
Day 
8
Day 
1
Day 
8
Day 
1
Day 
1
Day 
1
EOT
14 d 
post-
EOT (± 
2 days)
28 d 
post-
EOT (± 
2 days)
Safety 
Follow-up 
70 d 
post-EOT (+ 
5 days)
F/U (6 and 12 mo after 
ETO)
Informed 
consent
X
Review of 
inclusion
/exclusion 
criteria
X
Medical 
history
X
Physical 
examination
X
X
X
X
X
X
X
X
X
X
X
CBC/CMP
PSA/
Testosterone/
TSH
X
X
X
X
X
X
X
X
X
X
X
PT/PTTΔ
X
X
X
X
X
X
X
X
X
X
XmAb20717
X
X
X
X
X
X
Abiraterone + 
prednisone
X
CT or MRI 
chest/
abdomen/
pelvis*
(every 12 
weeks)
X
X
X
Nuclear 
medicine bone 
scan*
(every 12 
weeks)
X
X
X

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 9 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
EOT = end of treatment, PT=prothrombin time, PTT= partial thromboplastin time.
# Screening procedures performed within 72 hours of Cycle 1 Day 1 (C1D1) do not need to be repeated on C1D1.
*A MRI can be pursued when a CT scan is contraindicated. Either a CT chest/abdomen/pelvis or MRI 
chest/abdomen/pelvis are needed. Staging scans are every 12 weeks (+/- 7 days).
^ Research blood: peripheral blood collection. To be collected only if the subject received the experimental drug 
(Xmab20717) on day 1 of the corresponding cycle and as indicated by the schedule of events. 
 † All days indicated in the table are +/- 2 days, except imaging (+/- 7 days)
ǂ ADT may include LHRH agonist or antagonist. Subjects can enroll to this trial within 3 months of start of ADT. Participant 
must maintain continuous ADT during study treatment or have a history of bilateral orchiectomy.
§ PSMA PET and FDG PET should be separated by > 24 hours (typically at least the second day after one or the other 
PET/CT).
¶ Future stool samples are not needed if a baseline stool sample is not collected.
Δ Collect if the subject is receiving Xmab20717 on Day 1 of the corresponding cycle
PSMA PET §
X
FDG PET §
X
Stool sample ¶
X
X
X
Archival tissue 
collection
X
Research 
blood^
X
X
X
X
X
Monitor
/record 
adverse events
X
X
X
Record of 
medications
X
X
X
X
X
X
X
X
X
X
X
Phone/email/
mail contact 
for progression
/survival
X

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 10 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
Table 2B: Cohort B Schedule of Assessments (XmAb20717 plus enzalutamide plus ADT) † ǂ
(Cycle=21 days)
Pre-
treat
ment
Cycle 1
Cycle 2
Cycle 3
Cycle 
4
Cycle 
5
Cycle 
6 +
Day
Screen 
(Days 
-28 to 
-1)
Day 
1
Day 
8
Day 
1
Day 
8
Day 
1
Day 
8
Day 
1
Day 
1
Day 
1
EOT
14 d 
post-
EOT (± 
2 days)
28 d 
post-
EOT (± 
2 days)
Safety 
Follow-up 
70 d 
post-EOT (+ 
5 days)
F/U (6 and 12 mo after 
ETO)
Informed 
consent
X
Review of 
inclusion
/exclusion 
criteria
X
Medical 
history
X
Physical 
examination
X
X
X
X
X
X
X
X
X
X
X
CBC/CMP/PSA/
Testosterone/
TSH
X
X
X
X
X
X
X
X
X
X
X
PT/PTT Δ
X
X
X
X
X
X
X
X
X
X
XmAb20717
X
X
X
X
X
X
Enzalutamide
X
CT or MRI 
chest/
abdomen/
pelvis*
(every 12 
weeks)
X
X
X
Nuclear 
medicine bone 
scan*
(every 12 
weeks)
X
X
X

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 11 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
EOT = end of treatment, PT=prothrombin time, PTT= partial thromboplastin time.
# Screening procedures performed within 72 hours of Cycle 1 Day 1 (C1D1) do not need to be repeated on C1D1.
*A MRI can be pursued when a CT scan is contraindicated. Either a CT chest/abdomen/pelvis or MRI 
chest/abdomen/pelvis are needed. Staging scans are every 12 weeks.
^ Research blood: peripheral blood collection. To be collected only if the subject received the experimental drug 
(Xmab20717) on day 1 of the corresponding cycle and as indicated by the schedule of events.
† All days indicated in the table are +/- 2 days
ǂ ADT may include LHRH agonist or antagonist. Subjects can enroll to this trial within 3 months of start of ADT. Participant 
must maintain continuous ADT during study treatment or have a history of bilateral orchiectomy.
§ PSMA PET and FDG PET should be separated by > 24 hours (typically at least the second day after one or the other 
PET/CT).
¶ Future stool samples are not needed if a baseline stool sample is not collected.
Δ Collect if the subject is receiving Xmab20717 on Day 1 of the corresponding cycle 
PSMA PET §
X
FDG PET §
X
Stool sample ¶
X
X
X
Archival tissue 
collection
X
Research 
blood^
X
X
X
X
X
Monitor
/record 
adverse events
X
X
X
Record of 
medications
X
X
X
X
X
X
X
X
X
X
X
Phone/email/
mail contact 
for progression
/survival
X

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 12 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
Table 1C: Cohort C Schedule of Assessments (XmAb20717 plus docetaxel plus abiraterone) † ǂ
(Cycle = 21 days)
Pre-
treat
ment
Cycle 1
Cycle 2
Cycle 3
Cycle 
4
Cycle 
5
Cycle 
6 +
Day
Scree
n 
(Day
s -28 
to -1)
Day 
1
Day 
8
Day 1
Day 
8
Da
y 1
Day 
8
Day 
1
Day 
1
Day 
1
EOT
14 d 
post-
EOT (± 
2 days)
28 d 
post-
EOT (± 
2 days)
Safety 
Follow-up 
70 d 
post-EOT (+ 
5 days)
F/U (6 and 12 mo after 
ETO)
Informed 
consent
X
Review of 
inclusion
/exclusion 
criteria
X
Medical 
history
X
Physical 
examination
X
X
X
X
X
X
X
X
X
X
X
CBC/CMP
PSA/
Testosterone/
TSH
X
X
X
X
X
X
X
X
X
X
X
PT/PTT Δ
X
X
X
X
X
X
X
X
X
X
XmAb20717
X
X
X
X
X
X
Docetaxel
X
X
X
X
X
X
Abiraterone + 
prednisone
X
CT or MRI 
chest/
abdomen/
pelvis*
(every 12 
weeks)
X
X
X

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 13 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
EOT = end of treatment, PT=prothrombin time, PTT= partial thromboplastin time.
# Screening procedures performed within 72 hours of Cycle 1 Day 1 (C1D1) do not need to be repeated on C1D1.
*A MRI can be pursued when a CT scan is contraindicated. Either a CT chest/abdomen/pelvis or MRI 
chest/abdomen/pelvis are needed. Staging scans are every 12 weeks.
^ Research blood: peripheral blood collection. To be collected only if the subject received the experimental drug 
(Xmab20717) on day 1 of the corresponding cycle and as indicated by the schedule of events.
 † All days indicated in the table are +/- 2 days
ǂ ADT may include LHRH agonist or antagonist. Subjects can enroll to this trial within 3 months of start of ADT. Participant 
must maintain continuous ADT during study treatment or have a history of bilateral orchiectomy.
§ PSMA PET and FDG PET should be separated by > 24 hours (typically at least the second day after one or the other 
PET/CT).
¶ Future stool samples are not needed if a baseline stool sample is not collected.
Δ Collect if the subject is receiving Xmab20717 on Day 1 of the corresponding cycle
Nuclear 
medicine 
bone scan*
(every 12 
weeks)
X
X
X
PSMA PET §
X
FDG PET §
X
Stool sample 
¶
X
X
X
Archival 
tissue 
collection
X
Research 
blood^
X
X
X
X
X
Monitor
/record 
adverse 
events
X
X
X
Record of 
medications
X
X
X
X
X
X
X
X
X
X
X
Phone/email/
mail contact 
for 
progression
/survival
X

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 14 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
2. Objectives (and Endpoints)
OBJECTIVES
ENDPOINTS
Primary
To determine the safety and tolerability of 
XmAb20717 in combination with standard of care 
treatment in subjects with metastatic castration 
sensitive prostate cancer (mCSPC) as assessed by 
frequency and intensity of adverse events.

Safety: frequency and intensity of adverse 
events, vital signs, physical examinations, 
clinical laboratory test.
Secondary
To assess the preliminary antitumor activity of 
XmAb20717 with standard of care treatment

rPFS per PCWG-modified RECIST 1.1 as 
outlined in PCWG31 (soft tissue to be 
assessed by RECIST 1.1, and bone 
disease to be assessed by PCWG3)

Time to: initiation of the first 
subsequent therapy or death, PSA 
progression, radiographic soft tissue 
progression, bone progression, first 
symptomatic skeletal-related event

PSA response rate: PSA decline ≥50% 
from baseline up to 24 weeks from 
treatment initiation

PSA undetectable rate: PSA < 0.2 
ng/mL up to 24 weeks from treatment 
initiation

Overall response rate (ORR) and 
duration of response (DOR) per PCWG-
modified RECIST 1.1
Tertiary/Exploratory 
To identify factors that may be indicative of response 
to XmAb20717 in combination with standard of care 
treatments.

Correlate baseline tumor tissue 
characteristics with response:

Expression profile of tumor 
cells and surrounding immune 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 15 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
OBJECTIVES
ENDPOINTS
cells by immunohistochemistry 
and immunofluorescence

Genomic molecular signatures

Assessment of peripheral blood by 
flow cytometry for expression of T-
cell subsets, T-cell activation and 
exhaustion, and myeloid derived 
suppressor cells (MDSC)

Role of baseline PET PSMA and 
FDG PET in mCSPC
3. Background
In 2020, it is estimated that 191,000 men in the United States were diagnosed with prostate cancer, of which 
around 20% had metastatic disease. Prostate cancer continues to be the second most common cause of 
cancer-related death in men1. The treatment landscape of advanced prostate cancer is now characterized by a 
variety of systemic therapy options for both metastatic castration sensitive prostate cancer (mCSPC) and 
castration resistant prostate cancer (mCRPC). Most prostate cancer deaths occur in the mCRPC stage 2, and 
preventing or delaying progression from mCSPC to mCRPC remains a major treatment goal. 
The backbone of mCSPC treatment is androgen deprivation therapy (ADT) as the androgen signaling pathway is 
critical for cancer cell growth in this disease. Several large phase III trials have demonstrated that the 
intensification of upfront therapy with either docetaxel chemotherapy or oral androgen signaling pathway 
inhibitors (abiraterone, enzalutamide, or apalutamide) results in significant improvement in overall survival 
compared to ADT alone 3-7. Those agents in addition to ADT are now standard of care in mCSPC. More recently, 
the PEACE-1 trial showed that further treatment intensification with triplet therapy of docetaxel plus 
abiraterone plus ADT results in improved overall survival, setting the stage for a new standard of care option in 
mCSPC, one that is expected to be increasingly used in the frontline setting of mCSPC.8
The choice of upfront therapy in addition to ADT is guided by the volume of metastatic disease (high vs. low), 
performance status, the desired treatment duration, cost, the patient’s comorbid conditions, among other 
factors 9. Docetaxel treatment every three weeks for 6 cycles is a standard of care and preferred option for 
patients with high-volume and/or rapidly progressive mCSPC. Oral androgen signaling inhibitors are approved 
in all patients with mCSPC and are taken continuously until disease progression or unacceptable toxicity. In the 
absence of direct comparator trials of those three agents and no validated biomarker, the choice of the oral 
agent also depends on patient comorbid conditions, their preferences, concomitant medications, and 
treatment cost 10. For instance, abiraterone is given with low-dose prednisone, making it a less desirable option 
in patients where there is a need to avoid mineralocorticoid excess6. Both enzalutamide and apalutamide carry 
an increased risk of falls and fractures compared to ADT alone. Further, there is risk of seizures with 
enzalutamide (0.5%)5 and rash with apalutamide (27%)4. 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Immune-checkpoint blockade with PD-1/PD-L1 inhibitors +/- CTLA-4 inhibitors is now a bedrock of anti-cancer 
therapy across multiple tumor types. This group of therapies offers the potential for durable response in a 
significant subset of patients. Nonetheless, the benefit remains small in prostate cancer with regulatory 
approval only in mCRPC patients with microsatellite instability (<3% incidence). This has been attributed to an 
immunosuppressive tumor microenvironment with few tumor-infiltrating T cells 11. So far, ipilimumab (anti-
CTLA-4) or anti-PD-1/PD-L1 monotherapy failed to show significant benefit in unselected mCRPC patients, with 
overall response rates (ORR) ranging from 0 to 5%12, 13. Novel ways to target immune checkpoint pathways are 
critically needed, especially in prostate cancer, where the tumor microenvironment needs to be converted 
from “cold” to “hot”. Such conversion is possible with anti-CTLA-4 blockade but insufficient alone to generate 
antitumor response 14. 
 
