A Phase II Multicenter, Open-label Study to Evaluate the Safety and Efficacy of the CD40 Agonistic Antibody Sotigalimab (APX005M) With or Without Stereotactic Body Radiation Therapy in Adults With Unresectable or Metastatic Melanoma
Phase: PHASE2
Conditions: Unresectable Melanoma, Metastatic Melanoma, Cancer, Cancer of Skin, Melanoma, Melanoma (Skin)
Sponsor: Apexigen America, Inc.

Apexigen, Inc. 
 
APX005M-010 Clinical Protocol 
APX005M 
 
Amendment 2 
 
Date: December 28, 2020 
CONFIDENTIAL 
Page 1 of 68 
 
 
 
Protocol Number: 
 
APX005M-010 
IND Number: 
EudraCT Number: 
122725 
2018-003864-30 
Date of Original Protocol: November 2, 2018 
  
 
 
 
 
 
CLINICAL PROTOCOL APX005M-010 
A Phase II Multicenter, Open label Study to Evaluate the Safety and Efficacy of the CD40 
Agonistic Antibody APX005M With or Without Stereotactic Body Radiation Therapy in 
Adults with Unresectable or Metastatic Melanoma 
 
 
 
 
Sponsor: 
Apexigen, Inc. 
75 Shoreway Rd, Suite C 
San Carlos, CA 94070 
 
 
Central Medical Monitor: 
Thomas Jahn, M.D., Ph.D. 
75 Shoreway Rd, Suite C 
San Carlos, CA 94070 
Telephone: +1 (650) 822-4401 
Fax: +1 (650) 259-7655 
Email: TJahn@apexigen.com 
 
Date of Amendment 2: December 28, 2020 
  
  
  
The information contained in this document is the confidential and proprietary 
information of Apexigen, Inc. 
 
This study will be conducted in accordance with the protocol, the International Conference on 
Harmonisation (ICH) Guidelines for Good Clinical Practice (GCP) and the applicable country 
and regional (local) regulatory requirements. 
 

Apexigen, Inc. 
APX005M 
SPONSOR APPROVAL PAGE 
I 
Tho 
s Jahn, M.D., Ph.D. 
Vice President Clinical Development, 
Apexigen, Inc. 
Date: December 28, 2020 
CONFIDENTIAL 
APX005M-010 Clinical Protocol 
Amendment 2 
1/ P(c{ 
Date 
Page 2 of68 

Apexigen, Inc. 
 
APX005M-010 Clinical Protocol 
APX005M 
 
Amendment 2 
Date: December 28, 2020 
CONFIDENTIAL 
Page 3 of 68 
SIGNATURE PAGE OF THE INVESTIGATOR 
Title: 
 
A Phase II Multicenter, Open label Study to Evaluate the Safety 
and Efficacy of the CD40 Agonistic Antibody APX005M With or 
Without Stereotactic Body Radiation Therapy in Adults with 
Unresectable or Metastatic Melanoma 
Protocol Number: APX005M-010 
Amendment: 2 
Date: December 28, 2020 
EudraCT Number: 2018-003864-30 
Sponsor: Apexigen, Inc. 
 
 
I have read and agreed to the protocol of the above-mentioned clinical study. I am aware of my 
responsibilities as an Investigator and will conduct this study in compliance with ICH guidelines for GCP, 
local regulations (as applicable) and the study protocol. I agree to conduct the study according to these 
guidelines and to appropriately direct and assist the staff under my control, who are involved in the study. 
 
 
 
 
 
Signature 
 
 
 
_______________________ 
 
 
 
______________________ 
Name, title and affiliation of  
 
 
 
Date 
Investigator 
 
 

Apexigen, Inc. 
 
APX005M-010 Clinical Protocol 
APX005M 
 
Amendment 2 
Date: December 28, 2020 
CONFIDENTIAL 
Page 4 of 68 
DOCUMENT HISTORY 
Version 
Date 
Replaces 
Description of Changes 
Original Protocol  
November 2, 2018  
N/A 
New Document  
Version 1.1 
January 16, 2019 
Original Protocol 
The protocol was amended to add 
methods of contraception (Appendix C) 
Amendment 1.0 
March 8, 2019 
Version 1.1 
The protocol title was amended to 
reflect study design. 
 
The protocol was amended to edit 
Inclusion Criteria #2. 
 
The protocol was amended to add 
Exclusion Criteria of previous 
participation in another clinical trial of 
an investigational drug (or a medical 
device) within 30 days of study 
enrollment. 
 
The protocol was amended to update 
and resolve inconsistencies in sample 
collection schedule for correlative 
studies described in Section 4.4. 
Amendment 2.0 
December 28, 2020 
Amendment 1.0 
The protocol was amended to introduce 
Cohort 3 combining APX005M with 
stereotactic body radiation therapy in 
subjects with unresectable or metastatic 
melanoma that failed available therapies 
and to adjust the sample size in Cohorts 
1 and 2. 

Apexigen, Inc. 
 
APX005M-010 Clinical Protocol 
APX005M 
 
Amendment 2 
Date: December 28, 2020 
CONFIDENTIAL 
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SYNOPSIS 
Protocol Number:  APX005M-010 
Protocol Title: A Phase II Multicenter, Open label Study to Evaluate the Safety and 
Efficacy of the CD40 Agonistic Antibody APX005M With or Without 
Stereotactic Body Radiation in Adults with Unresectable or Metastatic 
Melanoma  
Phase of Development: Phase 2 
Investigational  
Therapy(ies): 
APX005M  
Stereotactic Body Radiation (SBRT) 
Study Design: This is a multicenter, open label, Phase 2 study, with 3 parallel cohorts. 
The aim of the study is to evaluate the efficacy of:  
a) APX005M administered at 2 different schedules to adult subjects 
with unresectable or metastatic melanoma who have not received 
prior immunotherapy. Enrolled subjects will be alternately assigned 
to one of the following 2 cohorts as long as both cohorts are open: 
Cohort 1: APX005M administered IV at 0.3 mg/kg every 3 weeks 
(21-day cycle)  
Cohort 2: APX005M administered IV at 0.3 mg/kg every 2 weeks 
(14-day cycle)   
The intent of the alternating cohort assignment is to maintain 
approximately the same number of treated subjects in each of these 
2 cohorts at any given time. Therefore, enrolled subjects assigned to 
Cohorts 1 or 2 that do not receive APX005M or are not evaluable for 
tumor response will be replaced in that cohort before assigning new 
subjects to the other cohort. 
b) APX005M in combination with stereotactic body radiation therapy 
(SBRT) in adults with unresectable or metastatic melanoma who 
have failed approved immunotherapy regimens: 
Cohort 3: APX005M administered IV at 0.3 mg/kg in combination 
with radiation therapy every 2 weeks (14-day cycle) up to 16 weeks 
followed by APX005M administered IV at 0.3 mg/kg every 2 weeks 
(14-day cycle). 
Study Objectives: Primary Objective 
• 
Evaluate the overall response rate (ORR) by RECIST 1.1 in 
each cohort 
Secondary Objectives 
• 
Evaluate the safety of APX005M alone or in combination with 
radiation therapy in each cohort 
• 
Evaluate ORR by modified RECIST 1.1 for immune-based 
therapeutics (iRECIST) in each cohort 
• 
Evaluate median duration of response (DOR) in each cohort 

Apexigen, Inc. 
 
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APX005M 
 
Amendment 2 
Date: December 28, 2020 
CONFIDENTIAL 
Page 6 of 68 
Exploratory Objectives 
• 
Evaluate PFS (by RECIST 1.1 and iRECIST) in each cohort 
• 
Evaluate the association between potential tumor and blood 
biomarkers and antitumor activity and/or resistance 
• 
Determine the presence and titer of anti-APX005M antibodies 
(ADA) 
Study Population  Inclusion Criteria  
1. Histologically or cytologically confirmed unresectable or 
metastatic melanoma 
2. Subjects with BRAF activating mutation must have received a 
BRAF inhibitor and/or MEK inhibitor regimen prior to study 
entry 
3. Signed written informed consent approved by the relevant local 
ethics committee(s) 
4. Male or female ≥18 years old at time of consent  
5. Measurable disease by RECIST 1.1 
a. 
For Cohort 3 only, subjects must have at least 3 
measurable target lesions 
6. ECOG performance status of 0 or 1 
7. Resolution of all disease or prior treatment-related toxicities to 
Grade ≤1, with the exception of alopecia, Grade 2 neuropathy 
and laboratory abnormalities (parameters below apply). If 
subject received major surgery or radiation therapy of >30 Gy, 
they must have recovered from the toxicity and/or 
complications from the intervention 
8. Adequate organ function within 14 days prior to first dose of 
investigational therapy(ies): 
a. WBC ≥2 x 109/L in absence of growth factor support 
b. ANC ≥1.0 x 109/L in absence of growth factor support 
c. Platelet count ≥100 x 109/L 
d. Hemoglobin ≥9 g/dL 
e. Serum creatinine ≤1.5 mg/dL 
f. Calculated (using the formula of local laboratory) or 
measured creatinine clearance ≥60 mL/min 
g. AST and ALT ≤2.5 x ULN 
h. Total bilirubin ≤1.5 x ULN, or direct bilirubin ≤ULN 
for subjects with total bilirubin levels >1.5 x ULN 
i. 
INR or PT ≤1.5 x ULN unless subject is receiving 
anticoagulant therapy as long as PT or PTT is within 
therapeutic range of intended use of anticoagulants 

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APX005M 
Amendment 2 
Date: December 28, 2020 
CONFIDENTIAL 
Page 7 of 68 
j.
aPTT ≤1.5 x ULN unless subject is receiving
anticoagulant therapy as long as PT or PTT is within
therapeutic range of intended use of anticoagulants
9.
Women of childbearing potential (WOCBP) must have a
negative serum pregnancy test within the 7 days prior to first
dose of investigational therapy(ies) and a negative urine
pregnancy test within the 3 days prior to first dose of
investigational therapy(ies), or a negative serum pregnancy test
within the 3 days prior to first dose of investigational
therapy(ies)
10. Women of childbearing potential must agree to follow
instructions for method(s) of contraception for the duration of
study treatment and 5 months after the last dose of
investigational therapy(ies). Males who are sexually active with
WOCBP must agree to follow instructions for method(s) of
contraception for the duration of study treatment and 7 months
after the last dose of investigational therapy(ies).
11. Available archived or fresh tumor tissue sample for biomarker
analysis.  Note: For Cohort 3, only available archived tissue is
required.
12. For subjects that consent to collection of tumor biopsies at
study entry and before the first scheduled tumor assessment,
primary or metastatic tumor that can be safely biopsied. Up to
18 subjects (6 subjects within each cohort) should consent to
fresh core biopsies.
Exclusion Criteria 
1.
Prior Therapy:
a.
Cohorts 1 and 2 only: Previous exposure to any 
immunomodulatory agent (such as CTLA-4, PD-1/
PD-L1, IDO inhibitors, interferon, CD40 agonists etc.).
b.
Cohort 3 only: Prior therapy with a CD40 agonist.
Any number of prior lines of therapy are eligible.
A minimum washout period of 21 days from last line of
therapy until investigational therapy(ies) administration
should be observed
2.
Second malignancy (solid or hematologic) within the past 3
years except locally curable cancers that have been apparently
cured, such as basal or squamous cell skin cancer, superficial
bladder cancer, or carcinoma in situ of the prostate, cervix, or
breast
3.
Active, known, clinically serious infections (≥ Grade 2
according to NCI-CTCAE v4.03) within the 14 days prior to
first dose of investigational therapy(ies)
4.
Use of systemic corticosteroids or other systemic
immunosuppressive drugs within 28 days prior to first dose of

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APX005M 
 
Amendment 2 
Date: December 28, 2020 
CONFIDENTIAL 
Page 8 of 68 
investigational therapy(ies) (except inhaled corticosteroids) 
a. The use of physiologic doses of corticosteroids may be 
approved after consultation with the Apexigen Medical 
Monitor (or designee) 
5. Major surgery within 4 weeks prior to first dose of 
investigational therapy(ies) 
6. Concurrent treatment with any anticancer agent (except for 
hormonal therapy) and palliative radiation, unless approved by 
the Apexigen Medical Monitor (or designee) 
7. History of allogeneic bone marrow transplantation  
8. Active, known or suspected autoimmune disease  
9. Active autoimmune disease that has required systemic 
treatment in past 2 years (i.e. with use of disease modifying 
agents, corticosteroids or immunosuppressive drugs). Subjects 
with Type 1 diabetes mellitus, hypothyroidism only requiring 
hormone replacement, skin disorders (such as vitiligo, psoriasis, 
or alopecia) not requiring systemic treatment, or conditions not 
expected to recur in the absence of an external trigger are 
permitted to enroll 
10. History of (non-infectious) pneumonitis that required 
corticosteroids or current pneumonitis 
11. History of interstitial lung disease 
12. History of sensitivity or allergy to mAbs or IgG  
13. Congestive heart failure (New York Heart Association Class III 
to IV), symptomatic ischemia, conduction abnormalities 
uncontrolled by conventional intervention, or myocardial 
infarction within 6 months prior to the first dose of 
investigational therapy(ies) 
14. History of any thromboembolic event within 3 months prior to 
first dose of investigational therapy(ies) or active coagulopathy  
15. Known active central nervous system (CNS) metastases and/or 
carcinomatous meningitis. Subjects with untreated brain 
metastases ≤3mm that are asymptomatic, do not have 
significant edema, cause shift, and do not require steroids or 
anti-seizure medications are eligible after discussion with the 
Medical Monitor. Lesions of any size in posterior fossa are 
excluded. Subjects with previously treated brain metastases 
may participate provided they are stable after treatment 
(without evidence of progression by imaging for at least 
4 weeks prior to the first dose of trial treatment and any 
neurologic symptoms have returned to baseline), have no 
evidence of new or enlarging brain metastases, and are not 
using corticosteroids for at least 7 days prior to trial treatment. 
This exception does not include carcinomatous meningitis 
which is excluded regardless of clinical stability 

Apexigen, Inc. 
 
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APX005M 
 
Amendment 2 
Date: December 28, 2020 
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16. Known human immunodeficiency virus (HIV), hepatitis B or 
hepatitis C infection 
17. Has received a live (attenuated) vaccine within 30 days prior to 
the first dose of investigational therapy(ies). Seasonal flu 
vaccines that do not contain live virus and COVID-19 vaccines 
are permitted (See Section 3.2.3.4) 
18. Has participated in another clinical trial of an investigational 
drug (or a medical device) within 30 days of study enrollment 
19. Pregnant, breastfeeding, or unwilling to practice birth control 
during participation in the study 
20. Any clinically significant psychiatric, social, or medical 
condition that, in the opinion of the Investigator, could increase 
subject’s risk, interfere with protocol adherence, or affect a 
subject’s ability to give informed consent. 
Statistical Methods and 
Analyses: 
Safety Analyses  
Safety will be assessed by cohort through summaries of AEs, laboratory 
test results, ECG, vital signs, and APX005M exposure. All AE data 
collected will be listed by study site, cohort, subject number, and cycle 
day. 
Efficacy Analyses  
Tumor assessments by Investigator will follow RECIST 1.1 and 
iRECIST. ORR (and 90% confidence interval by exact distribution), 
DOR and PFS (Kaplan-Meier estimate) will be estimated for each 
cohort and for each tumor assessment method. Additional details will 
be provided in the Statistical Analysis Plan.  
Exploratory Analyses  
Potential tumor and blood biomarkers identified in the exploratory 
biomarker research may be correlated with safety and efficacy 
outcomes.  
 
