An Adaptive, Multicenter, Open-Label Study to Evaluate the Safety, Tolerability, Efficacy, and Pharmacokinetics of Intra-articular AMB-05X Injections in Subjects With Tenosynovial Giant Cell Tumor of the Knee
Phase: PHASE2
Conditions: Tenosynovial Giant Cell Tumor, Pigmented Villonodular Synovitis (PVNS)
Sponsor: AmMax Bio, Inc.



AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 2 
 
 
SPONSOR APPROVAL 
 
Title: 
An Adaptive, Multicenter, Open-Label Study to Evaluate the 
Safety, Tolerability, Efficacy, and Pharmacokinetics of Intra-
articular AMB-05X Injections in Subjects with Tenosynovial 
Giant Cell Tumor of the Knee 
Protocol Number: 
AMB-051-01 
Sponsor: 
AmMax Bio, Inc. 
 
Signatures verify the information in this document is accurate and complete. 
 
 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 3 
 
 
INVESTIGATOR’S SIGNATURE 
 
Title: 
An Adaptive, Multicenter, Open-Label Study to Evaluate the Safety, 
Tolerability, Efficacy, and Pharmacokinetics of Intra-articular AMB-05X 
Injections in Subjects with Tenosynovial Giant Cell Tumor of the Knee 
 
 
Protocol Number: 
AMB-051-01 
 
I confirm that I have read this protocol. I will comply with the protocol, statutory requirements 
as described in the United States Code of Federal Regulations (CFR) 21 Parts 11, 50, 54, 56, 
and 312, and local requirements in the countries where the study is performed, the principles of 
Good Clinical Practice (GCP) in relevant guidance documents from the International Council 
for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), and 
the ethical principles of the Declaration of Helsinki. 
I will provide copies of the protocol and all pertinent information to all study site personnel 
who participate in the conduct of this clinical study. I will discuss this material with them to 
ensure they are fully informed regarding the study medication, the conduct of the study, and the 
obligations of confidentiality. 
 
 
 
Principal Investigator Name (printed) 
 
Signature 
 
 
 
Date 
 
Study Center Number 
 
 
 
Institution Name 
 
City, State or Province, Country 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 4 
 
 
CONTACTS IN THE EVENT OF AN EMERGENCY 
 
SPONSOR 
AmMax Bio, Inc.  
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
A change in administrative information does not require a protocol amendment. 
 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 5 
 
 
TABLE OF CONTENTS 
 
SPONSOR APPROVAL .................................................................................................................2 
INVESTIGATOR’S SIGNATURE .................................................................................................3 
CONTACTS IN THE EVENT OF AN EMERGENCY..................................................................4 
TABLE OF CONTENTS .................................................................................................................5 
LIST OF ABBREVIATIONS AND DEFINITIONS OF TERMS ................................................10 
1. 
PROTOCOL SUMMARY ..........................................................................................12 
1.1. 
Protocol Synopsis .......................................................................................................12 
1.2. 
Study Schema .............................................................................................................19 
1.3. 
Schedule of Events .....................................................................................................20 
2. 
INTRODUCTION ......................................................................................................22 
2.1. 
Tenosynovial Giant Cell Tumor .................................................................................22 
2.2. 
AMB-05X ...................................................................................................................23 
2.3. 
Summary of Nonclinical Data ....................................................................................23 
 
Pharmacology .............................................................................................................23 
 
Pharmacokinetics ........................................................................................................24 
 
Toxicology ..................................................................................................................24 
 
Non-Human Primate Intra-articular Administration of AMB-05X ............................25 
 
Clinical Safety Extrapolation ......................................................................................25 
2.4. 
Summary of Clinical Data ..........................................................................................26 
 
Clinical Studies of AMB-05X ....................................................................................26 
2.4.1.1. 
Monotherapy Study ....................................................................................................26 
2.4.1.2. 
Combination Study with Pembrolizumab ...................................................................27 
 
Intra-articular Administration of Antibodies in Clinical Studies ...............................28 
3. 
STUDY OBJECTIVES AND ENDPOINTS ..............................................................30 
3.1. 
Primary Endpoint ........................................................................................................30 
3.2. 
Secondary Endpoints ..................................................................................................30 
4. 
INVESTIGATIONAL PLAN .....................................................................................31 
4.1. 
Overall Study Design ..................................................................................................31 
4.2. 
Rationale for Dose Regimen and Duration of Treatment ...........................................32 
4.3. 
Number of Subjects ....................................................................................................33 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 6 
 
 
4.4. 
Treatment Assignment ................................................................................................33 
4.5. 
Subject and Study Early Termination .........................................................................33 
 
End of Study Definition ..............................................................................................33 
 
Subject Early Termination ..........................................................................................34 
 
Study Premature Termination .....................................................................................34 
5. 
SELECTION OF SUBJECTS ....................................................................................35 
5.1. 
Subject Inclusion Criteria ...........................................................................................35 
5.2. 
Subject Exclusion Criteria ..........................................................................................35 
5.3. 
Contraception Guidelines ...........................................................................................36 
 
Contraception Guidelines for Female Subjects ..........................................................36 
 
Contraception Guidelines for Male Subjects ..............................................................37 
6. 
ASSESSMENTS BY STUDY VISIT ........................................................................39 
6.1. 
Visit 1 / Screening ......................................................................................................39 
6.2. 
Visit 2 / Baseline (Day 1, Week 0) .............................................................................40 
 
Visit 2 – Pre-dose Procedures .....................................................................................40 
 
Visit 2 – Dosing and Post-dose Procedures ................................................................40 
6.3. 
Visit 3 (Week 2 ± 2 Days) ..........................................................................................41 
6.4. 
Visit 4 (Week 4 ± 2 Days) ..........................................................................................41 
6.5. 
Visit 5 (Week 6 ± 3 days) ...........................................................................................41 
6.6. 
Visit 6 (Week 8 ± 3 days) ...........................................................................................42 
6.7. 
Visit 7 (Week 10 ± 3 days) .........................................................................................43 
6.8. 
Visit 8 (Week 12 ± 3 days) or Early Termination ......................................................43 
6.9. 
Visit 9 (Week 14 ± 3 days) .........................................................................................44 
6.10. 
Visit 10 (Week 24 ± 7 days) .......................................................................................44 
6.11. 
Early Termination Procedures ....................................................................................44 
7. 
TREATMENT OF SUBJECTS ..................................................................................45 
7.1. 
Description of Study Drug ..........................................................................................45 
7.2. 
Concomitant Medications ...........................................................................................45 
7.3. 
Prohibited and Permitted Treatment ...........................................................................45 
7.4. 
Treatment Compliance ................................................................................................45 
8. 
STUDY DRUG MATERIALS AND MANAGEMENT ...........................................46 
8.1. 
Study Drug, Labeling, Packaging, and Dispensing ....................................................46 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 7 
 
 
8.2. 
Study Drug Storage .....................................................................................................46 
8.3. 
Study Drug Administration.........................................................................................46 
8.4. 
Study Drug Accountability .........................................................................................47 
8.5. 
Study Drug Handling and Disposal ............................................................................47 
9. 
STUDY ASSESSMENTS AND PROCEDURES ......................................................48 
9.1. 
Screening Assessments ...............................................................................................48 
 
Demographic and Medical History .............................................................................48 
 
Tumor Biopsy .............................................................................................................48 
9.2. 
Efficacy Assessments .................................................................................................48 
 
Tumor Assessment ......................................................................................................48 
 
MRI .............................................................................................................................48 
9.3. 
Clinical Outcome Assessments ...................................................................................48 
 
Worst Stiffness NRS ...................................................................................................48 
 
PROMIS .....................................................................................................................49 
 
BPI ..............................................................................................................................49 
 
EQ-5D-5L Health Assessment ...................................................................................49 
 
ROM ...........................................................................................................................49 
9.4. 
Pharmacokinetic/Pharmacodynamic Assessments .....................................................49 
9.5. 
Safety Assessments .....................................................................................................50 
 
Vital Signs ..................................................................................................................50 
 
Physical Examination .................................................................................................50 
 
Electrocardiogram .......................................................................................................50 
 
Clinical Laboratory Tests ...........................................................................................51 
 
Pregnancy Tests ..........................................................................................................51 
9.6. 
Adverse Events and Serious Adverse Events .............................................................51 
 
Definition of Adverse Event .......................................................................................51 
 
Definition of Serious Adverse Event ..........................................................................51 
 
Classification of an Adverse Event .............................................................................52 
9.6.3.1. 
Severity .......................................................................................................................52 
9.6.3.2. 
Relationship to Study Drug ........................................................................................52 
9.6.3.3. 
Expectedness ...............................................................................................................53 
 
Time Period and Frequency for Event Assessment and Follow-up ...........................53 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 8 
 
 
 
Adverse Event Reporting ............................................................................................53 
 
Serious Adverse Event Reporting and Follow-up ......................................................54 
9.7. 
Pregnancy ...................................................................................................................55 
9.8. 
Pharmacokinetic Assessments ....................................................................................55 
9.9. 
Blood and Synovial Fluid Sampling ...........................................................................55 
10. 
STATISTICS ..............................................................................................................56 
10.1. 
General Considerations ...............................................................................................56 
10.2. 
Sample Size Determination ........................................................................................56 
10.3. 
Efficacy Analyses .......................................................................................................56 
10.4. 
Pharmacokinetic Analysis ..........................................................................................56 
10.5. 
Safety Analyses ..........................................................................................................56 
11. 
DIRECT ACCESS TO SOURCE DATA AND DOCUMENTS ...............................58 
11.1. 
Source Documents ......................................................................................................58 
11.2. 
Study Monitoring ........................................................................................................58 
11.3. 
Audits and Inspections ................................................................................................59 
12. 
ADMINISTRATIVE PROCEDURES .......................................................................60 
12.1. 
Ethics Review .............................................................................................................60 
12.2. 
Good Clinical Practice ................................................................................................60 
12.3. 
Written Informed Consent ..........................................................................................60 
12.4. 
Subject Confidentiality ...............................................................................................61 
12.5. 
Protocol Deviation ......................................................................................................61 
12.6. 
Protocol Amendment ..................................................................................................62 
12.7. 
Protocol Termination ..................................................................................................62 
13. 
DATA HANDLING AND RECORDKEEPING .......................................................63 
13.1. 
Case Report Forms .....................................................................................................63 
13.2. 
Inspection of Records .................................................................................................63 
13.3. 
Retention of Records ..................................................................................................63 
14. 
PUBLICATION POLICY ..........................................................................................64 
14.1. 
Clinical Trial Database ...............................................................................................64 
14.2. 
Publishing Study Results ............................................................................................64 
15. 
LIST OF REFERENCES ............................................................................................65 
 WORST STIFFNESS NRS ................................................................................67 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 9 
 
 
 PROMIS PHYSICAL FUNCTION SCALE .....................................................68 
 BPI (SHORT FORM) ........................................................................................69 
 EQ-5D-5L ASSESSMENT ................................................................................70 
 COVID-19 CONTINGENCY PLAN ................................................................72 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 10 
 
 
LIST OF ABBREVIATIONS AND DEFINITIONS OF TERMS 
 
Abbreviation 
Definition 
AE 
adverse event 
ALT 
alanine aminotransferase 
AST 
aspartate aminotransferase 
ATC 
Anatomical Therapeutic Chemical (drug classification system) 
BPI 
Brief Pain Inventory 
COVID-19 
coronavirus disease 2019 
CR 
complete response 
CSF1 
colony-stimulating factor 1 
CSF1R 
colony-stimulating factor 1 receptor 
DMC 
Data Monitoring Committee 
ECG 
electrocardiogram 
eCRF 
electronic case report form 
EDC 
electronic data capture 
ET 
early termination 
FDA 
US Food and Drug Administration 
FSH 
follicle-stimulating hormone 
GCP 
Good Clinical Practice 
HEENT 
head, eyes, ears, nose, throat 
HIPAA 
Health Insurance Portability & Accountability Act 
ICF 
informed consent form 
ICH 
International Council for Harmonisation of Technical Requirements for 
Pharmaceuticals for Human Use 
IEC 
Independent Ethics Committee 
IRB 
Institutional Review Board 
IUD 
intrauterine device 
IUS 
intrauterine hormone-releasing system 
IV 
intravenous 
IWRS 
interactive web response system 
MedDRA 
Medical Dictionary for Regulatory Activities 
MRI 
magnetic resonance imaging 
NRS 
numeric rating scale 
OR 
overall response 
PD 
pharmacodynamic(s) 
PI 
principal investigator: the investigator who leads study conduct at an individual 
study center. Every study center has a principal investigator. 
PK 
pharmacokinetic(s) 
PR 
partial response 
PROMIS 
Patient-Reported Outcomes Measurement Information System 
PT 
Preferred Term 
RECIST 
Response Evaluation Criteria in Solid Tumors 
ROM 
range of motion 
SAE 
serious adverse event 
SAP 
statistical analysis plan 
SAS 
Statistical Analysis System 
SD 
standard deviation 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 11 
 