3.1 Study Rationale
Based on recent data, there is a now resurgence of interest in immune-checkpoint inhibition in prostate cancer. 
The preliminary analysis of the CheckMate 650 Trial combining anti-CLTA-4 plus anti-PD-1 (nivolumab 1 mg/kg 
plus ipilimumab 3 mg/kg) in mCRPC showed encouraging ORR of 25% in pre-chemotherapy patients and 10% in 
post-chemotherapy patients, a favorable outcome compared with historical data for immune-checkpoint 
inhibition monotherapies (ORR, 0-5%)15. The results are proof-of-concept that immune-driven antitumor effect 
can indeed be achieved in prostate cancer when both PD-1/PD-L1 and CTLA-4 axes are targeted. However, the 
combination resulted in significant toxicities, with Grade 3-4 treatment-related adverse events in 42%-53% of 
patients. Overcoming such high level of toxicity along with identifying predictive biomarkers will be needed. 
Although most PD-1/PD-L1 +/- Anti-CTLA-4 studies were in mCRPC patients, investigations are now also 
focusing on the mCSPC to prevent or delay the invariable progression to mCRPC. For instance, Arm 3 of the 
ongoing Phase II/III PROSTRATEGY trial (NCT03879122) is investigating the combination of ADT plus ipilimumab 
alternating with docetaxel and nivolumab in patients with Mcspc
XmAb20717 is a bispecific antibody with simultaneous inhibitory effect on PD-1 and CTLA-4. This antibody has 
the potential of both targeting double-checkpoint positive cells in the tumor microenvironment along with 
alleviating the high rate of toxicities associated with combination PD-1/PD-L1 and CTLA-4 blockade, as seen in 
the CheckMate 650 trial. The combined PD-1/CTLA-4 blockade could allow converting the immune-
microenvironment in prostate cancer from “cold” to “hot” and achieve antitumor activity. As such, we propose 
a Phase I-Ib trial of XmAb20717 plus standard treatments in patients with advanced or metastatic castration 
sensitive prostate cancer. 
3.2 Clinical Experience
Data from the DUET 2 Phase 1 study of XmAb20717 in advanced solid tumors were promising, with responses 
observed only at the 10 mg/kg dose level15. The ongoing XmAb20717-04 trial sponsored by Xencor is 
investigating XmAb20717 alone or in combination with chemotherapy or targeted therapies in mCRPC.
In the Xencor Inc. XmAb20717-01 study, the safety profile of XmAb20717 at a dose of 10 mg/kg Q2W was 
considered tolerable and consistent with other anti-PD-1 and anti-CTLA-4 antibodies as single agents or in 
combination. Exposure-safety analysis of data from Study XmAb20717-01 indicated that Ctrough after first 
dose is the best predictor of Grade 3+ irAEs. A range of doses from 500 mg to 1100 mg were modeled for both 
safety and efficacy. Based on this modeling, a dose of 750 mg Q3W is equivalent to 10 mg/kg Q2W for a typical 

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75 kg patient, and the extended interval between doses would lead to lower Ctrough values that may improve 
safety outcomes. Additionally, exposure-efficacy analyses demonstrate that 750 mg Q3W is expected to 
overlap with 10 mg/kg Q2W in terms of clinical activity (Xencor XmAb20717-01 Exposure Response Analysis 
Report-ClinPharm-0001). Thus, a dose of 750 mg Q3W is anticipated to provide improved tolerability and 
similar clinical activity.
4. Study Intervention/Investigational Agent
4.1 Description
XmAb20717
XmAb20717 is a humanized bsAb that binds the immune checkpoint molecules PD1 and CTLA4 in order 
to block signaling that prevents activated T cells from attacking and clearing tumor cells from the body.
XmAb20717 has been designed to maintain full-length humanized monospecific antibody properties in a 
bsAb, enabling the design of stable molecules with favorable in vivo half-life and allowing for the use of 
standard antibody production methods. To generate XmAb20717, Xencor humanized and affinity 
optimized anti-PD1 and anti-CTLA4 antibodies and combined them in a single bispecific molecule. 
XmAb20717 is produced as a 3-chain scFv-Fab-Fc antibody (Figure 1), in which the single chain variable 
fragment (scFv) domain targets PD1 and the fragment, antigen-binding (Fab) domain targets CTLA4. The 
neonatal Fc receptor (FcRn) affinity has been increased via amino acid engineering to improve serum 
half-life relative to antibodies containing native immunoglobulin G (IgG) Fc domains.
Figure 1: Schematic of XmAb20717 PD1 × CTLA4 Bispecific Monoclonal Antibody
Abiraterone

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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Abiraterone acetate, the active ingredient of ZYTIGA is the acetyl ester of abiraterone. Abiraterone is an 
inhibitor of CYP17 (17α-hydroxylase/C17,20-lyase). Each ZYTIGA tablet contains 250 mg of abiraterone 
acetate. Abiraterone acetate is designated chemically as (3β)- 17-(3-pyridinyl)androsta-5,16-dien-3-yl 
acetate. 
Abiraterone acetate is a white to off-white, non-hygroscopic, crystalline powder. Its molecular formula 
is C26H33NO2 and it has a molecular weight of 391.55. Abiraterone acetate is a lipophilic compound 
with an octanol-water partition coefficient of 5.12 (Log P) and is practically insoluble in water. The pKa 
of the aromatic nitrogen is 5.19.
Inactive ingredients in the tablets are lactose monohydrate, microcrystalline cellulose, croscarmellose 
sodium, povidone, sodium lauryl sulfate, magnesium stearate, and colloidal silicon dioxide.
For full information, see FDA label for ZYTIGA (Abiraterone):
https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/202379lbl.pdf
Enzalutamide
Enzalutamide is an androgen receptor inhibitor. The chemical name is 4-{3-[4-cyano-3-
(trifluoromethyl)phenyl]-5,5- dimethyl-4-oxo-2-sulfanylideneimidazolidin-1-yl}-2-fluoro-N-
methylbenzamide.
The molecular weight is 464.44 and molecular formula is C21H16F4N4O2S.
Enzalutamide is a white crystalline non-hygroscopic solid. It is practically insoluble in water.
XTANDI is provided as liquid-filled soft gelatin capsules for oral administration. Each capsule contains 
40 mg of enzalutamide as a solution in caprylocaproyl polyoxylglycerides. The inactive ingredients are 
caprylocaproyl polyoxylglycerides, butylated hydroxyanisole, butylated hydroxytoluene, gelatin, 
sorbitol sorbitan solution, glycerin, purified water, titanium dioxide, and black iron oxide.
For full information, see FDA label for Xtandi (Enzalutamide)
https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/203415s014lbl.pdf
Docetaxel
Docetaxel is an antineoplastic agent belonging to the taxoid family. It is prepared by semisynthesis 
beginning with a precursor extracted from the renewable needle biomass of yew plants. The chemical 
name for docetaxel is (2R,3S)-N-carboxy-3-phenylisoserine,N-tert-butyl ester, 13-ester with 5β-20-
epoxy-1,2α,4,7β,10β,13α-hexahydroxytax-11-en-9-one 4-acetate 2-benzoate, trihydrate. 
Docetaxel is a white to almost-white powder with an empirical formula of C43H53NO14•3H2O, and a 
molecular weight of 861.9. It is highly lipophilic and practically insoluble in water.
TAXOTERE (docetaxel) Injection is a sterile, non-pyrogenic, pale-yellow to brownish-yellow solution at 
20 mg/mL concentration. 
Each mL contains 20 mg docetaxel (anhydrous) in 0.54 grams polysorbate 80 and 0.395 grams 
dehydrated alcohol (50% v/v) solution, with citric acid for pH adjustment. 

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TAXOTERE is available in single-dose vials containing 20 mg (1 mL) or 80 mg (4 mL) docetaxel 
(anhydrous). 
TAXOTERE Injection requires NO prior dilution with a diluent and is ready to add to the infusion 
solution.
For full information, see FDA label for Taxotere (Docetaxel)
https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/020449s084lbl.pdf
4.2 Drug Accountability
The study drugs provided for this study will be used only as directed in the study protocol. The Winship IDS 
(Investigational Drug Service) personnel will account for all study drugs. Drug accountability should be performed 
until the patient stops study treatment completely. Study site personnel will account for all study drugs received 
at the site. Study drug supplies will be kept in an appropriate, secure locked area and stored in accordance with 
the conditions specified on the labels. The Investigator, pharmacist, or designee must maintain an accurate 
record of dispensing the study drug/s in a Drug Accountability Log.
The Drug Accountability Log will record specifics to study drug dispensation such as: 
• Records of product delivery, inventory, temperature monitoring, destruction, and return.
• Dosages prepared, time prepared, doses dispensed. 
• Doses and/or vials destroyed. 
Drug accountability may be noted by the internal monitor during site visits and at the completion of the study. 
The study drug supply will be disposed of per Winship’s Investigational Drug Service (IDS) SOP.
Compliance will be assessed by the investigator and/or study personnel at each patient visit. This information 
must be captured in the source document at each patient visit. 
Dose changes and interruptions of study drug must be specifically documented in the patient source 
documents and eCRF.
The designated site personnel will be responsible for maintaining accurate records of the quantity and dates of 
all study drug supplies received, dispensed, and returned, in accordance with applicable regulations and the site’s 
SOPs.  The quantity of study drug lost, destroyed, or otherwise unaccounted for must also be accounted for and 
documented.
5. Procedures Involved
5.1 Study Design
This is a multi-arm Phase 1-1b study of XmAb20717 in combination with standard of care treatment in patients 
with metastatic castration sensitive prostate cancer.
Subjects meeting inclusion criteria will be enrolled into one of the three cohorts, starting with Cohort B 
(enzalutamide) first. After Cohort B has completed enrollment with no safety concerns leading to pausing the 
trial as defined by the safety stopping rule, the principal investigator and Xencor will both review the safety 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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data from Cohort B. Once approved by the principal investigator and Xencor, the enrollment in Cohort A 
(abiraterone) and C (abiraterone plus docetaxel) can start.  
The study is divided into a Screening period, Treatment period, End of Treatment (EOT) period, and Follow-up 
period.
During Screening period patients will provide written informed consent to participate in the study before 
completing any protocol-specified procedures or evaluations not considered to be part of the patient’s 
standard care.  Procedures that were performed for standard of care prior to signing informed consent may be 
used for screening purposes (e.g., full physical exam) as long as the procedures were completed within the 28-
day screening period.  After signing the ICF, patients will be evaluated for entry criteria during the screening 
period within 28 days before administration of study drug(s).  
Treatment will continue until unacceptable toxicity, death, or disease progression per RECIST 1.1, Investigator’s 
decision to discontinue treatment, the patient withdraws consent, is lost to follow-up, or Institution decides to 
terminate the trial.
Patients with PD per RECIST 1.1 but with otherwise stable or improved performance and clinical status may 
continue to be treated in the event of a perceived benefit per Investigator and if all of following criteria are 
met:

Absence of symptoms and signs indicating clinically significant progression of disease

No decline in ECOG or Karnofsky performance status

Absence of symptomatic rapid disease progression requiring urgent medical intervention (e.g., 
symptomatic pleural effusion, spinal cord compression)

Re-consent of patients using an informed consent document that details all FDA-approved therapies for 
their condition and the clinical benefits of those therapies that the patient would be foregoing to 
continue on study
Patients with a PR or SD will continue to receive treatment until achievement of a confirmed complete 
response (CR), disease progression, or intolerability to therapy.  It is at the discretion of the Investigator to 
continue treating patients with a confirmed CR.
5.2 Dosing and Administration
Cohort A: XmAb20717 plus abiraterone
Regimen Description
Agent
Dose
Route
Schedule
Cycle Length
XmAb20717 750mg
IV
Every 3 weeks
Abiraterone 1000mg
PO
Daily
3 weeks

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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Cohort B: XmAb20717 plus enzalutamide
Regimen Description
Agent
Dose
Route
Schedule
Cycle Length
XmAb20717
750mg
IV
Every 3 weeks
Enzalutamide 160mg
PO
Daily
3 weeks
Cohort C: XmAb20717 plus docetaxel plus abiraterone
Regimen Description
Agent
Dose
Route
Schedule
Cycle Length
XmAb20717 750mg
IV
Every 3 weeks
Docetaxel
75mg/m2
IV
Every 3 weeks
Abiraterone
1000mg
PO
Daily
3 weeks
Participant must maintain continuous ADT during study treatment or have a history of bilateral orchiectomy. 
ADT may include LHRH agonist or antagonist. Subjects can enroll to this trial within 3 months of start of ADT. 
XmAb20717 administration
XmAb20717 administration should begin as soon as possible after the dosing solution is made. If there is a 
delay in administration, the dosing solution may be stored at 2 °C to 8 °C for no more than 24 hours or at room 
temperature for no more than 4 hours prior to infusion. The full calculated dose will be administered based on 
the subject’s actual baseline weight measurement in kilograms. Following the first dose, subsequent doses will 
be modified only if the subject’s weight changes by more than 10% from the baseline (Day -1 or Day 1, 
assessment closest to the first dose) weight, at which point it will be recalculated using the current weight.
XmAb20717 SHOULD NOT BE ADMINISTERED AS AN IV PUSH OR BOLUS.
XmAb20717 will be administered as an open-label solution at a constant rate over a 1-hour period. Precautions 
for infusion reactions/anaphylaxis should be observed during XmAb20717 administration. Due to the possibility 
that allergic/infusion reactions may occur, emergency resuscitation equipment (a “crash cart”) should be 
present in the immediate area where subjects are receiving their infusions. Additional supportive measures 
should be available and may include, but are not limited to, acetaminophen, antihistamines, corticosteroids, IV 
fluids, bronchodilators, epinephrine, vasopressors, diphenhydramine, and oxygen. 
All supportive measures consistent with optimal subject care will be provided throughout the study according 
to institution standards.
Abiraterone
Abiraterone is 1,000 mg (four 250 mg capsules) will be administered orally once daily in combination with 
prednisone 5 mg administered orally daily. Abiraterone must be taken on an empty stomach. No food should be 

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consumed for at least two hours before the dose of abiraterone is taken and for at least one hour after the dose 
of abiraterone is taken. Abiraterone will be prescribed by the treating physician and dispensed by Winship IDS. 
Abiraterone will be supplied and packaged commercially. Store as directed on the package insert. 
Enzalutamide
Enzalutamide 160 mg (four 40 mg capsules) will be administered orally once daily. Swallow capsules whole. 
Enzalutamide can be taken with or without food. Enzalutamide will be prescribed by the treating physician and 
dispensed by Winship IDS. Enzalutamide will be supplied and packaged commercially. Store as directed on the 
package insert. 
Docetaxel 
Docetaxel will be administered 75 mg/m2 IV every 3 weeks. Docetaxel will be prescribed by the treating 
physician and dispensed by Winship IDS. Docetaxel will be supplied and packaged commercially. Store as 
directed on the package insert.
5.3 Dose Modification
The investigator will decide whether any AE that occurs is related to either of both drug categories 
(experimental and standard of care) and determine whether dose modification or discontinuation of one or all 
drugs is required per the guidance below.
General Safety Considerations
The following should be taken into consideration in decisions regarding management of treatment-
related AEs.

The study drug (XmAb20717) and standard of care drugs administered on the study have class-
specific safety profiles based on the mechanism of action but may also cause AEs that overlap.

As a general approach, all AEs should be managed with supportive care at the earliest signs of 
toxicity, including both pharmacological and nonpharmacological treatments, according to 
consensus management guidelines.

Grade 2 and 3 AEs usually require dose modifications including dose reductions and 
interruptions.  Dose interruptions of any study drug for adverse events may occur at any time 
and independently at the discretion of the investigator.

Dose modifications as specified in the United States Package Insert (USPI) should be followed for each 
commercial drug administered.

If XmAb20717 is interrupted for more than 12 weeks, treatment should be discontinued unless 
continuation is approved by the Principal Investigator. 