 

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APX005M 
 
Amendment 2 
Date: December 28, 2020 
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TABLE OF CONTENTS 
Sponsor Approval Page ................................................................................................................ 2 
Signature Page Of The Investigator ............................................................................................ 3 
Document History ......................................................................................................................... 4 
Synopsis .......................................................................................................................................... 5 
Table of Contents ........................................................................................................................ 10 
List of Tables ............................................................................................................................... 13 
List of Figures .............................................................................................................................. 13 
1. 
Introduction and Rationale ................................................................................................ 14 
1.1 
Background .................................................................................................................... 14 
1.2 
APX005M ...................................................................................................................... 15 
1.2.1 
Pharmacology ......................................................................................................... 15 
1.2.2 
Pharmacokinetics .................................................................................................... 16 
1.2.3 
Clinical Experience ................................................................................................. 16 
1.2.4 
Summary of the Known and Potential Risks and Benefits ..................................... 17 
2. 
Investigational Plan ............................................................................................................ 17 
2.1 
Study Objectives ............................................................................................................ 17 
2.1.1 
Primary Objective ................................................................................................... 17 
2.1.2 
Secondary Objectives .............................................................................................. 17 
2.1.3 
Exploratory Objectives ........................................................................................... 18 
2.2 
Study Design and Duration ............................................................................................ 18 
2.2.1 
Study Population ..................................................................................................... 20 
2.2.2 
Rationale for APX005M Dose ................................................................................ 23 
3. 
Study Periods ....................................................................................................................... 23 
3.1 
Screening Period ............................................................................................................ 23 
3.1.1 
Informed Consent.................................................................................................... 23 
3.1.2 
Subject Enrollment.................................................................................................. 23 
3.2 
Treatment Period ............................................................................................................ 23 
3.2.1 
APX005M Administration ...................................................................................... 24 
3.2.2 
Radiation Therapy ................................................................................................... 24 
3.2.3 
Concomitant Treatments ......................................................................................... 28 
3.2.4 
Retreatment Criteria ................................................................................................ 33 

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3.2.5 
Dose Modifications ................................................................................................. 33 
3.2.6 
Duration of Treatment............................................................................................. 34 
3.3 
Follow-up Period ............................................................................................................ 36 
3.3.1 
Discontinuation of Subjects from Study ................................................................. 36 
3.3.2 
Subject Premature Withdrawal ............................................................................... 37 
3.4 
Study Termination .......................................................................................................... 37 
4. 
Study Assessments and Procedures ................................................................................... 37 
4.1 
Procedures by Visits ....................................................................................................... 37 
4.1.1 
Screening Period ..................................................................................................... 37 
4.1.2 
Treatment Period ..................................................................................................... 38 
4.1.3 
Follow-up Period .................................................................................................... 41 
4.2 
Safety Assessments ........................................................................................................ 41 
4.2.1 
Medical History ...................................................................................................... 41 
4.2.2 
Physical Examinations ............................................................................................ 42 
4.2.3 
Electrocardiogram ................................................................................................... 42 
4.2.4 
Vital Signs ............................................................................................................... 42 
4.2.5 
ECOG Performance Status ..................................................................................... 42 
4.2.6 
Laboratory Tests ..................................................................................................... 43 
4.3 
Efficacy Assessments ..................................................................................................... 44 
4.3.1 
Collection of Tumor Assessment Images ............................................................... 45 
4.3.2 
Modified RECIST 1.1 for Immune-based Therapeutics ......................................... 45 
4.4 
Correlative Studies ......................................................................................................... 45 
4.4.1 
APX005M Pharmacokinetic Assessments .............................................................. 45 
4.4.2 
APX005M Anti-drug Antibodies ............................................................................ 45 
4.4.3 
Blood and Tumor Biomarkers ................................................................................ 45 
4.4.4 
Cytokines ................................................................................................................ 46 
5. 
Adverse Events .................................................................................................................... 46 
5.1 
Definitions ...................................................................................................................... 46 
5.1.1 
Adverse Event ......................................................................................................... 46 
5.1.2 
Suspected Adverse Reaction ................................................................................... 46 
5.1.3 
Life-threatening AE or Life-threatening SAR ........................................................ 47 
5.1.4 
Serious AE or Serious SAR .................................................................................... 47 

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5.1.5 
Unexpected AE or Unexpected SAR ...................................................................... 47 
5.1.6 
Overdose ................................................................................................................. 48 
5.2 
Adverse Event Classification ......................................................................................... 48 
5.2.1 
Relationship to Investigational Therapy(ies) .......................................................... 48 
5.2.2 
Severity ................................................................................................................... 49 
5.3 
AE Collection and Reporting ......................................................................................... 49 
5.3.1 
General AE Reporting ............................................................................................. 49 
5.3.2 
Intermittent Adverse Events ................................................................................... 50 
5.3.3 
Reporting Symptoms Versus Syndromes ............................................................... 50 
5.3.4 
Disease Progression ................................................................................................ 50 
5.3.5 
Reporting Serious AEs ............................................................................................ 51 
5.3.6 
Handling of Expedited Safety Reports ................................................................... 51 
5.3.7 
Non-Serious AEs .................................................................................................... 52 
5.3.8 
Laboratory Test Abnormalities ............................................................................... 52 
5.4 
Pregnancy ....................................................................................................................... 52 
6. 
Statistics ............................................................................................................................... 53 
6.1 
Sample Size Determination ............................................................................................ 53 
6.2 
Populations for Analyses ................................................................................................ 53 
6.3 
Endpoint Definitions ...................................................................................................... 53 
6.4 
Analyses ......................................................................................................................... 54 
6.4.1 
Demographics and Baseline Characteristics ........................................................... 54 
6.4.2 
Safety Analyses ....................................................................................................... 54 
6.4.3 
Efficacy Analyses ................................................................................................... 54 
6.4.4 
Exploratory Analyses .............................................................................................. 54 
7. 
Administrative Section ....................................................................................................... 54 
7.1 
Ethics .............................................................................................................................. 54 
7.1.1 
Compliance with the Protocol and Protocol Revisions ........................................... 54 
7.1.2 
Institutional Review Board / Independent Ethics Committee ................................. 55 
7.1.3 
Informed Consent.................................................................................................... 55 
7.2 
Study Materials .............................................................................................................. 56 
7.3 
Monitoring ...................................................................................................................... 56 
7.3.1 
APX005M ............................................................................................................... 56 

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7.4 
Confidentiality ................................................................................................................ 58 
7.5 
Investigational Site Training .......................................................................................... 58 
7.6 
Data Collection and Handling ........................................................................................ 58 
7.7 
Publications .................................................................................................................... 59 
8. 
List of Abbreviations .......................................................................................................... 60 
9. 
References ............................................................................................................................ 63 
Appendix A: Study APX005M-010 Schedule of Events ....................................................... 65 
Appendix B: Vital Signs and Correlative Lab Schedule ...................................................... 67 
Appendix C: Methods of Contraception ................................................................................ 68 
 
LIST OF TABLES 
Table 1A: 
Radiation Dose Constraints - Serial Tissue ..........................................................26 
Table 1B: 
Radiation Dose Constraints - Parallel Tissue .......................................................27 
Table 1C: 
Radiation Dose Criteria ........................................................................................27 
Table 2: 
Guidance for Management of Cytokine Release/Infusion Reaction  
Symptoms .............................................................................................................31 
Table 3: 
Dose Modifications for Toxicity ..........................................................................33 
Table 4: 
ECOG Performance Criteria ................................................................................42 
Table 5: 
Toxicity Grading for AEs Not Covered in NCI-CTCAE (Version 4.03) ............49 
 
LIST OF FIGURES 
Figure 1: 
Cohort 3 Study Design ...........................................................................................19 
 
 

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1. INTRODUCTION AND RATIONALE  
1.1 
Background  
Among the promising approaches to activating therapeutic antitumor immunity is the modulation 
of host immune system. Immune modulation includes inhibitory or stimulatory pathways in the 
immune system that are crucial for activating the immune response, maintaining self-tolerance, 
and modulating the duration and amplitude of physiological immune responses. Modulation of 
immune checkpoints by antibodies against immune inhibitory molecules has shown clinical 
benefits for patients with various solid tumors such as melanoma, lung cancer, bladder cancer, 
renal cell carcinoma [1–3]. Currently, both antagonistic monoclonal antibodies (mAb) against 
immune inhibitory molecules such as cytotoxic T-lymphocyte associated protein 4 (CTLA-4) 
and programmed death receptor-1 (PD-1)/ programmed death-ligand 1 (PD-L1) and agonistic 
antibodies against immune costimulatory molecules such as CD40 and OX40 are under active 
development for different cancer indications [4]. 
Apexigen has developed the mAb APX005M, which binds and activates CD40, a costimulatory 
molecule expressed by antigen presenting cells (APC). As such, APX005M is a CD40 agonistic 
antibody. The cell surface molecule CD40, a member of the tumor necrosis factor receptor 
(TNFR) superfamily, plays an important role in induction of tumor apoptosis and regulation of 
immune activation, especially in crosstalk between T cells and APCs [5]. CD40 is expressed by 
dendritic cells (DC), B cells, monocytes, and some non-lymphoid cells [6]. The natural ligand 
(CD40L) for CD40 is CD154, which is expressed on activated T cells and provides a major 
component of T cell “help” for immune response. Agonistic CD40 antibodies can substitute for 
the function of CD154 on T cells to boost immunity. Signaling through CD40 on APCs, 
including dendritic cells (DCs), monocytes, and B cells, can, in turn, enhance the T cell response 
via improvement in antigen processing and presentation, upregulation of costimulatory 
molecules and through the release of cytokines from activated APCs [7, 8]. Therefore, an 
agonistic CD40 antibody can activate and stimulate both innate and adaptive immunity.  
CD40 is also expressed on many tumor cells and can mediate a direct cytotoxic effect. In 
addition to B cell lymphoma, CD40 expression has been reported in 30−70% of primary human 
solid tumor samples including melanoma and carcinomas [9]. Activation of CD40 on tumor cells 
results in tumor cell apoptosis and inhibition of tumor growth [10]. Due to its action on both 
immune and tumor cells, CD40 has been studied as a target for novel cancer immunotherapy; 
agonistic anti-CD40 antibodies have been demonstrated to be potent stimulators of tumor 
immune responses in both animal models and cancer subjects [11–14]. 
The potential mechanisms of action for an agonistic anti-CD40 antibody, depending on its 
isotype, include stimulation of immune response by activating antigen processing and 
presentation, recruitment of immune effectors such as natural killer (NK) cells and macrophages, 
and direct cytotoxic effects on tumor cells, all of which could lead to therapeutic effects in 
tumors with high mutational burden such as melanoma. Thus, the desired therapeutic CD40 
agonist antibody should have these functionalities. 

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A few CD40 agonistic antibodies have been evaluated in human clinical trials. Many of the 
clinical studies in cancer subjects with solid tumors have been conducted with the fully human 
IgG2 CD40 antibody CP-870,893. In a Phase 1 clinical trial, CP-870,893 was well tolerated; the 
MTD was found to be 0.2 mg/kg. The main toxicity of CP-870,893 was cytokine release 
syndrome (CRS) of mild to moderate severity. Single agent antitumor activity was observed in 
several melanoma subjects treated with CP-870,893 [15, 16]. 
In several preclinical models the combination of RT with drugs that activate APCs results in 
synergistic anti-tumor effects [17, 18]. Activating tumor APCs via CD40 will enhance tumor 
antigen presentation and help prime or boost antitumor T cells in lymph nodes or in tumor-
embedded tertiary lymphoid structures. In addition, properly activated APCs provide potent 
costimulatory signals to CD8+ tumor-infiltrating lymphocytes in the tumor microenvironment 
and release appropriate chemokines, which guide effector T cells to home in the tumor 
microenvironment. In a triple-negative breast cancer model the combination of a CD40 agonist 
antibody and RT resulted in improved innate and adaptive immune response. Importantly, CD40 
treatment increased tumor response to radiotherapy and protected against metastatic spread in a 
metastatic model [19]. 
1.2 
APX005M 
1.2.1 
Pharmacology  
APX005M is an IgG1 humanized mAb with the S267E mutation at the Fc region. APX005M 
binds with high affinity to human CD40 (Kd = 1.2 × 10−10 M) and monkey CD40 (Kd = 3.5 × 
10−10 M), but does not cross-react with mouse or rat CD40. APX005M blocks the binding of 
CD40 to CD40L. The APX005M binding epitope has been mapped to 2 specific regions on 
CD40. These are 92TSEACESCVLHRSCSP107 and 125PCPVGFFSNVSSAFEKCHPW144. 
The region 92TSEACESCVLHRSCSP107 is known as a CD40L binding domain. It has been 
shown that CD40L-blocking antibodies tend to have more potent CD40 agonistic activities than 
CD40L-non-blocking antibodies [20]. 
Preclinical experiments with APX005M showed that it activates the CD40 signaling pathway, 
leading to APC activation, as demonstrated by an increased expression of CD80, CD83, and 
CD86 and by expression and release of cytokines from human DCs and lymphocytes. As a result 
of APC activation, APX005M enhances T-cell proliferation to alloantigen, triggers production of 
IFN-γ in response to viral antigens, and enhances T-cell response to tumor antigens. APX005M 
combined with a TLR 4 agonist or an antibody against programmed death ligand 1 (PD-L1) 
synergistically enhances T-cell responses. In comparison with other CD40-agonistic antibodies, 
such as CP-870,893, SGN-40, and ADC-1013 analogs, APX005M is the most potent CD40 
agonist. APX005M did not appear to have a substantive effect on normal human DC and T-cell 
counts, but could partially reduce B cell counts in vitro. The potential for APX005M to induce 
expression of cytokines was evaluated with peripheral blood mononuclear cells (PBMC) 
obtained from normal humans and treatment naïve cynomolgus monkeys, including anti CD3 
antibody as a positive control. Cytokine secretion differed significantly between species with 
much less secretion from monkey PBMCs compared with human PBMCs. These data suggest 

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that APX005M is a strong CD40-agonistic antibody that can activate APCs (DCs, B cells, and 
monocytes) and in turn stimulate T-cell response. 
The direct cytotoxicity effect and the antibody effector functions such as antibody-dependent 
cellular phagocytosis (ADCP) of APX005M were determined in CD40 positive human 
lymphoma xenograft models in mice. In human lymphoma Ramos models, APX005M was 
capable of inhibiting tumor growth in a dose-dependent manner, and eradicated established 
tumors at 3 mg/kg and 10 mg/kg. A significant anti-tumor effect was also observed in the 
rituximab-resistant Namalwa model [21]. These data suggest that APX005M, as a single agent, 
can induce potent growth inhibition of CD40-expressing human tumors. 
Preliminary human data shows that APX005M induces a dose-dependent activation of APCs 
(as demonstrated by increases in expression of activation markers such as CD54, CD70, CD80, 
CD86, HLA-DR), T-cell activation and increases in circulating levels of IL12, INF-γ, TNF-α 
and IL6. 
1.2.2 
Pharmacokinetics 
Nonclinical pharmacokinetics (PK) of APX005M was determined in a Good Laboratory Practice 
(GLP) repeat-dose toxicology study using cynomolgus monkeys. Weekly intravenous (IV) 
administration of 5 doses of APX005M was well tolerated at 0.3, 3, and 30 mg/kg. The PK 
properties of APX005M are typical of other mAbs and comprise low clearance (average range of 
0.401–7.27 mL/h/kg), small volume of distribution (average range of 57–80.1 mL/kg), and long 
terminal half-life (average >66 hours at 3 mg/kg and 30 mg/kg). Positive anti-drug antibodies 
(ADA) titers were observed in all animals in the low-dose group (0.3 mg/kg) but not in the high-
dose group (30 mg/kg) [18]. Based on these results, the no observed adverse effect level 
(NOAEL) was considered 30 mg/kg. 
There are limited human PK data with APX005M at this time. Exposures to every 3-week IV 
administration of APX005M at dose levels of 0.03 mg/kg or less were for the most part below 
the limit of quantitation (BLOQ). Administration of APX005M at dose levels between 0.1 and 
1 mg/kg lead to rapid increase in serum concentrations, reaching a maximum just after the end of 
the infusion. Concentrations declined rapidly thereafter and were for the most part BLOQ 
between 24 and 168 hours after the start of dosing. Increases in the dose of APX005M 
(0.1 mg/kg to 1 mg/kg) led to approximately dose-proportional increases in maximum serum 
concentration (Cmax) and area under the curve at the last measurable time point (AUC0–t). 
No accumulation of APX005M was observed with every 21 days dosing.  
1.2.3 
Clinical Experience  
APX005M has been administered to cancer patients with heavily pretreated solid tumors at doses 
ranging from 0.0001 mg/kg to 1 mg/kg body weight every 3 weeks, 0.1 mg/kg and 0.3 mg/kg 
every 2 weeks and 0.1 mg/kg and 0.3 mg/kg every 1 week. In all 3 administration schedules, the 
dose of 0.3 mg/kg body weight was well tolerated, with toxicities ≤ Grade 2, and is the 
recommended Phase 2 dose. In the every 3-week administration schedule, APX005M 

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demonstrated a dose-dependent activation of APCs, T-cell activation, and increases in circulating 
levels of cytokines.  
1.2.4 
Summary of the Known and Potential Risks and Benefits  
Symptoms associated with cytokine release syndrome (including but not limited to flushing, 
itchiness, chills, fever, rash, tachycardia, hypotension, hypertension, rigor, and myalgia) after 
administration of APX005M are possible and have been observed in some of the subjects 
receiving APX005M. Guidance for monitoring and management of cytokine release syndrome 
are included in this protocol and in the APX005M Investigator’s Brochure.  
Asymptomatic transient transaminase elevations, with or without transient bilirubin increase, 
have been observed in subjects receiving APX005M and these elevations seem to correlated with 
the presence of liver metastases. Liver function test abnormalities tend to resolve to baseline 
within 7 days from APX005M administration. 
Transient decreases in peripheral blood lymphocyte count in general and B-cell count in 
particular have been observed for APX005M as well as for other CD40-agonistic mAbs, and are 
believed to be a pharmacodynamic (PDn) effect. Transient decreases in platelet counts were 
observed for some of the subjects receiving higher doses of APX005M but were not associated 
with bleeding or other clinical manifestations.  
Other symptoms might also occur, including allergic reactions, which could be severe, 
pulmonary edema, and rarely, thromboembolic events, myocardial infarction and/or death. 
In the Phase 1 study APX005M-001, APX005M demonstrated a dose-dependent activation of 
APCs, T-cell activation and increases in circulating levels of cytokines. 
The biological effects and the overall tolerability of APX005M up to 1 mg/kg body weight 
suggest a best-in-class profile for APX005M and the possibility of a safe and efficacious 
treatment for patients with melanoma. 
2. INVESTIGATIONAL PLAN  
2.1 
Study Objectives  
2.1.1 
Primary Objective 
• Evaluate the overall response rate (ORR) by RECIST 1.1 in each cohort 
2.1.2 
Secondary Objectives 
• Evaluate the safety of APX005M alone or in combination with radiation therapy in 
each cohort 
• Evaluate ORR by modified RECIST 1.1 for immune-based therapeutics (iRECIST) in 
each cohort 
• Evaluate median duration of response (DOR) in each cohort 