 
Abbreviation 
Definition 
SOC 
System Organ Class 
TEAE 
treatment-emergent adverse event 
TGCT 
tenosynovial giant cell tumor 
TVS 
tumor volume score 
UDS 
urine drug screen 
ULN 
upper limit of normal 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 12 
 
 
1. 
PROTOCOL SUMMARY 
1.1. 
Protocol Synopsis 
Protocol 
Number 
AMB-051-01 
Study Title 
An Adaptive, Multicenter, Open-Label Study to Evaluate the Safety, 
Tolerability, Efficacy, and Pharmacokinetics of Intra-articular AMB-05X 
Injections in Subjects with Tenosynovial Giant Cell Tumor of the Knee 
Investigational 
Product  
AMB-05X drug substance is a human monoclonal antibody against the 
colony-stimulating factor 1 receptor (CSF1R). Study drug is packaged as a 
 of  mL of 
mg/mL in 
mL glass vials. 
Development 
Phase 
Phase 2 
Duration of 
Trial 
Approximately 28 weeks of participation for each subject. This includes up to 
4 weeks for screening, 12 weeks for dosing, and 12 weeks for post-treatment 
safety and efficacy evaluation. 
Study 
Objective 
Obtain safety and efficacy data for the investigational drug AMB-05X in the 
treatment of tenosynovial giant cell tumor (TGCT) 
Primary 
Outcome 
Measure 
Frequency and severity of reported treatment-emergent adverse events 
(TEAEs) 
Secondary 
Outcome 
Measures 
 
1. The proportion of subjects who achieve an overall tumor response 
(objective response [OR], which includes both complete response [CR] 
and partial response [PR]), per the Response Evaluation Criteria in Solid 
Tumors Version 1.1 (RECIST 1.1) (Eisenhauer, 2009) at Week 12 
2. Proportion of subjects with overall response based on tumor volume 
score (TVS), a TGCT–specific method that calculates tumor volume as a 
percentage of the estimated maximally distended synovial activity 
3. Mean change from Baseline in range of motion (ROM)  
4. Mean change from Baseline in the Patient-Reported Outcomes 
Measurement Information System (PROMIS) Physical Function score  
5. Mean change from Baseline in Worst Stiffness Numeric Rating Scale 
(NRS) score 
6. Percentage of subjects who respond with a decrease of at least 30% in 
mean Brief Pain Inventory (BPI) score 
7. Mean change from Baseline in BPI  
8. Mean change from Baseline in Worst Pain NRS score 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 13 
 
 
9. EQ-5D-5L Health Assessment 
10. Serum and synovial CSF1 levels 
11. Serum and synovial AMB-05X levels 
12. Serum and synovial anti-AMB-05X antibody levels 
Study Design 
This is a multicenter study with an adaptive design that will enroll 
approximately 12 subjects with TGCT of the knee for 12 weeks of multiple-
dose, open-label treatment with AMB-05X.  
The study schema is provided in Section 1.2, and the Schedule of Events is 
provided in Section 1.3. There will be a screening period of up to 4 weeks, a 
treatment period of 12 weeks, and a post-treatment follow-up period of 
12 weeks. Clinic visits will occur at Screening (Visit 1, within 4 weeks prior 
to Baseline); Baseline/Week 0 (Visit 2, when subjects receive their first 
injection of AMB-05X); Week 2 (Visit 3); Week 4 (Visit 4); Week 6 (Visit 
5); Week 8 (Visit 6); Week 10 (Visit 7, when subjects receive their last 
injection of AMB-05X); Week 12 (Visit 8, end of treatment period and 
assessment of primary and secondary endpoints); Week 14 (Visit 9, for post-
treatment follow-up 2 weeks after completing the treatment period); and 
Week 24 (Visit 10, for final post-treatment follow-up 12 weeks after 
completing the treatment period). 
The study will begin dosing AMB-05X at 150 mg administered via intra-
articular injection to the affected knee joint. Subjects will receive an injection 
of AMB-05X once every 2 weeks for 12 weeks (for 6 treatments total). 
Safety, pharmacokinetics (PK), pharmacodynamics (PD), and efficacy 
assessments will be reviewed by the Sponsor on a continuous, subject-by-
subject basis to determine whether the assigned dose is appropriate. 
Depending on these results, the Sponsor may either decrease the dosage 
strength to 90 mg or increase the dosage strength to 210 mg in subsequent 
subjects who enroll. In general, subjects are expected to complete the study at 
the dose strength which they started the study, unless they experience a 
clinically significant AE that would warrant a dose reduction. As a general 
rule, clinically significant AEs include, but are not limited to, any AE 
considered to be at least possibly related to study drug and severe in intensity 
or meets the criteria for a SAE. Subjects who are unable to tolerate a dosage 
strength of 90 mg will be withdrawn from the study. 
When at least 3 subjects have completed Week 6, a data monitoring 
committee (DMC) will review the available safety, tolerability, PK, PD, and 
efficacy data. Study enrollment and conduct may continue unchanged during 
DMC review. Based on the recommendations of the DMC, the Sponsor may 
then implement any one of the following adaptive changes without a protocol 
amendment: 
• Continuation of enrollment under the existing design, without any 
changes to the study. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 14 
 
 
• Continuation of enrollment with a new dose. Specifically, the DMC may 
recommend a dose reduction to 90 mg or a dose increase to 210 mg in 
subsequent subjects. Subjects may not exceed a dose of 210 mg or go 
below a dose of 90 mg. Subjects who are unable to tolerate a dose of 90 
mg will be discontinued from the study. 
• Discontinuation of further enrollment and/or suspension/termination of 
the study. 
Thereafter, the DMC should continue to review available data on a regular 
basis throughout the study (each time 3 subjects complete study treatment) 
and provide ongoing recommendations regarding appropriate next steps in 
study conduct (as outlined above). If a change in dose is made during the 
study, the DMC will again review the available data when 3 subjects have 
completed Week 6 at the new dose and provide further recommendations as 
outlined above. 
Dosage and 
Administration 
The study will begin dosing AMB-05X at 150 mg administered via intra-
articular injection to the affected knee joint as described in Section 8. 
Subjects will receive an injection of AMB-05X once every 2 weeks for 12 
weeks (for 6 treatments total). A total of 3 dose levels are permitted in this 
study: 90 mg, 150 mg, and 210 mg. Based on ongoing review of the available 
safety, PK, PD, and efficacy data, the Sponsor may decrease the dose to 
90 mg or increase the dose to 210 mg in subsequent subjects. 
Study drug will be administered at the study center by qualified study staff. 
Subjects will remain at the study center for a minimum of 90 minutes after 
dosing to monitor for any adverse reactions, including any injection-site 
reactions. 
Assessments 
Safety and Tolerability 
Safety and tolerability will be assessed on an ongoing basis by monitoring 
adverse events (AEs) (including any serious AEs [SAEs], AEs leading to 
withdrawal, injection-site reactions [ISRs], and any other dose-limiting 
toxicities [DLTs]), physical examinations/vital signs, changes in clinical 
laboratory values, and ECG results. 
A DMC composed of qualified medical/clinical representatives will review 
the clinical data and will provide recommendations to the Sponsor regarding 
the acceptability of continued enrollment in the study and whether any 
modifications are warranted. 
Efficacy 
1. OR will be centrally assessed from magnetic resonance imaging (MRI) 
scans using RECIST v1.1 (Eisenhauer, 2009). A CR is defined as 
disappearance of all tumors, and a PR is defined as at least a 30% 
decrease in the sum of diameters of target tumors from the baseline sum 
of diameters. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 15 
 
 
2. TVS is a semi-quantitative MRI scoring system that describes tumor 
mass and is based on 10% increments in the estimated volume of the 
maximally distended synovial cavity or tendon sheath involved. A score 
of 0 indicates no evidence of tumor; a score of 10 indicates a tumor that 
is equal in volume to that of a maximally distended synovial cavity or 
tendon sheath. The overall number of responses and the number of 
subjects with and without disease progression will be assessed. 
3. ROM of the joint will be assessed by qualified assessors at the clinical 
site. Measurements will be recorded in degrees. At baseline, the plane of 
movement with the smallest (worst) relative value will be identified; only 
this plane will be used for evaluating change in ROM subsequently. 
4. The PROMIS Physical Function Scale will be used to assess physical 
function of the upper and lower limbs. The scale ranges from 1 ('unable 
to do' or 'cannot do') to 5 ('without any difficulty' or 'not at all'), where 
higher scores represent better outcomes. 
5. The Worst Stiffness NRS is a 1-item, self-administered questionnaire 
assessing the "worst" stiffness within the last 24 hours. The NRS for this 
item ranges from 0 (no stiffness) to 10 (stiffness as bad as you can 
imagine). 
6. The Worst Pain NRS is a component of the Brief Pain Inventory 
assessing the "worst" pain in the last 24 hours. The NRS for this item 
ranges from 0 (no pain) to 10 (pain as bad as you can imagine). 
7. Brief Pain Inventory (BPI) Short Form is a self-administered 
questionnaire used to evaluate the severity of a subject's pain and the 
impact of this pain on the subject's daily functioning. The subject is 
asked to rate their worst, least, average, and current pain intensity, list 
current treatments and their perceived effectiveness, and rate the degree 
that pain interferes with general activity, mood, walking ability, normal 
work, relations with other persons, sleep, and enjoyment of life on a scale 
from 0 to 10. 
8. EQ-5D-5L is a widely used quality of life instrument that includes 
questions in each of 5 domains: mobility, self-care, usual activities, 
pain/discomfort, and anxiety/depression. The choices include 5 levels of 
severity for each domain followed by a general health visual analogue 
scale (VAS). 
Pharmacokinetics/Pharmacodynamics 
Serum AMB-05X concentrations will be measured at Week 0 (pre-dose and 
2 hours after the first dose), Week 2 (pre-dose [trough]), and Week 10 during 
steady state (including pre-dose [trough] and 2 hour after the last dose).  
Synovial AMB-05X concentrations will be measured at Weeks 0, 2, 4, 6, 8, 
and 10 (all at pre-dose [trough]). Anti-drug antibody analysis will also be 
performed on select serum and synovial samples. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 16 
 
 
Serum and synovial fluid CSF1 levels will be analyzed as a biomarker. 
Study 
Population 
This study will enroll approximately 12 male and female adult subjects with 
local or diffuse TGCT of the knee.  
Inclusion 
Criteria 
 
A subject may be included if ALL of the following criteria are met: 
1. Subject ≥ 18 years must be able to communicate well with study staff, 
understand and comply with the requirements of the study, and read and 
voluntarily sign the ICF and the Health Insurance Portability and 
Accountability Act (HIPAA) authorization, if applicable, prior to the 
conduct of any study specific procedures.  
2. A diagnosis of TGCT of the knee joint that has been histologically 
confirmed either by a pathologist at the treating institution or by a central 
pathologist. If not previously confirmed, biopsy with histological 
confirmation is required. 
3. Measurable disease of at least 1 cm based on RECIST v1.1, assessed 
from MRI scans by a central radiologist. Subjects with one knee joint 
involvement only, and only limited posterior extra-articular nodular 
TGCT lesions as assessed by central radiologist and tumor review 
committee. 
4. Stable prescription of analgesic regimen during the 2 weeks before 
Baseline 
5. Negative urine drug screen (UDS) at Screening and Baseline 
6. Women of childbearing potential must have a negative serum pregnancy 
test at Screening and a negative urine pregnancy test at Baseline. 
7. Agrees to follow contraception guidelines (see Section 5.3) 
8. Adequate hematologic, hepatic, and renal function, at Screening Visit 
defined by: 
• Absolute neutrophil count ≥ 1.5 × 109/L 
• Aspartate aminotransferase (AST) or alanine aminotransferase 
(ALT) ≤ 1.5 × upper limit of normal (ULN)  
• Hemoglobin > 10 g/dL 
• Total bilirubin ≤ 1.5 × ULN  
• Platelet count ≥ 100 × 109/L  
• Serum creatinine ≤ 1.5 × ULN 
9. Willing and able to complete the Brief Pain Inventory (BPI), Worst 
Stiffness NRS item, PROMIS Physical Function Scale, EQ-5D-5L, and 
other self-assessment instruments throughout the study 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 17 
 