If XmAb20717 is permanently discontinued due to toxicity, the subject can remain on the study while 
receiving the standard of care drugs administered on the study (see Schedule of Events: the subject 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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would not need the research peripheral blood, PT/PTT collections for trial purposes on cycles where 
they are not receiving XmAb20717)
XmAb20717
IrAEs can happen with XmAb20717 and may involve every organ or tissue. Most irAEs occur within the first 12 
weeks of exposure to an immune-checkpoint inhibitor, but some of them may appear with a delayed onset. 
Diagnosis of irAEs should be based on exposure to XmAb20717 and a reasonable immune-based mechanism of 
the observed AE. Whenever possible, histologic examination or other immune-based diagnostic evaluations 
should be used to support the diagnosis. Other etiologic causes, including AEs due to tumor progression, should 
be ruled out.
The spectrum of irAEs is wide and can be general or organ specific. Examples of general irAEs in subjects 
treated with immune-checkpoint inhibitors are fatigue, fever, and chills. Organ-specific irAEs consist of 
pneumonitis, colitis, hepatitis, nephritis and renal dysfunction, skin adverse reactions, encephalitis, 
myocarditis, and endocrinopathies. 
Early recognition and management of irAEs associated with immune-oncology agents may mitigate severe 
toxicity. Medical management of irAEs should focus on suppressing the immune response with nonsteroidal 
and steroidal anti-inflammatory medication. Management algorithms have been developed by the National 
Comprehensive Cancer Network (NCCN) and should be followed for subjects with suspected irAEs. 
Dose Modification for Adverse Events Associated XmAb20717
The management principles of XmAb20717 follow the NCCN guidelines for Management of Immunotherapy-
Related Toxicities. Please refer to those guidelines for any additional immune-related adverse events or for 
additional details as needed. 
XmAb20717 should be permanently discontinued for any patient who experiences any Grade 4 toxicity that is 
at least possibly treatment-related. 
Dermatological Adverse Event Management Algorithm
Adverse Event
Grade
Management
1
Continue immunotherapy 
Topical emollient 
Oral antihistamine for pruritus 
Treatment with moderate potency topical steroids to affected 
areas 
2
Continue immunotherapy 
Topical emollient 
Oral antihistamine for pruritus 
Treatment with moderate potency topical steroids to affected 
areas
If unresponsive to topical within 1 week, consider prednisone 
0.5mg/kg/day
Maculopapular Rash 
3 or 4
G3: withhold immunotherapy
G4: permanently discontinue immunotherapy 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Topical emollient 
Oral antihistamine for pruritus 
Treatment with moderate potency topical steroids to affected 
areas 
1
Continue immunotherapy 
Oral antihistamines 
Treatment with moderate potency topical steroids to affected 
areas or lidocaine patches for localized pruritus 
2
Continue immunotherapy with intensified antipruritic therapy 
Oral antihistamines 
Consider GABA agonists (gabapentin, pregabalin) 
Treatment with high potency topical steroids to affected areas 
Dermatology consultation 
Pruritus 
3 or 4
G3: withhold immunotherapy
G4: permanently discontinue immunotherapy 
Oral antihistamines 
Prednisone/methylprednisolone 0.5 – 1 mg/kg/day 
Consider GABA agonists (gabapentin, pregabalin) 
Consider aprepitant or omalizumab for refractory cases 
Urgent dermatology consultation 
1
Hold immunotherapy 
High potency topical steroids to affected areas 
2
Hold immunotherapy until < G1 
Prednisone/methylprednisolone 0.5 – 1 mg/kg/day 
If no improvement after 3 days, consider adding rituximab 
Bullous dermatitis 
3 or 4
G3 and G4: Permanently discontinue immunotherapy 
Prednisone/methylprednisolone 1 – 2 mg/kg/day 
If no improvement after 3 days, consider adding rituximab or 
IVIG (1 g/kg/day in divided doses per package insert for 3 – 4 
days) 
Inpatient care required 
Urgent dermatology, ophthalmology, and urology consultation 
SJS or TEN
N/A
Permanently discontinue immunotherapy 
Prednisone/methylprednisolone 1 – 2 mg/kg/day 
Consider IVIG (1 g/kg/day in divided doses per package insert for 
3 – 4 days) 
Inpatient care required 
Urgent dermatology, ophthalmology, and urology consultation 
Gastrointestinal Adverse Event Management Algorithm 
Adverse Event 
Grade 
Management 
Diarrhea or colitis 
1 
Consider holding immunotherapy 
Loperamide or diphenoxylate/atropine for 2 – 3 days 

If no improvement and not already done, obtain 
labs for infectious workup 

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Hydration 
Close monitoring 
o
If persistent or progressive symptoms, check 
lactoferrin o If positive, treat as G2 (below) 
o If negative and no infection, continue G1 
management and add mesalamine, cholestyramine 
2 
Hold immunotherapy Prednisone/methylprednisolone 
(1 – 2 mg/kg/day) 
No response in 2 – 3 days, continue steroids, consider 
adding infliximab or vedolizumab within 2 weeks 
3 or 4 
G3: discontinue immunotherapy, consider resuming 
after resolution of toxicity 
G4: Permanently discontinue immunotherapy. Consider 
inpatient care for provision of supportive care 
IV methylprednisolone (1 – 2 mg/kg/day) 

No response in 2 days, continue steroids, 
strongly consider adding infliximab or 
vedolizumab within 2 weeks 

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Hepatic Adverse Event Management Algorithm 
Adverse Event 
Grade 
Management 
1 
< 3 × ULN 
Continue immunotherapy, consider holding immunotherapy for 
concerning lab value trend 
Assess transaminases and bilirubin with increased frequency 
2 
3 – 5 × ULN 
Hold immunotherapy 
Monitor LFTs every 3 – 5 days 
Consider prednisone 0.5 – 1 mg/kg/day 
3 
5 – 20 × ULN 
Permanently discontinue immunotherapy 
Initiate prednisone 1 – 2 mg/kg/day 
Consider inpatient care 
Monitor liver enzymes every 1 – 2 days 
Hepatology consultation 
If steroid refractory or no improvement after 3 days, consider adding 
mycophenolate 
Infliximab should not be used for hepatitis 
Transaminitis without elevated 
bilirubin 
4 
> 20 × ULN 
Permanently discontinue immunotherapy 
Initiate prednisone/methylprednisolone 2 mg/kg/day 
Inpatient care 
Monitor liver enzymes daily 
Hepatology consultation 
Liver biopsy if no contraindications 
If steroid refractory or no improvement after 3 days, consider adding 
mycophenolate 
Infliximab should not be used for hepatitis 
Grade > 1 transaminitis with 
bilirubin > 1.5 × ULN (unless 
Gilbert’s syndrome) 
N/A 
Permanently discontinue immunotherapy 
Initiate prednisone/methylprednisolone 2 mg/kg/day 
Inpatient care 
Monitor liver enzymes daily 
Hepatology consultation 
If steroid refractory or no improvement after 3 days, consider adding 
mycophenolate 
Infliximab should not be used for hepatitis 

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Pancreatic Adverse Event Management Algorithm 
Adverse Event 
Grade
Management
Mild ≤ 3 × ULN amylase and/or ≤ 3 × ULN lipase 
If isolated elevation of enzymes without 
evidence of pancreatitis, continue 
immunotherapy 
Evaluate for pancreatitis 
•
• Clinical assessment 
•
• Consider abdominal CT with 
contrast 
•
• Consider MRCP 
If evidence of pancreatitis, manage according 
to pancreatitis algorithm (below) 
Consider other causes for elevated 
amylase/lipase 
Moderate > 3 – 5 × ULN amylase and/or > 3 – 5 
× ULN lipase 
If isolated elevation of enzymes without 
evidence of pancreatitis, consider continuing 
immunotherapy 
Evaluate for pancreatitis 
•
• Clinical assessment 
•
• If persistent moderate to severe 
amylase and/or lipase elevation, abdominal CT 
with contrast or MRCP 
Consider other causes for elevated 
amylase/lipase 
If evidence of pancreatitis, manage according 
to pancreatitis algorithm (below) 
Elevation in 
amylase/lipase 
(asymptomatic) 
Severe 
> 5 × ULN amylase and/or > 5 × ULN lipase 
If isolated elevation of enzymes without 
evidence of pancreatitis, consider continuing 
immunotherapy 
Evaluate for pancreatitis 
•
• Clinical assessment 
•
• If persistent moderate to severe 
amylase and/or lipase elevation, abdominal CT 
with contrast or MRCP 
Consider other causes for elevated 
amylase/lipase 
If evidence of pancreatitis, manage according 
to pancreatitis algorithm (below) 
1
Consider gastroenterology referral 
IV hydration 
Manage as per elevation in amylase/lipase 
(asymptomatic; above) 
Acute pancreatitis 
2
Hold immunotherapy 
Prednisone/methylprednisolone 0.5 – 1 
mg/kg/day 
IV hydration 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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3 or 4
G3 and G4: Permanently discontinue 
immunotherapy 
Prednisone/methylprednisolone 1 – 2 
mg/kg/day 
IV hydration 
CT =computed tomography; IV = intravenous; MRCP =magnetic resonance cholangiopancreatography; N/A = not 
applicable; ULN = upper limit of normal. 
Pulmonary Adverse Event Management Algorithm 
Adverse Event 
Grade 
Management 
1
Consider holding immunotherapy 
Reassess in 1 – 2 weeks 
•
• H&P 
•
• Pulse oximetry (resting and with ambulation) 
Consider chest CT with contrast 
•
• Consider repeat chest CT in 4 weeks or as clinically indicated for 
worsening symptoms 
2
Hold immunotherapy 
Consider pulmonary consultation 
Consider infectious workup: 
•
• Nasal swab for potential viral pathogens 
•
• Sputum culture, blood culture, and urine antigen test 
(pneumococcus, legionella) 
Consider bronchoscopy with BAL to rule out infection (if feasible, perform 
bronchoscopy with BAL prior to initiation of treatment to rule out infection) 
Consider chest CT with contrast 
•
• Repeat chest CT in 3 – 4 weeks 
Recommend infectious evaluation with institutional immunocompromised 
panel 
Consider empiric antibiotics if infection has not yet been fully excluded 
Prednisone/methylprednisolone 1 – 2 mg/kg/day 
Monitor every 3 – 7 days with: 
•
• H&P 
•
• Pulse oximetry (resting and with ambulation) 
If no improvement after 48 – 72 hours of corticosteroids, treat as Grade 3 
Pneumonitis
3 or 4 
G3 and G4: Permanently discontinue immunotherapy 
Inpatient care 
Infectious workup: 
•
• Consider that patient may be immunocompromised 
•
• Nasal swab for potential viral pathogens 
•
• Sputum culture, blood culture, and urine culture 
Pulmonary and infectious disease consultation 
Bronchoscopy with BAL to rule out infection and malignant lung infiltration 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Consider empiric antibiotics if infection has not yet been fully excluded 
Methylprednisolone 1 – 2 mg/kg/day. Assess response within 48 hours and 
plan taper over ≥ 6 weeks 
Consider adding any of the following if no improvement after 48 hours: 
• Infliximab 5 mg/kg IV, a second dose may be repeated 14 days later at the 
discretion of the treating provider 
• IVIG 
•
Mycophenolate mofetil 1 – 1.5 g BID then taper in consultation with 
pulmonary service 
BAL = bronchoalveolar lavage; BID = twice a day; CT =computed tomography; H&P = history and physical; IV = intravenous; 
IVIG = intravenous immunoglobulin
 Endocrine Adverse Events Management Algorithm
Event
Management
Asymptomatic hypothyroidism

Continue immunotherapy.

Monitor TSH and T4 closely, every 4-6 weeks

Consider treatment with levothyroxine if TSH >10
Symptomatic hypothyroidism

Continue immunotherapy

Initiate treatment with levothyroxine

Monitor TSH and T4 closely, every 4-6 weeks

Consider patient referral to endocrinologist.

Exclude concomitant adrenal insufficiency (morning cortisol level)
Thyrotoxicosis

Suspected with low or suppressed TSH with high free T4/total T3

Consider endocrine consultation

Can continue immunotherapy if asymptomatic

Consider propranolol or atenolol or metoprolol PRN for symptoms until 
thyrotoxicosis resolves.

Repeat TSH/free T4/total T3 in 4-6 weeks
Hypophysitis

Check cortisol, ACTH, TSH, free T4, LH, FSH, testosterone

Obtain Brain MRI with and without contrast with pituitary/sellar cuts if 
symptomatic

Endocrine consultation

Hold immunotherapy until acute symptoms resolve and hormone 
replacement is initiated

If acute severe symptoms with concern for mass effect, may carefully 
consider high-dose steroids
Hyperglycemia

Consider new-onset immunotherapy-related Type I Diabetes Mellitus 
(DM)

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Renal Adverse Event Management Algorithm
Adverse Event 
Grade
Management 
Elevated serum creatinine/acute 
renal failure 
1
Consider holding immunotherapy 
Follow creatinine and urine protein every 3 – 7 days 
2 
Hold immunotherapy 
Follow creatinine and urine protein every 3 – 7 days 
Nephrology consultation, consider renal biopsy 
Start prednisone 0.5 – 1 mg/kg/day if other causes are ruled out 
For persistent G2 beyond 1 week, prednisone/methylprednisolone 1 
– 2 mg/kg/day
3 or 4 
Permanently discontinue immunotherapy 
Consider inpatient care 
Prednisone/methylprednisolone 1 – 2 mg/kg/day 
Nephrology consultation 
Consider renal biopsy 
Consider adding one of the following if > G2 after 1 week of steroids: 
• Azathioprine 
• Cyclophosphamide (monthly) 
• Cyclosporine 
• Infliximab 
• Mycophenolate 
Additional Immune-related adverse events management algorithm (cardiac/vascular, nervous system, 
musculoskeletal and connective tissue, and hematologic/immune)
Management will follow the NCCN Guidelines on Management of Immunotherapy-Related Toxicities 
(Version 01.2022)16.

Investigate for diabetic ketoacidosis if needed and per institutional 
guidelines.

If C-peptide is low (consistent with Type I DM), obtain endocrine consult, 
initiate insulin, and management any present DKA per institutional 
guidelines

If C-peptide is appropriate for serum glucose, continue serum glucose 
monitoring, continue immunotherapy, and consider alternative causes of 
hyperglycemia. 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Docetaxel
Dose modifications is required for febrile neutropenia, ANC <500/mm3 for >1 week, severe/cumulative 
cutaneous reactions, or moderate neurosensory symptoms (e.g., paresthesia, dysesthesia, pain): 

Reduce dose to 60 mg/m2; discontinue therapy if toxicities persist at lower dose.
Abiraterone
Hepatotoxicity
For patients who develop hepatotoxicity during treatment with abiraterone (ALT and/or AST greater than 5X 
ULN or total bilirubin greater than 3X ULN), interrupt treatment with abiraterone. Treatment may be restarted 
at a reduced dose of 750 mg once daily following return of liver function tests to the patient’s baseline or to 
AST and ALT less than or equal to 2.5X ULN and total bilirubin less than or equal to 1.5X ULN. For patients who 
resume treatment, monitor serum transaminases and bilirubin at a minimum of every two weeks for three 
months and monthly thereafter.
If hepatotoxicity recurs at the dose of 750 mg once daily, re-treatment may be restarted at a reduced dose of 
500 mg once daily following return of liver function tests to the patient’s baseline or to AST and ALT less than or 
equal to 2.5X ULN and total bilirubin less than or equal to 1.5X ULN.
If hepatotoxicity recurs at the reduced dose of 500 mg once daily, discontinue treatment with ZYTIGA. The 
safety of ZYTIGA re-treatment of patients who develop AST or ALT greater than or equal to 20X ULN and/or 
bilirubin greater than or equal to 10X ULN is unknown.
Enzalutamide
If a patient experiences a ≥ Grade 3 toxicity or an intolerable side effect, withhold dosing for one week or until 
symptoms improve to ≤ Grade 2, then resume at the same or a reduced dose (120 mg or 80 mg), if warranted. 
See package insert for full information
5.4 Concomitant medication
Medications or vaccinations specifically prohibited in the exclusion criteria are not allowed during the ongoing 
trial.  If there is a clinical indication for one of these or other medications or vaccinations specifically prohibited 
during the trial, discontinuation from trial therapy or vaccination may be required

Concurrent anti-cancer therapy with agents other than the Primary Study combination drug therapy 
is not allowed at any time during the study.