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2.1.3 
Exploratory Objectives 
•
Evaluate PFS (by RECIST 1.1 and iRECIST) in each cohort
•
Evaluate the association between potential tumor and blood biomarkers and antitumor
activity and/or resistance
•
Determine the presence and titer of anti-APX005M antibodies (ADA)
2.2 
Study Design and Duration  
This is a multicenter, open label, Phase 2 study, with 3 parallel cohorts. The aim of the study is 
to evaluate the efficacy of: 
a) APX005M administered at 2 different schedules to adult subjects with unresectable or
metastatic melanoma who have not received prior immunotherapy. Enrolled subjects will
be alternately assigned to one of the following 2 cohorts as long as both cohorts are open:
Cohort 1: APX005M administered IV at 0.3 mg/kg every 3 weeks (21-day cycle)
Cohort 2: APX005M administered IV at 0.3 mg/kg every 2 weeks (14-day cycle)
The intent of the alternating cohort assignment is to maintain approximately the same
number of treated subjects in each of these 2 cohorts at any given time. Therefore,
enrolled subjects assigned to Cohorts 1 or 2 who do not receive APX005M or are not
evaluable for tumor response (see below) will be replaced in that cohort before assigning
new subjects to the other cohort.
b) APX005M in combination with stereotactic body radiation therapy (SBRT) in adults with
unresectable or metastatic melanoma who have failed approved immunotherapy
regimens:
Cohort 3: APX005M administered IV at 0.3 mg/kg in combination with radiation
therapy every 2 weeks (14-day cycle) up to 16 weeks followed by APX005M
administered IV at 0.3 mg/kg every 2 weeks (14-day cycle).
Subjects enrolled in Cohort 3 are required to have a minimum of 3 non-central nervous
system (CNS) measurable target lesions as defined in RECIST 1.1 (see Section 3.2.2).
Subjects will receive APX005M combined with SBRT followed by single agent
APX005M:
•
Four cycles consisting of radiation (one fraction of 800 cGy per cycle delivered to
the same target lesion) followed by systemic administration of APX005M every
2 weeks for a total period of 8 weeks.
•
Tumor assessment
•
Four additional cycles consisting of radiation (one fraction of 800 cGy per cycle
delivered to one target lesion different from the one previously irradiated)
followed by systemic administration of APX005M every 2 weeks for a total
period of 8 weeks.
•
Tumor assessment

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•
Single agent APX005M until any of the criteria in Section 3.2.6.1 are met.
If the first or second radiation therapy targets disappear during radiation treatment, 
radiation induced toxicity occurs, or radiation dose constrains are met, the remaining 
radiation fraction scheduled for that particular radiation therapy target can be omitted 
(Sections 3.2.2 and 3.2.5).  
Figure 1: 
Cohort 3 Study Design 
Subjects in all 3 cohorts with unconfirmed PD (iUPD, iRECIST) (Section 4.3.2) will be 
permitted to continue treatment as long as  
•
they meet the criteria in Section 3.2.6.2and
•
they do not have confirmed PD as defined by iRECIST on a repeated tumor assessment
4-8 weeks later.
Subjects that are deemed clinically unstable are not required to have repeat imaging for 
confirmation of PD. 
For every subject the participation in the study consists of 3 periods: Screening Period, 
Treatment Period and Follow-up Period. 
All subjects signing the informed consent form will enter the Screening Period. Procedures and 
timing of all study related procedures are outlined in Section 4. Treatment period will start with 
the administration of 1st dose of APX005M ± SBRT and will continue for up to 12 months or 
until criteria in Section 3.2.6.1 are met.  
For the first 2 treatment cycles, subjects will be observed for at least 4 hours following the 
infusion of APX005M and will return for safety evaluations on Day 2 (24 hours post infusion) 
and Day 8 (168 hours post infusion). In subsequent cycles, the 4-hour post-infusion observation 
period and any intracycle safety visits should be scheduled as clinically indicated.  

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Tumor responses will be evaluated approximately every 8 weeks following the first dose of 
APX005M. Subjects that discontinue treatment before the first scheduled on-study tumor 
assessment (8 weeks following the first dose of APX005M) should have the tumor response 
evaluated at the end of treatment visit. Subjects that are non-evaluable for tumor response will be 
replaced. 
Subjects consenting to collection of tumor biopsies for tumor biomarkers must have a primary or 
metastatic lesion that can be biopsied without interfering with subsequent tumor assessments. 
Subjects who discontinue APX005M will enter the Follow-up Period unless treatment 
discontinuation is due to withdrawal of consent for all study procedures, initiation of any 
anticancer therapy, subject lost to follow-up, death, or study termination by Apexigen. 
2.2.1 
Study Population 
2.2.1.1 
Inclusion Criteria 
1) Histologically or cytologically confirmed unresectable or metastatic melanoma
2) Subjects with BRAF activating mutation must have received a BRAF inhibitor and/or
MEK inhibitor regimen prior to study entry
3) Signed written informed consent approved by the relevant local ethics committee(s)
4) Male or female ≥18 years old at time of consent
5) Measurable disease by RECIST 1.1
a.
For Cohort 3 only, subjects must have at least 3 measurable non-CNS target
lesions
6) ECOG performance status of 0 or 1
7) Resolution of all disease or prior treatment-related toxicities to Grade ≤1, with the
exception of alopecia, Grade 2 neuropathy and laboratory abnormalities (parameters
below apply). If subject received major surgery or radiation therapy of >30 Gy, they must
have recovered from the toxicity and/or complications from the intervention
8) Adequate organ function within 14 days prior to first dose of investigational therapy(ies):
a.
WBC ≥2 x 109/L in absence of growth factor support
b. ANC ≥1.0 x 109/L in absence of growth factor support
c.
Platelet count ≥100 x 109/L
d. Hemoglobin ≥9 g/dL
e.
Serum creatinine ≤1.5 mg/dL
f.
Calculated (using the formula of local laboratory) or measured creatinine
clearance ≥60 mL/min

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g. AST and ALT ≤2.5 x ULN
h. Total bilirubin ≤1.5 x ULN, or direct bilirubin ≤ULN for subjects with total
bilirubin levels >1.5 x ULN
i.
INR or PT ≤1.5 x ULN unless subject is receiving anticoagulant therapy as long
as PT or PTT is within therapeutic range of intended use of anticoagulants
j.
aPTT ≤1.5 x ULN unless subject is receiving anticoagulant therapy as long as PT
or PTT is within therapeutic range of intended use of anticoagulants
9) Women of childbearing potential (WOCBP) must have a negative serum pregnancy test
within the 7 days prior to first dose of investigational therapy(ies) and a negative urine
pregnancy test within the 3 days prior to first dose of investigational therapy(ies), or a
negative serum pregnancy test within the 3 days prior to first dose of investigational
therapy(ies)
10) Women of childbearing potential must agree to follow instructions for method(s) of
contraception for the duration of study treatment and 5 months after the last dose of
investigational therapy(ies). Males who are sexually active with WOCBP must agree to
follow instructions for method(s) of contraception for the duration of study treatment and
7 months after the last dose of investigational therapy(ies)
11) Available archived or fresh tumor tissue sample for biomarker analysis. Note: For Cohort
3, only available archived tissue is required.
12) For subjects that consent to collection of tumor biopsies at study entry and before the first
scheduled tumor assessment, primary or metastatic tumor that can be safely biopsied. Up
to 18 subjects (6 subjects within each cohort) should consent to fresh core biopsies.
2.2.1.2 
Exclusion Criteria 
1) Prior Therapy:
a.
Cohorts 1 and 2 only: Previous exposure to any immunomodulatory agent (such as 
CTLA-4, PD-1/PD-L1, IDO inhibitors, interferon, CD40 agonist etc.).
b. Cohort 3 only: Prior therapy with a CD40 agonist. Any number of prior lines of
therapy are eligible. A minimum washout period of 21 days from last line of
therapy until investigational therapy(ies) administration should be observed
2) Second malignancy (solid or hematologic) within the past 3 years except locally curable
cancers that have been apparently cured, such as basal or squamous cell skin cancer,
superficial bladder cancer, or carcinoma in situ of the prostate, cervix, or breast
3) Active, known, clinically serious infections (≥ Grade 2 according to NCI-CTCAE v4.03)
within the 14 days prior to first dose of investigational therapy(ies)
4) Use of systemic corticosteroids or other systemic immunosuppressive drugs within
28 days prior to first dose of investigational therapy(ies) (except inhaled corticosteroids)
a.
The use of physiologic doses of corticosteroids may be approved after
consultation with the Apexigen Medical Monitor (or designee)
5) Major surgery within 4 weeks prior to first dose of investigational therapy(ies)

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6) Concurrent treatment with any anticancer agent (except for hormonal therapy) and 
palliative radiation, unless approved by the Apexigen Medical Monitor (or designee) 
7) History of allogeneic bone marrow transplantation  
8) Active, known or suspected autoimmune disease  
9) Active autoimmune disease that has required systemic treatment in past 2 years (i.e. with 
use of disease modifying agents, corticosteroids or immunosuppressive drugs). Subjects 
with Type 1 diabetes mellitus, hypothyroidism only requiring hormone replacement, skin 
disorders (such as vitiligo, psoriasis, or alopecia) not requiring systemic treatment, or 
conditions not expected to recur in the absence of an external trigger are permitted to 
enroll 
10) History of (non-infectious) pneumonitis that required corticosteroids or current 
pneumonitis 
11) History of interstitial lung disease 
12) History of sensitivity or allergy to mAbs or IgG  
13) Congestive heart failure (New York Heart Association Class III to IV), symptomatic 
ischemia, conduction abnormalities uncontrolled by conventional intervention, or 
myocardial infarction within 6 months prior to the first dose of investigational 
therapy(ies) 
14) History of any thromboembolic event within 3 months prior to first dose of 
investigational therapy(ies) or active coagulopathy  
15) Known active central nervous system (CNS) metastases and/or carcinomatous meningitis. 
Subjects with untreated brain metastases ≤3mm that are asymptomatic, do not have 
significant edema, cause shift, and do not require steroids or anti-seizure medications are 
eligible after discussion with the Medical Monitor. Lesions of any size in posterior fossa 
are excluded. Subjects with previously treated brain metastases may participate provided 
they are stable after treatment (without evidence of progression by imaging for at least 4 
weeks prior to the first dose of trial treatment and any neurologic symptoms have returned 
to baseline), have no evidence of new or enlarging brain metastases, and are not using 
corticosteroids for at least 7 days prior to trial treatment. This exception does not include 
carcinomatous meningitis which is excluded regardless of clinical stability 
16) Known human immunodeficiency virus (HIV), hepatitis B or hepatitis C infection 
17) Has received a live (attenuated) vaccine within 30 days prior to the first dose of 
investigational therapy(ies). Seasonal flu vaccines that do not contain live virus and 
COVID-19 vaccines are permitted (see Section 3.2.3.4) 
18) Has participated in another clinical trial of an investigational drug (or a medical device) 
within 30 days of study enrollment 
19) Pregnant, breastfeeding, or unwilling to practice birth control during participation in the 
study 
20) Any clinically significant psychiatric, social, or medical condition that, in the opinion of 
the Investigator, could increase subject’s risk, interfere with protocol adherence, or affect 

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a subject’s ability to give informed consent. 
2.2.2 
Rationale for APX005M Dose   
The APX005M regimens (dose and frequency) for all cohorts have been evaluated in prior 
studies and determined to be well-tolerated and pharmacodynamically-active. In an ongoing 
study, the combination of APX005M with local radiation treatment and chemotherapy did not 
result in excess or synergistic toxicity.  
3. STUDY PERIODS 
3.1 
Screening Period 
3.1.1 
Informed Consent  
All subjects will provide written informed consent prior to any study-related activities. All 
subjects who sign a consent form will enter the Screening Period and be assigned a unique 
Subject Identification Number. This number will be used to identify the subject throughout the 
study and must be used on all study documentation.  
Subjects will be reconsented, as appropriate, during the course of the study if the informed 
consent document is revised. Reconsent should be obtained as soon as practicable (e.g., prior to 
subsequent study drug exposure) or as directed by the local ethics committee(s).  
3.1.2 
Subject Enrollment  
Investigative sites will submit Subject Eligibility Packets (SEPs) for Apexigen Medical Monitor 
(or designee) review and approval. SEPs will include study-specific eligibility checklist and 
redacted/anonymized source documents such as the most recent history and physical, imaging 
reports, and laboratory reports. The Apexigen Medical Monitor (or designee) will review the 
subject’s medical information to confirm eligibility and approve subject’s enrollment in the 
study. During normal business days, a minimum of 2 business days will be required for the 
Apexigen Medical Monitor (or designee) to review a subject for enrollment. Additional time may 
be required when approval is sought during a weekend or holiday.  
Consented subjects who do not meet eligibility criteria will be considered screen failures. 
Enrolled subjects will be alternately assigned to one of the 2 cohorts as long as both cohorts are 
open. Enrolled subjects assigned to a certain cohort that do not receive APX005M or are not 
evaluable for tumor response will be replaced in that cohort before assigning new subjects to the 
other cohort. 
3.2 
Treatment Period 
Enrolled subjects who do not receive APX005M will be considered to have been withdrawn. The 
Treatment Period will start with the first administration of investigational therapy(ies) and will 
continue for up to 12 months or until criteria in Section 3.2.6.1 are met.  

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3.2.1 
APX005M Administration  
For Cohorts 1 and 2, APX005M is administered on Day 1 of each 3-week or 2-week treatment 
cycle. In Cohort 3 APX005M will be administered after each fraction of SBRT during the time 
of combination treatment.  
The APX005M infusion time will be 60 minutes. Sites should make every effort to target 
infusion timing to be as close to 60 minutes as possible. A window between -5 minutes and 
+10 minutes is permitted (i.e., infusion time is 55 minutes to 70 minutes).  
The Pharmacy Manual contains specific instructions for the preparation of the APX005M 
infusion and administration of infusion solution. 
The APX005M infusion can be interrupted in the case of infusion reaction (see Section 3.2.3.2). 
Once symptoms resolve, infusion should be restarted at 50% of the initial infusion rate (e.g., 
from 100 mL/hr to 50 mL/hr). 
All subjects will be discharged from clinic after a clinical evaluation. Subjects should have stable 
vital signs including: lack of orthostatic hypotension (systolic blood pressure >100 mmHg, or no 
lower than 10 mm from baseline) without IV hydration (no hydration for at least 2 hours prior to 
discharge), lack of hypoxia (oxygen saturation >90% without oxygen), temperature <38◦C, and 
heart rate <110 beats/min. After discharge, all subjects should be monitored by a caregiver or by 
a healthcare professional for 24 hours after the first 2 infusions of APX005M and as clinically 
indicated thereafter.  
APX005M and SBRT may be administered up to 3 days after the scheduled Day 1 of Cycle 2 
and beyond in case of medical/surgical events, or logistical reasons not related to study therapy 
(e.g., elective surgery, unrelated medical events, patient vacation, and/or holidays). Treatment 
delays related to study therapy are discussed in Section 3.2.4. 
Administration of APX005M will continue for up to 12 months or until criteria in Section 3.2.6.1 
are met. 
3.2.2 
Radiation Therapy 
All subjects should be evaluated and treated by a local radiation oncologist. All radiation 
treatment will follow the standard guidelines for a SBRT treatment course. Each radiation 
therapy target lesion will receive up to a total of 3200 cGy in 4 fractions of 800 cGy, 
administered on the same day and prior to infusion of APX005M. Fractions will be delivered 
every 2 weeks with the requirement of a minimum of 4 field 3D conformal planning to meet 
dose constraints to limit normal tissue toxicity of organs at risk (OAR). The first target lesion 
and the subsequent target lesion will be identified by the treating investigator based upon 
considerations of clinical benefit and toxicity risk. The RT target lesions shall not be CNS 
metastases. 
First Radiation Therapy Target: One of 3 or more measurable disease lesions (as defined by 
RECIST 1.1) will be selected as the first radiation therapy target and will be treated every 

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2 weeks during the first 8 weeks. The radiation field of the first target shall not overlap with any 
other target lesions.  
Second Radiation Therapy Target: The second target shall be one of the remaining 
non-irradiated lesions where the radiation field does not overlap with the first radiation target. 
The radiation field shall not overlap with at least one non-irradiated target lesion. 
3.2.2.1 
Treatment Technology  
Based upon the location and size of tumors, treatment planning will be determined by clinical 
appropriateness. This protocol requires treatment with photons with minimum nominal energy 
specification of 6 MV. Intensity modulated radiotherapy (IMRT) is encouraged when dosimetric 
benefit would reduce risk to OARs and may be implemented with static gantry or volumetric 
modulated arc therapy (VMAT). Tomotherapy delivery is allowed. Though each individual dose 
may not require high level of precision requiring high level of technology, immobilization and 
verification the total dose over the 8 weeks will require close monitoring.  
3.2.2.2 
Immobilization and Simulation  
Immobilization: Proper immobilization is important for this protocol. Subject setup 
reproducibility must be achieved using appropriate clinical devices. A custom immobilization 
device (such as Alpha Cradle or Vac-Loc) is suggested to minimize set-up variability. SBRT 
frame and abdominal compression may be appropriate for thoracic and abdominal treatments to 
minimize motion.  
Simulation Imaging: CT Simulation is required, and the images must be acquired using a 
CT-simulator with a slice thickness ≤3 mm. Care should be taken to use the smallest possible 
FOV that contains the entire surface of the patient with a 512x512 image matrix. Oral and IV CT 
contrast is optional depending upon the location of the target lesions. The CT simulation must be 
performed with the patient in the treatment position.  
Typical CT scan limits will vary depending on the site. However, it is recommended that the 
patient will be imaged at least 10 cm cranial and caudal to the target especially if noncoplanar 
beams will be used.  
3.2.2.3 
Definition of Target Volumes and Margins  
The volumes are to be defined by planning CT/MRI techniques. The extent of palpable tumors 
should be determined by physical examination to complement imaging and external markers may 
be helpful for target delineation on CT scans. 
3.2.2.4 
Detailed Specification 
Gross tumor volume (GTV): This includes the target lesion and any adjacent extent or lymph 
nodes that are considered part of the target lesion. Assessment of the target lesion CT, PET-CT, 
MRI, or physical exam.  