 
Exclusion 
Criteria 
 
A subject will be excluded if ANY of the following criteria is met:  
1. Prior investigational drug use within 4 weeks or 5 half-lives (whichever 
is longer) before Baseline 
2. Use of pexidartinib, any other oral tyrosine kinase inhibitors (e.g., 
imatinib or nilotinib), or any biologic treatment targeting CSF1 or 
CSF1R within 3 months before Baseline 
3. History of extensive or reconstructive knee surgery, except for prior 
diagnostic synovectomy, which is not exclusionary if at least 3 months 
prior to Baseline 
4. Active cancer (either currently or within 1 year before Baseline) that 
requires therapy (e.g., surgery, chemotherapy, or radiation therapy), with 
the exception of adequately treated basal or squamous cell carcinoma of 
the skin, melanoma in situ, carcinoma in situ of the cervix or breast, or 
prostate carcinoma not requiring treatment apart from active surveillance 
5. Known metastatic TGCT  
6. Hepatitis C virus (HCV) or hepatitis B virus (HBV) or known active or 
chronic infection with human immunodeficiency virus (HIV) 
7. Known active tuberculosis 
8. Significant concomitant arthropathy in the affected joint, serious illness, 
uncontrolled infection, or a medical or psychiatric history that, in the 
Investigator's opinion, would likely interfere with the subject’s study 
participation or the interpretation of his or her results 
9. Women who are breastfeeding 
10. A screening Fridericia-corrected QT interval (QTcF) ≥ 450 ms (men) or 
≥ 470 ms (women) 
11. MRI contraindications (e.g., pacemaker, loose metallic implants) 
12. History of hypersensitivity to any ingredient of the study drug 
13. History of drug or alcohol abuse within 3 months before the first dose of 
study drug 
14. Any other severe acute or chronic medical or psychiatric condition or 
clinically significant laboratory abnormality that may increase the risk 
associated with study participation/treatment or interfere with 
interpretation of study results and, in the Investigator’s opinion, make the 
subject inappropriate for this study 
15. Subjects who, in the Investigator’s opinion, should not participate in the 
study for any reason, including if there is a question about their ability to 
comply with study requirements 
Statistical 
Methods 
 
Sample Size Determination 
Based on prior Phase 1 experience and an anticipated treatment effect with 
AMB-05X in this population, the sample size of approximately 12 subjects is 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 18 
 
 
anticipated to provide sufficient data for PK/PD analysis and an estimate of 
safety, tolerability, and efficacy. 
Analysis Methods 
All study data will be summarized by treatment using descriptive statistics. 
Safety Analyses 
Safety analyses will include all subjects who received at least 1 dose of study 
drug.  
All AEs reported will be listed, documenting severity, start and stop date and 
time, possible relationship to study drug, action taken, and outcome. TEAEs 
are defined as AEs recorded after the first dose of study drug. Verbatim terms 
will be mapped to Preferred Terms (PTs) and related System Organ Classes 
(SOCs) using the Medical Dictionary for Regulatory Activities (MedDRA). 
PTs and SOCs will be tabulated by treatment group. All reported AEs will be 
summarized by the number of subjects reporting AEs, SOC, PT, severity, and 
relationship to study drug. 
Safety labs (including hematology, chemistry, and urinalysis), vital signs, 
tolerability data, and ECGs will be tabulated using descriptive statistics. 
Abnormal/out-of-range findings and changes from pre-dose to post-dose will 
be listed by subject. Shift tables will be provided for all laboratory variables. 
Efficacy Analyses  
Efficacy endpoints will be summarized using descriptive statistics and 95% 
confidence intervals. Exploratory hypotheses testing may be conducted using 
a significance level of 0.05 without adjustment for multiplicity. 
Pharmacokinetic Analyses  
AMB-05X concentration data will be summarized by collection time. PK 
parameters will be deduced where possible by WinNonlin analysis. 
 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 22 
 
 
2. 
INTRODUCTION 
2.1. 
Tenosynovial Giant Cell Tumor 
Tenosynovial giant cell tumor (TGCT), also known as giant cell tumor of the tendon sheath 
(GCT-TS) or pigmented villonodular synovitis (PVNS), is a rare, locally aggressive and 
destructive, mesenchymal neoplasm that arises in the synovium of joints, bursae, or tendon 
sheaths (Staals, 2016; de Saint Aubain Somerhausen, 2013).  
TGCTs are caused by the abnormal expression of colony-stimulating factor 1 (CSF1) as a result 
of genomic mutations (balanced translocations) at the CSF1 gene locus of chromosome 1p13 
(West, 2006; Cupp, 2007). This translocation results in the dysregulation of CSF1 and 
COL6A3.8 CSF1 (Ohjimi,1996; Mertens, 1993) leading to excessive production of CSF1. CSF1 
acts at the CSF1 receptor (CSF1R) resulting in the proliferation of synovial-like mononuclear 
cells and recruitment of multinucleate giant cells, foam cells, siderophages, and inflammatory 
cells, which compose the bulk of the neoplasm (de Saint Aubain Somerhausen, 2013; West, 
2006; Cupp, 2007). Although TGCTs are nonmetastatic in nature, they can develop into locally 
destructive lesions causing significant local tissue injury, loss of joint function, and impaired 
quality of life (West, 2006). 
The annual incidence of TGCT is estimated to be ~43 cases per 1 million individuals, with 
approximately 40,000 new cases per year in the US and Europe combined (Ehrenstein, 2017; 
Mastboom, 2017). Two TGCT subtypes have generally been recognized: localized (l-TGCT) and 
diffuse (d-TGCT). Approximately 10% of TGCT are classified as diffuse (Mastboom, 2017). 
Regardless of subtype, TGCT nearly always involves a single joint, with the knee being the most 
commonly affected (up to 66–80%), followed by the ankle, elbow, shoulder, wrist/hand, and hip 
(Murphey, 2008).  
TGCT most commonly affects individuals between 20-50 years of age and presents clinically as 
a joint swelling or a firm, slowly-enlarging mass (Ostuni, 2015). As the disease advances, 
patients experience attacks of pain, swelling, loss of range-of-motion, hemorrhagic joint 
effusions, cartilage destruction, leading to eventual loss of joint function, impaired quality of life, 
and severe morbidity (Tap, 2019; Giustini, 2018). 
The standard of care in TGCT is surgical resection via synovectomy (Granowitz, 1976). 
However, recurrence after surgery is common and occurs in up to 55% of patients with the 
diffuse subtype (Mastboom, 2017; Staals, 2016; Brahmi, 2016; Palmerini, 2015). Repeated 
surgeries may be necessary but often lead to further morbidity, complications, and reduced 
function of affected joints (Staals, 2016). Radiotherapy is occasionally used, typically for larger 
joints with diffuse lesions, but their use is limited due to late sequela (Benner, 2020).  
Persistent disease can cause cartilage destruction and bone erosion, in addition to functional 
limitations from long-term pain, swelling, and limitations to range-of-motion. Joint replacement 
or even amputation might be necessary in these cases (Staals, 2016). While TGCT is not lethal, it 
is a serious, chronic debilitating illness with long term consequences for joint function and 
quality of life (Mastboom, 2017). 
In late 2019, pexidartinib, an oral small molecule tyrosine-kinase inhibitor with activity against 
CSF1R was approved by the US Food and Drug Administration for the treatment of adult 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 23 
 
 
patients with symptomatic TGCT with severe morbidity/functional limitations, not amenable to 
surgery (Turalio™ US FDA Package Insert, 2019). Results from the Phase 3 ENLIVEN study 
showed that pexidartinib was superior to placebo in achieving overall responses per RECIST 
criteria (39% vs. 0%; p<0.0001). However, systemic side effects including serious/life 
threatening cases of mixed or cholestatic hepatotoxicity were observed and remains a concern 
among patients treated with pexidartinib (Tap, 2019; Gelderblom, 2020).  
The viability of CSF1R inhibition as treatment modality was further established in an early-stage 
clinical trial in TGCT patients evaluating emactuzumab, a monoclonal antibody that targets 
CSF1R (Cassier, 2015). Following systemic (IV) administration, 86% of patients achieved an 
objective response associated with early onset of symptomatic and functional improvement.  
In summary, TGCT is a rare but serious, debilitating chronic illness with limited treatment 
options. Given the limitations of current treatment options, the localized nature of the disease, 
and prior clinical validation of CSF1R as an effective treatment target, AmMax Bio, Inc. is 
developing AMB-05X, a human monoclonal antibody inhibiting the CSF1R, as a direct, local 
injectable therapeutic for the treatment of TGCT. 
2.2. 
AMB-05X 
AMB-05X is an antagonistic fully human antibody (immunoglobulin G, type 2 [IgG2]) specific 
to the extracellular domain of human c-fms (CSF1R). It potently blocks both CSF1- and IL-34–
mediated proliferation of growth factor–dependent human myelomonocytic cells in vitro and 
also effectively interacts with the monkey receptor but not other species such as rodents. 
2.3. 
Summary of Nonclinical Data 
 
Pharmacology 
AMB-05X binds with high affinity to c-fms expressed on the surface of human myelomonocytic 
cells (AML-5 cells) and to cynomolgus monkey c-fms expressed on the surface of human 
embryonic kidney cells transformed by adenovirus (2936E cells). 
AMB-05X inhibits CSF1-induced phosphorylation of human c-fms. In addition, this antibody 
caused immunoprecipitation of human c-fms and its known single nucleotide polymorphism 
(SNP) variants. AMB-05X potently inhibits CSF1-driven proliferation of both human and 
cynomolgus monkey primary-bone-marrow-derived monocyte/macrophage cells in vitro as well 
as CSF1- and IL-34–driven proliferation of human myelomonocytic AML-5 cells. 
AMB-05X does not cross-react with mouse c-fms. Therefore, a surrogate anti-mouse c-fms 
antibody, M279, was developed and tested for activity to be used in nonclinical tumor model 
studies in mice. This antibody, in an analogous manner to AMB-05X, potently and specifically 
inhibits c-fms-mediated activity in vitro. In vivo, M279 significantly inhibited the growth of a 
variety of xenograft and syngeneic tumor models, including MDA-MB-231 (human breast 
adenocarcinoma), Renca (mouse renal cell carcinoma, syngeneic), and NCI-H1650 and NCI-
H1975 (human non-small-cell lung carcinomas) tumor models by 50% to 70% based on tumor 
volume. In addition, TAM content in all tumors treated with M279 compared with control-
treated was shown to be significantly decreased by a variety of methods, including 
immunohistochemistry (IHC), flow cytometry, and immunofluorescence. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 24 
 
 
 
Pharmacokinetics 
In cynomolgus monkeys, exposure to AMB-05X showed a nonlinear increase at single 
intravenous (IV) doses of 0.1 to 5 mg/kg but was approximately dose proportional in the dose 
range of 5 to 100 mg/kg. When the receptor-mediated clearance had been saturated at higher 
serum concentrations of AMB-05X 
 μg/mL), the kinetics of this protein became linear. 
The volume of distribution at steady state for AMB-05X in monkeys was approximately equal to 
plasma volume, indicating limited extravascular distribution. 
Toxicokinetics (TK) of AMB-05X, as assessed in both the 4-week and 14-week repeat-dose 
toxicity studies, did not differ markedly between male and female monkeys. In general, exposure 
to AMB-05X increased approximately dose proportionally in monkeys over the dose range of 10 
to 300 mg/kg. No marked (> 2-fold) accumulation of AMB-05X was observed after 4 or 13 
once-weekly doses in monkeys. During the dosing phase of these studies, treatment-associated 
anti-AMB-05X-binding antibodies (ADAs) in monkeys administered AMB-05X were detected 
in 1 of 30 animals in the 4-week study and 13 of 35 animals in the 14-week study; during the 
recovery phase of the 14-week study, ADAs were detected in 8 of 10 animals. In general, ADAs 
decreased the exposure of AMB-05X in these animals. For both studies, high concentrations of 
AMB-05X in the serum samples may have interfered with detection of ADAs in animals that 
tested ADA-negative. 
 