Participant must maintain continuous ADT during study treatment or have a history of bilateral 
orchiectomy. ADT may include LHRH agonist or antagonist with or without concurrent first-
generation antiandrogens. Subjects can enroll to this trial within 3 months of start of ADT. 

Systemic pharmacologic doses of corticosteroids ≥ 10 mg/day prednisone are generally not 
permitted at the time of study enrollment.  However, higher doses of corticosteroids may be allowed 
for subjects with a diagnosis of adrenal insufficiency.  IND Sponsor consultation is required prior to 
enrollment of subjects with adrenal insufficiency.  Subjects who require corticosteroid therapy in 
such doses for the management of autoimmune toxicities or palliation for pain, brain metastases, or 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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other disorders may remain on study if in the Investigator’s judgment this is in the best interest of 
the subject.
5.5 Study Procedures
Before study entry, throughout the study, and following study drug discontinuation, various clinical and 
diagnostic laboratory evaluations are outlined.  The purpose of obtaining these detailed measurements is to 
ensure adequate safety and tolerability assessments.  Clinical evaluations and laboratory studies may be 
repeated more frequently if clinically indicated.  The Schedules of Assessments during the screening and 
treatment period is provided following the Protocol Synopsis. 
Screening Phase
Screening procedures will be performed up to 28 days prior to enrollment unless otherwise specified.  All subjects 
must first read, understand, and sign the IRB-approved ICF before any study-specific screening procedures are 
performed.  After signing the ICF, completing all screening procedures, and being deemed eligible for entry, 
subjects will be enrolled in the study.  Procedures that are performed prior to the signing of the ICF and are 
considered standard of care may be used as screening assessments if they fall within the screening window. 
The following procedures will be performed during the Screening Visit:

Informed Consent

Review of eligibility criteria

Medical history and demographics

Complete physical exam 

ECOG Performance Status

Vitals signs, weight and height 

Review of prior/concomitant medications 

Imaging by CT or MRI (chest, abdomen, pelvis) 

PSMA PET

FDG PET

Stool sample collection

Clinical laboratory tests for:
o
Hematology 
o
Clinical chemistry 
o
TSH
o
Coagulation (PT, PTT)
o
PSA
o
Testosterone
Treatment Phase 
Procedures to be conducted during the treatment phase of the study are presented in the Schedule of 
Assessments (Section 1.3). Screening procedures performed within 72 hours of Cycle 1 Day 1 (C1D1) do not need 
to be repeated on C1D1.

Symptom-directed physical exam 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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
ECOG Performance Status

Vitals signs, weight 

Imaging by CT/MRI

Review of prior/concomitant medications

Review of Adverse events 

Administration study drugs

Stool sample collection

Clinical laboratory tests for:
o
Hematology 
o
Clinical chemistry
o
TSH
o
Coagulation (PT, PTT) (only if the subject is receiving Xmab20717 during the corresponding cycle)
o
PSA
o
Testosterone
End of Treatment
o
End of treatment is defined as the last planned dosing visit within the dosing period. For subjects who 
discontinue drug treatment, end of treatment is considered the last visit where the decision is made to 
discontinue treatment. All required procedures may be completed within ± 7 days of the end of treatment 
visit. Repeat disease assessment is not required if performed within 28 days prior to the end of treatment 
visit.
o
Assessments for subjects who have completed treatment and achieved disease control or have discontinued 
treatment due to toxicity in the absence of confirmed progressive disease are provided in the Schedule of 
Event.   
o
All subjects will be followed for survival until the end of the study regardless of further treatments, or until 
the sponsor ends the study.
5.6 Description of Study Procedures
Informed consent
Subjects must sign a written informed consent form(s) (ICF) prior to the initiation of any study procedures and 
thereafter if there are any ICF changes.  Subjects will be given a signed copy of the ICF to take home.  Subjects 
unable to provide written informed consent on their own behalf will not be eligible for the study.
Eligibility criteria
Subjects must meet all inclusion and exclusion criteria to be eligible for the study.
Medical history
Findings from medical history (obtained at screening) and physical examination shall be given a baseline grade 
according to the procedure for AEs. Increases in severity of pre-existing conditions during the study will be 
considered AEs, with resolution occurring when the grade returns to the pre-study grade or below.
Details regarding all prior cancer treatments will be documented, including drug generic name, dose (if available), 
route of administration, start date, end date, best response, and last response to prior therapy on a separate 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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page in the EDC.  Combination treatments should be considered as a single regimen and recorded as such in the 
EDC.
At Screening, a detailed prostate cancer history will be obtained, including date of initial diagnosis and cancer 
staging.
All medications administered to the subject from 30 days prior to first dose of XmAb20717 until 30 days after 
discontinuation of both XmAb20717mand the corresponding standard of care drug. 
Physical examination
Physical examinations will be conducted according to the Schedule of Events.  Full physical examinations will be 
conducted at screening/baseline, and EOT (evaluate all major organ systems, including the following categories:  
general, head, eyes, ears, mouth/throat, neck, heart, lungs, abdomen, lymph nodes, joints, extremities, 
integumentary, neurologic, and psychiatric). 
If the Screening full physical exam is performed > 72 hours prior to the C1D1 visit, then a brief (symptom directed) 
physical exam must be performed within 72 hours prior to the first injection of XmAb20717.  
Other examinations may be focused, at the discretion of the Investigator, to identify changes from baseline or 
evaluate changes based on the patient’s clinical symptoms.  Weight is to be recorded at each visit, height at 
screening/baseline visit only.  
Vital signs
Vital signs (measurement of blood pressure (systolic and diastolic blood pressure), respiratory rate, heart rate, 
body temperature) will be evaluated according to the assessment schedules.  Body weight and height is also 
recorded along with vital signs.  
Additional monitoring with assessment of vital signs is at the discretion of the Investigator per standard clinical 
practice or as clinically indicated.  
Clinical laboratory tests
The following clinical laboratory tests will be performed (see Schedule of Assessments 1.3)
Additional tests may be performed as clinically indicated.
Clinical laboratory parameters to be obtained include:

Hematology and Clinical Chemistry

Coagulation parameters: (Partial thromboplastin time, Prothrombin time, and International normalized 
ratio) assessments at baseline and as clinically indicated 

Thyroid function tests
o
TSH  (Free T3 and Free T4 only if TSH is abnormal)

PSA and total serum testosterone level.
The Investigator is responsible for reviewing local and central laboratory results and assessing all out-of-range 
findings as either clinically significant or non-clinically significant.  Clinically significant laboratory results should 
be recorded as medical history if prior to XmAb20717 dosing at C1D1, or AEs following XmAb20717 at C1D1 in 
the eCRF. Clinically significant lab results based on local and central lab reports should also be reported in the 
EDC.

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Imaging
Standard radiological assessments should take place per the study calendar with the institution standard 
protocol. In addition, at baseline as an exploratory imaging biomarker, 18F-PSMA (PYLARIFY) PET/CT and 18F-
FDG PET/CT will be performed in the screening period and separated by > 24 hours (typically at least the 
second day after one or the other PET/CT). Both studies will take place on either the PET/CT at the Center for 
Systems Imaging or in case of unavailability, on any available PET/CT in the Emory Healthcare system deemed 
appropriate by the investigators. Typical institutional protocol will be carried out specific to that scanner from 
skull to thigh. This includes at least 4-6 hour NPO for FDG PET and standard point of care check for plasma 
glucose; if glucose over 200 mg/dL, there will be consultation with the PI as to potential rescheduling. PSMA 
PET does not require fasting or plasma glucose check. 
Images will undergo post-hoc analysis for total tumor burden utilizing standard imaging biomarkers such as 
SUVmax, SUVmean, SUVpeak, and total lesion activity on absolute basis and as compared to normal liver and 
blood pool as measured at the aortic arch. Analysis will take place on an advanced workstation with manual 
and/or semi-automated tools and will be correlated to outcome at end of study. A visual analysis will also take 
place in which each patient will be rated as: PSMA-dominant, FDG-dominant, similar FDG and PSMA total 
activity, or negative PSMA and FDG.
6. Data and Specimen Banking 
Blood and tumor samples will be obtained and used for medical research by the investigators of this study. Data 
and specimens from this study may be useful for other research being done by investigators at Emory or 
elsewhere. To help further science, Investigators may provide de-identified data and/or specimens to other 
researchers. Any information that could identify participants will not be included. If data or specimens are labeled 
with study ID, we will not allow other investigators to link that ID to identifiable information.
Samples and data collected under this protocol may be used to study Prostate Cancer. Access to stored samples 
will be limited to IRB-approved investigators. Samples and data will be stored using codes assigned by the 
investigators or their designees. Data will be kept in password-protected computers. Only investigators will have 
access to the samples and data.
All stored samples will be maintained in the laboratory to which it was sent initially for analysis. Study participants 
who request destruction of samples will be notified of compliance with such request and all supporting details 
will be maintained for tracking.
The results of some study tests and procedures will be used only for research purposes and will not be placed 
in subject’s medical record.  For this study, those items include: research blood collection. 
Peripheral blood samples
Approximately 30 mL of peripheral blood will be collected during screening, on treatment on C1D8, C2D8, C3D8 
(to be collected only if the subject received Xmab20717 on day 1 of the corresponding cycle) and at the time of 
end of treatment visit.  
 The peripheral blood mononuclear cells will be isolated from these samples and stored in -80°C freezers until 
analysis. Plasma will be stored in 80°C freezers until analysis.
Samples will be evaluated including but not limited to:

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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i.
Determine whether there are phenotypic changes in of T-cell or myeloid cell surface markers (including 
co-stimulatory/immune checkpoint molecules) in PBMCs after treatment. 
ii.
Determine whether functional changes are evident in PBMCs in response to treatment and whether 
these data correlate with clinical outcome measures. Pending quantity of cells a variety of assays may be 
performed
iii. Plasma sample will be stored for future ctDNA and cytokine analysis. 
Stool Samples
Stool sample for microbiome analysis will be collected at baseline, prior to C4D1 for cohort A and B, and C3D1 
for cohort C, and post-treatment phase within the 14 days after the last dose of study drug.

Stool sample for microbiome analysis
After appropriate processing, the blood samples, tissue blocks, slides or frozen tissue samples will be sent to:   
Kissick Laboratory
1462 Clifton Rd, Room 420
Atlanta, Georgia, 30322
ph: 617 259 8364
email: haydn.kissick@emory.edu
7. Statistical Analysis Plan
Statistical consideration section: 
Study Design and Sample Size:
This will be a multi-arm study aimed at enrolling 10 patients per cohort. The study aims to determine the safety 
and tolerability of XmAb20717 in combination with standard of care treatment in subjects with metastatic 
castration sensitive prostate cancer (mCSPC) as assessed by frequency and intensity of adverse events. Subjects 
meeting inclusion criteria will be enrolled into one of the three cohorts, starting with Cohort B (enzalutamide) 
first. After Cohort B has completed enrollment with no safety concerns leading to pausing the trial as defined 
by the safety stopping rule, the principal investigator and Xencor will both review the safety data from Cohort 
B. Once approved by the principal investigator and Xencor, the enrollment in Cohort A (abiraterone) and C 
(abiraterone plus docetaxel) can start.
The sample size is not hypothesis driven. In the primary analyses, descriptive statistics will be used to 
summarize the toxicity profile of the intervention. Toxicities will be tabulated by grade, association, and cycle 
number. 
In the secondary analyses, the Objective response rate (ORR) or PSA response rate will be summarized with the 
2-sided 95% CI using the Clopper-Pearson method. Kaplan-Meier methods will be used to estimate median 
survival time or time-specific survival rate with a 95% confidence interval for rPFS or a time-to-event outcome. 
For exploratory correlative analysis, logistic regression or Cox proportional hazard model would be applied to 
assess the association with baseline biomarkers measured by tissue or blood samples, e.g., peripheral T-cell 
profile. For the measurement repeatedly over time, a time-varying covariate analysis strategy will be 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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considered, such as the extended Cox model. However, due to the small sample size, the analyses will mainly 
be exploratory.
Stopping Rule: The safety stopping boundary is calculated based on the Bayesian Toxicity Monitoring (BTM) 
application (https://www.trialdesign.org) to control for the probability of excessive toxicity being less than 70%, 
and the target rate of grade 3 or 4 toxicity is ≤40%. 
Toxicity assessment will occur after first 5 patients are enrolled in each cohort (starting with Cohort B first), and 
if there are ≥2 out of 5 patients who experienced grade 3 or 4 toxicity during the first cycle, the trial will be 
paused for further evaluation about whether to proceed. Otherwise, we will proceed until 10 patients are 
enrolled in cohort B, and if 5 and more patients out of 10 in cohort B have grade 3 or 4 toxicity during the first 
cycle, we will claim the safety concern for the proposed treatment.  Once approved by the principal 
investigator and Xencor (as described in the above Study Design and Sample Size section), Cohort A and C can 
begin enrollment.
We justify the Grade 4 toxicity target rate of ≤40% based on the relatively high incidence of adverse events with 
anti-PD-1/CTLA-4 combined therapy. In the CheckMate 067 trial of nivolumab plus ipilimumab treatment for 
advanced melanoma, 59% of patients had Grade 3 or 4 treatment-related adverse events17. When the same 
combination was used for advanced renal cell carcinoma in the Checkmate 214 trial, 46% of patients had grade  
3 or 4 adverse events18. In Checkmate 650 trial, this incidence was 42% in pre-chemotherapy cohort and 53% in 
post-chemotherapy cohort of men with mCRPC treated with nivolumab plus ipilimumab19.
Safety Analysis: All patients who receive at least one dose of Xmab20717 will be evaluable for toxicity.  The list 
of adverse events will be summarized descriptively using frequencies and percentages of all captured toxicities 
by severity and relevance.  
Analysis of Secondary Endpoints: PSA response rate, PSA undetectable rate, ORR by immune-related RECIST 
(irRECIST), and ORR based on RECIST version 1.1 will be calculated along with 95% exact confidence intervals.
The fold change of the numbers of CD8 T-cells or other tumor-specific T-cells before and after treatment will be 
described by summary statistics (mean, median, Q1, Q3, standard deviation).
Time-to-event endpoint (e.g. Time to PSA progression, rPFS, OS) will be estimated with the Kaplan-Meier 
method with time-specific rate estimated with 95%CI.
Analysis of Exploratory Endpoints: The change in immune system biomarkers before and after treatment will be 
compared using paired test, such as Wilcoxon signed-rank test.
8. Sharing of Results with Participants
In general, study staff will not provide any individual results to subjects (ex. outcome trial results or results from 
subject’s samples studies). If something of urgent medical importance to the participating subjects will be found, 
the PI (or co-Is) will inform the subject, although we expect that this will be a very rare occurrence. Samples and 
data will only be used for research.
9. Study Timelines