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Clinical target volume (CTV): This includes the GTV and suspected microscopic extension and 
at-risk excluding bone and muscle. Appropriate expansion shall be determined by the treating 
radiation oncologist and made appropriate for the target site and risk.  
Internal target volume (ITV): For target lesions in regions of motion an ITV may be indicated 
that will take into consideration motion of the target during certain phases of respiration. An 
appropriate ITV shall be created using 4DCT scans or breath hold scans as indicated for the 
motion management strategy.  
Planning target volume 3200 (PTV): This will provide a margin around the CTV or ITV if 
appropriate to compensate for the inter- and intra-fraction uncertainty consequent to daily setup 
uncertainty. By definition, the PTV will consist of a symmetrical 3-7 mm expansion around the 
CTV or ITV as defined for by radiation oncologist that is specific to institutional standard for the 
site. In the event that a PTV extends outside of the skin surface, the clinician should manually 
trim the PTV contours to be 3 mm inside the outer skin (unless there is direct skin involvement).  
3.2.2.4.1 
Definition of Critical Structures  
Because treatment sites may vary throughout the body, the treating radiation oncologist shall 
define the critical structures for the case. This should be defined by the dose constraints (see 
Tables 1A and 1B) and the proximity of the treated lesion.  
Table 1A: 
Radiation Dose Constraints - Serial Tissue 
Serial Tissue 
Vol. 
(cc) 
Vol. Max 
(Gy) 
Max Point 
Dose (Gy)** 
Endpoint 
(≥ Grade 3) 
Optic Pathway 
<0.2 
19.2 
21.2 
neuritis 
Cochlea 
- 
- 
18 
hearing loss 
Brainstem (not medulla) 
<0.5 
20.8 
27.2 
cranial neuropathy 
Spinal Cord and Medulla 
<5 
30 
25.6 
myelitis 
Cauda Equina 
<5 
26 
28.8 
neuritis 
Sacral Plexus 
<5 
26 
28.8 
neuropathy 
Esophagus* 
<5 
30.4 
34 
esophagitis 
Brachial Plexus 
<3 
24.8 
29.6 
neuropathy 
Heart/Pericardium 
<15 
28 
33 
pericarditis 
Great Vessels 
<10 
32 
36 
aneurysm 
Trachea and Large Bronchus* 
<5 
32 
35 
impairment of pulmonary 
toilet 
Bronchus- Smaller Airways 
<0.5 
28.8 
35 
stenosis with atelectasis 
Rib 
<5 
32 
35 
pain or fracture 
Skin 
<10 
32 
35 
ulceration 
Stomach 
<5 
25 
33 
ulceration/fistula 
Bile Duct 
- 
- 
35 
stenosis 
Duodenum* 
<5 
25 
33 
ulceration 
Jejunum/Ileum* 
<30 
22.4 
31.6 
enteritis/obstruction 

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Serial Tissue 
Vol. 
(cc) 
Vol. Max 
(Gy) 
Max Point 
Dose (Gy)** 
Endpoint 
(≥ Grade 3) 
Colon* 
<20 
30.8 
35 
colitis/fistula 
Rectum* 
<20 
32 
35 
proctitis/fistula 
Ureter 
- 
- 
35 
stenosis 
Bladder Wall 
<15 
18.5 
35 
cystitis/fistula 
Penile Bulb 
<3 
27 
- 
impotence 
Femoral Heads 
<10 
27 
- 
necrosis 
Renal Hilum/Vascular Trunk 
15 
21.5 
- 
malignant hypertension 
* 
avoid circumferential irradiation 
** 
“point” defined as 0.035cc or less 
*** or one third of the “native” total organ volume (prior to any resection or volume reducing disease), whichever 
is greater 
Table 1B: 
Radiation Dose Constraints - Parallel Tissue 
Parallel Tissue 
Critical 
Volume (cc) 
Critical 
Volume Dose 
Max (Gy) 
Volumetric 
Constraint 
Endpoint 
(≥ Grade 3) 
Lung (right & left) 
1500 cc for 
males and 
950 cc for 
females*** 
12 
- 
basic lung function 
Lung (right & left) 
- 
- 
V12.8Gy <37% 
pneumonitis 
Liver 
700*** 
19.6 
- 
basic liver function 
Renal Cortex (right & left) 
200*** 
1 
- 
basic renal function 
*** or one third of the “native” total organ volume (prior to any resection or volume reducing disease), whichever 
is greater 
3.2.2.4.2 
Planning Technique  
A 3D conformal or IMRT planning technique must be used. If not using IMRT, field edges and 
MLC blocking must be conformal to the PTV. The dose distributions must include corrections 
for tissue density heterogeneities. Regardless of planning technique, the dose prescription criteria 
specified shall be prioritized.  
Table 1C: 
Radiation Dose Criteria 
Name of Structure 
Dosimetric Parameter 
Per Protocol 
Variation Acceptable 
PTV 
Dmin (%) 
D100% (%) 
Dmax (%) 
≥90 
≥95 
≤130 
≥85 
≥85 
≤150 
 
Replanning: Because melanoma can respond robustly to radiation and treatments will be every 
2 weeks it is possible that the tumor volume will be considerably smaller for subsequent 
fractions. It is recommended that response be assessed after two fractions for bigger tumors or 

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tumors where decrease in size can considerably impact OARs and toxicity risk. If there has been 
a decrease of tumor volume by more than 2-fold then a new plan should be considered.  
3.2.2.4.3 
Patient specific Quality Assurance (QA)  
For photon IMRT plans, patient specific QA is highly recommended. QA is performed by 
delivering the plan onto a phantom and measuring the dose using an ion chamber array or other 
2D/3D device. Typically, measured dose distributions will be compared to planned dose 
distribution using a Gamma criterion of 4% dose difference and 3 mm distance to agreement. 
The pass rate should be at least 90% measured for the entire plan.  
3.2.2.4.4 
Daily Treatment Localization/IGRT  
Daily image-guided radiation therapy (IGRT) localization is required for all patients. Either a 
daily orthogonal kV pair, or cone-beam computed tomography CBCT is acceptable. Institutional 
guidelines should be followed for daily treatment localization and IGRT. IGRT credentialing is 
not required for this protocol. 
3.2.2.4.5 
Duration of Radiation Therapy 
Duration of therapy will be per treatment schedule as above. Duration will be shortened, and 
treatment can be ended early if the patient develops: 
• Inter-current illness that prevents further administration of treatment 
• Unacceptable adverse event(s) 
• Participant decides to withdraw from the study, OR 
• General or specific changes in the patient’s condition render the participant unacceptable 
for further treatment in the judgment of the principal investigator or medical oncologist.  
3.2.3 
Concomitant Treatments 
3.2.3.1 
Premedication prior to APX005M  
All subjects should be premedicated 30 ± 5 minutes before the administration of APX005M with 
a regimen containing: 
• Oral H1 antagonist (e.g., loratadine 10 mg) 
• Optional oral H2 antagonist (e.g., ranitidine 150−300 mg, cimetidine 300−800 mg, 
nizatidine 150−300 mg, and famotidine 20−40 mg) 
• Oral nonsteroidal anti-inflammatory drug (may comprise ibuprofen 400 mg or equivalent) 
• Acetaminophen 650 mg. 
Equivalent quantities of IV formulations of these drugs should be completed 10 ± 5 minutes 
before the administration of APX005M. 

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3.2.3.2 
Rescue Medications & Supportive Care Guidelines  
Subjects should receive appropriate supportive care measures as deemed necessary by the 
treating investigator. Suggested supportive care measures for the management of adverse events 
(AEs) with potential immunologic etiology are outlined below. These treatment guidelines are 
intended to be applied when the investigator determines the events to be related to the APX005M 
and should not substitute for dose delays and/or modifications. Additional guidance for 
management of AEs suspected to be related to APX005M is provided in the APX005M 
Investigator’s Brochure. 
If after evaluation the event is determined by the investigator not to be related, the investigator 
does not need to follow the treatment guidance outlined in this section. For each disorder, 
attempts should be made to rule out other causes (such as metastatic disease or bacterial/viral 
infection) which might require additional supportive care. 
• Diarrhea/Colitis 
Subjects should be carefully monitored for signs and symptoms of enterocolitis (such as 
diarrhea, abdominal pain, blood or mucus in stool, with or without fever) and of bowel 
perforation (such as peritoneal signs and ileus). All subjects who experience diarrhea/colitis 
should be advised to drink liberal quantities of clear fluids. If sufficient oral fluid intake is 
not feasible, fluid and electrolytes should be substituted via IV infusion. For Grade 2 or 
higher diarrhea, consider GI consultation and endoscopy to confirm or rule out colitis. 
o Grade 1-2: for subjects developing Grade 1–2 diarrhea loperamide (2 mg every 
2 hours) is strongly recommended at the first onset of symptoms. For subjects 
with persistent diarrhea despite the use of loperamide, or Grade 2 colitis, the use 
of oral corticosteroids is recommended. Other antidiarrheal agents (e.g. octreotide) 
may be used if necessary. 
o Grade 3-4: treat with IV corticosteroids followed by oral corticosteroids until 
symptoms improve to Grade 1 or less. Add prophylactic antibiotics for 
opportunistic infections and consider lower endoscopy. 
• Creatinine Elevation Due to Inflammatory Causes 
o Grade 2-3: treat with IV or oral corticosteroids until symptoms improve to 
Grade 1 or less. Consider renal biopsy with nephrology consult.  
o Grade 4: treat with IV corticosteroids followed by oral corticosteroids until 
symptoms improve to Grade 1 or less. Consider renal biopsy and consult 
nephrologist. 
• Pneumonitis  
o Grade 2: request pulmonary and infectious disease consults. Treat with IV or oral 
corticosteroids until symptoms improve to Grade 1 or less. Consider 
bronchoscopy, lung biopsy and hospitalization.  
o Grade 3-4: request pulmonary and infectious disease consults. Hospitalize and 
treat immediately with IV corticosteroids. Administer additional anti-

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inflammatory measures, as needed. Consider adding prophylactic antibiotics for 
opportunistic infections. Consider bronchoscopy and lung biopsy.  
• Liver Function Tests 
o Grade 2, and Grade 3 transaminase elevation ≤72 hours: monitor liver 
function tests (incl. total bilirubin levels) more frequently until returned to 
Grade ≤1. 
o All other Grade 3, and any Grade 4 transaminase elevation: treat with 
IV corticosteroids for 24-48 hours followed by oral corticosteroids until 
symptoms improve to Grade ≤1. If no improvement in 3–5 days administer 
additional immunosuppressive measures (e.g. mycophenolate mofetil), as needed. 
Consider adding prophylactic antibiotics for opportunistic infections. Consult 
gastroenterologist.  
• Skin Adverse Events 
o Grade 1-2: symptomatic treatment (e.g. antihistamines, topical steroids). For 
persistent (>1–2 weeks) or recurrent symptoms consider skin biopsy and 
treatment delay. 
o Grade 3–4: consider skin biopsy and consult dermatologist. Treat with 
IV corticosteroids followed by oral corticosteroids until symptoms improve to 
Grade 1 or less.  
• Infusion Reaction/Cytokine Release Syndrome 
Precautions should be observed during the administration of APX005M. Emergency 
treatment including oxygen, oral and endotracheal airways, intubation equipment 
epinephrine, antihistamines, and corticosteroids should be available and used as 
medically required and at the Investigator’s discretion. 
o Grade 2: stop infusion and treat symptoms following guidance in Table 2. If 
symptoms resolve within two hours, the infusion may be restarted at 50% of the 
original infusion rate (e.g., from 100 mL/hr to 50 mL/hr).  
o Grade 3–4: stop infusion and treat symptoms following guidance in Table 2. 
Subjects should be instructed that symptoms associated with cytokine release 
syndrome/infusion reaction may occur within 48 hours following the administration of 
APX005M and if such symptoms develop while they are at home, they should contact the 
Investigator and/or seek emergency medical care if necessary. 

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Table 2: 
Guidance for Management of Cytokine Release/Infusion Reaction Symptoms  
Suspected Cytokine Release/Infusion-related Toxicity 
Recommended Treatment 
• Mild toxicity requiring symptomatic treatment 
only (e.g., fever, nausea, fatigue, headache, 
myalgia, malaise) 
• Vigilant supportive care 
• Maintain adequate hydration 
• Antipyretics, non-steroidal anti-
inflammatory drugs, 
antihistaminics, anti-emetics, 
analgesics as needed 
• In case of mild symptoms 
persisting for >24 hours assess for 
infections; empiric treatment of 
concurrent bacterial infections 
• Symptoms or clinical findings 
requiring and responding to 
moderate intervention, such 
as: 
o O2 requirement <40% 
o Hypotension responsive to 
fluids ± low dose of one 
vasopressor (e.g., <50 
mg/min phenylephrine) 
o CTCAE Grade 2 organ 
toxicity 
• No extensive 
co-morbidities 
• All of the above 
• Monitor cardiac and other organ 
functions closely 
• Extensive 
co-morbidities 
• Age ≥70 years 
• All of the above 
• Administer tocilizumab first 
• Administer corticosteroids if 
symptoms worsen or do not 
improve in <4 hours 
• Symptoms or clinical findings requiring aggressive 
intervention, such as: 
o O2 requirement ≥40% 
o Hypotension requiring high dose or 
multiple vasopressors 
o Ventilator support required 
o CTCAE Grade ≥3 organ toxicity 
• Any Other Possibly Immune Mediated Toxicity 
o Grade 2: symptomatic treatment per local guidelines  
o Grade 3–4: Consult Apexigen Medical Monitor (or designee). Administer IV 
corticosteroids followed by oral corticosteroids until symptoms improve to 
Grade 2 or less. Consider adding prophylactic antibiotics for opportunistic 
infections. If symptoms worsen or for atypical presentation consider and 
additional immunosuppressive measures per local guidelines.  

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3.2.3.3 
Permitted Concomitant Medications  
All treatments that the investigator considers necessary for a subject’s welfare may be 
administered at the discretion of the investigator in keeping with the community standards of 
medical care. All concomitant medication received from the time of first dose of APX005M and 
up to 30 days after the last dose will be recorded on the electronic case report form (eCRF) 
including all prescription, over-the-counter, herbal supplements and IV medications and fluids.  
3.2.3.4 
Prohibited and/or Restricted Therapies  
Subjects are prohibited from receiving the following therapies during the Screening Period and 
Treatment Period of this trial: 
• Antineoplastic systemic chemotherapy or biological therapy  
• Investigational agents other than APX005M 
• Radiation therapy not specified in this protocol (radiation therapy to a 
symptomatic solitary lesion or to the brain may be considered on a case-by-case 
basis after consultation with Apexigen Medical Monitor [or designee]). The 
subject must have clear measurable disease outside the radiated field.  
• Live vaccines within 30 days prior to the first dose of trial treatment and while 
participating in the trial. Examples of live vaccines include, but are not limited to, 
the following: measles, mumps, rubella, chicken pox, yellow fever, rabies, BCG, 
intranasal influenza vaccines and typhoid (oral) vaccine. Seasonal influenza 
vaccines for injection and COVID-19 vaccines are allowed as long as they can be 
administered 6–7 days after last dose of APX005M. 
• Systemic corticosteroids for any purpose other than to modulate symptoms from 
an event of clinical interest of suspected immunologic etiology. The use of 
physiologic doses of corticosteroids may be approved after consultation with the 
Apexigen Medical Monitor (or designee). Inhaled corticosteroids are allowed for 
management of asthma. 
• Medications described in the Exclusion Criteria. 
Subjects who, in the assessment by the investigator, require the use of any of the aforementioned 
treatments for clinical management will be discontinued from study treatment.  
Herbal medicine for anticancer treatment (such as botanical formulation ‘Xiao Chai Hu Tang’) 
should be stopped 1 week prior to first dose of APX005M. Subjects taking narrow therapeutic 
index medications (such as warfarin, phenytoin, quinidine, carbamazepine, phenobarbital, 
cyclosporine, and digoxin) should be monitored proactively.  
There are no prohibited therapies during the Follow-up Period. 