Toxicology 
In the in vivo toxicology studies in the cynomolgus monkey, animals received up to 300 mg/kg, 
IV, weekly for 4 or 14 weeks. In the 4-week and in both 14-week studies, all direct AMB-05X-
related findings were attributed to the expected pharmacology of inhibition of macrophages. 
Additionally, changes related to the acute post-dosing formation of ADA/drug complex (also 
called circulating immune complexes [CICs]) occurred in some animals on the 14-week study. 
Clinical observations attributed to AMB-05X pharmacology consisted of reversible periorbital 
swelling due to increased extracellular matrix as observed by light microscopy. Clinical 
pathology changes included reversible increases in serum ALT, AST, and glutamate 
dehydrogenase (GLDH) without a light microscopic correlate in the liver and without elevations 
in sorbitol dehydrogenase (SDH), a liver-specific marker of injury. The increased extracellular 
matrix and elevated activities of serum enzymes are considered to result from decreased 
clearance due to inhibition of macrophages (Radi, 2011). Additional AMB-05X-related changes 
included decreased bone turnover, characterized by elongation of bone growth plates and 
decreased number of osteoclasts, and decreases in serum markers of bone turnover, both of 
which were reversible. The presence of yeast organisms in the lung and protozoal organisms in 
the gastrointestinal tract in a few animals (contributing to death in 1 animal) may be incidental or 
a pharmacologic effect of AMB-05X. Increased neutrophil counts occurred in association with 
myeloid hyperplasia. 
During the last 2 months of the dosing phase in the 14-week study, acute post-dosing sequelae 
(platelet effects and clinical signs including death) were observed in ADA-positive animals at 10 
and 50 mg/kg. The role of ADA/drug complexes in the acute post-dosing findings was confirmed 
by demonstration of ADA/drug complexes serologically and immunohistochemically. No post-
dosing CICs or related effects occurred at 300 mg/kg. Retrospective analyses correlating 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 27 
 
 
Serious adverse events were reported for 11 subjects (44%), adverse events leading to study 
discontinuation were reported for 4 subjects (16%), and adverse events leading to withdrawal 
from investigational product were reported for 5 subjects (20%). Fatal adverse events were 
reported for 3 subjects (12%); the events occurred in the setting of progressive disease and were 
considered not related to treatment with AMB-05X by the investigators. 
Adverse events considered treatment-related by the investigator were reported by 19 subjects 
(76%). Periorbital edema (without clinical sequelae) was the most common treatment-related 
adverse event (11 subjects, [44%]), the majority of events resolved and were managed without 
intervention. Aspartate aminotransferase increased was also a common treatment-related adverse 
event (7 subjects, [28%]). Seven subjects (28%) had treatment-related adverse events that were ≥ 
Grade 3 in severity, and one subject (4%) discontinued AMB-05X due to a treatment-related 
adverse event (the above-mentioned bilateral deafness DLT). There were no treatment-related 
serious or fatal adverse events. 
Macrophages were quantitated on skin biopsies as an indicator of pharmacologic effect. In all 
subjects in the 10-mg/kg and 20-mg/kg dose groups who had available skin biopsy data, 
reductions from baseline in macrophages, as indicated by positive staining for CD68 and/or 
CD163, were observed at week 5. 
2.4.1.2. 
Combination Study with Pembrolizumab 
The primary objective of Study 20150195 was to evaluate the safety, tolerability, and objective 
response rate (ORR) of AMB-05X administered in combination with pembrolizumab in subjects 
with select advanced solid tumors. 
This study was conducted in 2 parts. Part 1 (phase 1b) evaluated the safety of AMB-05X in 
combination with pembrolizumab using a 6+3 design. The starting dose was 1400 mg AMB-05X 
plus 200 mg pembrolizumab every 3 weeks (Q3W). Part 2 (phase 2) further evaluated the safety 
and tested whether AMB-05X could enhance the antitumor activity observed historically with 
pembrolizumab alone and/or overcome lack of response to pembrolizumab monotherapy in 
subjects with select solid tumors. 
A total of 15 subjects were enrolled in part 1 of the study, all of whom received ≥ 1 dose of 
AMB-05X and pembrolizumab. Subjects were treated with AMB-05X and pembrolizumab for a 
mean (SD) of 0.8 (0.7) months. In part 2 of the study, 101 subjects were enrolled all of whom 
received ≥ 1 dose of AMB-05X and pembrolizumab. Ninety (90) subjects received AMB-05X 
1100 mg every 3 weeks plus pembrolizumab 200 mg every 3 weeks and 11 subjects received 
AMB-05X 1400 mg every 3 weeks plus pembrolizumab 200 mg every 3 weeks. Subjects were 
treated with AMB-05X and pembrolizumab for a mean (SD) of 1.6 (2.5) months. 
The objective response rate was 0% in Part 1 and 3.0% in Part 2. 
PK results from a total of 116 subjects were available from the study. Following administration 
in cycles 1 and 2, AMB-05X exposures increased in an approximately dose-proportional manner 
over the dose range of 1100 to 1400 mg. Mean Cmax and mean AUC over the dosing interval  
(AUC) increased by 1.4- and 1.5-fold, respectively, in cycle 1 and 1.4-fold and 1.5-fold, 
respectively, in cycle 2, for a 1.3-fold increase in dose. Median time to reach Cmax (tmax) values 
ranged from 2.0 to 3.0 hours postdose in cycles 1 and 2. No significant serum accumulation of 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 28 
 
 
AMB-05X was observed in subjects between cycles 1 and 2 with mean accumulation ratio for 
AUC ranging from 1.25 to 1.27. 
In Part 1, one subject (14.3%) in the AMB-05X 1400 mg plus pembrolizumab 200 mg group had 
dose-limiting toxicities (DLTs) of autoimmune pancreatitis, autoimmune hepatitis, cholecystitis, 
and electrolyte imbalance, after which the AMB-05X dose was decreased to 1100 mg. No 
subject in the AMB-05X 1100 mg plus pembrolizumab 200 mg group had a DLT. All subjects 
had ≥1 TEAE. The most common adverse events were fatigue (66.7%), aspartate 
aminotransferase increased (60.0%), periorbital edema (53.3%), decreased appetite and diarrhea 
(each in 33.3% of subjects), and dyspnea, hypophosphatemia, nausea, and pyrexia (each in 
26.7% of subjects). A total of 14 subjects (93.3%) had events that were ≥ Grade 3, including 6 
subjects (40.0%) who had Grade 4 events and 5 subjects (33.3%) who had fatal (Grade 5) 
adverse events. All of the fatal (Grade 5) adverse events were not considered related to study 
treatment. Seven subjects (46.7%) had ≥1 SAEs, none of which occurred in more than 1 subject. 
Adverse events considered treatment-related to AMB-05X were reported in 12 subjects (80.0%). 
The most common AMB-05X–related adverse events were periorbital edema and aspartate 
aminotransferase increased (each in 46.7% of subjects) and fatigue (26.7%). No subject had a 
TEAE leading to withdrawal of investigational product. No clinically relevant trends in 
hematology, serum chemistry, or urinalysis laboratory values were reported. 
In Part 2, 6 subjects (5.9%) who received AMB-05X 1100 mg plus pembrolizumab 200 mg had 
DLTs of aspartate aminotransferase increased (2 subjects) and fatigue, lipase increased, epilepsy, 
rash generalized, and rash maculo-papular (1 subject each). All subjects (100.0%) had ≥1 TEAA. 
The most common adverse events were fatigue (53.5%), periorbital edema (39.6%), anemia 
(37.6%), nausea (29.7%), constipation (28.7%), pyrexia (26.7%), and decreased appetite and 
rash (each in 25.7% of subjects). A total of 99 subjects (98.0%) had events that were ≥ Grade 3, 
including 68 subjects (67.3%) who had Grade 4 events and 57 subjects (56.4%) who had fatal 
(Grade 5) adverse events. Of the fatal (Grade 5) adverse events, only tumor flare and 
pneumonitis (1 subject each) were considered related to study treatment. Seventy-three subjects 
(72.3%) had ≥1 or more SAEs. The most common SAEs were pyrexia (6.9%) and pneumonia 
and urinary tract infection (each in 5.0% of subjects). TEAEs considered treatment-related to 
AMB-05X were reported in 90 subjects (89.1%) and 86 subjects (85.1%), respectively. The most 
common AMB-05X–related adverse events were aspartate aminotransferase increased (53.5%), 
periorbital edema (38.6%), and fatigue (30.7%). Seventeen subjects (16.8%) had a treatment-
emergent adverse event leading to withdrawal of investigational product. The only treatment-
emergent adverse events leading to withdrawal reported in more than 1 subject were periorbital 
edema and pneumonitis (2 subjects each). During the study, 4 subjects (4.0%) treated with 
AMB-05X and pembrolizumab had liver function test results that potentially met the criteria of 
Hy’s Law (ALT or AST > 3 x ULN and total bilirubin> 2 x ULN and alkaline phosphatase < 2 x 
ULN). After further evaluation, none of the subjects met the definitive criteria for Hy’s law. No 
clinically relevant trends in hematology, serum chemistry, or urinalysis laboratory values were 
reported. 
 
Intra-articular Administration of Antibodies in Clinical Studies 
There are multiple reports of the intra-articular administration of antibodies, typically into the 
knee for arthritic conditions, at doses ranging 10-600 mg (more commonly 100-150 mg) which 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 29 
 
 
have been generally well-tolerated (Evans, 2014; Wang, 2018). Notably, there is also a case 
report for 100 mg bevacizumab (AvastinR, anti-VEGF) administered monthly for 1 year intra-
articular to the knee of a GCT patient with no adverse local nor systemic effects (Nissen, 2014).  
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 30 
 
 
3. 
STUDY OBJECTIVES AND ENDPOINTS 
The objectives of this study are to evaluate the safety and efficacy of AB-05X post intra-articular 
injection of 150 mg biweekly for up to 12 weeks in the treatment of TGCT. 
3.1. 
Primary Endpoint 
The primary outcome measure is the frequency and severity of reported TEAEs. 
3.2. 
Secondary Endpoints 
1. The proportion of subjects who achieve an overall tumor response (objective response 
[OR], which includes both complete response [CR] and partial response [PR]), per the 
Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1) (Eisenhauer, 
2009) at Week 12 
2. Proportion of subjects with overall response based on TVS, a TGCT-specific method that 
calculates tumor volume as a percentage of the estimated maximally distended synovial 
activity 
3. Mean change from Baseline in ROM score 
4. Mean change from Baseline in the PROMIS Physical Function score  
5. Mean change from Baseline in Worst Stiffness NRS score 
6. Percentage of subjects who respond with a decrease of at least 30% in mean BPI score 
7. Mean change from Baseline in BPI  
8. Mean change from Baseline in Worst Pain NRS score 
9. EQ-5D-5L Health Assessment 
10. Serum and synovial CSF1 levels 
11. Serum and synovial AMB-05X levels 
12. Serum and synovial anti-AMB-05X antibody levels 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 31 
 