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Duration of therapy
XmAb20717 will be administered Q3weeks until the subject meets a condition for discontinuation of 
study treatment or up to 1 year in the absence of disease progression or unacceptable toxicity.
In the absence of treatment delays due to adverse event(s), patients will be treated until any one of the following: 
• Tumor progression per PCWG-modified RECIST 1.1 as outlined in PCWG31
• Death 
• Unacceptable toxicity 
• Symptomatic deterioration 
• Investigator’s decision to discontinue treatment 
• Patient decision to discontinue treatment 
• Patient withdraws consent 
• Lost to follow up 
In the event of a patient’s withdrawal, the Investigator will make every effort to complete the End of Treatment 
procedures specified in the Schedule of Events.
Duration of follow-up 
Patients will be followed for approximately 28 days (Safety Follow-up) after the last dose of study drug or before 
initiation of new antineoplastic or investigational therapy whichever occurs first.  Patients removed from study 
for unacceptable adverse event(s) will be followed until resolution or stabilization of the adverse event.
Long-term follow-up should continue until the patient’s withdrawal of consent or loss to follow up, death, or 
study termination. 
Patient records may be reviewed until death to assess progression and survival.  Survival information may be 
collected by clinic visit, email, or telephone after ending protocol treatment and until the study is terminated, 
the patient dies, or the patient is lost to follow-up.
A participant will be considered lost to follow-up if he fails to return for three scheduled visits and is unable to 
be contacted by the study site staff after three attempts at contact by phone.
The following actions must be taken if a participant fails to return to the clinic for a required study visit:
The site will attempt to contact the participant and reschedule the missed visit and counsel the participant on 
the importance of maintaining the assigned visit schedule and ascertain if the participant wishes to and/or should 
continue in the study.
Patients removed from study for unacceptable adverse event(s) will be followed until resolution or stabilization 
of the adverse event.
• All patients will be contacted for survival every 12 weeks following the End of Treatment (EOT) visit. 
• Immunogenicity samples will be taken as per schedule of events 
10. Inclusion and Exclusion Criteria

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Inclusion Criteria
1.
Age ≥18 years.  
2.
Histologically confirmed adenocarcinoma of the prostate with metastatic disease
3.
Castration-sensitive status: either not have been treated with ADT (hormone therapy)  or not on ADT at 
the time of progression
o
Participants can have received up to 3 months of ADT with LHRH agonists or antagonists or 
orchiectomy with or without concurrent first-generation antiandrogens prior to enrolment, 
with no radiographic evidence of disease progression or rising PSA prior to enrollment.
4.
ECOG performance status ≤2 (Karnofsky ≥60%, see Appendix A).  
5.
Life expectancy > 12 weeks as determined by the Investigator
6.
Patients must have adequate organ and marrow function, within 28 days of Cycle 1 Day 1, as defined 
below:
                      Hematology  
Hemoglobin 
≥ 9.0 g/dl (no transfusions allowed within 7 days of Cycle 1 Day 1 to meet entry 
criteria)  
White blood cell (WBC) 
≥ 2000/μL (after at least 7 days without growth factor support or 
transfusion)  
Absolute neutrophil count (ANC)
 ≥ 1,500/mcL (after at least 7 days without growth factor 
support or transfusion)  
Platelets 
≥ 100,000/mcL (no transfusions allowed within 7 days of Cycle 1 Day 1 to meet entry 
criteria)  
PT/PTT 
 ≤ 1.5 x ULN  
Chemistry  
Total bilirubin               ≤1.5 institutional upper limit of normal (ULN)
 AST/ALT
 ≤ 3 institutional upper limit of normal (ULN)  
Serum creatinine
 ≤ 2 mg/dL (or glomerular filtration rate ≥ 40 mL/min)  
7.
Male subjects must be surgically sterile or must agree to use adequate method of contraception from 
the time of consent until at least 120 days after the last dose of Xmab27017
8.
Willingness and ability of the subject to comply with scheduled visits, drug administration plan, protocol-
specified laboratory tests, other study procedures, and study restrictions.
9.
Completion of all previous surgery, radiotherapy, chemotherapy, immunotherapy, or investigational 
therapy for the treatment of cancer ≥ 2 weeks before the start of study therapy.  (No radiotherapy to 
Xmab27017 injection site within 4 weeks). 
10. Evidence of a personally signed informed consent indicating that the subject is aware of the neoplastic 
nature of the disease and has been informed of the procedures to be followed, the experimental nature 
of the therapy, alternatives, potential risks and discomforts, potential benefits, and other pertinent 
aspects of study participation.
Exclusion criteria
An individual who meets any of the following criteria will be excluded from participation in this study:

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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1.
Patients who have had chemotherapy or radiotherapy within 4 weeks prior to entering the study or those 
who have not recovered from adverse events due to agents administered more than 4 weeks earlier (i.e., 
have residual toxicities > Grade 1).
2.
Patients who are receiving any other investigational agents or an investigational device within 21 days 
before administration of first dose of study drugs
3.
Prior treatment with any CTLA4, PD1, or PDL1, or directed immunotherapy
4.
History of allergic reactions attributed to compounds of similar chemical or biologic composition to [IND 
Agent(s)] or other agents used in study.
5.
Have known active central nervous system metastases and/or carcinomatous meningitis. Subjects with 
previously treated brain metastases may participate provided they are radiologically stable, ie, are 
without evidence of progression for at least 4 weeks by repeat imaging (note that the repeat imaging 
should be performed during study screening), are clinically stable, and are without requirement of 
steroid treatment for at least 14 days prior to first dose of study treatment.
6.
Active known or suspected autoimmune disease (except that subjects are permitted to enroll if they have 
vitiligo; type 1 diabetes mellitus or residual hypothyroidism due to an autoimmune condition that is 
treatable with hormone replacement therapy only; psoriasis, atopic dermatitis, or another autoimmune 
skin condition that is managed without systemic therapy; or arthritis that is managed without systemic 
therapy beyond oral acetaminophen and nonsteroidal anti-inflammatory drugs).
7.
Has any condition requiring systemic treatment with corticosteroids, prednisone equivalents, or other 
immunosuppressive medications within 14 days prior to first dose of study drug (except that inhaled or 
topical corticosteroids or brief courses of corticosteroids given for prophylaxis of contrast dye allergic 
response are permitted.) 
8.
Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic 
congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social 
situations that would limit compliance with study requirements.
9.
Receipt of an organ allograft
10.
Known history of left ventricular ejection fraction ≤ 40%. There is no need for an echocardiogram unless 
clinically indicated 
11.
Receipt of a live-virus vaccine within 30 days prior to first dose of study drug (seasonal flu vaccines that 
do not contain live virus are permitted. COVID-19 vaccines are permitted).
12.
Known human immunodeficiency virus (HIV) positive subject with CD4+ T-cell (CD4+) counts < 350 
cells/μL, or an HIV viral load greater than 400 copies/mL, or a history of an AIDS (acquired 
immunodeficiency syndrome)-defining opportunistic infection within the past 12 months, or who has not 
been on established antiretroviral therapy (ART) for at least 4 weeks prior to initiation of study drug 
dosing. (Effective ART is defined as a drug, dosage, and schedule associated with reduction and control 
of the viral load.)
13.
Known positive test for hepatitis C RNA (a subject who is hepatitis C virus [HCV] antibody positive but 
HCV RNA negative due to documented, curative prior antiviral treatment or natural resolution is eligible).
14.
Known positive test for hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb; a subject 
whose HBsAg is negative and HBcAb is positive may be enrolled if a hepatitis B virus [HBV] DNA test is 
negative, 
and 
the 
subject 
is 
retested 
for 
HBsAg 
and 
HBV 
DNA 
every 
2 
months)
11. Local Number of Participants
We will be recruiting 30 participants at Winship.  Patients will be registered after signing of the informed consent 
document and meeting all entry requirements.

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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12. Recruitment Methods
Investigators, nurses (CRNs), research coordinators (CRCs) and/or data managers review lists of cancer 
patients who have cancer and will determine if there are patients who might be eligible for a clinical trial. 
The CRN/CRC/data manager reviews accessible medical records to screen further for eligibility. The 
CRN/CRC reviews the eligibility with the physician.  Subjects will be identified by their treating physicians. 
Clinical care team at Winship will inform potential subjects about the known benefits and potential risks 
of a clinical trial as well as other available treatment options. Some of the subjects recruited for this 
protocol will be patients being treated at Emory and under the care of one or more of the study 
investigators. Some potential subjects will be identified by their treating physician and referred to Emory 
for possible participation in the protocol.
No incentives are provided to patients for trial participation.
Study personnel will notify Winship Central Subject Registration (WCSR) by email at 
winshipcsr@emory.edu, once subject has been consented for a trial. 
Email notification must be done within 24 hours after consent has been obtained and it will include 
scanned copies of:

Signed patient consent form

HIPAA authorization form
The WCSR will enter the subject into the OnCore Research Management System, which is the system of 
record for Winship Cancer Institute Clinical Trials.
Enrolling a subject requires careful screening and determination of eligibility. 
Eligible patients will be enrolled on study centrally at Winship Cancer Institute by the Study Coordinator.  
When all required test results are available, complete the eligibility checklist and provide the checklist 
and the supporting documentation to the IRB approved investigator for review and sign-off. Once the 
investigator (sub-investigator, Co-Investigator) has signed the eligibility checklist, randomization and or 
enrollment may proceed. OnCore must be updated to reflect eligibility and on treatment status. 
13. Withdrawal of Participants
Participants are free to withdraw from participation in the study at any time upon request.
An investigator may discontinue or withdraw a participant from the study for the following reasons:

Significant study intervention non-compliance 

If any clinical adverse event, laboratory abnormality, or other medical condition or situation occurs such 
that continued participation in the study would not be in the best interest of the participant

Disease progression which requires discontinuation of the study intervention

If medically necessary in the opinion of the Investigator

If the participant meets an exclusion criterion (either newly developed or not previously recognized) that 
precludes further study participation

Subject withdraws consent for the study (note that a subject who withdraws consent for additional study 
treatment and procedures but not for antitumor response will continue to be followed)

Subject is lost to follow-up

Death

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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
End of Clinical Trial
The reason for participant discontinuation or withdrawal from the study will be recorded on the Case Report 
Form (CRF). Subjects who sign the informed consent form but do not receive the study intervention may be 
replaced.  Subjects who sign the informed consent form, and receive the study intervention, and subsequently 
withdraw, or are withdrawn or discontinued from the study, will not be replaced.
Subjects who discontinue study treatment should undergo the EOT assessments per Section 1.3.1
14. Risks to Participants
XmAb 20717
The most common adverse reactions with XmAb20717 are skin reactions (rash and pruritus) and 
gastrointestinal reactions (nausea and diarrhea). The safety risks for XmAb20717 include irAEs and infusion-
related reactions. An irAE of any organ can happen. In the Phase I trial of XmAb20717 in advanced solid tumors 
(N=145), Grade 3/4 irAE reported for ≥3 patients included rash (10.3%), aspartate aminotransferase increase 
(4.8%), alanine aminotransferase increase and hyperglycaemia (3.5%), lipase increase (4.2%), amylase increase 
and acute kidney injury (2.8%), and pneumonitis (2.1%). There were 2 Grade 5 irAEs: immune-mediated 
pancreatitis and myocarditis (which was heavily confounded by the subject’s preexisting conditions)15.
Abiraterone
The most common adverse reactions (≥10%) are fatigue, arthralgia, hypertension, nausea, edema, 
hypokalemia, hot flush, diarrhea, vomiting, upper respiratory infection, cough, and headache. (6.1)
The most common laboratory abnormalities (>20%) are anemia, elevated alkaline phosphatase, 
hypertriglyceridemia, lymphopenia, hypercholesterolemia, hyperglycemia, and hypokalemia
Enzalutamide
The most common adverse reactions (≥ 10%) are asthenia/fatigue, back pain, decreased appetite, constipation, 
arthralgia, diarrhea, hot flush, upper respiratory tract infection, peripheral edema, dyspnea, musculoskeletal 
pain, weight decreased, headache, hypertension, and dizziness/vertigo.
Docetaxel
Most common adverse are infections, neutropenia, anemia, febrile neutropenia, hypersensitivity, 
thrombocytopenia, neuropathy, dysgeusia, dyspnea, constipation, anorexia, nail disorders, fluid retention, 
asthenia, pain, nausea, diarrhea, vomiting, mucositis, alopecia, skin reactions, and myalgia.
Other Risks

Blood draws - The physical risk of drawing blood is local pain and bruising at the site of venipuncture. 
Qualified phlebotomists or designee will draw blood samples. Care will be taken to obtain these specimens 
in a safe and hygienic manner. A small number of people experience lightheadedness or fainting. There is a 
slight risk of infection. To minimize these risks, attempts will be made to draw study blood samples at the 
same time as blood draws needed for routine clinical care are obtained. Repeated blood drawing may be 
associated with iron deficiency anemia.

Data security- Subjects will be asked to provide personal health information (PHI). All attempts will be made 
to keep this PHI confidential within the limits of the law. However, there is a chance that unauthorized 
persons will see the subjects’ PHI. All records will be kept in a locked file cabinet or maintained in a locked 

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room at the participating sites. Electronic files will be password protected behind an academic institutional 
firewall. Only people who are involved in the conduct, oversight, monitoring, or auditing of this study will be 
allowed access to the PHI that is collected. Any publications from this study will not use information that will 
identify subjects. Organizations that may inspect and/or copy research records maintained at the 
participating sites for quality assurance and data analysis include groups such as the National Cancer Institute 
(NCI) and Food and Drug Administration (FDA).