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3.2.4 
Retreatment Criteria  
Subjects that do not meet any of the criteria for treatment discontinuation may start a new cycle 
of APX005M ± SBRT as scheduled if WBC ≥2,000/mm3, ANC≥1,000/mm3, platelets 
≥100,000/mm3, and suspected adverse reactions have resolved to baseline or Grade ≤1 
(excluding Grade 2 alopecia and Grade 2 fatigue). Subjects who have experienced a Grade ≤2 
skin suspected adverse reaction may resume treatment in the presence of Grade 2 skin toxicity. 
If a subject fails to meet criteria for retreatment then the treatment cycle should be delayed and 
the subject should be re-evaluated weekly. 
3.2.5 
Dose Modifications  
Management of suspected adverse drug reactions may require reduction of the APX005M dose 
or interruptions of the radiotherapy. If a subject experiences several toxicities, the recommended 
dose adjustment should be based on the highest grade toxicity. All dose reductions for 
APX005M, if required, will follow the instructions described in Table 3.  
Table 3: 
Dose Modifications for Toxicity 
 
Action Taken with APX005M 
Action Taken 
with SBRT 
1st Occurrence 
2nd Occurrence 
3rd Occurrence 
Hematologic Toxicity 
Neutrophils (ANC) 
<500/mm3 Lasting ≥5 days 
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Defer to radiation 
oncologist* 
Neutropenic Fever 
(Body Temperature 
≥38.5ºC (oral) and ANC 
<1000/mm3) 
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Defer to radiation 
oncologist* 
Platelets <25,000/mm3  
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Defer to radiation 
oncologist* 
Platelets <50,000/mm3 
with Significant Bleeding 
or Requiring Blood 
Transfusion 
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Defer to radiation 
oncologist* 
Non-hematologic Toxicities 
Nausea/Vomiting 
≥ Grade 3 Despite Optimal 
Medical Treatment 
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Hold treatment 
until symptoms 
improve to 
Grade ≤1 
Diarrhea ≥ Grade 3 Despite 
Optimal Medical 
Treatment 
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Hold treatment 
until symptoms 
improve to 
Grade ≤1 
CRS Grade 3 ≤7 days 
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Defer to radiation 
oncologist* 
CRS Grade 3 >7 days 
Discontinue 
- 
- 
Discontinue 
CRS Grade 4 
Discontinue 
- 
- 
Discontinue 
Increased Bilirubin 
Grade ≥ 3 
Discontinue 
- 
- 
Discontinue 

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Action Taken with APX005M 
Action Taken 
with SBRT 
1st Occurrence 
2nd Occurrence 
3rd Occurrence 
Increased AST, ALT 
Grade 3 
Reduce to 
0.2 mg/kg# 
Reduce to 
0.1 mg/kg# 
Discontinue 
Hold treatment 
until Grade ≤1 
Increased AST, ALT 
Grade 4 
Discontinue 
- 
- 
Discontinue 
Pneumonitis Grade 2 
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Hold treatment 
until Grade ≤1. 
Discontinue on 2nd 
occurrence 
Pneumonitis Grade ≥3 
Discontinue 
- 
- 
Discontinue 
Esophagitis Grade 2 
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Hold treatment 
until Grade ≤1 
Esophagitis Grade ≥3 
Discontinue 
- 
- 
Discontinue 
Gastric or Small Bowel 
Ulcer Grade ≥2  
Reduce to 
0.2 mg/kg 
Reduce to 
0.1 mg/kg 
Discontinue 
Discontinue 
Colitis or Proctitis 
Grade ≥3 
Discontinue 
- 
- 
Discontinue 
Other ≥3 Grade Toxicities 
(except Alopecia)§ 
Adjusted as medically indicated after discussion with 
Sponsor 
Defer to radiation 
oncologist* 
Abbreviations: CRS = cytokine release syndrome 
For all toxicity ≤Grade 2, the current dose should be maintained 
* Investigator will defer to the radiation oncologist as to whether an interruption of the radiation therapy is also 
indicated. 
# For subjects with liver metastasis reduce dose only if Grade 3 >72 hours 
§ In the event of the “other” Grade 3 or 4 non-hematologic toxicities that, in the opinion of the Investigator, are 
unrelated to the investigational therapy, subject may continue on therapy with or without dose reduction only after 
documented discussion with the Apexigen Medical Monitor (or designee). 
3.2.6 
Duration of Treatment 
Subjects may continue to receive SBRT and APX005M up to 16 weeks and APX005M for up to 
12 months or until any of the criteria in Section 3.2.6.1 are met.  
Tumor assessment will be performed within 21 days prior to start of investigational therapy and 
during the Treatment Period (every 8 ± 1 weeks). Tumor assessments will follow RECIST 1.1 
guidelines. 
Subjects with confirmed CR may continue APX005M up to 24 weeks, on a case-by-case basis, 
after careful evaluation and Investigator discussion with the Apexigen Medical Monitor (or 
designee) to determine whether the risk-benefit ratio supports administration of further study 
drug. 

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3.2.6.1 
Discontinuation of Subjects from Treatment  
Subjects MUST discontinue receiving APX005M for any of the following reasons: 
• Disease progression by RECIST 1.1, or disease progression following treatment beyond 
progression (Section 3.2.6.2) 
• Death 
• Toxicity requiring discontinuation of investigational therapy(ies) as outlined in the dose 
modification guidelines 
• Failure to recover from a disease or treatment-related AE to baseline or ≤ Grade 1 within 
12 weeks of last dose of APX005M (except Grade 2 alopecia, Grade 2 fatigue or Grade 2 
skin toxicity), unless the subject is benefiting from therapy and after discussion with and 
approval by Apexigen Medical Monitor (or designee) 
• Failure to recover from an AE related to infusion reaction/cytokine release within 
4 weeks of last dose of APX005M  
• Inability to reduce corticosteroid to ≤10 mg of prednisone or equivalent per day within 
12 weeks of last dose of APX005M 
• Subject’s decision to withdraw for any reason from study treatment (if subject withdraws 
from study treatment the subject should enter the Follow-up Period) 
• Pregnancy 
• Any clinical AE, laboratory abnormality or coincident illness which, in the opinion of the 
investigator, indicates that continued participation in the study is not in the best interest of 
the subject 
• Requirement for alternative therapy 
• Noncompliance with study procedures, including use of prohibited medications 
• Subject is lost to follow-up 
• Loss of ability to freely provide consent through imprisonment or involuntarily 
incarceration for treatment of either a psychiatric or physical (e.g., infectious disease) 
illness 
• Study termination by Apexigen 
Apexigen (or designee) must be notified within 24 hours if a subject is withdrawn from 
treatment. The primary reason for treatment discontinuation will be documented in the eCRF.  
3.2.6.2 
Treatment beyond Progression  
Accumulating evidence indicates that patients with solid tumors treated with immunotherapy or 
the combination of immunotherapy with RT may derive clinical benefit despite initial evidence 
of progressive disease. Subjects will be permitted to continue on treatment beyond initial 
RECIST 1.1-defined progressive disease (iUPD, [iRECIST]) as long as they meet the following 
criteria:  

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• Investigator-assessed clinical benefit, without rapid disease progression, or with disease 
progression based primarily on changes in lymph nodes appearance 
• Subject continues to meet retreatment criteria (Section 3.2.4) 
• Subject tolerates study treatment 
• Subject has stable ECOG performance status  
• Treatment beyond progression will not delay an imminent intervention to prevent serious 
complications of disease progression (e.g., CNS metastases).  
The assessment of clinical benefit should take into account whether the subject is clinically 
deteriorating and unlikely to receive further benefit from continued treatment. All decisions to 
continue treatment beyond initial progression should be discussed with the Apexigen Medical 
Monitor (or designee), and an assessment of the risk/benefit of continuing with study therapy 
must be documented in the study records.  
For subjects who stay on treatment beyond RECIST 1.1-defined progressive disease, all study 
procedures should be performed continuously, including tumor assessments (Section 4). 
Subjects will be discontinued from the treatment upon further evidence of disease progression, as 
described in the iRECIST guidelines by Seymour et al [22]. 
3.3 
Follow-up Period 
Subjects who discontinue APX005M will enter the Follow-up Period until criteria in 
Section 3.3.1 are met. Regular follow-up visits (or phone contact or chart reviews) should be 
scheduled every 3 months or more frequently if clinically indicated. 
All AEs that are considered related to APX005M must be followed to resolution, stabilization, 
until improvement is not expected, 30 days after receiving the last dose of APX005M, death, or 
initiation of new anticancer therapy, whichever occurs first. Serious AEs (SAEs), pregnancies 
and AEs with potential immunologic etiology will be recorded and followed up to 90 days after 
the last dose of APX005M, death, or initiation of new anticancer therapy, whichever occurs first. 
3.3.1 
Discontinuation of Subjects from Study  
Subjects who are withdrawn from APX005M will enter the Follow-up Period unless study 
treatment discontinuation is due to any of the following: 
• Subject death 
• Withdrawal of consent for all study procedures 
• Initiation of any anticancer therapy (except for subjects continuing immediately following 
this study on a PD-1/PD-L1 containing regimen for whom the regimen and the response 
to that regimen should be documented) 
• Subject is lost to follow-up 
• Study termination by Apexigen. 

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Subsequent anticancer regimen should be documented. For subjects, who switch to a 
PD-1/PD-L1 containing regimen immediately after study treatment the response to that regimen 
should be documented. Once this information is collected, a subject is considered off-study. 
3.3.2 
Subject Premature Withdrawal 
Any subject has the right to withdraw consent or to discontinue study treatment or study 
participation at any time for any reason. 
In the case that a subject decides to prematurely discontinue study treatment (“refuses 
treatment”), he/she should be asked if he/she agrees to continue to be followed-up until criteria 
for discontinuation from study are met (enter Follow-up Period). 
3.4 
Study Termination  
Apexigen has the right to terminate this study or a study site from participating in the study at 
any time. Reasons for terminating the study at a specific study site may include, but are not 
limited to, the following: 
• Subject enrollment is unsatisfactory 
• Data recording is inaccurate or incomplete 
• Investigator does not adhere to the protocol or applicable regulatory requirements in 
conducting the study 
Reasons for terminating the study overall may include, but are not limited to, the following: 
• The incidence or severity of AEs in this or other APX005M studies indicates a potential 
health hazard to subjects 
• All subjects enrolled in the study have completed the Treatment Period 
• All subjects enrolled in the study have completed the Follow-up Period. 
4. STUDY ASSESSMENTS AND PROCEDURES  
Time and events schedule is presented in Appendix A.  
4.1 
Procedures by Visits  
4.1.1 
Screening Period  
All patients must provide written informed consent before any study specific assessments or 
procedures are performed.  
The screening assessments should be performed within 21 days before beginning of the 
Treatment Period. The following study evaluations will be performed during the screening 
period:  

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• Collect demographics 
• Collect medical history (including concomitant medications) 
• Perform physical examination including (including weight, height, and vital signs) and a 
12-lead electrocardiogram 
• ECOG performance status 
• Laboratory evaluations: 
1) urinalysis 
2) serum chemistry 
3) hematology 
4) coagulation 
• Assess eligibility (inclusion/exclusion criteria) 
• Tumor assessment following RECIST 1.1 Guidelines 
• Collect archived tumor tissue 
• Collect and submit a tumor core biopsy from consenting subjects. Selection of tumor 
lesions should not interfere with subsequent tumor assessments when feasible 
• For Cohort 3: SBRT treatment planning 
• Pregnancy test (if applicable) 
4.1.2 
Treatment Period  
The following procedures and investigations should be performed during the Treatment Period: 
4.1.2.1 
Cycles 1 & 2: Day 1 
• Confirm eligibility (only in Cycle 1) 
• Perform physical examination (including weight and vital signs at preinfusion, end of 
infusion, 4 hours after the end of infusion) 
• ECOG performance status 
• Laboratory evaluations: 
1) Serum chemistry 
2) Hematology 
3) Coagulation 
• PK serum sample (preinfusion, end of infusion, 4 hours ± 30 minutes after the end of 
infusion) 
• ADA serum sample (preinfusion) 
• Whole blood and plasma (preinfusion) 

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• Cytokines plasma samples (preinfusion, end of infusion, 4 hours ± 30 minutes after the 
end of infusion) 
• Record AEs and concomitant medications (ConMeds) 
• For Cohort 3: administer SBRT 
• Administer premedication before APX005M 
• Administer APX005M 
4.1.2.2 
Cycles 1 & 2: Day 2 
• Collect vital signs 
• Laboratory evaluations: 
 Serum chemistry 
 Hematology 
 Coagulation 
• PK serum sample (24 ± 2 hours after the end of infusion) 
• Whole blood and plasma (24 ± 2 hours after the end of infusion) 
• Cytokines plasma sample (24 ± 2 hours after the end of infusion) 
• Record AEs and ConMeds 
4.1.2.3 
Cycles 1 & 2: Day 8 
• Collect vital signs 
• Laboratory evaluations: 
1) Serum chemistry 
2) Hematology 
3) Coagulation 
• Whole blood and plasma (168 ± 2 hours after the end of infusion) 
• Cytokines plasma sample (168 ± 2 hours after the end of infusion) 
• Record AEs and ConMeds 
4.1.2.4 
Cycles 3+ Day 1 
• Perform physical examination (including weight and vital signs at preinfusion, end of 
infusion) 
• ECOG performance status 
• Laboratory evaluations: 

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1) Serum chemistry 
2) Hematology 
3) Coagulation 
4) Pregnancy test every other cycle (if applicable) 
• PK serum sample in Cycles 3 and 5 (preinfusion, end of infusion) 
• ADA serum sample in Cycles 3 and 5 (preinfusion) 
• Whole blood and plasma -- Cohort 1: Cycles 3 and 6 (preinfusion); Cohorts 2 and 3: 
Cycles 4 and 8 (preinfusion) 
• Record AEs and ConMeds 
• For Cohort 3: administer SBRT for up to 8 cycles 
• Administer premedication before APX005M 
• Administer APX005M 
4.1.2.5 
Cycles 3+ Optional Safety Visit 
• Collect vital signs 
• Laboratory evaluations: 
1) Serum chemistry 
2) Hematology 
• Record AEs and ConMeds 
4.1.2.6 
Tumor Assessment Visit  
• Tumor Assessment  
4.1.2.7 
Second Tumor Biopsy Visit 
• Laboratory evaluations: 
1) Serum chemistry 
2) Hematology 
• Record AEs and ConMeds 
• Whole blood and plasma 
• Cytokines plasma sample 
• Collect fresh tumor tissue sample 

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4.1.2.8 
End of Treatment Visit  
• Perform physical examination (including weight and vital signs) 
• ECOG performance status 
• Laboratory evaluations: 
1) Serum chemistry 
2) Hematology 
3) Coagulation 
4) Pregnancy test (if applicable) 
• ADA serum sample 
• Whole blood and plasma 
• Cytokines plasma sample  
• Record AEs and ConMeds 
• Tumor assessment (for subjects that discontinue treatment before the first scheduled on 
study tumor assessment)  
4.1.3 
Follow-up Period  
• Follow-up AEs related to APX005M until resolution, stabilization, until improvement is 
not expected, 30 days, death, or initiation of new anticancer therapy, whichever occurs 
first 
• Record SAEs, pregnancies and AEs with potential immunologic etiology up to 90 days, 
death, or initiation of new anticancer therapy, whichever occurs first. Follow-up SAEs, 
pregnancies and AEs with potential immunologic etiology until resolution, stabilization, 
until improvement is not expected, 90 days from APX005M, death, or initiation of new 
anticancer therapy, whichever occurs first 
• Record ConMeds  
• Report date of death or progressive disease 
• Record subsequent treatment and date 
• For subjects continuing immediately following this study on a PD-1/PD-L1 containing 
regimen, the regimen and the response to that regimen should be documented. 
4.2 
Safety Assessments  
4.2.1 
Medical History 
At screening, a medical history will be obtained to capture relevant underlying conditions. 

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4.2.2 
Physical Examinations 
A physical examination will include examination of the skin, head and neck, chest (heart and 
lungs), abdomen, limbs, and a brief neurological examination. Rectal and pelvic examinations 
are optional.  
4.2.3 
Electrocardiogram  
A 12-lead electrocardiogram (ECG) including calculation of corrected QT interval will be 
conducted locally and is required at screening only. Additional ECGs can be performed as 
clinically indicated. 
4.2.4 
Vital Signs  
Vital sign measurements include blood pressure, pulse rate, respiration rate, and temperature. 
Subjects should be monitored during and after APX005M infusions for potential infusion 
reactions. Vital signs will be measured: 
• within 30 minutes prior to APX005M dose (pre-infusion) 
• within 30 minutes after the end of the APX005M infusion 
• 4 hours (±30 minutes) after the end of APX005M infusion (Cycles 1 and 2 only) 
• 24 hours and 168h after the end of APX005M infusion (Cycles 1 and 2 only) 
• On Day 1 of subsequent cycles (preinfusion, end of infusion) 
• As medically indicated 
• End of treatment visit 
4.2.5 
ECOG Performance Status 
ECOG performance status should be assessed a time points indicated in Appendix A. 
Table 4: 
ECOG Performance Criteria 
Grade 
Description 
0 
Normal activity, fully active, able to carry on all pre-disease performance without restriction 
1 
Symptoms, but fully ambulatory, restricted in physically strenuous but ambulatory and able to carry 
out work of a light or sedentary nature (e.g., light housework, office work) 
2 
Ambulatory and capable of all self-care but unable to carry out any work activities. Up and about 
more than 50% of waking hours 
3 
Capable of only limited self-care, confined to bed or chair more than 50% of waking hours 
4 
Completely disabled. Cannot carry on any self-care. Totally confined to bed or chair 
5 
Death 
It is recommended, where possible, that a patient’s performance status will be assessed by the 
same person throughout the study.  