 
4. 
INVESTIGATIONAL PLAN 
4.1. 
Overall Study Design 
This is a Phase 2, multicenter study with an adaptive design that will enroll approximately 12 
subjects with TGCT of the knee for 12 weeks of multiple-dose, open-label treatment with 
AMB-05X. 
The study schema is provided in Section 1.2, and the Schedule of Events is provided in Section 
1.3. The subject will sign an informed consent prior to any study screening activities. There will 
be a screening period of up to 4 weeks, a treatment period of 12 weeks, and a post-treatment 
follow-up period of 12 weeks. Clinic visits will occur at Screening (Visit 1; within 4 weeks prior 
to Baseline); Baseline/Week 0 (Visit 2; when subjects receive their first injection of AMB-05X); 
Week 2 (Visit 3); Week 4 (Visit 4); Week 6 (Visit 5); Week 8 (Visit 6); Week 10 (Visit 7, when 
subjects receive their last injection of AMB-05X); Week 12 (Visit 8, end of treatment period and 
assessment of primary and secondary efficacy endpoints); Week 14 (Visit 9, for post-treatment 
follow-up 2 weeks after completing the treatment period); and Week 24 (Visit 10, for final post-
treatment follow-up 12 weeks after completing the treatment period). 
The study will begin dosing AMB-05X at 150 mg administered via intra-articular injection to the 
affected knee joint. Subjects will receive an injection of AMB-05X once every 2 weeks for 12 
weeks (for 6 treatments total). 
Tumor assessment via centrally read MRI will be performed at Screening and Weeks 6, 12, and 
24. Worst pain NRS, worst stiffness NRS, PROMIS, BPI, and joint ROM will be evaluated 
periodically throughout the study.  
Safety will be characterized, including reported AEs and SAEs and changes in physical 
examinations, vital signs, clinical laboratory studies (including pregnancy testing for females of 
childbearing potential), and ECGs.  
For PK, serum AMB-05X concentrations will be measured at Week 0 (pre-dose and 2 hours after 
first dose), Week 2 (pre-dose [trough]), and Week 10 during steady state (including pre-dose 
[trough] and 2 hours after the last dose). Synovial AMB-05X concentrations will be measured at 
pre-dose at Weeks 0, 2, 4, 6, 8, and 10. 
For PD, serum CSF1 levels will be measured at Week 0 (including pre-dose and 2 hours after 
first dose), Week 2 (pre-dose [trough]), and Week 10 during steady state (including pre-dose 
[trough] and 2 hours after the last dose). Synovial CSF1 levels will be measured at pre-dose at 
Weeks 0, 2, 4, 6, 8, and 10. 
Serum anti-AMB-05X antibody levels will be measured pre-dose at Week 0 and Week 10. 
Synovial anti-AMB-05X antibody levels will be measured pre-dose at Weeks 0, 4, and 10. 
Safety, PK, PD, and efficacy assessments will be reviewed by the Sponsor on a continuous, 
subject-by-subject basis to determine whether the assigned dose is appropriate. Depending on 
these results, the Sponsor may either decrease the dosage strength to 90 mg or increase the 
dosage strength to 210 mg in subsequent subjects who enroll. In general, subjects are expected to 
complete the study at the dose strength which they started the study, unless they experience a 
clinically significant AE that would warrant a dose reduction. As a general rule, clinically 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 32 
 
 
significant AEs include, but are not limited to, any AE considered to be at least possibly related 
to study drug and severe in intensity or meets the criteria for a SAE. Subjects who are unable to 
tolerate a dosage strength of 90 mg will be withdrawn from the study 
When at least 3 subjects have completed Week 6, a data monitoring committee (DMC) will 
review the available safety, tolerability, PK, PD, and efficacy data. Study enrollment and conduct 
may continue unchanged during DMC review. Based on the recommendations of the DMC, the 
Sponsor may then implement any one of the following adaptive changes without a protocol 
amendment: 
• Continuation of enrollment under the existing design, without any changes to the study. 
• Continuation of enrollment with a new dose or dose frequency criteria. Specifically, the 
DMC may recommend a dose reduction to 90 mg or a dose increase to 210 mg in 
subsequent subjects. Subjects may not exceed a dose of 210 mg or go below a dose of 90 
mg. Subjects who are unable to tolerate a dose of 90 mg will be discontinued from the 
study. 
• Discontinuation of further enrollment and/or suspension/termination of the study 
Thereafter, the DMC should continue to review available data on a regular basis throughout the 
study (each time 3 subjects complete study treatment) and provide ongoing recommendations 
regarding appropriate next steps in study conduct (as outlined above). If a change in dose is 
made during the study, the DMC will again review the available data when 3 subjects have 
completed Week 6 at the new dose and provide further recommendations as outlined above. 
Refer to Appendix 5 for potential changes to study conduct in the context of COVID-19 
(coronavirus disease 2019). 
4.2. 
Rationale for Dose Regimen and Duration of Treatment 
While AMB-05X has not been administered into the joints of TGCT patients, monoclonal 
antibodies (mAbs) have been used as intra-articular therapies at doses ranging from 10 to 
600 mg, albeit more commonly at 100 to 150 mg in adults (Wang, 2018; Evans, 2014; 
NCT01160822). Moreover, another anti-CSF1R mAb has demonstrated preliminary efficacy 
administered systemically to TGCT patients (Cassier, 2015) thus supporting the class approach. 
There is limited data in the literature on the synovial and systemic pharmacokinetics of 
antibodies following intra-articular administration, but based on the cynomolgus monkey results 
described above, published systemic PK with this mAb (Papadopoulos, 2017), and some 
published relevant modeling data (Stepensky, 2012), a projection of serum and synovial 
AMB-05X concentrations vs time following a first administration of 150 mg intra-articular is 
described in the figure below: 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 33 
 
 
 
 
The estimated systemic exposure is consistent with safe and well-tolerated regimens from the 
prior Phase 1 study and the synovial fluid concentrations are projected to remain well above an 
effective level throughout the 12-week, bimonthly dosing period.  
4.3. 
Number of Subjects 
This study will enroll approximately 12 male and female adult subjects with local or diffuse 
TGCT. 
4.4. 
Treatment Assignment 
This is an open-label study. Subjects will be initially assigned to receive 150 mg administered 
via intra-articular injection to the affected knee joint. Subjects will receive an injection of AMB-
05X once every 2 weeks for 12 weeks (for 6 treatments total). The Sponsor may decrease the 
dose to 90 mg or increase the dose to 210 mg in subsequent subjects based on its ongoing review 
of the available data. 
4.5. 
Subject and Study Early Termination 
 
End of Study Definition 
A subject is considered to have completed study treatment if the subject has completed all 12 
weeks of the treatment period. 
A subject is considered to have completed the study if the subject has completed all study visits 
required for that subject, including the last follow-up visit. 
The end of the study is defined as the date of the last study visit of the last subject in the study. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 34 
 
 
 
Subject Early Termination 
Subjects can choose to discontinue study participation at any time, for any reason, specified or 
unspecified, without prejudice. Subjects may be considered withdrawn and subject to ET 
procedures if they state an intention to withdraw, fail to return for visits, or become lost to 
follow-up for any other reason.  
The Investigator will terminate a subject’s study participation if the subject withdraws consent, 
the subject becomes pregnant, or the Investigator concludes that continuation would be 
detrimental to the subject’s safety or well-being. 
If a subject fails to appear for study visits without stating an intention to withdraw, the site must 
make every effort to regain contact with the subject, including making 3 telephone calls to the 
subject and, if necessary, sending a registered letter to the subject’s last known mailing address. 
Attempts to contact the subject will be documented in the subject’s site file. If the subject 
continues to be unreachable, the subject will be considered lost to follow-up. 
If ET occurs for any reason, the Investigator must make every effort to determine the primary 
reason for a subject’s early withdrawal from the study and record this information on the 
electronic case report form (eCRF). 
All subjects who receive study drug after enrollment at Visit 2 and discontinue prior to Visit 8 
should complete the procedures for Visit 8/ET and Visit 9 follow-up. Subjects who discontinue 
after Visit 8 should complete the procedures for Visit 9 follow-up. All subjects who complete 
study treatment should be encouraged to return for Visit 10 (12 weeks post-treatment). 
Reasons a subject may terminate participation early include: 
• 
Adverse event 
• 
Study terminated by Sponsor  
• 
Death 
• 
Lost to follow-up 
• 
Protocol violation 
• 
Lack of efficacy 
• 
Physician decision 
• 
Other, to be specified 
• 
Withdrawal of consent by the subject  
 
 
Study Premature Termination 
This study may be stopped prematurely, that is, before completion as defined in this protocol, by 
AmMax or a controlling regulatory authority if new information arises that suggests continuing 
the study may pose an undue risk to subject safety or well-being.  
AmMax will review emerging safety data to identify safety and tolerability signals. These data 
include AEs and their associated frequency and severity, TEAEs, SAEs, suspected unexpected 
serious adverse reactions, and clinically significant changes in laboratory results, ECGs, vital 
signs, and physical examinations.  
New nonclinical safety data will also be assessed and considered in decisions on termination.  

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 35 
 
 
5. 
SELECTION OF SUBJECTS 
This study will enroll approximately 12 qualified subjects  18 years old with TGCT of the knee. 
The study will enroll subjects at approximately 10 investigative sites in the United States and 
Europe. 
5.1. 
Subject Inclusion Criteria 
A subject may be included in the study if ALL of the following criteria are met: 
1. Subject ≥ 18 years must be able to communicate well with study staff, understand and 
comply with the requirements of the study, and read and voluntarily sign the ICF and the 
Health Insurance Portability and Accountability Act (HIPAA) authorization, if 
applicable, prior to the conduct of any study-specific procedures. 
2. A diagnosis of TGCT of the knee joint that has been histologically confirmed either by a 
pathologist at the treating institution or by a central pathologist. If not previously 
confirmed, biopsy with histological confirmation is required. 
3. Measurable disease of at least 1 cm and based on RECIST v1.1 (Eisenhauer, 2009) 
assessed from MRI scans by a central radiologist. Subjects with one knee joint 
involvement only, and only limited posterior extra-articular nodular TGCT lesions as 
assessed by central radiologist and tumor review committee.  
4. Stable prescription of analgesic regimen during the 2 weeks before Baseline 
5. Negative urine drug screen (UDS) at Screening and Baseline 
6. Women of childbearing potential must have a negative serum pregnancy test at Screening 
and a negative urine pregnancy test at Baseline 
7. Agrees to follow contraception guidelines (see Section 5.3) 
8. Adequate hematologic, hepatic, and renal function, at Screening visit, defined by: 
• Absolute neutrophil count ≥ 1.5 × 109/L 
• AST or ALT ≤ 1.5 × ULN 
• Hemoglobin > 10 g/dL 
• Total bilirubin ≤ 1.5 × ULN 
• Platelet count ≥ 100 × 109/L 
• Serum creatinine ≤ 1.5 × ULN 
9. Willing and able to complete the BPI, Worst Stiffness NRS item, PROMIS Physical 
Function Scale, EQ-5D-5L, and other self-assessment instruments throughout the study 
5.2. 
Subject Exclusion Criteria 
A subject will be excluded if ANY of the following criteria is met: 
1. Prior investigational drug use within 4 weeks or 5 half-lives (whichever is longer) before 
Baseline 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 36 
 
 
2. Use of pexidartinib, any other oral tyrosine kinase inhibitors (e.g., imatinib or nilotinib), 
or any biologic treatment targeting CSF1 or CSF1R within 3 months before Baseline 
3. History of extensive or reconstructive knee surgery, except for prior diagnostic 
synovectomy, which is not exclusionary if at least 3 months prior to  
Baseline 
4. Active cancer (either currently or within 1 year before Baseline) that requires therapy 
(e.g., surgery, chemotherapy, or radiation therapy), with the exception of adequately 
treated basal or squamous cell carcinoma of the skin, melanoma in situ, carcinoma in situ 
of the cervix or breast, or prostate carcinoma not requiring treatment apart from active 
surveillance 
5. Known metastatic TGCT  
6. HCV or HBV or known active or chronic infection with HIV 
7. Known active tuberculosis 
8. Significant concomitant arthropathy in the affected joint, serious illness, uncontrolled 
infection, or a medical or psychiatric history that, in the Investigator's opinion, would 
likely interfere with the subject’s study participation or the interpretation of his or her 
results 
9. Women who are breastfeeding 
10. A screening Fridericia-corrected QT interval (QTcF) ≥ 450 ms (men) or ≥ 470 ms 
(women) 
11. MRI contraindications (e.g., pacemaker, loose metallic implants) 
12. History of hypersensitivity to any ingredient of the study drug 
13. History of drug or alcohol abuse within 3 months before the first dose of study drug 
14. Any other severe acute or chronic medical or psychiatric condition or clinically 
significant laboratory abnormality that may increase the risk associated with study 
participation/treatment or interfere with interpretation of study results and, in the 
Investigator’s opinion, make the subject inappropriate for this study 
15. Subjects who, in the Investigator’s opinion, should not participate in the study for any 
reason, including if there is a question about their ability to comply with study 
requirements 
5.3. 
Contraception Guidelines 
Subjects must agree to adhere to the following contraception guidelines (Heads of Medicines 
Agencies, 2014) throughout the study and for 90 days after the last dose of study drug. 
 