Radiation-Related Risks: You will be exposed to radiation from nuclear medicine and CT scans. These 
procedures are necessary for your medical care and will occur even if you do not participate in this study. 
The radiation dose estimate that you will receive is equal to or less than the radiation exposure allowed to 
be received by a radiation worker for 2 years. The principal risk associated with a radiation dose is the 
possibility of developing a radiation-induced cancer later in life.  Although the risk from radiation is 
cumulative it is not expected to adversely affect your condition or treatment.  The Emory University 
Radiation Safety Committee has reviewed and approved the use of radiation in this research study. 
15. Potential Benefits to Participants
There is no guarantee of benefit to subjects who enroll in this protocol.
16. Data Management and Confidentiality
Data/specimens:
Participant confidentiality is strictly held in trust by the participating investigators, their staff, and the sponsor(s) 
and their agents. Therefore, the study protocol, documentation, data, and all other information generated will 
be held in strict confidence. No information concerning the study or the data will be released to any unauthorized 
third party without prior written approval of the Principal Investigator. The study participant’s contact 
information will be securely stored at each clinical site for internal use during the study. At the end of the study, 
all records will continue to be kept in a secure location for as long a period as dictated by local IRB and 
Institutional regulations.
Data and/or data forms will be submitted in the clinical management system - Online Collaborative Research 
Environment (ONCORE)- per Winship SOP 4.2 Data Completion Metrics.
All information in original records and certified copies of original records or clinical findings, observations, or 
other activities necessary for the reconstruction and evaluation of the trial is considered source data. Source data 
are contained in source documents, which can be original records or certified copies of hospital records, clinical 
and office charts, laboratory notes, memoranda, subjects' diaries of evaluation checklists, pharmacy dispensing 
records, recorded data from automated instruments, copies or transcriptions certified after verification as being 
accurate and complete, microfiches, photographic negatives, microfilm or magnetic media, x-rays, subject files, 
and records kept at the pharmacy, at the laboratories, and at medico-technical departments involved in the 
clinical trial. Case Report Forms (CRFs) - Source data may be collected in the source documents or entered directly 
onto the case report forms.
All documentation of adverse events, records of study drug receipt and dispensation, and all IRB correspondence 
will be maintained for at least 2 years after the investigation is completed.

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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Study participant research data, which is for purposes of statistical analysis and scientific reporting, will be stored. 
This will not include the participant’s contact or identifying information. Rather, individual participants and their 
research data will be identified by a unique study identification number. The study data entry and study 
management systems used by clinical sites and research staff will be secured and password protected. At the 
end of the study, all study databases will be de-identified and archived.
Samples and data collected under this protocol may be used to study prostate cancer. Access to stored samples 
will be limited to IRB-approved investigators. Samples and data will be stored using codes assigned by the 
investigators or their designees. Data will be kept in password-protected computers. Only investigators will 
have access to the samples and data.
All stored samples will be maintained in the laboratory to which it was sent initially for analysis. Study 
participants who request destruction of samples will be notified of compliance with such request and all 
supporting details will be maintained for tracking.
17. Provisions to Monitor the Data to Ensure the Safety of Participants
Definition of Adverse Events (AE)
Adverse event means any untoward medical occurrence associated with the use of an intervention in humans, 
whether or not considered intervention-related (21 CFR 312.32 (a)).
Definition of Serious Adverse Events (SAE) 
An adverse event (AE) or suspected adverse reaction is considered "serious" if, in the view of either the 
investigator or sponsor, it results in any of the following outcomes: 

Death

Life-threatening adverse event 

Inpatient hospitalization or prolongation of existing hospitalization

A persistent or significant incapacity or substantial disruption of the ability to conduct normal life 
functions, or a congenital anomaly/birth defect. 

Important medical events that may not result in death, be life-threatening, or require hospitalization may 
be considered serious when, based upon appropriate medical judgment, they may jeopardize the 
participant and may require medical or surgical intervention to prevent one of the outcomes listed in this 
definition. (Examples of such medical events include allergic bronchospasm requiring intensive 
treatment in an emergency room or at home, blood dyscrasias or convulsions that do not result in 
inpatient hospitalization, or the development of drug dependency or drug abuse).
Classification of an Adverse Event
Severity of Event
For adverse events (AEs) not included in the protocol defined grading system, the following guidelines will be 
used to describe severity, consistent with CTCAE version 5.0
 

Grade 1: Mild; asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention 
not indicated. 

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
Grade 2: Moderate; minimal, local or noninvasive intervention indicated; limiting age appropriate 
instrumental activities of daily living. 

Grade 3: Severe or medically significant but not immediately life-threatening; hospitalization or 
prolongation of hospitalization indicated; disabling; limiting self-care activities of daily living

Grade 4: Life-threatening consequences; urgent intervention indicated. 

Grade 5: Death related to AE.
Relationship to Study Intervention
All adverse events (AEs) must have their relationship to each component of the investigational regimen assessed by 
the clinician who examines and evaluates the participant based on temporal relationship and his/her clinical 
judgment. The degree of certainty about causality will be graded using the categories below. In a clinical trial, 
the study product(s) must always be suspect(s). When possible, the investigator should assign attribution of 
each component of the investigational regimen (i.e. XmAb20717 vs. abiraterone or enzalutamide or docetaxel) 
when assessing an AE.
•
Definitely Related – There is clear evidence to suggest a causal relationship, and other possible 
contributing factors can be ruled out. The clinical event, including an abnormal laboratory test result, 
occurs in a plausible time relationship to study intervention administration and cannot be explained by 
concurrent disease or other drugs or chemicals. The response to withdrawal of the study intervention 
(dechallenge) should be clinically plausible. The event must be pharmacologically or phenomenologically 
definitive, with use of a satisfactory rechallenge procedure if necessary.
•
Probably Related – There is evidence to suggest a causal relationship, and the influence of other factors 
is unlikely. The clinical event, including an abnormal laboratory test result, occurs within a reasonable 
time after administration of the study intervention, is unlikely to be attributed to concurrent disease or 
other drugs or chemicals, and follows a clinically reasonable response on withdrawal (dechallenge). 
Rechallenge information is not required to fulfill this definition.
•
Potentially Related – There is some evidence to suggest a causal relationship (e.g., the event occurred 
within a reasonable time after administration of the trial medication). However, other factors may have 
contributed to the event (e.g., the participant’s clinical condition, other concomitant events). Although 
an AE may rate only as “possibly related” soon after discovery, it can be flagged as requiring more 
information and later be upgraded to “probably related” or “definitely related”, as appropriate.
•
Unlikely to be related – A clinical event, including an abnormal laboratory test result, whose temporal 
relationship to study intervention administration makes a causal relationship improbable (e.g., the event 
did not occur within a reasonable time after administration of the study intervention) and in which other 
drugs or chemicals or underlying disease provides plausible explanations (e.g., the participant’s clinical 
condition, other concomitant treatments).
•
Not Related – The AE is completely independent of study intervention administration, and/or evidence 
exists that the event is definitely related to another etiology. There must be an alternative, definitive 
etiology documented by the clinician.
Adverse Event and Serious Adverse Event Reporting 
Expectedness 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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Principal Investigator will be responsible for determining whether an adverse event (AE) is expected or 
unexpected (based on the current version of IB’s RSI).  An AE will be considered unexpected if the nature, severity, 
or frequency of the event is not consistent with the risk information previously described for the study 
intervention.
Adverse Event Reporting 
From the time of treatment allocation through 70 days following cessation of treatment, all adverse events, that 
begin or worsen after informed consent, must be recorded by the investigator or designee at each examination 
on the Adverse Event case report forms/worksheets.  
The investigator will make every attempt to follow all subjects with non-serious adverse events for outcome.
Conditions that were already present at the time of informed consent should be recorded in the Medical History 
page of the patient’s CRF/worksheet.
Adverse events will be assessed and graded according to the Common Terminology Criteria for Adverse Events 
(CTCAE) version 5.0. Grade 1 to 5 will be used to characterize the severity of the Adverse Event. 
If CTCAE grading does not exist for an adverse event, the severity of mild, moderate, severe, and life-threatening, 
death related to the AE corresponding respectively to Grades 1 - 5, will be used. Information about any deaths 
(related to an Adverse Event or not) will also be collected through a Death form (or EOT/SEC/Survival Information 
in NOVDD). The occurrence of adverse events should be sought by non-directive questioning of the patient 
(patient) during the screening process after signing informed consent and at each visit during the study. Adverse 
events also may be detected when they are volunteered by the patient (patient) during the screening process or 
between visits, or through physical examination, laboratory test, or other assessments. As far as possible, each 
adverse event should be evaluated to determine: 
1. The severity grade (CTCAE Grade 1-5) 
2. Its duration (Start and end dates)  
3. Its relationship to the study treatment(s) (Reasonable possibility that AE is related: No, Yes) or Its relationship 
to the study treatment (Reasonable possibility that AE is related: No, Yes, investigational treatment, Yes, the 
study treatment (non-investigational), Yes, both and/or indistinguishable) 
4. Action taken with respect to study or investigational treatment (none, dose adjusted, temporarily interrupted, 
permanently discontinued, unknown, not applicable) 
5. Whether medication or therapy was given (no concomitant medication/non-drug therapy, concomitant 
medication/non-drug therapy) 
6. Whether it is serious, where a serious adverse event (SAE) is defined as in Section 9.2 and which seriousness 
criteria have been met (include for NCDS trials).
7. Outcome (not recovered/not resolved, recovered/resolved, recovering/resolving, recovered/resolved with 
sequelae, fatal, unknown)  
 
If the event worsens, the event should be reported a second time in the CRF noting the start date when the event 
worsens in toxicity. For grade 3 and 4 adverse events only, if improvement to a lower grade is determined a new 
entry for this event should be reported in the CRF noting the start date when the event improved from having 
been Grade 3 or Grade 4.   For phase I studies any AE that constitutes a DLT should be reported like a grade 3 
and 4 adverse event.  All adverse events should be treated appropriately. If a concomitant medication or non-
drug therapy is given, this action should be recorded on the Adverse Event CRF.

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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Once an adverse event is detected, it should be followed until its resolution or until it is judged to be permanent, 
and assessment should be made at each visit (or more frequently, if necessary) of any changes in severity, the 
suspected relationship to the study treatment, the interventions required to treat it, and the outcome. 
Progression of malignancy (including fatal outcomes), if documented by use of appropriate method (for example, 
as per RECIST criteria for solid tumors), should not be reported as a serious adverse event. 
Adverse events separate from the progression of malignancy (example, deep vein thrombosis at the time of 
progression or hemoptysis concurrent with finding of disease progression) will be reported as per usual 
guidelines used for such events with proper attribution regarding relatedness to the drug.
Laboratory abnormalities that constitute an Adverse event in their own right (are considered clinically significant, 
induce clinical signs or symptoms, require concomitant therapy or require changes in study treatment), should 
be recorded on the Adverse Events CRF.
Laboratory abnormalities, that do not meet the definition of an adverse event, should not be reported as adverse 
events. A Grade 3 or 4 event (severe) as per CTCAE does not automatically indicate a SAE unless it meets the 
definition of serious as defined below and/or as per investigator’s discretion. A dose hold or medication for the 
lab abnormality may be required by the protocol in which case the lab abnormality would still, by definition, be 
an adverse event and must be reported as such.
Serious Adverse Event Reporting 
For the time period beginning at treatment allocation/randomization through 70 days following cessation of 
treatment, any serious adverse event, or follow up to a serious adverse event, including death due to any cause 
whether or not related to the study drug, must be submitted on an SAE form and assessed by the Sponsor-
Investigator in order to determine reporting criteria to regulatory authorities, IRB, DSMC, FDA and/or Xencor. 
All SAEs will be followed until satisfactory resolution or until the site investigator deems the event to be chronic 
or the adherence to be stable. Other supporting documentation of the event may be requested by the study 
sponsor and should be provided as soon as possible. The study IND sponsor will be responsible for notifying FDA 
of any unexpected fatal or life-threatening suspected adverse reaction as soon as possible but in no case later 
than 7 calendar days after the sponsor's initial receipt of the information and all other unexpected serious 
adverse reactions in no case later than 15 calendar days after the sponsor's initial receipt of the information.
Reporting to study supporter/IRB and or FDA.
All subjects with serious adverse events must be followed up for outcome.
Any additional information for the SAE including complications, progression of the initial SAE, and recurrent 
episodes must be reported as follow-up to the original episode within 24 hours of the investigator receiving the 
follow-up information. 
An SAE occurring at a different time interval or otherwise considered completely unrelated to a previously 
reported one should be reported separately as a new event. 
Any SAEs experienced after the reporting period described above should only be reported to FDA/IRB if the 
investigator suspects a causal relationship to the study treatment.   
Information about all SAEs is collected and recorded on the Serious Adverse Event Report Form; all applicable 
sections of the form must be completed in order to provide a clinically thorough report. The investigator must 
assess and record the relationship of each SAE to each specific study treatment (if there is more than one study 
treatment), complete the SAE Report Form, and submit the completed form.  