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4.2.6 
Laboratory Tests  
All clinical laboratory tests (e.g., urinalysis, serum chemistry, hematology, coagulation) will be 
performed at local laboratories. Assessments performed within 3 days (with results available) 
prior to the administration of study treatment could be used for Day 1 of any cycle. 
4.2.6.1 
Urinalysis  
Routine urinalysis will be performed at screening and whenever clinically indicated. 
4.2.6.2 
Serum Chemistry  
The laboratory tests included in the full chemistry panel are: 
• Albumin 
• Alkaline phosphatase 
• Bicarbonate 
• Blood urea nitrogen 
• Calcium 
• Chloride 
• Creatinine 
• Creatinine clearance (calculated or measured) 
• Glucose 
• Lactate dehydrogenase 
• Magnesium 
• Phosphorous 
• Potassium 
• SGOT/AST 
• SGPTALT 
• Sodium 
• Total bilirubin 
• Total protein 
• Uric acid 
• Hematology  
• The laboratory tests included in the hematology panel are: 
• Hemoglobin 
• Hematocrit 

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• White blood cell count with complete manual or automated differential (reported as 
absolute counts): 
o Total neutrophils 
o Lymphocytes 
o Monocytes 
o Eosinophils 
o Basophils 
• Red blood cell count 
• Platelet count 
4.2.6.3 
Coagulation  
The laboratory tests included in the coagulation panel are: 
• Prothrombin time 
• Activated partial thromboplastin time 
• INR; required only at screening and as clinically indicated thereafter 
• D-dimer test; D-dimer test should be performed if available at local lab at baseline and on 
Day 8 in Cycles 1 and 2 and as clinically indicated thereafter. 
4.2.6.4 
Pregnancy Test  
For WOCBP, a pregnancy test is required for eligibility determination and should be performed 
at the local laboratory. A WOCBP as a sexually mature woman who: 
• has not undergone a hysterectomy or bilateral oophorectomy, or 
• has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had 
menses at any time in the preceding 12 consecutive months) 
At a minimum, serum pregnancy test will be done within 7 days followed by a urine pregnancy 
test within 3 days prior to first dose of investigational therapy(ies), or a serum pregnancy test 
will be done within 3 days prior to first dose of investigational therapy(ies). Pregnancy testing 
should be conducted every other cycle and at the End of Treatment Visit. More frequent 
pregnancy tests may be conducted if required per local regulations. 
4.3 
Efficacy Assessments  
Tumor assessment will be performed within 21 days prior to start of investigational therapy and 
during the Treatment Period (every 8 ± 1 week). Subject that discontinue treatment before the 
first scheduled on study tumor assessment (8 weeks following the first dose of APX005M) 
should have the tumor response evaluated at the end of treatment visit. Tumor assessments will 
follow RECIST 1.1 guidelines. Complete or partial responses should be confirmed at a 
subsequent time point 4 weeks later. 

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Subjects enrolled in Cohort 3 are required to have a minimum of 3 measurable target lesions. 
The lesions which are the first and second radiation therapy targets should be recorded.  
4.3.1 
Collection of Tumor Assessment Images 
Copies of all diagnostic and post-treatment tumor assessment images may be collected and may 
be used to confirm disease responses.  
4.3.2 
Modified RECIST 1.1 for Immune-based Therapeutics  
Accumulating evidence indicates that patients with solid tumors treated with immunotherapy 
may derive clinical benefit despite initial evidence of PD. For the purpose of establishing the 
Phase 2 secondary endpoint the iRECIST (modified RECIST 1.1 for immune-based therapeutics 
[22]) will be used to assess tumor response for all treated subjects. 
Subjects with RECIST 1.1-defined PD (iUPD [iRECIST]) should have a repeated tumor 
assessment 4-8 weeks later in order to confirm PD and will be permitted to continue treatment as 
long as they meet the criteria in Section 3.2.6.2 and they do not have confirmed PD as defined by 
iRECIST. Subjects that are deemed clinically unstable are not required to have repeat imaging 
for confirmation of PD.  
4.4 
Correlative Studies 
Correlative laboratory samples will be obtained in relation to the APX005M infusion. End of 
infusion sample should be collected within the 10 minutes after the completion of the infusion 
(before flush). Other post infusion time points in the within the first 24 hours are ± 30 minutes. 
A ± 2 hours window is allowed for the 24 hours and 168-hour time point. If samples cannot be 
collected within the protocol-specified window they should be collected as soon as practicable.  
4.4.1 
APX005M Pharmacokinetic Assessments  
Serum samples for pharmacokinetics (PK) will be obtained from all subjects in Cycles 1 and 2 
Day 1 (preinfusion, end of infusion, 4 hours ± 30 min after end of infusion), Day 2 (24 ± 2 hours 
after the end of infusion), and in Cycles 3 and 5 Day 1 (preinfusion, end of infusion).   
4.4.2 
APX005M Anti-drug Antibodies  
Serum samples will be collected for anti-drug antibody (ADA) analysis in Cycles 1, 2, 3 and 5 
Day 1 (preinfusion) and at the EOT Visit.  
4.4.3 
Blood and Tumor Biomarkers  
Whole blood and plasma will be collected from all participating subjects in Cycles 1 and 2 
(Day 1 [preinfusion], Day 2 [24 ± 2 hours]) and Day 8 [168 ± 2 hours]), Cycles 3 and 6 Day 1 
(preinfusion) for subjects in Cohort 1, Cycles 4 and 8 Day 1 (preinfusion) for subjects in Cohorts 
2 and 3, time of 2nd tumor core biopsy (if applicable; see below) and at the EOT visit. 
Submission of archived formalin-fixed paraffin embedded tumor tissue or 15 unstained slides is 
mandatory. Tissues may be from the primary tumor, or a metastatic site (or site of local 

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recurrence or advancement) if the primary tumor is unavailable, or if possible, from both primary 
tumor and a metastatic site.  
Subjects who enter Screening Period will be asked to consent to collection of paired fresh tumor 
tissue whenever possible. Up to 18 subjects (6 subjects within each cohort) should consent to 
fresh core biopsies.  
Fresh tumor core biopsies will be collected from consenting subjects prior to the first dose of 
APX005M and prior to first scheduled tumor assessment (at approximately 8 weeks from first 
dose of APX005M). 
For sampling procedures, storage conditions and shipment instructions, see the study Laboratory 
Manual.  
Markers of inflammation, angiogenesis, tumor biology, tumor necrosis, vascularity, cell 
turnover, and expression of molecules in gene families and their signaling pathway molecules 
may be assessed in tissue and blood samples. 
These data will also be used to derive new hypotheses about mechanisms of drug response, 
resistance, and safety. 
4.4.4 
Cytokines  
Plasma samples for cytokine analysis will be obtained from all subjects in Cycles 1 and 2 Day 1 
(preinfusion, end of infusion, 4 hour ± 30 min after end of infusion), Day 2 (24 ± 2 hours) and 
Day 8 (168 ± 2 hours) time of 2nd tumor core biopsy (if applicable; see below), and at EOT visit. 
5. ADVERSE EVENTS  
5.1 
Definitions  
The AE definitions and reporting procedures provided in this protocol comply with current 
21 Code of Federal Regulations Part 312.32. The Apexigen Medical Monitor (or designee) must 
promptly review all information relevant to the safety of APX005M received from any source. 
The investigator or appropriately qualified designee (e.g., a certified nurse practitioner or 
physician’s assistant) will carefully monitor each subject throughout the study for possible AEs, 
the designee must be properly listed on the Form FDA 1572.  
5.1.1 
Adverse Event  
Adverse event (AE) means any untoward medical occurrence associated with the use of a drug in 
humans, whether or not considered drug related. Abnormal laboratory findings should be 
reported as AEs only if they are clinically relevant.  
5.1.2 
Suspected Adverse Reaction  
Suspected adverse reaction (SAR) means any AE for which there is a reasonable possibility that 
the drug caused the AE. For the purposes of IND safety reporting, "reasonable possibility" means 
there is evidence to suggest a causal relationship between the drug and the AE. SAR implies a 

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lesser degree of certainty about causality than adverse reaction, which means any AE caused by a 
drug. 
5.1.3 
Life-threatening AE or Life-threatening SAR  
An AE or SAR is considered "life-threatening" if, in the view of either the Investigator or 
sponsor, its occurrence places the patient or subject at immediate risk of death. It does not 
include an AE or SAR that, had it occurred in a more severe form, might have caused death. 
5.1.4 
Serious AE or Serious SAR  
An AE or SAR is considered "serious" (SAE or SSAR) if, in the view of either the Investigator 
or sponsor, it results in any of the following outcomes: 
• Death 
• A life-threatening AE 
• Inpatient hospitalization or prolongation of existing hospitalization 
• A persistent or significant incapacity or substantial disruption of the ability to conduct 
normal life functions 
• 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 patient or subject 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. 
5.1.5 
Unexpected AE or Unexpected SAR 
An AE or SAR is considered "unexpected" if it is not listed in the Investigator Brochure or is not 
listed at the specificity or severity that has been observed; or, if an Investigator Brochure is not 
required or available, is not consistent with the risk information described in the general 
investigational plan or elsewhere in the current application, as amended. For example, under this 
definition, hepatic necrosis would be unexpected (by virtue of greater severity) if the Investigator 
brochure referred only to elevated hepatic enzymes or hepatitis. Similarly, cerebral 
thromboembolism and cerebral vasculitis would be unexpected (by virtue of greater specificity) 
if the Investigator Brochure listed only cerebral vascular accidents. "Unexpected," as used in this 
definition, also refers to AEs or SARs that are mentioned in the Investigator’s Brochure as 
occurring with a class of drugs or as anticipated from the pharmacological properties of the drug, 
but are not specifically mentioned as occurring with the particular drug under investigation. 

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5.1.6 
Overdose  
For this trial, an overdose will be defined as a dose of APX005M that is >1 mg/kg body weight. 
It is expected that an overdose of APX005M will be associated with severe cytokine release 
syndrome. In the event of overdose, the subject should be observed closely for signs of toxicity. 
Appropriate supportive treatment should be provided if clinically indicated. Retreatment after an 
overdose must be discussed with Apexigen Medical Monitor (or designee). 
5.2 
Adverse Event Classification  
5.2.1 
Relationship to Investigational Therapy(ies) 
The Investigator will assign attribution of the possible association of the event with use of the 
investigational therapy(ies) (APX005M and/or radiation), and this information will be entered 
into electronic data capture (EDC) system using the classification system listed below:  
Related to Investigational Therapy(ies) 
The event is suspected to be related if: 
• There is a clinically plausible time sequence between the AE onset and administration of 
investigational therapy(ies) 
• There is a biologically plausible mechanism for the investigational therapy(ies) to cause 
or contribute to the AE 
• The event improves or diminishes upon temporary interruption of the investigational 
therapy(ies) without the initiation of any specific treatment for the event (dose delay) 
and/or recurs or worsens when resuming treatment after criteria for retreatment are met 
• The AE cannot be reasonably attributed to concurrent or underlying illness, other drugs, 
or procedures 
Apexigen Medical Monitor (or designee) will review all Investigator-reported assessments of 
relationship and confirm.  
Unrelated to Investigational Therapy(ies) 
The event is not suspected to be related if: 
• The AE is more likely to be explained by the subject’s underlying disease, clinical state, 
concomitant medical, or study or non-study procedure 
• The time occurrence of the AE is not reasonably related to administration of 
investigational therapy(ies) 
• The event is not related to the investigational therapy(ies) 

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5.2.2 
Severity 
AE will be reported at the highest grade experienced. The NCI-CTCAE v 4.03 will be used to 
describe the event and to assess the severity of AEs. For AEs not adequately addressed in the 
NCI-CTCAE Version 4.03, Table 5 should be used. 
Table 5: 
Toxicity Grading for AEs Not Covered in NCI-CTCAE (Version 4.03) 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Mild; asymptomatic 
or mild symptoms; 
clinical or 
diagnostic 
observations only; 
intervention not 
indicated 
Moderate; minimal, 
local or noninvasive 
intervention 
indicated; limiting 
age-appropriate 
instrumental 
activities of ADL* 
Severe; medically 
significant but not 
immediately life 
threatening; 
hospitalization or 
prolongation of 
hospitalization 
indicated; disabling; 
limiting self-care 
ADL** 
Life-threatening 
consequences; urgent 
intervention 
indicated 
Death 
Semi-colon indicates “or” within the description 
Abbreviations: ADL = activities of daily living.  
* 
Instrumental ADL refer to preparing meals, shopping for groceries or clothes, using the telephone, managing 
money, etc. 
** Self-care ADL refer to bathing, dressing and undressing, feeding self, using the toilet, taking medications, 
and not bedridden. 
5.3 
AE Collection and Reporting  
5.3.1 
General AE Reporting  
All AEs will be collected from the time the subject receives any investigational therapy(ies) 
through 30 days after receiving the last dose of investigational therapy(ies), death, or initiation of 
new anticancer therapy, whichever occurs first. SAEs, pregnancies and AEs with potential 
immunologic etiology will be recorded up to 90 days after the last dose of investigational 
therapy(ies), death, or initiation of new anticancer therapy, whichever occurs first. In addition, 
the investigator should report any AEs that may occur after this time period which are assessed 
to have a reasonable possibility of being associated with investigational therapy(ies). 
Events that occur after the subject signs the informed consent but prior to the first dose of 
APX005M will be recorded as past medical history; events that start after the first dose of 
APX005M will be recorded as AEs.  
All AEs must be promptly documented on the AE eCRF. The minimum information required for 
each AE includes event, duration (start and end dates), severity, seriousness, relationship to 
iAPX005M, action taken, and outcome. Whenever possible, reporting specific diagnosis is 
preferred when reporting AEs in the AE eCRF rather than reporting individual signs and 
symptoms except for infusion-related reactions (See Section 5.3.3) and Cytokine Release 
Syndrome (See Section 5.3.3).  
All AEs that are considered related to APX005M must be followed to resolution, stabilization, 
until improvement is not expected, 30 days after receiving the last dose of APX005M, death, or 

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initiation of new anticancer therapy, whichever occurs first. SSAR will be followed until 
resolution, stabilization, 90 days or until resolution is not anticipated. 
AE will be reported at the highest grade experienced. AEs which completely resolve and then recur 
will be recorded as a new AE. All AEs that are considered related to investigational therapy(ies) must 
be followed to resolution, stabilization, until improvement is not expected, 30 days after receiving the 
last dose of investigational therapy(ies), death, or initiation of new anticancer therapy, whichever 
occurs first. SSAR will be followed until resolution, stabilization, or until resolution is not 
anticipated. 
If an office visit is not possible, a follow-up of ongoing AEs should be attempted by telephone 
and documented in the subject’s source file. AEs continuing at 30 days after the last dose of 
investigational therapy(ies) should have a comment in the source file by the Investigator that the 
event has stabilized or is not expected to improve. 
The investigator is responsible for evaluating all AEs, obtaining supporting source documents, 
and determining that documentation of the event is adequate. The Investigator may delegate 
these duties to sub-investigators and must ensure that these sub- investigators are qualified to 
perform these duties under the supervision of the Investigator and that they are listed on the FDA 
Form 1572. 
5.3.2 
Intermittent Adverse Events  
AEs which completely resolve and then recur will be recorded as a new AE. 
5.3.3 
Reporting Symptoms Versus Syndromes  
The constellation of symptoms that comprise an APX005M infusion related reaction or cytokine 
release syndrome has not been completely defined, so it is important that all symptoms be 
reported and not just the all-inclusive event of infusion-related reaction or cytokine release 
syndrome. All AEs and the overall syndrome will be graded in accordance with NCI-CTCAE 
criteria. 
5.3.4 
Disease Progression  
Progression of underlying malignancy is not reported as an AE if it is clearly consistent with the 
suspected progression of the underlying cancer as defined by RECIST, or other criteria as 
determined by protocol. Hospitalization due solely to the progression of underlying malignancy 
should NOT be reported as an SAE. Clinical symptoms of progression may be reported as AEs if 
the symptom cannot be determined as exclusively due to the progression of the underlying 
malignancy or does not fit the expected pattern of progression for the disease under study. 
If there is any uncertainty about an AE being due only to the disease under study, it should be 
reported as an AE or SAE. 
Symptomatic deterioration may occur in some patients. In this situation, progression is evident in 
the patient’s clinical symptoms, but is not supported by the tumor measurements. Or, the disease 
progression is so evident that the Investigator may elect not to perform further disease 

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assessments. In such cases, the determination of clinical progression is based on symptomatic 
deterioration. These determinations should be a rare exception as every effort should be made to 
document the objective progression of underlying malignancy. 
Disease progression will be documented in an eCRF intended to capture such information. Signs 
and symptoms related to disease progression should be reported in the appropriate eCRF as an 
AE or as a SAE if applicable. Verbatim terms such as “disease progression,” “progressive 
disease,” etc. should not be reported as AEs or SAEs unless the investigator considers the 
progression to be atypical, accelerated, or caused by the APX005M. Similarly, death occurring 
as a result of disease progression should be reported on the eCRF intended to capture death 
information and should not be reported as an SAE. 
5.3.5 
Reporting Serious AEs 
Apexigen (or designee) must be notified of the occurrence of any SAE/SSAR within 24 hours of 
Investigator’s knowledge of the event. The SAE/SSAR will be reported by completing and 
submitting the SAE/SSAR report form by: 
Email:  DrugSafety010@apexigen.com 
If only limited information is initially available, follow-up reports are required and must be 
submitted in a timely fashion as additional information becomes available. The immediate and 
follow-up reports should identify subjects by unique code numbers assigned to the trial subjects 
rather than by the subjects' names, personal identification numbers, and/or addresses. 
The investigator should also comply with the applicable regulatory requirements related to the 
reporting of SAEs/SSARs to the regulatory authorities and the Institutional Review Board 
(IRB)/Independent Ethics Committee (IEC). Apexigen (or designee) may request additional 
source documentation pertaining to the SAE/SSAR from the investigational site. If a subject is 
permanently withdrawn from the study due to an SAE/SSAR, this information must be included 
in the initial or follow up SAE/SSAR report in the eCRF. 
Apexigen (or designee) is responsible for notifying the appropriate health authorities of serious 
and unexpected SAR (SUSAR) through expedited IND safety reports (ISR) in accordance with 
applicable laws and regulations. 
5.3.6 
Handling of Expedited Safety Reports  
Apexigen (or designee) will notify investigators of all ISRs. Upon receiving an ISR from 
Apexigen (or designee), the investigator must review and retain the ISR with the Investigator’s 
Brochure. Where required by local regulations or when there is a central IRB/IEC for the study, 
Apexigen (or designee) will submit the ISR to the appropriate IRB/IEC. The Investigator and 
IRB/IEC will determine if the informed consent requires revision. The Investigator should also 
comply with the IRB/IEC procedures for reporting any other safety information. 