Contraception Guidelines for Female Subjects 
A female enrolling in this study must meet ONE of the following contraceptive criteria: 
1. She is not a female of childbearing potential because of one of the following: 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 37 
 
 
a. She is postmenopausal. 
A postmenopausal state is defined as having no menses for at least 1 year without 
an alternative medical cause. A high follicle-stimulating hormone (FSH) level in 
the postmenopausal range may be used to confirm a postmenopausal state in 
women not using hormonal contraception or hormonal replacement therapy. 
However, a single FSH measurement is insufficient to establish a postmenopausal 
state without at least 1 year of amenorrhea. 
b. She is permanently sterile by hysterectomy, bilateral salpingectomy, or bilateral 
oophorectomy. 
2. She is totally abstinent from heterosexual intercourse as her preferred and usual lifestyle 
(abstinent on a long-term and persistent basis) and agrees to remain abstinent throughout 
the study and for 90 days after the last dose of study drug. Periodic abstinence (e.g., 
calendar, symptothermal, or post-ovulation methods) and withdrawal are not acceptable. 
Subjects who practice total abstinence must use another method of contraception if they 
become sexually active. 
3. She has only 1 male sexual partner, that partner is vasectomized, and the vasectomized 
partner has received medical assessment of the surgical success. 
4. She agrees to use one of the following highly effective contraceptive methods: 
a. Combined hormonal contraception (containing estrogen and progestogen) 
associated with inhibition of ovulation: oral, intravaginal, or transdermal 
b. Progestogen-only hormonal contraception associated with inhibition of ovulation: 
oral, injectable, or implantable  
c. Intrauterine device (IUD) 
d. Intrauterine hormone-releasing system (IUS) 
e. Bilateral tubal occlusion 
5. Where allowed by local laws and regulations, a double-barrier contraceptive method—
specifically, female subject use of cap, diaphragm, or sponge with spermicide AND male 
partner use of condom—is acceptable. 
 
Contraception Guidelines for Male Subjects 
A male enrolling in this study must meet ONE of the following contraceptive criteria: 
1. He is not a fertile male because of one of the following: 
a. He is in Tanner Stage 1 (preadolescent). 
b. He is permanently sterile by bilateral orchiectomy. 
2. He is totally abstinent from heterosexual intercourse as his preferred and usual lifestyle 
(abstinent on a long-term and persistent basis) and agrees to remain abstinent throughout 
the study and for 90 days after the last dose of study drug. Periodic abstinence (e.g., 
calendar, symptothermal, or post-ovulation methods) and withdrawal are not acceptable. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 38 
 
 
Subjects who practice total abstinence must use another method of contraception if they 
become sexually active. 
3. He is vasectomized and has received medical assessment of the surgical success. 
4. He agrees to use a male condom AND his female partner, if she is a female of 
childbearing potential, uses one of the following highly effective contraceptive methods: 
a. Combined hormonal contraception (containing estrogen and progestogen) 
associated with inhibition of ovulation: oral, intravaginal, or transdermal 
b. Progestogen-only hormonal contraception associated with inhibition of ovulation: 
oral, injectable, or implantable 
c. IUD 
d. IUS 
e. Bilateral tubal occlusion 
5. Where allowed by local laws and regulations, a double-barrier contraceptive method—
specifically, male subject use of condom AND female partner of childbearing potential 
use of cap, diaphragm, or sponge with spermicide—is acceptable. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 39 
 
 
6. 
ASSESSMENTS BY STUDY VISIT 
Section 1.3 provides the Schedule of Events for this study. Visits should be planned according to 
the schedule to ensure subjects receive 12 weeks of treatment and 12 weeks of follow-up.  
Refer to Appendix 5 for potential changes to study conduct in the context of COVID-19, 
including the possibility of remote visits. 
6.1. 
Visit 1 / Screening 
After the subject provides signed consent and HIPAA authorization (if applicable), the following 
procedures should be completed. Note that if necessary, screening assessments may be 
performed at more than one visit during the 4-week screening period. 
• Assign a Subject ID. Each subject will be assigned a 6-digit Subject ID that consists 
of a 3-digit number representing the study site and a 3-digit subject number, 
sequential within each study site. 
o Thus, if the center number is 101, Subject IDs will be assigned as 101-001, 
101-002, 101-003, etc., in ascending order. If the center number is 202, the Subject 
IDs will be 202-001, 202-002, 202-003, etc., in ascending order. 
• Collect demographic information and take medical history. 
• Record all concomitant medications, including dose amount and dosing frequency, 
taken within 4 weeks prior to Screening. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
subject in a sitting position after having rested for 5 minutes. 
• Conduct a full physical examination (including height and weight). 
• Perform a 12-lead ECG. 
• Collect blood samples for clinical laboratory tests (chemistry and hematology), HBV, 
HCV, HIV, TB (QuantiFERON), and serum pregnancy test for females of 
childbearing potential. 
• Collect a urine sample for urinalysis and urine drug screen. 
• Perform MRI. 
• Tumor assessment. 
• Tumor biopsy for subjects who do not have histologically confirmed TGCT. Any 
required biopsies should be performed after MRI review of the tumor by the central 
reader. 
• Perform the following clinical assessments: 
o Worst stiffness NRS 
o PROMIS Physical Function Scale 
o BPI 
o EQ-5D-5L 
o Joint ROM 
• Review results and confirm eligibility. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 40 
 
 
Individuals who successfully complete Screening procedures and meet all eligibility criteria may 
be enrolled in the study. These subjects will be notified and scheduled for Visit 2 (Baseline). The 
interval between Visit 1 (Screening) and Visit 2 (Baseline) should not exceed 4 weeks.  
For any subject who does not meet study eligibility criteria, capture screen failure information, 
report screen failure status, and record any changes in concomitant medications and AEs since 
Screening. 
6.2. 
Visit 2 / Baseline (Day 1, Week 0) 
 
Visit 2 – Pre-dose Procedures  
Confirm that subject meets all inclusion/exclusion criteria, then complete the following 
procedures prior to administration of first dose of study drug: 
• Perform a urine pregnancy test for female subjects of childbearing potential. 
o Any subject with a positive result will be recorded as a screen failure. 
• Collect a urine sample for urinalysis and urine drug screen. 
• Update any changes in concomitant medications since Visit 1 (Screening). 
• Record any AEs that may have occurred since the subject signed the ICF. AEs that 
occur before the first application of study drug will be recorded as such to distinguish 
them from TEAEs. 
• Conduct a full physical exam and document any changes since the previous visit. 
• Obtain weight. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
the subject in a sitting position after having rested for 5 minutes. 
• Perform a 12-lead ECG. 
• Collect blood samples for clinical laboratory tests (chemistry and hematology). 
• Collect serum samples prior to dosing for measurement of AMB-05X concentration, 
CSF1 levels, and anti-AMB-05X antibodies. 
• Collect synovial fluid for measurement of AMB-05X concentration, CSF1 levels, and 
anti-AMB-05X antibodies. 
• Perform the following clinical assessments: 
o Worst stiffness NRS 
o PROMIS Physical Function Scale 
o BPI 
o EQ-5D-5L 
o Joint ROM 
 
Visit 2 – Dosing and Post-dose Procedures 
• Inject study drug. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 41 
 
 
• Observe subject for a minimum of 90 minutes after dosing to monitor for any adverse 
reactions, including any injection-site reactions. 
• Collect serum samples for measurement of AMB-05X concentration and CSF1 levels 
at 2 hours post-dose. 
6.3. 
Visit 3 (Week 2 ± 2 Days)  
Complete the following procedures during the visit: 
• Record any changes in concomitant medications since the previous visit. 
• Record any AEs that may have occurred since the previous visit and follow up on the 
status of any existing AEs. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
the subject in a sitting position after having rested for 5 minutes. 
• Obtain weight. 
• Collect serum samples prior to dosing for measurement of AMB-05X concentration 
and CSF1 levels. 
• Collect synovial fluid for measurement of AMB-05X concentration and CSF1 levels 
prior to study drug injection. 
• Inject study drug. 
• Observe subject for a minimum of 90 minutes after dosing to monitor for any adverse 
reactions, including any injection-site reactions. 
6.4. 
Visit 4 (Week 4 ± 2 Days) 
Complete the following procedures during the visit: 
• Perform a urine pregnancy test for female subjects of childbearing potential. 
• Record any changes in concomitant medications since the previous visit. 
• Record any AEs that may have occurred since the previous visit and follow up on the 
status of any existing AEs. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
the subject in a sitting position after having rested for 5 minutes. 
• Obtain weight. 
• Collect synovial fluid for measurement of AMB-05X concentration, CSF1 levels, and 
anti-AMB-05X antibodies prior to study drug injection. 
• Inject study drug. 
• Observe subject for a minimum of 90 minutes after dosing to monitor for any adverse 
reactions, including any injection-site reactions. 
6.5. 
Visit 5 (Week 6 ± 3 days)  
Complete the following procedures during the visit: 
• Record any changes in concomitant medications since the previous visit. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 42 
 
 
• Record any AEs that may have occurred since the previous visit and follow up on the 
status of any existing AEs. 
• Conduct a full physical exam and document any changes since the previous visit. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
the subject in a sitting position after having rested for 5 minutes. 
• Obtain weight. 
• Perform a 12-lead ECG. 
• Collect a urine sample for urinalysis. 
• Collect blood samples for clinical laboratory tests (chemistry and hematology). 
• Collect synovial fluid for measurement of AMB-05X concentration and CSF1 levels 
prior to study drug injection. 
• Perform MRI. 
• Tumor assessment. 
• Perform the following clinical assessments: 
o Worst stiffness NRS 
o PROMIS Physical Function Scale 
o BPI 
o EQ-5D-5L 
o Joint ROM 
• Inject study drug. 
• Observe subject for a minimum of 90 minutes after dosing to monitor for any adverse 
reactions, including any injection-site reactions. 
6.6. 
Visit 6 (Week 8 ± 3 days) 
• Perform a urine pregnancy test for female subjects of childbearing potential. 
• Record any changes in concomitant medications since the previous visit. 
• Record any AEs that may have occurred since the previous visit and follow up on the 
status of any existing AEs. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
the subject in a sitting position after having rested for 5 minutes. 
• Obtain weight. 
• Collect synovial fluid for measurement of AMB-05X concentration and CSF1 levels 
prior to study drug injection. 
• Inject study drug. 
• Observe subject for a minimum of 90 minutes after dosing to monitor for any adverse 
reactions, including any injection-site reactions. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 43 
 
 
6.7. 
Visit 7 (Week 10 ± 3 days) 
• Record any changes in concomitant medications since the previous visit. 
• Record any AEs that may have occurred since the previous visit and follow up on the 
status of any existing AEs. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
the subject in a sitting position after having rested for 5 minutes. 
• Obtain weight. 
• Collect serum samples prior to dosing for measurement of AMB-05X concentration 
and CSF1 levels. 
• Collect synovial fluid for measurement of AMB-05X concentration, CSF1 levels, and 
anti-AMB-05X antibodies prior to study drug injection. 
• Inject study drug. 
• Observe subject for a minimum of 90 minutes after dosing to monitor for any adverse 
reactions, including any injection-site reactions. 
• Collect serum samples 2 hours post-dosing for measurement of AMB-05X 
concentration and CSF1 levels. 
6.8. 
Visit 8 (Week 12 ± 3 days) or Early Termination 
• Perform a urine pregnancy test for female subjects of childbearing potential. 
• Record any changes in concomitant medications since the previous visit. 
• Record any AEs that may have occurred since the previous visit and follow up on the 
status of any existing AEs. 
• Conduct a full physical exam and document any changes since the previous visit. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
the subject in a sitting position after having rested for 5 minutes. 
• Obtain weight. 
• Perform a 12-lead ECG. 
• Collect a urine sample for urinalysis. 
• Collect blood samples for clinical laboratory tests (chemistry and hematology). 
• Perform MRI. 
• Tumor assessment. 
• Perform the following clinical assessments: 
o Worst stiffness NRS 
o PROMIS Physical Function Scale 
o BPI 
o EQ-5D-5L 
o Joint ROM 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 44 
 
 
6.9. 
Visit 9 (Week 14 ± 3 days)  
• Record any changes in concomitant medications since the previous visit. 
• Record any AEs that may have occurred since the previous visit and follow up on the 
status of any existing AEs. 
• Conduct a full physical exam and document any changes since the previous visit. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
the subject in a sitting position after having rested for 5 minutes. 
• Obtain weight. 
• Perform the following clinical assessments: 
o Worst stiffness NRS 
o Joint ROM 
6.10. 
Visit 10 (Week 24 ± 7 days) 
• Record any changes in concomitant medications since the previous visit. 
• Record any AEs that may have occurred since the previous visit and follow up on the 
status of any existing AEs. 
• Conduct a full physical exam and document any changes since the previous visit. 
• Measure vital signs (blood pressure, heart rate, temperature, and respiratory rate) with 
the subject in a sitting position after having rested for 5 minutes. 
• Obtain weight. 
• Collect a urine sample for urinalysis. 
• Collect blood samples for clinical laboratory tests (chemistry and hematology). 
• Perform MRI. 
• Tumor assessment. 
• Perform the following clinical assessments: 
o Worst stiffness NRS 
o PROMIS Physical Function Scale 
o BPI 
o EQ-5D-5L 
o Joint ROM 
6.11. 
Early Termination Procedures 
A subject who terminates from the study prior to Visit 8 should return to the site to complete the 
procedures for Visit 8/ET and Visit 9 follow-up. A subject who terminates from the study after 
Visit 8 should return to the site to complete the procedures for Visit 9 follow-up. All subjects 
who complete study treatment should be encouraged to return for Visit 10 (12 weeks post-
treatment). Study personnel should make every effort to conduct all protocol-specified 
procedures to complete the study. Every effort should also be made to obtain a final MRI.  