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Each reoccurrence, complication, or progression of the original event should be reported as a follow-up to that 
event regardless of when it occurs. The follow-up information should describe whether the event has resolved 
or continues, if and how it was treated, whether the blind was broken or not, and whether the patient continued 
or withdrew from study participation. 
All SAE must be recorded on a MedWatch 3500 Form. SAE reports and any other relevant safety information are 
to be forwarded to the following 
MedWatch 3500 Reporting Guidelines:
Note:  MedWatch 3500 forms and other information related to MedWatch reporting are available at 
http://www.fda.gov/medwatch/index.html.
A copy of all 15 Day Reports and Annual Progress Reports is submitted as required by FDA and Xencor. 
Investigators will cross reference this submission according to local regulations to the Investigational Compound 
Number (IND, CSA, etc.) at the time of submission. 
An investigator who is a qualified physician will evaluate all adverse events according to the NCI Common 
Terminology for Adverse Events (CTCAE), version 5.0. Any adverse event which changes CTCAE grade over the 
course of a given episode will have each change of grade recorded on the adverse event case report 
forms/worksheets. All adverse events regardless of CTCAE grade must also be evaluated for seriousness.
Reporting Requirements for IND holder
For Investigator-sponsored IND studies, reporting requirements for the FDA apply in accordance with the 
guidance set forth in 21 CFR, Part 312.32.  Events meeting the following criteria need to be submitted to the FDA 
as Expedited IND Safety Reports.
7 Calendar-Day Telephone or Fax Report
The Sponsor-Investigator is required to notify the FDA of a fatal or life-threatening adverse event that is 
unexpected and assessed by the investigator to be possibly related to the use of investigational agents.  An 
unexpected adverse event is one that is not already described in the most recent Guidance for Investigator 
section of the Investigator’s Brochure.  Such reports are to be telephoned or faxed to the FDA, within 7 calendar 
days of the first learning of the event.
15 Calendar-Day Written Report
The Investigator is also required to notify the FDA and all participating investigators, in a written IND Safety 
Report, of any serious unexpected adverse event that is considered reasonably or possibly related to the use of 
investigational agent.
Written IND Safety Reports with analysis of similar events are to be submitted to the FDA and Xencor, within 15 
calendar days of first learning of the event.  The FDA prefers these reports on a MedWatch 3500 Form but 
alternative formats (e.g., summary letter) are acceptable.
FDA Fax number of IND Safety Reports: 1-(800)-FDA-1078.
The IND sponsor will also make an assessment of whether the event constitutes an unanticipated problem posing 
risks to subjects or others (UP). This assessment will be provided to the Emory University IRB, which, in turn will 

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make a final determination.  If the Emory IRB determines an event is a UP it will notify the appropriate regulatory 
agencies and institutional officials.
All Adverse Events will be reported to regulatory authorities, Xencor, IRB/IECs and investigators in accordance 
with all applicable global laws and regulations. 
Coordinating center reporting to the Food and Drug Administration (FDA)
The Sponsor-Investigator, as holder of the IND, will be responsible for all communication with the FDA. The 
Sponsor Investigator [or designee] will report to the FDA, regardless of the site of occurrence, any adverse event 
that is serious, unexpected and reasonably related (i.e., possible, probable, definite) to the study treatment. 
Unexpected fatal or life-threatening experiences associated with the use of the study treatment will be reported 
to FDA as soon as possible but no later than 7 calendar days after initial receipt of the information. 
All other serious unexpected experiences associated with the use of the study treatment will be reported to FDA 
as soon as possible but in no event later than 15 calendar days after initial receipt of the information. Events will 
be reported to the FDA by telephone (1-800-FDA-1088) or by fax (1-800- FDA-0178) using MEDWATCH Form FDA 
3500A 
(Mandatory 
Reporting 
Form 
for 
investigational 
agents). 
Forms 
are 
available 
at 
http://www.fda.gov/medwatch/getforms.htm. 
An annual safety report containing all SAEs, expected and unexpected, will be sent to the FDA and other 
applicable regulatory authorities. 
Definition of unanticipated problems (UP) and reporting requirements
The Office for Human Research Protections (OHRP) considers unanticipated problems involving risks to 
participants or others to include, in general, any incident, experience, or an outcome that meets all the following 
criteria:  Unexpected in terms of nature, severity, or frequency given (a) the research procedures that are 
described in the protocol-related documents, such as the IRB-approved research protocol and informed consent 
document; and (b) the characteristics of the participant population being studied; Related or possibly related to 
participation in the research (“possibly related” means there is a reasonable possibility that the incident, 
experience, or outcome may have been caused by the procedures involved in the research); and Suggests that 
the research places participants or others at a greater risk of harm (including physical, psychological, economic, 
or social harm) than was previously known or recognized.  This study will use the OHRP definition of unanticipated 
problems. Incidents or events that meet the OHRP criteria for UPs require the creation and completion of a UP 
report form. It is the site investigator’s responsibility to report UPs to their IRB and to the DCC/study sponsor. 
The UP report will include the following information:  Protocol identifying information: protocol title and number, 
PI’s name, and the IRB project number; A detailed description of the event, incident, experience, or outcome; An 
explanation of the basis for determining that the event, incident, experience, or outcome represents an UP; A 
description of any changes to the protocol or other corrective actions that have been taken or are proposed in 
response to the UP.  The IND sponsor will make an assessment of whether the event constitutes an unanticipated 
problem posing risks to subjects or others (UP). This assessment will be provided to the Emory University IRB.  If 
the Emory IRB determines an event is a UP it will notify the appropriate regulatory agencies and institutional 
officials. 
The Data and Safety Monitoring Committee (DSMC)

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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The Data and Safety Monitoring Committee (DSMC) of the Winship Cancer Institute will provide oversight for the 
conduct of this study. The DSMC functions independently within Winship Cancer Institute to conduct internal 
monitoring functions to ensure that research being conducted by Winship Cancer Institute Investigators 
produces high-quality scientific data in a manner consistent with good clinical practice (GCP) and appropriate 
regulations that govern clinical research. Depending on the risk level of the protocol, the DSMC review may occur 
every 6 months or annually. For studies deemed High Risk, initial study monitoring will occur within 6 months 
from the date of the first subject accrued, with 2 of the first 5 subjects being reviewed. The DSMC will review 
pertinent aspects of the study to assess subject safety, compliance with the protocol, data collection, and risk-
benefit ratio. Specifically, the Winship Cancer Institute Internal Monitors assigned to the DSMC may verify 
informed consent, eligibility, data entry, accuracy and availability of source documents, AEs/SAEs, and essential 
regulatory documents. Following the monitoring review, monitors will provide a preliminary report of monitoring 
findings to the PI and other pertinent individuals involved in the conduct of the study. The PI is required to 
address and respond to all the deficiencies noted in the preliminary report. Prior to the completion of the final 
summary report, monitors will discuss the preliminary report responses with the PI and other team members 
(when appropriate). A final monitoring summary report will then be prepared by the monitor. Final DSMC review 
will include the final monitoring summary report with corresponding PI response, submitted CAPA (when 
applicable), PI Summary statement, and available aggregate toxicity and safety data.  The DSMC will render a 
recommendation and rating based on the overall trial conduct. The PI is responsible for ensuring that instances 
of egregious data insufficiencies are reported to the IRB. Continuing Review submissions will include the DSMC 
recommendation letter. Should any revisions be made to the protocol-specific monitoring plan after initial DSMC 
approval, the PI will be responsible for notifying the DSMC of such changes. The Committee reserves the right to 
conduct additional audits if necessary.  

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Monitoring Table 2
DSMP Requirement
How this Requirement is Met 
Frequency
Responsible Party(ies)
Real-time review of 
participant data during 
initial data collection.
This requirement will be met per 
Winship’s NCI approved DSMP
This will occur every 
time new 
information is 
obtained.
SI/study team
Site Monitoring at pre-
determined intervals: The 
Principal Investigator has a 
responsibility to ensure 
that the study is following 
all aspects of the protocol. 
This requirement will be met per 
Winship’s NCI approved DSMP
biannually
DSMC
100% review of regulatory 
files
DSMC monitors will review the 
protocol, amendments, informed 
consent documents, IRB 
submissions and meet with the 
principal investigator for 
clarification of study objectives
Reviewed at first and 
close-out visits
DSMC
100% review of consent 
forms
Monthly QA check of 5-10 
randomly selected consents to 
validate Central Subject 
Registration (CSR) and PRMS to 
conduct QA consent checks in real 
time as subjects are registered in 
OnCore vis CSR process
biannually
PRMS, QM
Review of credentials, 
training records, the 
delegation of responsibility 
logs (if applicable)
The Winship Associate Director for 
Clinical Research will establish the 
scope and allocate staff support to 
include procedures for obtaining 
charts, facilitating access to the 
electronic medical record, etc.
biannually
DSMC
Comparison of case report 
forms (CRF) to source 
documentation for 
accuracy and completion
The PI is responsible for ensuring 
that instances of egregious data 
insufficiencies that may impact the 
scientific integrity of the trial
biannually
DSMC
Review of documentation 
of all adverse events
During the monitoring process, the 
DSMB reviews trial safety data for 
stopping rules, deviations, study 
amendments, accrual rates and 
monitoring reports for therapeutic 
investigator-initiated clinical trials 
and any other trial as deemed 
necessary
biannually
DSMC
Monitoring of critical data 
points (eligibility, study 
endpoints, etc.)
The assigned monitor will 
randomly select subject(s) for 
review based on parameters in 
biannually
DSMC

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Table 1 or 2 as noted above. 
Although the principal investigator 
and applicable study team 
members will receive notification 
of trial monitoring in advance, the 
subject selection will not be 
revealed in advance of the 
monitoring visit.
Laboratory review of 
processing and storage of 
specimens
The assigned monitor will 
randomly select subject(s) for 
review based on parameters in 
Table 1 or 2 as noted above
Reviewed at first and 
close-out visits and 
at least biannually
DSMC
Assessment of laboratory 
specimens stored locally
If accrual at time of initial 
monitoring is> IO but :S 20, I 0% of 
subjects will be monitored at 
minimum. Thereafter, monitoring 
will not occur unless accrual 
reaches 30
Reviewed at first and 
close-out visits and 
at least biannually
DSMC
Test article accountability 
review
In addition to a comprehensive 
review of available toxicity data, 
the DSMC reviews all internal 
monitoring reports of trials under 
its purview
Reviewed at first and 
close-out visits and 
at least biannually
DSMC
Accountability logs, 
dispensing records, and 
other participant records 
If accrual at time of initial 
monitoring is> IO but :S 20, I 0% of 
subjects will be monitored at 
minimum. Thereafter, monitoring 
will not occur unless accrual 
reaches 30.
At least biannually
DSMC
For FDA regulated studies, 
the following requirements 
apply:
monitoring activities meet the 
FDA's requirements as delineated 
in 21 CFR 50, 21 CFR 56, 21 CFR 812 
for studies conducted under an IDE 
and 21 CFR 312 for studies 
conducted under an IND.
biannually
DSMC
Monitoring methods (may 
include centralized, on-site, 
and self-monitoring)
The internal monitoring team is 
independent from any study 
protocol and does not perform any 
trial-related specific duties in order 
to uphold an unbiased approach to 
study monitoring. Oversight of the 
monitoring process and 
identification/assignment of 
studies for monitoring is provided 
by the Manager of the Internal 
Monitors.
biannually                       DSMC

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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*For international studies, you are required to engage a CRO that is working in the site country and/or to consult 
with Emory’s legal counsel regarding compliance with the country’s clinical research regulations.
                                                                                                                       
18.  Provisions to Protect the Privacy Interests of Participants
Participants will be assured of their voluntary participation in the study, their choice to answer or not answer 
any question, and the protocol for maintaining confidentiality.
Participant confidentiality is strictly held in trust by the participating investigators, their staff, and the sponsor(s) 
and their agents. This confidentiality is extended to cover testing of biological samples and genetic tests in 
addition to the clinical information relating to participants. Therefore, the study protocol, documentation, data, 
and all other information generated will be held in strict confidence. No information concerning the study or the 
data will be released to any unauthorized third party without prior written approval of the IND sponsor.
The study monitor, other authorized representatives of the sponsor, representatives of the IRB or pharmaceutical 
company supplying study product may inspect all documents and records required to be maintained by the 
investigator, including but not limited to, medical records (office, clinic, or hospital) and pharmacy records for 
the participants in this study. The clinical study site will permit access to such records.
The study participant’s contact information will be securely stored at each clinical site for internal use during the 
study. At the end of the study, all records will continue to be kept in a secure location for as long a period as 
dictated by local IRB and Institutional regulations.
Study participant research data, which is for purposes of statistical analysis and scientific reporting, will be 
transmitted to and stored. This will not include the participant’s contact or identifying information. Rather, 
individual participants and their research data will be identified by a unique study identification number. The 
study data entry and study management systems used by clinical sites and research staff will be secured and 
password protected. At the end of the study, all study databases will be de-identified and archived
19.   Economic Burden to Participants
The study supporter will pay for certain items and services the subject may receive in this study.  Subjects will 
have to pay for the items or services for which the study sponsor does not pay. The sponsor will not pay for 
regular medical care. If subjects have insurance, Emory will submit claims to the insurance for items and services 
that the sponsor does not cover.  Emory will send in only those claims for items and services that it reasonably 
believes the insurance will pay and that the sponsor has not paid. The actual amount that participants have to 
pay depends on whether or not they have health insurance and whether or not that insurance will pay for any 
research study costs. Generally, insurance companies will not pay for items and services that are required just 
for a research study. Some insurance companies will not pay for regular medical treatment or treatment for 
complications if in a study.  If subject do not have insurance, Emory will review that particular case as part of its 
program for low-income patient care.  The standard policies of that program will apply.  The program will figure 
out if subjects have to pay any costs for taking part in the study and what those costs will be.
20.  Consent Process
The initial informed consent discussion will occur in Winship Cancer Institute or the Emory Clinic.

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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At Winship Cancer Institute, the informed consent is an ongoing, interactive process rather than a one-time 
information session. The consent form document is designed to begin the informed consent process, which 
provides the patient with ongoing explanations that will help them make educational decisions about whether 
to begin or continue participating in the trial. The research team knows that a written document alone may not 
ensure that the patient fully understands what participation means. Therefore, the research team will discuss 
with the patient the trial's purpose, procedures, risks and potential benefits, and their rights as a participant. The 
team will continue to update the patient on any new information that may affect their situation.
Consent will be obtained prior to any research-driven procedures. The investigator will assess the patient’s 
capacity during his/her encounters with him or her. The investigator will give the person providing consent 
adequate opportunity to read the consent document before it is signed and dated.
It will be explained to prospective participants that the study involves research, the purpose of the research, the 
expected duration of participation, as well as the approximate number of participants to be enrolled. The study 
procedures, and identification of research procedures v. non-research will also be thoroughly discussed. It will 
be explained to participants that participation is voluntary and that the subject may discontinue at any time.
Refusal to participate or withdraw will not involve a penalty or loss of benefits to which the participant is 
otherwise entitled. Refusal will in no way affect the participant's future are. The participant will also be told of 
the possible consequences of the decision to withdraw from the research, and procedures for orderly 
termination of participation.
Any significant new findings developed during the course of the research that may affect the participant's 
willingness to continue to participate will be provided. Also explained will be anticipated circumstances under 
which the subject's participation may be terminated by the investigator without the participant's consent.
Prospective participants will be provided with a description of any reasonably foreseeable risks or discomforts as 
well as a description of any benefits to the participant or to others that might be reasons expected from the 
research. Alternative procedures or courses of treatment will also be thoroughly discussed.
Prospective participants will also be given detailed information describing the extent to which confidentiality of 
records identifying the participant will be maintained and what records may be examined by the research staff, 
IRBs, sponsor, their representatives, and possibly the FDA or OHRP.
Also communicated to the participant will be an explanation that emergency medical care will be arranged for a 
study-related illness or injury, and an explanation of whether funds are set aside to pay for this care and/or 
compensation, and if so by whom (e.g., sponsor, subject, insurer). The participant is told the source of the study's 
funding.
All participants will be told of any additional costs that may result from participation in the research.
Consent will be done in person or remotely through secured email, phone or by electronic consenting using one 
of the methods that is Emory LITS approved (e.g. DocuSign) when available.  We will follow Emory’s guidance 
on use of electronic informed consent.
Non-English-Speaking Participants  
A certified translator/interpreter will be present during the consenting process and all questions and concerns 
will be answered by the treating physician. 
A Short Form in that specific language will be used. A certified translator/interpreter will be present during the 
consenting process and this will be documented. We will use what's available on Emory IRB website. For the 
languages that are not available, we will have the short form translated to that language and submit the IRB for 
review and approval prior to use. Process to Document Consent in Writing: Winship SOP 2.1:”Obtaining Informed 
consent for Interventional clinical trial” will be followed.