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5.3.7 
Non-Serious AEs  
The collection of AE information begins after subject’s written consent to participate in the 
study. AEs should be followed to resolution, stabilization, a minimum of 30 days after the last 
dose of APX005M or reported as SAEs if they become serious. 
5.3.8 
Laboratory Test Abnormalities  
Laboratory test values captured as part of the study should be recorded on the appropriate pages 
of the eCRF. Laboratory abnormalities that meet any of the following criteria will also be 
captured on the AE or SAE reporting eCRF page as appropriate: 
• Require the subject to have APX005M discontinued, delayed, or interrupted 
• Require the subject to receive specific corrective therapy 
• Are clinically significant 
• Meet the definition of an SAE/SSAR. 
5.4 
Pregnancy  
Subjects will be instructed to notify the investigator as soon as possible after becoming pregnant 
(or suspecting pregnancy) or learning of the pregnancy or suspected pregnancy of a partner. If a 
subject or partner of a subject becomes pregnant during treatment or up to 90 days following the 
last study drug administration, the investigator will notify Apexigen (or designee) within 
24 hours of learning of the pregnancy.  
If the subject becomes pregnant while receiving investigational therapy(ies), the investigational 
therapy(ies) will be permanently discontinued. Exceptions to the investigational therapy(ies) 
discontinuation may be considered for life-threatening conditions only after consultation with the 
Apexigen Medical Monitor (or designee). The Investigator will discuss the risks and concerns of 
investigational drug exposure to a developing fetus and counsel the subject and/or pregnant 
partner (or ensure that such counseling is provided).  
Pregnancies will be followed through the outcome of the pregnancy. Newborns should be 
followed for a minimum of 8 weeks.  
The Investigator will complete a Pregnancy Surveillance Form and report the information 
regarding the pregnancy, outcome, and status of the newborn, as appropriate. 
Protocol-required procedures for study discontinuation and follow-up must be performed on the 
subject unless contraindicated by pregnancy. Other appropriate pregnancy follow-up procedures 
should be considered if indicated. 

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6. STATISTICS  
6.1 
Sample Size Determination  
This is an exploratory Phase 2 study. Cohorts 1 and 2 will enroll 11 subjects each. Assuming a 
true response rate of about 18.2% (2 subjects with tumor response out of 11 subjects) in each of 
these cohorts, the estimated standard error of the response rate in each of these cohorts will be 
11.6%. Cohort 3 will enroll 18 subjects. Assuming a true response rate in this cohort of about 
16.7% (3 responders out of 18 patients) the estimated standard error will be 8.8%. 
6.2 
Populations for Analyses  
Analysis Population 
Description 
Safety 
All subjects receiving any APX005M 
Efficacy Evaluable  
All who have at least one on treatment (post baseline) tumor assessment 
6.3 
Endpoint Definitions  
Endpoint 
Description 
Primary 
• ORR (rate of CR and PR) by RECIST 1.1 in each cohort  
Secondary 
• Incidence and severity of AEs and specific laboratory abnormalities 
graded according to NCI-CTCAE, v4.03 
• Changes from baseline of vital signs and clinical laboratory results during 
and following investigational therapy(ies) administration 
• ORR (rate of CR and PR) by iRECIST in each cohort 
• DOR (by RECIST 1.1) by cohort, defined as the time from the first 
evidence of confirmed PR or better to disease progression or death due to 
any cause  
• DOR (by iRECIST) by cohort, defined as the time from the first evidence 
of confirmed PR or better to disease progression or death due to any cause  
Exploratory 
• PFS (by RECIST 1.1) by cohort, defined as time from first dose of 
investigational therapy(ies) to the earlier of PD or death due to any cause  
• PFS (by iRECIST) by cohort, defined as time from first dose of 
investigational therapy(ies) to the earlier of PD or death due to any cause 
• Association between potential tumor and/or blood biomarkers and 
antitumor activity and/or resistance to treatment 
• Presence and titer of anti-APX005M antibodies 

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6.4 
Analyses  
6.4.1 
Demographics and Baseline Characteristics  
Demographics and baseline characteristics by cohort will be summarized using descriptive 
statistics 
6.4.2 
Safety Analyses  
Safety will be assessed by cohort through summaries of AEs, laboratory test results, ECG, vital 
signs, and APX005M exposure. All AE data collected will be listed by study site, cohort, subject 
number, and cycle day. 
6.4.3 
Efficacy Analyses  
Tumor assessments by Investigator will follow RECIST 1.1 and iRECIST. ORR (and 90% 
confidence interval by exact distribution), DOR and PFS (Kaplan-Meier estimate) will be 
estimated for each cohort and for each tumor assessment method. Additional details will be 
provided in the Statistical Analysis Plan.  
6.4.4 
Exploratory Analyses  
Potential tumor and blood biomarkers identified in the exploratory biomarker research may be 
correlated with safety and efficacy outcomes.  
7. ADMINISTRATIVE SECTION  
7.1 
Ethics  
7.1.1 
Compliance with the Protocol and Protocol Revisions  
This study will be conducted in accordance with this study protocol and with ICH GCP 
guidelines, the United States Code of Federal Regulations, Title 21, Part 50 (21CFR50), as well 
as all other applicable country and regional legal and regulatory requirements. The Investigator is 
responsible for ensuring that this protocol, the site’s ICF, and any other information that will be 
presented to potential subjects are reviewed and approved by the appropriate IRB/IEC prior to 
the enrollment of any study subjects. 
If an amendment substantially alters the study design or increases the potential risk to the 
subject:  
• The consent form must be revised and submitted to the IRB/IEC for review and 
approval/favorable opinion 
• The revised consent form must be used to obtain consent from subjects currently enrolled 
in the study if they are affected by the amendment 
• The new consent form must be used to obtain consent from new subjects prior to 
enrollment. 
If the revision is in the form of an administrative letter, Investigators must inform their IRB/IEC. 

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7.1.2 
Institutional Review Board / Independent Ethics Committee  
The Investigator must obtain written and dated approval/favorable opinion from the IRB/IEC for 
the protocol, consent form, subject recruitment materials/process (e.g., subject leaflets), and any 
other written information to be provided to subjects. The Investigator or sponsor should also 
provide the IRB/IEC with a copy of the Investigator Brochure or product labeling, information to 
be provided to subjects and any updates. Amendments to the protocol must also be approved by 
the IRB/IEC prior to the implementation of changes in this study.  
The Investigator or sponsor should provide the IRB/IEC with reports, updates, and other 
information (e.g., expedited safety reports, amendments, and administrative letters) according to 
regulatory requirements or institution procedures. 
7.1.3 
Informed Consent  
Written informed consent is required from each subject prior to any testing under this protocol, 
including screening tests and evaluations. The ICF, as specified by the clinical site’s IRB/IEC, 
must follow the Protection of Human Subjects regulations listed in the CFR, Title 21, Part 50. 
Investigators must ensure that subjects or, in those situations where consent cannot be given by 
subjects, their legally acceptable representative, are clearly and fully informed about the purpose, 
potential risks, and other critical issues regarding this clinical study in which they volunteer to 
participate. The information that is given to the subject or the representative shall be in a 
language understandable to the subject or representative. Freely given written informed consent 
prior to clinical study participation must be obtained from every subject or, in those situations 
where consent cannot be given by subjects, their legally acceptable representative, including 
informed consent for any screening procedures conducted to establish subject eligibility for the 
study. 
If a subject is unable to read or if a legally acceptable representative is unable to read, an 
impartial witness should be present during the entire informed consent discussion. After the 
written ICF and any other written information to be provided to subjects, is read and explained to 
the subject or the subject’s legally acceptable representative, and after the subject or the subject’s 
legally acceptable representative has orally consented to the subject’s participation in the trial 
and, if capable of doing so, has signed and personally dated the ICF, the witness should sign and 
personally date the consent form. By signing the consent form, the witness attests that the 
information in the consent form, and any other written information, was accurately explained to, 
and apparently understood by, the subject or the subject's legally acceptable representative, and 
that informed consent was freely given by the subject or the subject’s legally acceptable 
representative. 
Preparation of the consent form is the responsibility of the Investigator and must include all 
elements required by ICH, GCP and applicable regulatory requirements as well as adhere to GCP 
and ethical principles that have their origin in the Declaration of Helsinki. The consent form 
must also include a statement that sponsor and Regulatory Authorities have direct access to 

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subject records. Apexigen (or designee) will provide the Investigator with a sample consent 
form.  
Prior to the beginning of the study, the Investigator must have the IRB/IEC’s written 
approval/favorable opinion of the written ICF and any other information to be provided to the 
subjects. The Investigator must provide the subject or legally acceptable representative with a 
copy of the consent form and allow time necessary for subject or subject’s legally acceptable 
representative to inquire about the details of the study, then informed consent must be signed and 
personally dated by the subject or the subject’s legally acceptable representative and by the 
person who conducted the informed consent discussion.  
The subject or legally acceptable representative should receive a copy of the signed informed 
consent and any other written information provided to study subjects prior to subject’s 
participation in the trial. 
7.2 
Study Materials  
The following study materials will be provided at study start: 
• NCI-CTCAE version 4.03 
• APX005M Investigator’s Brochure 
• Laboratory Manual for collection and handling of archived or fresh tumor tissue, fresh 
tumor core biopsies, PK, PDn, and cytokines samples 
• Pharmacy Manual. 
7.3 
Monitoring  
The Investigator/institution must agree to the inspection of study-related records by the 
regulatory authority/Apexigen (or designee) representative, and must allow direct access to 
source documents to the regulatory authority/Apexigen (or designee) representative/IRB/IEC. 
Apexigen (or designee) representative will review onsite study records and directly compare 
them with source documents, discuss the conduct of the study with the Investigator, and verify 
that the facilities remain acceptable. 
The Investigator must notify Apexigen (or designee) promptly of any inspections by regulatory 
authorities and forward promptly copies of inspection reports to Apexigen (or designee).  
7.3.1 
APX005M  
APX005M study drug packaging will bear a label with the identification required by local law, 
including the protocol number, drug identification, dosage, and expiry date. The study drug must 
be stored according to the details on the product label. Local packaging in some countries may 
be different.  
Upon arrival of investigational therapy at the site, site personnel should check the shipment for 
damage and verify proper identity, quantity, integrity of seals and temperature conditions, and 
report any deviations or product complaints to the Apexigen (or designee) upon discovery. 

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Date: December 28, 2020 
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7.3.1.1 
Assessment of Compliance 
Compliance will be assessed by maintaining adequate study drug dispensing records. The 
Investigator is responsible for ensuring that dosing is administered in compliance with the 
protocol. Delegation of this task must be clearly documented and approved by the investigator. 
The Investigator is responsible for the control of APX005M under investigation. Adequate 
records for the receipts (e.g. Drug Receipt Record) and disposition (e.g. Drug Dispensing Log) of 
the study drug must be maintained. Accountability and patient compliance will be assessed by 
maintaining adequate “drug dispensing” and return records. All records and drug supplies must 
be available for inspection by the Monitor at every monitoring visit. These records must contain 
the following information: 
• Documentation of drug shipments received from the Sponsor (date received, quantity, and 
batch numbers). 
• Disposition of unused study drug not dispensed for patient. 
A Drug Dispensing Log must be kept current and should contain the following information:  
• The identification of the patient for whom the study treatment was dispensed. 
• The date(s), quantity, and batch numbers of the study treatment dispensed. 
This inventory must be available for inspection by the Monitor. All supplies, including partially 
used or empty containers and copies of the dispensing and inventory logs, must be returned to 
Apexigen (or designee) at the end of the study, unless alternate destruction has been authorized 
by Apexigen (or designee), or required by local or institutional regulations (See Pharmacy 
Manual). 
The Pharmacy Manual contains further detailed information about packaging, labeling, storage, 
dispensing, preparation and administration of APX005M. 
7.3.1.2 
Destruction of the APX005M Investigational Therapy  
Local or institutional regulations may require immediate destruction of used APX005M for 
safety reasons e.g., cytotoxicity. In these cases, it may be acceptable for investigational site staff 
to destroy dispensed APX005M before a monitoring inspection provided that source document 
verification is performed on the remaining inventory and reconciled against the documentation of 
quantity shipped, dispensed, returned and destroyed. Written authorization must be obtained 
from the Apexigen at study start up before destruction. 
Written documentation of destruction must contain the following: 
• Identity (batch numbers and patient numbers) of investigational therapy destroyed 
• Quantity of investigational therapy destroyed 
• Date of destruction (date discarded in designated hazardous container for destruction) 
• Method of destruction (the site must provide the Sponsor with documentation of their 
institutional policy and procedures for handling and disposing of hazardous drugs) 

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• Name and signature of responsible person who discarded the investigational therapy in a 
hazardous container for destruction. 
7.4 
Confidentiality  
All records identifying the subject will be kept confidential to the full extent of the law. 
Subject names will not be supplied to Apexigen. Only the subject number will be recorded on the 
eCRF. If the subject name appears on any other document (e.g., pathologist report) or study 
materials (e.g., biopsy tissue slides), then that information must be redacted before a copy of the 
document is supplied to Apexigen (or designee). Study data stored on a computer will be stored 
in accordance with local data protection laws and regulations. Subjects will be informed in 
writing that representatives of Apexigen, IRB/IEC, or regulatory authorities may inspect their 
medical records to verify the information collected, and all personal information made available 
for inspection will be handled in strictest confidence and in accordance with local data protection 
laws and regulations. 
If the results of the study are published, the subject’s identity will remain confidential. 
The investigator will maintain a list to enable subjects’ records to be identified in accordance 
with applicable laws and regulations and according to the terms and agreed upon in such 
subjects’ signed consent forms. 
7.5 
Investigational Site Training  
Study personnel involved in conducting this study will be qualified by education, training, and 
experience to perform their respective task(s). This study will not use the services of study 
personnel where sanctions have been invoked or where there has been scientific misconduct or 
fraud (e.g., loss of medical licensure or debarment). Systems with procedures that assure the 
quality of every aspect of the study will be implemented. If necessary, Apexigen (or designee) 
will provide investigative site staff training prior to study initiation. Training topics will include, 
but are not limited to, GCP, AE reporting, study details and procedure, study documentation, 
informed consent, and enrollment of WOCBP. 
7.6 
Data Collection and Handling  
As part of the responsibilities assumed by participating in the study, the Investigator agrees to 
maintain adequate case histories for the subjects treated as part of the research under this 
protocol. The Investigator agrees to maintain accurate eCRFs and source documentation as part 
of the case histories. These source documents may include subject diaries, laboratory reports, and 
other documents. Apexigen (or designee) will supply the eCRF, which will be completed in 
English. Data collection will involve the use of the EDC system, to which only authorized 
personnel will have access. 
The investigator (or designee) must enter all results collected during the clinical study into 
eCRFs. Guidelines for completion of eCRFs will be reviewed with study site personnel at the site 

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Date: December 28, 2020 
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initiation visits. Investigators are responsible for approval of the entered/corrected data. Detailed 
instructions may be found in the other study-specific documents. 
All entries made on the eCRF must be verifiable against source documents. In addition to 
periodic monitoring occurring within the system by study monitors, programmatic edit checks 
and data listings will be used to review the data for completeness, logic, and adherence to study 
protocol. As a result of this monitoring and these checks and queries may be electronically issued 
to the clinical study sites and electronically resolved by those sites. 
All data collected in the context of this study will be stored and evaluated per regulatory 
requirements and applicable guidance for electronic records. Also, data will be stored and 
evaluated in such a way as to assure subject confidentiality in accordance with the legal and 
regulatory requirements applying to protected health information. Study records (e.g., copies of 
eCRFs and regulatory documents) will be retained at the study site, along with adequate source 
documentation. The study file and all source data should be retained for the time period required 
by applicable regulatory requirements and will not be destroyed until written notification is given 
by Apexigen (or designee) for destruction. 
7.7 
Publications  
The data collected during this study are confidential and proprietary to Apexigen. Any 
publications or abstracts arising from this study require approval by Apexigen prior to 
publication or presentation and must adhere to Apexigen’s publication requirements (as set forth 
in the approved clinical trial agreement). All draft publications, including abstracts or detailed 
summaries of any proposed presentations, must be submitted to the sponsor at the earliest 
practicable time for review, but at any event not less than 30 days before submission. Apexigen 
shall have the right to delete any confidential or proprietary information contained in any 
proposed presentation or abstract and may delay publication for up to 60 days for purposes of 
filing a patent application. 
 