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 45 
 
 
7. 
TREATMENT OF SUBJECTS 
7.1. 
Description of Study Drug 
Refer to Section 8.1 for information on the study drug. 
7.2. 
Concomitant Medications 
A review of concomitant medications will be conducted during the screening period.  
The Investigator should instruct the subject to notify the study site about any new medications 
he/she takes after the start of the study or any medications they have stopped using.  
All medications and significant non-drug therapies (including physical therapy and blood 
transfusions) administered from the time the ICF is signed through Visit 10 or ET must be listed 
on the Concomitant Medications/Therapy eCRF. 
7.3. 
Prohibited and Permitted Treatment 
The following treatments are prohibited: 
• Prior investigational drug use within 4 weeks or 5 half-lives (whichever is longer) before 
Baseline 
• Use of pexidartinib, any other oral tyrosine kinase inhibitor (e.g., imatinib or nilotinib), or 
any biologic treatment targeting CSF1 or CSF1R within 3 months before Baseline and for 
the duration of the study 
7.4. 
Treatment Compliance 
Subject compliance with study treatment will be monitored by site staff administering study drug 
injections.  
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 47 
 
 
8.4. 
Study Drug Accountability 
Site personnel must maintain an accurate drug accountability record of the receipt and dispensing 
of study drug. The Site Monitor will verify study drug accountability during monitoring visits. 
Site personnel must administer study drug only to individuals enrolled in the study. 
Administration of study drug must be recorded in the subject’s source documents, the eCRF, and 
the study drug inventory log. 
8.5. 
Study Drug Handling and Disposal 
Only after receiving written authorization by AmMax or its designee, the Investigator will send 
all unused and empty vials of study drug to the address provided at the time of authorization for 
destruction.  
With specific approval from AmMax, unused and empty vials of study drug may be destroyed at 
the site, following the standard operating procedures at the study site. The study staff must 
provide a drug destruction certificate to AmMax or its designee. 
 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 48 
 
 
9. 
STUDY ASSESSMENTS AND PROCEDURES 
9.1. 
Screening Assessments 
 
Demographic and Medical History 
A complete medical history and review of body systems along with demographic data will be 
documented for all subjects during the screening period. All data up to the time of enrollment 
will also be recorded in the eCRF.  
Any AE or change in the subject’s condition or health status occurring after consent but prior to 
the first application of study drug will be recorded but not considered treatment emergent. 
 
Tumor Biopsy  
Tumor biopsy will be performed for subjects at Screening who do not have histologically 
confirmed TGCT. Any required biopsies should be performed after MRI review of the tumor by 
the central reader. 
Tumor biopsy will be done via needle aspiration under CT or ultrasound guidance. 
9.2. 
Efficacy Assessments 
 
Tumor Assessment 
Overall Response (OR) will be centrally assessed from MRI scans using RECIST v1.1 
(Eisenhauer, 2009). A complete response (CR) is defined as disappearance of all tumors, and a 
partial response (PR) is defined as at least a 30% decrease in the sum of diameters of target 
tumors from the baseline sum of diameters. 
 
MRI 
A separate MRI Manual will be provided detailing MRI procedures. MRIs will be read and 
evaluated by a central independent blinded reader for assessment of tumor response. 
TVS is a semi-quantitative MRI scoring system that describes tumor mass and is based on 10% 
increments in the estimated volume of the maximally distended synovial cavity or tendon sheath 
involved. A score of 0 indicates no evidence of tumor; a score of 10 indicates a tumor that is 
equal in volume to that of a maximally distended synovial cavity or tendon sheath. The overall 
number of responses and the number of subjects with and without disease progression will be 
assessed. 
9.3. 
Clinical Outcome Assessments 
Clinical outcome assessments will include Worst Pain NRS, Worst Stiffness NRS, PROMIS 
Physical Function Scale, BPI, and evaluation of joint ROM. 
 
Worst Stiffness NRS 
This is a single item self-administered questionnaire designed to assess “worst” stiffness at the 
site of the tumor. This instrument uses an 11-point NRS, ranging from 0 (“no stiffness”) to 10 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 49 
 
 
(“worst stiffness imaginable”) (see Appendix 1). Subjects will be asked to recall their “worst” 
stiffness at the site of the tumor in the past 24 hours. Subjects will complete this assessment at 
Screening, Baseline (Week 0), Week 6, Week 12, and Week 14/ET.  
 
PROMIS 
The PROMIS Physical Function Scale will be used to assess physical function of the upper and 
lower limbs (see Appendix 2). The scale ranges from 1 ('unable to do' or 'cannot do') to 5 
('without any difficulty' or 'not at all'), where higher scores represent better outcomes. 
 
BPI 
The BPI Short Form is a self-administered questionnaire used to evaluate the severity of a 
subject's pain and the impact of this pain on the subject's daily functioning (see Appendix 3). The 
subject is asked to rate their worst, least, average, and current pain intensity, list current 
treatments and their perceived effectiveness, and rate the degree that pain interferes with general 
activity, mood, walking ability, normal work, relations with other persons, sleep, and enjoyment 
of life on a scale from 0-10. 
 
EQ-5D-5L Health Assessment 
The EQ-5D-5L assessment is a widely used quality of life instrument that includes questions in 
each of 5 domains: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. 
The choices include 5 levels of severity for each domain followed by a general health VAS (see 
Appendix 4). 
 
ROM 
ROM of the joint will be assessed by qualified assessors at the clinical site. Measurements will 
be recorded in degrees. At baseline, the plane of movement with the smallest (worst) relative 
value will be identified; only this plane will be used for evaluating change in ROM subsequently. 
9.4. 
Pharmacokinetic/Pharmacodynamic Assessments 
Serum AMB-05X concentrations will be measured at Week 0 (pre-dose and 2 hours after the 
first dose), Week 2 (pre-dose [trough]), and Week 10 during steady state (including pre-dose 
[trough] and 2 hour after the last dose). Synovial AMB-05X concentrations will be measured 
pre-dose at Weeks 0, 2, 4, 6, 8, and 10.  
Serum CSF1 levels will be measured at Week 0 (including pre-dose and 2 hours after first dose), 
Week 2 (pre-dose [trough]), and Week 10 during steady state (including pre-dose [trough] and 
2 hours after the last dose). Synovial CSF1 levels will be measured pre-dose at Weeks 0, 2, 4, 6, 
8, and 10. CSF1 will be measured by ELISA analysis. 
Serum anti-AMB-05X antibody levels will be measured pre-dose at Week 0 and at Week 10. 
Synovial anti-AMB-05X antibody levels will be measured pre-dose at Weeks 0, 4, and 10. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 50 
 
 
9.5. 
Safety Assessments 
Safety and tolerability will be assessed on an ongoing basis by monitoring adverse events (AEs) 
(including any serious AEs [SAEs], AEs leading to withdrawal, injection-site reactions [ISRs], 
and any other dose-limiting toxicities [DLTs]), physical examinations/vital signs, changes in 
clinical laboratory values, and ECG results. 
A DMC composed of qualified medical/clinical representatives will review the clinical data each 
time 3 new subjects complete treatment. The DMC will provide recommendations to the Sponsor 
regarding the acceptability of continued enrollment in the study and whether any modifications 
are warranted. 
Safety will be assessed with the following parameters: 
• Reported AEs (see Section 9.6) and concomitant medications (see Section 7.2) 
• Vital signs (including body weight, blood pressure, heart rate, temperature, and 
respiratory rate) 
• Physical examination 
• ECG 
• Clinical laboratory tests (chemistry, hematology, and urinalysis) 
• Pregnancy test 
 
Vital Signs 
Vital signs, including blood pressure (systolic and diastolic, in mmHg), body temperature (in 
°C), heart rate (in beats per minute), and respiratory rate (in breaths per minute) will be recorded 
with the subject in a sitting position after having rested for 5 minutes. 
 
Physical Examination 
A full physical exam will include, but not be limited to, an examination of general appearance, 
skin, HEENT (head, eyes, ears, nose, throat), lungs, heart, abdomen, back, lymph nodes, 
extremities, and basic nervous system evaluation. 
Information about the physical examination must be present in the source documentation at the 
study site. Significant findings that are present prior to the start of study drug must be included in 
the medical history / current medical conditions page of the eCRF.  
Significant findings made after the start of study drug that meet the definition of an AE must be 
recorded on the AE page of the eCRF. 
 
Electrocardiogram 
Standard 12-lead ECGs will be performed. The Subject ID and the subject’s initials or date of 
birth (as permitted by applicable practice), the date and actual time of the tracing, and the study 
code must appear on each page of the tracing. Tracings will be dated, signed, and interpreted by 
a qualified physician.  

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 51 
 
 
The overall interpretation will be collected with a Yes / No statement about whether any 
clinically significant abnormalities are present that need to be specified further in the source 
document and eCRF. 
Original ECG tracings, appropriately signed, will be archived at study sites. 
 
Clinical Laboratory Tests 
Blood samples will be drawn for chemistry and hematology. Urine samples will be collected for 
urinalysis and urine drug screen. Details on sample collection and processing will be described in 
the laboratory manual. 
 
Pregnancy Tests 
For each female of childbearing potential, a serum pregnancy test will be performed at Visit 1 
(Screening) and a urine pregnancy test will be performed at visits specified in the Schedule of 
Events and at the discretion of the Investigator (e.g., for a subject with irregular menses). 
The result of the serum pregnancy test at Screening and the urine pregnancy test at Visit 2 
(Baseline) must be received before a subject may be enrolled during Visit 2. 
9.6. 
Adverse Events and Serious Adverse Events 
 
Definition of Adverse Event 
An AE is any untoward medical occurrence associated with the use of a drug in humans, whether 
or not considered drug related. An AE (also referred to as an adverse experience) can be any 
unfavorable and unintended sign (e.g., an abnormal laboratory finding), symptom, or disease 
temporally associated with the use of a drug and does not imply any judgment about causality.  
An AE can arise with any use of the drug (e.g., off-label use, use in combination with another 
drug) and with any route of administration, formulation, or dose, including an overdose. An 
overdose with symptoms should be recorded as an AE.  
A worsening of previous illness or condition from baseline while participating in the study is 
also considered an AE. 
 
Definition of Serious Adverse Event 
An SAE is any event that meets any of the following criteria: 
• Results in death 
• Is life-threatening 
• Requires inpatient hospitalization or prolongation of existing hospitalization 
• Results in persistent or significant disability/incapacity 
• Is a congenital anomaly/birth defect 
• Is an important medical event. An important medical event that may not result in death, be 
life-threatening, or require hospitalization may be considered SAEs when, based upon 
appropriate medical judgment, the event may jeopardize the subject or require medical or 
surgical intervention to prevent one of the other outcomes listed in the definition above. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 52 
 
 
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. 
If, during follow-up, any non-serious AE worsens and eventually meets the criteria for an SAE, 
that AE should be recorded as a new SAE. 
 