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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Participants who are not yet adults (infants, children, teenagers): N/A
Cognitively Impaired Adults: N/A
Adults Unable to Consent: N/A
Waiver or Alteration of Consent Process (consent will not be obtained, required information 
will not be disclosed, or the research involves deception): N/A
21.   Setting
The research will be conducted at Emory University.
Potential participants will be identified in medical oncology clinics, multidisciplinary cancer clinic, surgical 
oncology clinics, and multidisciplinary tumor board at Emory University.
22.  Resources Available
Emory University was founded in 1836 and is a national center for teaching, research, and service. Emory 
University has been named as one of the nation’s top 25 universities for more than a decade by the U.S. News 
and World Report. Emory University research partners include the Georgia Institute of Technology, the University 
of Georgia, Morehouse School of Medicine, the US Centers for Disease Control and Prevention, Children's 
Healthcare of Atlanta, and the Georgia Clinical and Translational Science Alliance (GACTSA). Emory University 
researchers received $734 million from external funding agencies in fiscal year 2018, including approximately 
$441 million in funding from federal agencies, $359 million of this from the National Institutes of Health (NIH).
Winship Cancer Institute (Winship) is Georgia's first and only National Cancer Institute (NCI)-designated 
Comprehensive Cancer Center (P30CA138292) and is dedicated to the integration of innovative clinical and basic 
science research with outstanding patient care for the prevention, treatment and control of cancer. First 
designated in 2009, Winship’s NCI designation was renewed in 2012 and 2016, achieving an “outstanding” rating. 
Winship earned the prestigious Comprehensive Cancer Center designation from the NCI in 2016, after 
demonstrating that its outstanding programs are reducing the cancer burden on the state of Georgia through 
research conducted in its laboratories, its clinical trial program, and its population-based science. The 
institutional support for Winship was rated as ‘exceptional’ by the review panel.
The Winship Clinic Building C houses the primary offices and clinical space for cancer services including the 
medical oncology, hematology, and surgical oncology clinics, the radiation oncology program, and the Winship 
Ambulatory Infusion Center.  In summer 2017, Emory Healthcare completed the expansion of Emory University 
Hospital Tower on Clifton Road. This nine-floor facility adds 144 inpatient beds to the hospital, of which more 
than 80% are dedicated to cancer care. The hospital expansion also accommodates cancer patient-specific 
intensive care units, an expanded BMT Unit with peri-transplant clinics to facilitate continuity of care, and a 24-
hour cancer urgent care center, which serves as both a triage facility and short stay treatment center for patients 
with 
cancer-related 
medical 
concerns. 
The Winship Phase I Unit, on the fourth floor of the Emory University Hospital Tower, is the largest unit in Georgia 
dedicated to the earliest and most critical phase of new cancer therapy evaluation. There is space for 15 private 
treatment bays, four clinic rooms, its own lab for doing patient blood work, a dedicated secure medication room, 

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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computer workspace for research and other support staff, and a "fast track" bay with three chairs for rapid use 
in patients who, for example, might need only a research lab test done.
23.  References
1. Siegel RL, Miller KD, Jemal A. Cancer statistics, 2020. CA Cancer J Clin. 2020;70: 7-30.
2. Patrikidou A, Loriot Y, Eymard JC, et al. Who dies from prostate cancer? Prostate Cancer and 
Prostatic Diseases. 2014;17: 348-352.
3. Espinoza IC, Moreno CS, Gomez CR. Abstract C028: Hypoxia-associated genes on disparities in the 
aggressiveness of prostate cancer2020;29: C028-C028.
4. Chi KN, Agarwal N, Bjartell A, et al. Apalutamide for Metastatic, Castration-Sensitive Prostate 
Cancer. New England Journal of Medicine. 2019;381: 13-24.
5. Davis ID, Martin AJ, Stockler MR, et al. Enzalutamide with Standard First-Line Therapy in 
Metastatic Prostate Cancer. New England Journal of Medicine. 2019;381: 121-131.
6. Fizazi K, Tran N, Fein L, et al. Abiraterone plus Prednisone in Metastatic, Castration-Sensitive 
Prostate Cancer. New England Journal of Medicine. 2017;377: 352-360.
7. James ND, Sydes MR, Clarke NW, et al. Addition of docetaxel, zoledronic acid, or both to first-line 
long-term hormone therapy in prostate cancer (STAMPEDE): survival results from an adaptive, 
multiarm, multistage, platform randomised controlled trial. The Lancet. 2016;387: 1163-1177.
8. Fizazi K, Foulon S, Carles J, et al. Abiraterone plus prednisone added to androgen deprivation 
therapy and docetaxel in de novo metastatic castration-sensitive prostate cancer (PEACE-1): a 
multicentre, open-label, randomised, phase 3 study with a 2 × 2 factorial design. Lancet. 2022;399: 
1695-1707.
9. Schulte B, Morgans AK, Shore ND, Pezaro C. Sorting Through the Maze of Treatment Options for 
Metastatic Castration-Sensitive Prostate Cancer. Am Soc Clin Oncol Educ Book. 2020;40: 1-10.
10. Swami U, McFarland TR, Nussenzveig R, Agarwal N. Advanced Prostate Cancer: Treatment 
Advances and Future Directions. Trends Cancer. 2020;6: 702-715.
11. de Almeida DVP, Fong L, Rettig MB, Autio KA. Immune Checkpoint Blockade for Prostate 
Cancer: Niche Role or Next Breakthrough? American Society of Clinical Oncology Educational Book. 
2020;40: e89-e106.
12. Antonarakis ES, Piulats JM, Gross-Goupil M, et al. Pembrolizumab for Treatment-Refractory 
Metastatic Castration-Resistant Prostate Cancer: Multicohort, Open-Label Phase II KEYNOTE-199 
Study. Journal of Clinical Oncology. 2020;38: 395-405.
13. Kwon ED, Drake CG, Scher HI, et al. Ipilimumab versus placebo after radiotherapy in patients with 
metastatic castration-resistant prostate cancer that had progressed after docetaxel chemotherapy 
(CA184-043): a multicentre, randomised, double-blind, phase 3 trial. Lancet Oncol. 2014;15: 700-712.
14. Gao J, Ward JF, Pettaway CA, et al. VISTA is an inhibitory immune checkpoint that is increased 
after ipilimumab therapy in patients with prostate cancer. Nature medicine. 2017;23: 551.
15. Shum E, Daud A, Reilley M, et al. 407 Preliminary safety, pharmacokinetics/pharmacodynamics, 
and antitumor activity of XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with 
advanced solid tumors: BMJ Specialist Journals, 2020.
16. Thompson JA, Schneider BJ, Brahmer J, et al. Management of Immunotherapy-Related Toxicities, 
Version 1.2022, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw. 2022;20: 
387-405.

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
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17. Larkin J, Chiarion-Sileni V, Gonzalez R, et al. Five-Year Survival with Combined Nivolumab and 
Ipilimumab in Advanced Melanoma. New England Journal of Medicine. 2019;381: 1535-1546.
18. Motzer RJ, Rini BI, McDermott DF, et al. Nivolumab plus ipilimumab versus sunitinib in first-line 
treatment for advanced renal cell carcinoma: extended follow-up of efficacy and safety results from a 
randomised, controlled, phase 3 trial. The Lancet. Oncology. 2019;20: 1370-1385.
19. Sharma P, Pachynski RK, Narayan V, et al. Nivolumab Plus Ipilimumab for Metastatic Castration-
Resistant Prostate Cancer: Preliminary Analysis of Patients in the CheckMate 650 Trial. Cancer Cell. 
2020;38: 489-499.e483.

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APPENDIX A
PERFORMANCE STATUS CRITERIA
ECOG Performance Status Scale
Karnofsky Performance Scale
Grade
Descriptions
Percent
Description
100
Normal, no complaints, no evidence of 
disease.
0
Normal activity.  Fully active, able to 
carry on all pre-disease performance 
without restriction.
90
Able to carry on normal activity; minor 
signs or symptoms of disease.
80
Normal activity with effort; some signs 
or symptoms of disease.
1
Symptoms, 
but 
ambulatory.  
Restricted in physically strenuous 
activity, but ambulatory and able to 
carry out work of a light or sedentary 
nature (e.g., light housework, office 
work).
70
Cares for self, unable to carry on normal 
activity or to do active work.
60
Requires occasional assistance, but is 
able to care for most of his/her needs.
2
In bed <50% of the time.  Ambulatory 
and capable of all self-care, but unable 
to carry out any work activities.  Up 
and about more than 50% of waking 
hours.
50
Requires considerable assistance and 
frequent medical care.
40
Disabled, requires special care and 
assistance.
3
In bed >50% of the time.  Capable of 
only limited self-care, confined to bed 
or chair more than 50% of waking 
hours.
30
Severely 
disabled, 
hospitalization 
indicated.  Death not imminent.
20
Very sick, hospitalization indicated. 
Death not imminent.
4
100% 
bedridden. 
 
Completely 
disabled.  Cannot carry on any self-
care.  Totally confined to bed or chair. 10
Moribund, fatal processes progressing 
rapidly.
5
Dead.
0
Dead.
As published in Am. J. Clin. Oncol.:  Oken, M.M., Creech, R.H., Tormey, D.C., Horton, J., Davis, T.E., McFadden, E.T., 
Carbone, P.P.: Toxicity And Response Criteria Of The Eastern Cooperative Oncology Group. Am J Clin Oncol 5:649-655, 
1982. The Eastern Cooperative Oncology Group, Robert Comis M.D., Group Chair

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APPENDIX B 
Drug Diary
Study ID:
[Drug] Pill Diary
 Subject Initials: ___          Subject ID: _____                  Cycle: _____                                                               
Instructions:
 
 
 
 
 
 
 
 
 
Planned Daily Dose: __mg
 
REMINDERS:
1. 
2.
Day
Date 
Time
# of Tablets taken
Comments
1
 
 
 
2
 
 
 
3
 
 
 
4
 
 
 
5
 
 
 
6
 
 
 
7
 
 
 
8
 
 
 
9
 
 
 
10
 
 
 
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28

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Record all medications taken during this cycle for example prescriptions and over the counter 
including vitamins.
Name 
of 
 Medication
Why did you take the 
medication?
Date
 Medication
 Started
Date  
Medication 
Stopped

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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APPENDIX C   Abbreviations and definition of terms
The following abbreviations and special terms are used in this study Clinical Study Protocol.
Abbreviation or special term
Explanation
ADA
Anti-drug antibody
AE
Adverse event
AESI
Adverse event of special interest
ALK
Anaplastic lymphoma kinase
ALT
Alanine aminotransferase
APF12
Proportion of patients alive and progression free at 12 months from randomization
AST
Aspartate aminotransferase
BoR
Best objective response
BP
Blood pressure
C
Cycle
CD
Cluster of differentiation
CI
Confidence interval
CL
Clearance
Cmax
Maximum plasma concentration
Cmax,ss
Maximum plasma concentration at steady state
CR
Complete response
CSA
Clinical study agreement
CSR
Clinical study report
CT
Computed tomography
CTCAE
Common Terminology Criteria for Adverse Event
CTLA-4
Cytotoxic T–lymphocyte-associated antigen 4
Ctrough,ss
Trough concentration at steady state
CXCL
Chemokine (C-X-C motif) ligand
DoR
Duration of response
EC
Ethics Committee, synonymous to Institutional Review Board and Independent 
Ethics Committee

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
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IRB Form BIO 01192022
                                                                                                           
Abbreviation or special term
Explanation
ECG
Electrocardiogram
ECOG
Eastern Cooperative Oncology Group
eCRF
Electronic case report form
EDoR
Expected duration of response
EGFR
Epidermal growth factor receptor
EU
European Union
FAS
Full analysis set
FDA
Food and Drug Administration
GCP
Good Clinical Practice
GI
Gastrointestinal
GMP
Good Manufacturing Practice
hCG
Human chorionic gonadotropin
HIV
Human immunodeficiency virus
HR
Hazard ratio
IB
Investigator’s Brochure
ICF
Informed consent form
ICH
International Conference on Harmonisation
IDMC
Independent Data Monitoring Committee
IFN
Interferon
IgE
Immunoglobulin E
IgG
Immunoglobulin G
IHC
Immunohistochemistry
IL
Interleukin
ILS
Interstitial lung disease
IM
Intramuscular
IMT
Immunomodulatory therapy
IP
Investigational product 
irAE
Immune-related adverse event
IRB
Institutional Review Board
irRECIST
Immune-related Response Evaluation Criteria in Solid Tumors

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 63 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
Abbreviation or special term
Explanation
ITT
Intent-to-Treat
IV
Intravenous
IVRS
Interactive Voice Response System
IWRS
Interactive Web Response System
mAb
Monoclonal antibody
MDSC
Myeloid-derived suppressor cell
MedDRA
Medical Dictionary for Regulatory Activities
MHLW
Minister of Health, Labor, and Welfare
miRNA
Micro-ribonucleic acid
MRI
Magnetic resonance imaging
NCI
National Cancer Institute
NE
Not evaluable
NSCLC
Non–small-cell lung cancer
OAE
Other significant adverse event
ORR
Objective response rate
OS
Overall survival
PBMC
Peripheral blood mononuclear cell
PD
Progressive disease
PDx
Pharmacodynamic(s)
PFS
Progression-free survival
PFS2
Time to second progression
PGx
Pharmacogenetic research
PK
Pharmacokinetic(s)
PR
Partial response
q2w
Every 2 weeks
q3w
Every 3 weeks
q4w
Every 4 weeks
q6w
Every 6 weeks
q8w
Every 8 weeks
QTcF
QT interval corrected for heart rate using Fridericia’s formula

Protocol Title: Multiple-Arm Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb20717 in 
Combination with Standard of Care Treatment in Patients with Metastatic Castration Sensitive Prostate Cancer
  
Page 64 of 64                                                                                                                           Version: 8/1/2024
IRB Form BIO 01192022
                                                                                                           
Abbreviation or special term
Explanation
RECIST 1.1
Response Evaluation Criteria in Solid Tumors, version 1.1
RNA
Ribonucleic acid
RR
Response rate
RT-QPCR
Reverse transcription quantitative polymerase chain reaction
SAE
Serious adverse event
SAP
Statistical analysis plan
SAS
Safety analysis set
SCLC
Small cell lung cancer
SD
Stable disease
SNP
Single nucleotide polymorphism
SoC
Standard of Care
T3
Triiodothyronine
T4
Thyroxine
TSH
Thyroid-stimulating hormone
ULN
Upper limit of normal
US
United States
WBDC
Web-Based Data Capture
WHO
World Health Organization