 

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Date: December 28, 2020 
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8. LIST OF ABBREVIATIONS  
Abbreviation 
Definition 
ADA 
Anti-drug Antibodies 
ADCP 
Antibody-dependent Cellular Phagocytosis 
AE 
Adverse Event 
ALT 
Alanine Aminotransferase 
ANC 
Absolute Neutrophil Count 
APC 
Antigen-presenting Cell 
aPTT 
Activated Partial Thromboplastin Time  
AST 
Aspartate Aminotransferase 
AUC0‒∞ 
Area Under the Curve Extrapolated to Infinity 
BRAF 
Human Proto-oncogene Encoding B-Raf Protein 
CBCT 
Cone-beam Computed Tomography 
CD40 
Cluster of Differentiation 40 
CD40L 
CD40 Ligand 
Cmax 
Maximum Serum Concentration 
CNS 
Central Nervous System 
CR 
Complete Response 
CT 
Computed Tomography 
CTLA-4 
Cytotoxic T-lymphocyte Associated Protein 4 
CTV 
Clinical Target Volume 
DCs 
Dendritic Cells 
DOR 
Duration of Response 
DL 
Dose Level 
DLT 
Dose-Limiting Toxicity 
ECG 
Electrocardiogram 
ECOG 
Eastern Cooperative Oncology Group 
eCRF 
Electronic Case Report Form 
EDC 
Electronic Data Capture 
EOT 
End of Treatment 
FDA 
Food and Drug Administration 
FOV 
Field of Vision 
GCP 
Good Clinical Practice 
GLP 
Good Laboratory Practice 
GTV 
Gross Tumor Volume 
HIV 
Human Immunodeficiency Virus 
ICF 
Informed Consent Form 
ICH 
International Conference on Harmonisation 

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Abbreviation 
Definition 
IEC 
Independent Ethics Committee 
Ig 
Immunoglobulin 
IGRT 
Image-guided Radiation Therapy 
IMRT 
Intensity Modulated Radiotherapy 
IND 
Investigational New Drug Application 
INR 
International Normalized Ratio  
IRB 
Institutional Review Board 
iRECIST 
Immune-related RECIST 
iUPD 
iRECIST Unconfirmed Progressive Disease 
ISR 
IND Safety Report 
ITV 
Internal Target Volume 
IV 
Intravenous 
Kd 
Dissociation Constant 
mAb 
Monoclonal Antibody 
mL 
Milliliter 
MLC 
Multi-leaf Collimator 
MRI 
Magnetic Resonance Imaging 
MTD 
Maximum Tolerated Dose 
MV 
Megavolt 
NCI-CTCAE 
National Cancer Institute-Common Terminology Criteria for Adverse Events 
NOAEL 
No Observed Adverse Effect Level 
OAR 
Organ at Risk 
ORR 
Overall Response Rate 
PBMC 
Peripheral Blood Mononuclear Cells 
PD 
Progressive Disease/Disease Progression 
PD-1 
Programmed Death Receptor-1 
PD-L1 
Programmed Death-ligand 1 
PDn 
Pharmacodynamics 
PET 
Positron Emission Tomography 
PK 
Pharmacokinetics 
PFS 
Progression-free Survival 
PR 
Partial Response 
PT 
Prothrombin Time 
PTT 
Partial Thromboplastin Time 
PTV 
Planning Target Volume 
QA 
Quality Assurance 
RECIST 
Response Evaluation Criteria in Solid Tumors 

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Abbreviation 
Definition 
RT 
Radiation Therapy (or radiotherapy) 
SAE 
Serious Adverse Event 
SAR 
Suspected Adverse Reaction 
SBRT 
Stereotactic Body Radiation Therapy 
SEP 
Subject Eligibility Packet 
SSAR 
Serious Suspected Adverse Reaction 
TNFR 
Tumor Necrosis Factor Receptor 
ULN 
Upper Limit of Normal 
VMAT 
Volumetric Modulated Arc Therapy 
WOCBP 
Women of Childbearing Potential 

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9. REFERENCES 
1. 
Pardoll DM. The blockade of immune checkpoints in cancer immunotherapy. Nat Rev 
Cancer 2012;12:252–64. 
2. 
Wolchok JD, Kluger H, Callahan MK, Postow MA, Rizvi NA, Lesokhin AM, Segal NH, 
Ariyan CE, Gordon RA, Reed K, Burke MM, Caldwell A, Kronenberg SA, Agunwamba 
BU, Zhang X, Lowy I, Inzunza HD, Feely W, Horak CE, Hong Q, Korman AJ, Wigginton 
JM, Gupta A, Sznol M. Nivolumab plus ipilimumab in advanced melanoma. N Engl J Med 
2013;369:122–33. 
3. 
Motzer RJ, Escudier B, McDermott DF, George S, Hammers HJ, Srinivas S, Tykodi SS, 
Sosman JA, Procopio G, Plimack ER, Castellano D, Choueiri TK, Gurney H, Donskov F, 
Bono P, Wagstaff J, Gauler TC, Ueda T, Tomita Y, Schutz FA, Kollmannsberger C, Larkin 
J, Ravaud A, Simon JS, Xu LA, Waxman IM, Sharma P; CheckMate 025 Investigators. 
Nivolumab versus Everolimus in Advanced Renal-Cell Carcinoma. N Engl J Med 
2015;373:1803-13. 
4. 
Mahoney KM, Rennert PD, Freeman GJ. Combination cancer immunotherapy and new 
immunomodulatory targets. Nat Rev Drug Discov 2015;14:561-84. 
5. 
Aggarwal BB. Signalling pathways of the TNF superfamily: a double-edged sword. Nat 
Rev Immunol 2003;3:745–56. 
6. 
Banchereau J, Bazan F, Blanchard D, Briere F, Galizzi JP, van Kooten C, Liu YJ, Rousset 
F, Saeland S. The CD40 antigen and its ligand. Annu Rev Immunol 1994;12:881–922. 
7. 
Clark EA, Ledbetter JA. How B and T cells talk to each other. Nature 1994;367:425–8. 
8. 
Grewal IS, Flavell RA. CD40 and CD154 in cell-mediated immunity. Annu Rev Immunol 
1998;16:111–35. 
9. 
Eliopoulos AG, Young LS. The role of the CD40 pathway in the pathogenesis and 
treatment of cancer. Curr Opin Pharmacol 2004;4:360–7. 
10. Hess S, Engelmann H. A novel function of CD40: induction of cell death in transformed 
cells. J Exp Med 1996;183:159–67. 
11. Khong A, Nelson DJ, Nowak AK, Lake RA, Robinson BW. The use of agonistic anti-
CD40 therapy in treatments for cancer. Int Rev Immunol 2012;31:246–66. 
12. Law CL, Grewal IS. Therapeutic interventions targeting CD40L (CD154) and CD40: the 
opportunities and challenges. Adv Exp Med Biol 2009;647:8–36. 
13. Rakhmilevich AL, Alderson KL, Sondel PM. T-cell-independent anti-tumor effects of 
CD40 ligation. Int Rev Immunol 2012;31:267–78. 
14. Tong AW, Stone MJ. Prospects for CD40-directed experimental therapy of human cancer. 
Cancer Gene Ther 2003;10:1–13. 
15. Ruter J, Antonia SJ, Burris HA, Huhn RD, Vonderheide RH. Immune modulation with 
weekly dosing of an agonist CD40 antibody in a phase I study of patients with advanced 
solid tumors. Cancer Biol Ther 2010;10:983–93. 

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16. Vonderheide RH, Flaherty KT, Khalil M, Stumacher MS, Bajor DL, Hutnick NA, Sullivan 
P, Mahany JJ, Gallagher M, Kramer A, Green SJ, O'Dwyer PJ, Running KL, Huhn RD, 
Antonia SJ. Clinical activity and immune modulation in cancer patients treated with 
CP-870,893, a novel CD40 agonist monoclonal antibody. J Clin Oncol 2007;25:876-83. 
17. Herrera FG, Bourhis J, Coukos G. Radiotherapy combination opportunities leveraging 
immunity for the next oncology practice. CA Cancer J Clin, 2017;67:65-85. 
18. Rech AJ, Dada H, Kotzin JJ, Henao-Mejia J, Minn AJ, Twyman-Saint Victor C, 
Vonderheide RH. Radiotherapy and CD40 Activation Separately Augment Immunity to 
Checkpoint Blockade in Cancer. Cancer Res, 2018;78:4282-4291. 
19. Aguilera TA, Elghonaimy EA, Shehade H, Rafat M, Castellini L, Jiang D, Kariolis M, 
Koong AC, Le QT, Ellies LG, Rankin EB, Graves EE, Giaccia AJ. Induced Tumor 
Heterogeneity Reveals Factors Informing Radiation and Immunotherapy Combinations. 
Clin Cancer Res, 2020;26:2972-2985. 
20. Barr TA, Heath AW. Functional activity of CD40 antibodies correlates to the position of 
binding relative to CD154. Immunology 2001;102:39–43.  
21. APX005M Investigator's Brochure. 
22. Seymour L, Bogaerts J, Perrone A, et al. iRECIST: guidelines for response criteria for use 
in trials testing immunotherapeutics. The Lancet Oncology. 2017;18(3):e143-e152. 
 

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APPENDIX A: 
STUDY APX005M-010 SCHEDULE OF EVENTS 
 
Screening 
Period 
Treatment Period 
Follow-up 
 
Cycles 1 & 2 
Cycle 3+ 
EOT 
 
Day 1 
Day 2(24h) 
Day 8(168h) 
Day 1 
Optional Visit 
Tumor 
Assmnt 
2ndBiopsy 
Eligibility 
X 
X 
 
 
 
 
 
 
 
 
Demographics 
& Med History 
X 
 
 
 
 
 
 
 
 
 
Physical Examination 
X 
X 
 
 
X 
 
 
 
X 
 
12-lead ECG 
X 
 
 
 
 
 
 
 
 
 
Height 
X 
 
 
 
 
 
 
 
 
 
Weight 
X 
X 
 
 
X 
 
 
 
X 
 
Vital Signs1 
X 
X 
X 
X 
X 
X 
 
 
X 
 
ECOG Performance Status 
X 
X 
 
 
X 
 
 
 
X 
 
Urinalysis 
X 
 
 
 
 
 
 
 
 
 
Serum Chemistry 
X 
X 
X 
X 
X 
X 
 
X 
X 
 
Hematology 
X 
X 
X 
X 
X 
X 
 
X 
X 
 
Coagulation 
X 
X 
X 
X 
X 
 
 
 
X 
 
Pregnancy Test (if applicable)2 
X 
 
 
 
X 
 
 
 
X 
 
Tumor Assessment3 
X 
 
 
 
 
 
X 
 
X 
 
AEs and ConMeds 
 
X 
X 
X 
X 
X 
 
X 
X 
 
SBRT4 
 
X 
 
 
X 
 
 
 
 
 
Premedication 
 
X 
 
 
X 
 
 
 
 
 
APX005M Administration5 
 
X 
 
 
X 
 
 
 
 
 
PK6 
 
X 
X 
 
X 
 
 
 
 
 
ADA7 
 
X 
 
 
X 
 
 
 
X 
 
Whole Blood and Plasma for 
Biomarkers8 
 
X 
X 
X 
X 
 
 
X 
X 
 
Cytokines9 
 
X 
X 
X 
 
 
 
X 
X 
 
Archived Tumor Tissue 
Sample10 
X 
 
 
 
 
 
 
 
 
 
Fresh Tumor Tissue Sample11 
X 
 
 
 
 
 
 
X 
 
 
Date of PD and 
Subsequent Treatment 
 
 
 
 
 
 
 
 
 
X 

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1. Vital signs in Day 1 in Cycles 1 & 2 should be collected preinfusion, at the end of infusion, 4, 24, 168 hours after end of infusion, and as medically indicated. 
On Day 1 of subsequent cycles, vital signs should be collected preinfusion and at the end of infusion and as medically indicated. 
2. Serum pregnancy test will be done within 7 days followed by a urine pregnancy test within 3 days prior to first dose of investigational therapy(ies), or a serum 
pregnancy test will be done within 3 days prior to first dose of investigational therapy(ies). Pregnancy testing should be conducted every other cycle and at 
EOT. More frequent pregnancy tests may be conducted if required per local regulations. 
3. Tumor assessment will be performed within 21 days prior to start of investigational therapy(ies) and during Treatment Phase every 8 ± 1 weeks. Subjects that 
discontinue treatment before the first scheduled on study tumor assessment (8 weeks following the first dose of investigational therapy(ies)) should have the 
tumor response evaluated at the EOT visit. 
4. Cohort 3: SBRT will be administered the same day, prior to APX005M administration. 
5. APX005M may be administered up to 3 days after the scheduled Day 1 of Cycles 2 and beyond in case of medical/surgical events, or logistical reasons not 
related to study therapy (e.g., elective surgery, unrelated medical events, patient vacation, and/or holidays). 
6. PK serum samples will be obtained in Cycles 1 and 2 Day 1 (preinfusion, end of infusion, 4 hours ± 30 min after end of infusion) and Day 2 (24 ± 2 hours after 
the end of infusion), Cycles 3 and 5 Day 1 (preinfusion, end of infusion) 
7. ADA serum samples will be collected in Cycles 1, 2, 3, and 5 Day 1 (preinfusion) and at the EOT visit. 
8. Whole blood and plasma will be collected from all participating subjects in Cycles 1 and 2 (Day 1 [preinfusion], Day 2 [24 ± 2 hours] and Day 8 [168 ± 
2 hours]), Cycles 3 and 6 Day 1 (preinfusion) for subjects in Cohort 1, Cycles 4 and 8 Day 1 (preinfusion) for subjects in Cohorts 2 and 3, time of 2nd tumor 
core biopsy (if applicable) and at the EOT. 
9. Cytokine plasma samples will be obtained in Cycles 1 and 2 Day 1 (preinfusion, end of infusion, 4 hour ± 30 min after end of infusion), Day 2 (24 ± 2 hours) 
and Day 8 (168 ± 2 hours), time of 2nd tumor biopsy (if applicable) and at EOT.  
10. Submission of archived formalin-fixed paraffin embedded tumor tissue or 15 unstained slides is mandatory. 
11. Fresh tumor core biopsies will be collected from consenting subjects prior to first dose of investigational therapy(ies) and prior to first scheduled tumor 
assessment (at approximately 7–8 weeks from first dose of investigational therapy(ies)). 

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Date: December 28, 2020 
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APPENDIX B: 
VITAL SIGNS AND CORRELATIVE LAB SCHEDULE  
Cycle 1 
Cycle 2 
Cycle 3 
Cycle 4 
Cycle 5 
Cycle 6+ 
2nd Bx 
EOT 
Day 1 
Day 2 
Day 8 
Day 1 
Day 2 
Day 8 
Day 1 
Day 1 
Day 1 
Day 1 
Vital Signs  
  
  
  
  
  
  
  
  
  
  
  
X 
Preinfusion  
X 
  
  
X 
  
  
X 
X 
X 
X 
  
  
End of Infusion  
X 
  
  
X 
  
  
X 
X 
X 
X 
  
  
4 Hours After the End of Infusion  
X 
  
  
X 
  
  
  
  
  
  
  
  
24 Hours After the End of Infusion  
  
X 
  
  
X 
  
  
  
  
  
  
  
168 Hours After the End of Infusion  
  
  
X 
  
  
X 
  
  
  
  
  
  
Pharmacokinetics (PK) 
  
  
  
  
  
  
  
  
  
  
  
  
Preinfusion  
X 
  
  
X 
  
  
X 
 
X 
  
  
  
End of Infusion 
4 Hours After the End of Infusion 
X 
X 
  
  
X 
X 
  
  
X 
 
 
X 
 
  
  
  
24 Hours After the End of Infusion 
 
X 
 
 
X 
 
 
 
 
 
 
 
Anti-drug Antibodies (ADA) 
  
  
  
  
  
  
  
  
  
  
  
X 
Preinfusion  
X 
  
  
X 
  
  
X 
X 
  
Whole Blood and Plasma for Biomarkers 
X 
X 
X 
X 
X 
X 
Xa 
Xa 
 
Xa 
X 
X 
Cytokines  
  
  
  
  
  
  
  
  
  
  
  
X 
Preinfusion  
X 
  
  
X 
  
  
  
  
  
  
  
  
End of Infusion  
X 
  
  
X 
  
  
  
  
  
  
  
  
4 Hours After the End of Infusion  
X 
  
  
X 
  
  
  
  
  
  
  
  
24 Hours After the End of Infusion  
  
X 
  
  
X 
  
  
  
  
  
  
  
168 Hours After the End of Infusion  
  
  
X 
  
  
X 
  
  
  
  
  
  
a Cycles 3 and 6 Day 1 (preinfusion) for subjects in Cohort 1, Cycles 4 and 8 Day 1 (preinfusion) for subjects in Cohorts 2 and 3. 

Apexigen, Inc. 
 
APX005M-010 Clinical Protocol 
APX005M 
 
Amendment 2 
Date: December 28, 2020 
CONFIDENTIAL 
Page 68 of 68 
APPENDIX C: 
METHODS OF CONTRACEPTION  
Highly Effective Methods of 
Contraception 
Progestogen only hormonal contraception associated with inhibition of ovulation 
Hormonal methods of contraception including oral contraceptive pills (combination of estrogen and progesterone), 
vaginal ring, injectables, implants, transdermal, and intrauterine hormone-releasing system (IUS) 
Bilateral tubal ligation 
Vasectomized Partner 
Intrauterine Devices (IUD) 
Complete abstinence 
Additional Methods for Male 
Subjects 
Condom 
NOTE: Partners of male subjects are to use one highly effective method of contraception