Classification of an Adverse Event 
9.6.3.1. 
Severity 
The Investigator will provide an assessment of the severity of each AE by recording a severity 
rating on the AE page of the subject’s eCRF. Severity, which is a description of the intensity of 
manifestation of the AE, is distinct from seriousness. Severity will be assessed according to the 
following scale: 
• Mild: A type of AE that is usually transient and may require only minimal treatment or 
therapeutic intervention. The event does not generally interfere with usual activities of 
daily living. 
• Moderate: A type of AE that is usually alleviated with additional specific therapeutic 
intervention. The event interferes with usual activities of daily living, causing discomfort, 
but poses no significant or permanent risk of harm to the subject.  
• Severe: A type of AE that interrupts usual activities of daily living, or significantly affects 
clinical status, or may require intensive therapeutic intervention. 
9.6.3.2. 
Relationship to Study Drug 
The Investigator must assess the relationship of each AE to the study drug according to the 
categories defined below and record it on the AE page of the subject’s eCRF. 
• Definitely Related: There is clear evidence to suggest a causal relationship, and other 
possible contributing factors can be ruled out. The clinical event, including an abnormal 
laboratory test result, occurs in a plausible time relationship to study drug administration 
and cannot be explained by concurrent disease or other drugs or chemicals. The response 
to withdrawal of the study drug (dechallenge) should be clinically plausible. The event 
must be pharmacologically or phenomenologically definitive, with use of a satisfactory 
rechallenge procedure if necessary. 
• Probably Related: There is evidence to suggest a causal relationship, and the influence of 
other factors is unlikely. The clinical event, including an abnormal laboratory test result, 
occurs within a reasonable time after administration of the study drug, is unlikely to be 
attributed to concurrent disease or other drugs or chemicals, and follows a clinically 
reasonable response on withdrawal (dechallenge). Rechallenge information is not required 
to fulfill this definition. 
• Possibly Related: There is some evidence to suggest a causal relationship (e.g., the event 
occurred within a reasonable time after administration of the study drug). However, other 
factors may have contributed to the event (e.g., the participant’s clinical condition, other 
concomitant events). Although an AE may rate only as “possibly related” soon after 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 53 
 
 
discovery, it can be flagged as requiring more information and later be upgraded to 
“probably related” or “definitely related”, as appropriate. 
• Unlikely to be related: A clinical event, including an abnormal laboratory test result, 
whose temporal relationship to study drug administration makes a causal relationship 
improbable (e.g., the event did not occur within a reasonable time after administration of 
the study intervention) and in which other drugs or chemicals or underlying disease 
provides plausible explanations (e.g., the participant’s clinical condition, other concomitant 
treatments). 
• Not Related: The AE is completely independent of study drug administration, and/or 
evidence exists that the event is definitely related to another etiology. There must be an 
alternative, definitive etiology documented by the clinician. 
This assessment will help the Sponsor to determine whether an AE might be a suspected adverse 
reaction. A suspected adverse reaction is any AE for which there is a reasonable possibility that 
the drug caused the AE. ‘Reasonable possibility’ means there is evidence to suggest a causal 
relationship between the drug and the AE. A ‘suspected adverse reaction’ implies a lesser degree 
of certainty about causality than ‘adverse reaction’. 
The Investigator may change the causality assessment at any time based on new accumulated 
information. An AE with causal relationship not initially determined will require follow-up to 
assign causality. 
9.6.3.3. 
Expectedness 
An unexpected AE or unexpected, suspected adverse reaction refers to an event or reaction that 
is not listed in the Reference Safety Information section of the most recent version of the IB or is 
not listed at the specificity or severity that has been observed. The Sponsor will be responsible 
for determining whether an AE is expected or unexpected. 
 
Time Period and Frequency for Event Assessment and Follow-up 
AEs will be recorded from the time the ICF is signed until the subject completes the last study 
visit or withdraws from the study. 
AEs will be assessed at each study visit, and subjects should be encouraged to report any AEs at 
their onset. Study staff will elicit information about AEs using nonspecific questions such as 
“Have you experienced any change in your health status since your last visit?” Subjects will also 
be monitored closely for the development of an AE. 
Any AE or clinically significant abnormality of ECG, physical examination finding, or clinical 
laboratory measurement that occurs during the study should be followed until no further medical 
intervention is warranted (e.g., it resolves, becomes medically stable, or is assessed as chronic) 
or until the subject is lost to follow-up. AE follow-up must comply with International Council for 
Harmonisation (ICH) Good Clinical Practice (GCP) guidelines. 
 
Adverse Event Reporting 
Information about AEs will be recorded on the AE page of the subject’s eCRF. When known, the 
diagnosis (rather than individual symptoms) should be entered as the event term in the eCRF. For 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 54 
 
 
example, an upper respiratory infection with symptoms of cough, rhinitis, and sneezing should 
be recorded as upper respiratory infection. When the diagnosis is unclear, key symptoms may be 
entered separately, and the Investigator should obtain appropriate tests to establish a diagnosis, if 
possible. After a diagnosis is determined, the eCRF event term should be updated. 
For each AE, the onset date, seriousness, severity (Section 9.6.3.1), relationship to study drug 
(causality) (Section 9.6.3.2), action taken, outcome, and date of resolution (or continuing) will be 
recorded. The Investigator must make a causality assessment for each AE. 
 
Serious Adverse Event Reporting and Follow-up 
Any SAE, including death, due to any cause, that occurs from the time the ICF is signed until 
4 weeks after a subject’s last dose of study drug must be reported to the Sponsor or its designee 
within 24 hours of the study center staff learning of its occurrence. 
The Sponsor is required to inform worldwide regulatory authorities of SAEs that meet specific 
criteria and to do so in an expedited fashion. Specifically, suspected, unexpected serious adverse 
reactions (SUSARs) are subject to expedited safety reporting requirements. The Sponsor will 
report applicable SAEs to the appropriate authorities within the timelines and format required by 
local regulations. Therefore, the Sponsor must be notified of any SAE that occurs after informed 
consent is obtained within 24 hours of the study center staff learning of its occurrence. 
An SAE Form must be completed and reported via email at saereporting@egeeninc.com. All 
SAEs must be recorded on the AE page of the eCRF, marking the event as serious within the 
form. All relevant seriousness criteria should be recorded, and relationship to study drug should 
be assigned at the time of initial report, as this is required to determine regulatory reporting. 
SAEs must also be reported to the Institutional Review Board (IRB) / Independent Ethics 
Committee (IEC) according to the requirements of the IRB/IEC. 
The Investigator is expected to institute appropriate diagnostic and therapeutic measures 
necessary to treat and promote resolution of the SAE. Any medications or procedures used to 
treat the SAE must be recorded on the appropriate pages of the subject’s eCRF. The Investigator 
must determine whether the seriousness of the event warrants discontinuation of study drug. 
The Investigator is expected to proactively follow up on the SAE with the subject at subsequent 
visits/contacts. All SAEs will be followed until no further medical intervention is warranted 
(e.g., the event resolves, becomes medically stable, or is assessed as chronic) or until the subject 
is lost to follow-up. Follow-up information on the SAE will also be reported using the AE eCRF.  
The Sponsor or designee may contact the study center to solicit additional information or follow 
up on the event. If requested, medical records (such as laboratory results, radiology reports, 
progress notes, hospital admission and emergency room notes, holding and observation notes, 
discharge summaries, autopsy reports, and death certificates) should be emailed to the safety 
inbox after redacting all information that personally identifies the subject or hospital staff (per 
the European Global Data Protection Regulation). 
After 4 weeks after a subject’s last dose of study drug, the Investigator is not obligated to 
actively seek AEs or SAEs. However, if the Investigator learns of any SAE, including a death, at 
any time after a subject has been discharged from the study, and he/she considers the event 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 55 
 
 
reasonably related to the study drug or to study participation, the Investigator must notify the 
Sponsor or designee within 24 hours of learning of the event. 
9.7. 
Pregnancy 
Any pregnancy in a female subject or in the partner of a male subject that occurs from the time 
the subject signs an ICF until 90 days after the final application of study drug must be reported to 
AmMax or its designee within 24 hours of learning of its occurrence. A pregnant female subject 
will be immediately discontinued from study drug. 
The subject or pregnant partner should provide consent and be followed throughout the course of 
the pregnancy. Pregnancy follow-up information, including the outcome of the pregnancy, 
should be reported to AmMax or its designee. 
9.8. 
Pharmacokinetic Assessments 
Serum and synovial fluid will be collected from all subjects to assess AMB-05X concentrations 
and anti-drug antibody formation at the visits indicated in the Schedule of Events.  
9.9. 
Blood and Synovial Fluid Sampling 
All blood samples will be taken by direct venipuncture. Details on sample collection and 
processing will be described in a separate laboratory manual. Blood sampling volumes will be 
limited by the most stringent regulations applicable to a particular site or region.  
Synovial fluid (2 mL) will be collected from the affected joint prior to injection of study drug at 
Weeks 0, 2, 4, 6, 8, and 10. The expected total sampling volume over the course of the study is 
up to 12 mL. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 56 
 
 
10. 
STATISTICS 
10.1. 
General Considerations  
All study data will be summarized by treatment using descriptive statistics. Unless otherwise 
specified, descriptive statistics for numeric data (e.g., age, weight) will include the number of 
subjects with data to be summarized (n), mean, standard deviation (SD), median, minimum, and 
maximum. Categorical/qualitative data (e.g., sex, race) will be presented using absolute and 
relative frequency counts and percentages. All summaries, statistical analyses, and individual 
subject data listings described below will be completed using Version 9.3 or later of SAS 
software (SAS Institute, Inc., Cary, North Carolina).  
A detailed final SAP will be provided separately. The SAP will be finalized prior to the first 
DMC meeting.  
10.2. 
Sample Size Determination  
Based on prior Phase 1 experience and an anticipated treatment effect with AMB-05X in this 
population, the sample size of approximately 12 subjects is anticipated to provide sufficient data 
for PK/PD analysis and an estimate of safety, tolerability, and efficacy. 
10.3. 
Efficacy Analyses 
Efficacy endpoints will be summarized using descriptive statistics and 95% confidence intervals. 
Exploratory hypotheses testing may be conducted using a significance level of 0.05 without 
adjustment for multiplicity. 
10.4. 
Pharmacokinetic Analysis  
AMB-05X concentration data will be summarized by collection time. PK parameters will be 
deduced where possible by WinNonlin analysis.  
10.5. 
Safety Analyses  
Safety analyses will include all subjects who received at least 1 dose of study drug.  
The number of subjects exposed to each treatment group and the duration of exposure will be 
summarized.  
All AEs reported will be listed, documenting severity, start and stop date and time, possible 
relationship to study drug, action taken, and outcome. TEAEs are defined as AEs recorded after 
first dose of study drug. Verbatim terms will be mapped to Preferred Terms (PTs) and related 
System Organ Classes (SOCs) using Medical Dictionary for Regulatory Activities (MedDRA). 
PTs and SOCs will be tabulated by treatment group. All reported AEs will be summarized by the 
number of subjects reporting AEs, SOC, PT, severity, and relationship to study drug. Multiple 
occurrences of an AE will be counted only once per subject per SOC and PT in summary tables. 
The following TEAEs will be summarized by SOC, PT, and treatment group: 
• Incidence of all TEAEs 
• Incidence of all TEAEs by maximum severity (severe, moderate, and mild) specified by 
investigators 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 57 
 
 
• Incidence of TEAEs related to the study drug as determined by the investigators 
• Incidence of serious TEAEs 
• Incidence of TEAEs leading to early discontinuation withdrawn from study 
Safety labs (including hematology, chemistry, and urinalysis) will be tabulated using descriptive 
statistics. Abnormal/out-of-range findings and changes from pre-dose to post-dose will be listed 
by subject. Shift tables in all laboratory variables will be provided.  
Vital signs and ECGs will be tabulated using descriptive statistics. Abnormal/out-of-range 
findings and changes from pre-dose to post-dose will be listed by subject. For ECG parameters, 
heart rate, RR, PR, QRS, and QT corrected with Fridericia’s formula (QTcF) will be summarized 
by treatment group. 
Concomitant medication usage will be summarized by treatment group. The World Health 
Organization Drug Dictionary will be used to classify concomitant medications by therapeutic 
class and generic name based on ATC (Anatomical Therapeutic Chemical) code level 3. A 
subject will only be counted once in each unique ATC class and generic name if the subject uses 
multiple drugs. 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 58 
 
 
11. 
DIRECT ACCESS TO SOURCE DATA AND DOCUMENTS 
11.1. 
Source Documents 
Source data is defined as all information in original records and certified copies of original 
records of clinical findings, observations, or other activities in a clinical study necessary for the 
evaluation and reconstruction of the clinical study. Source data are contained in source 
documents (i.e., original records or certified copies).  
Source documents and the eCRFs will be completed for each study subject. It is the 
Investigator’s responsibility to ensure the accuracy, completeness, and timeliness of the data 
reported in the subject’s source document/eCRF. The source document/eCRF should indicate the 
subject’s participation in the study and should document the dates and details of study 
procedures, AEs, and subject status. 
The Investigator must sign and date at the end of the source document/eCRF to endorse the 
recorded data. 
The Investigator will retain all completed source documents. A site-specific eCRF archive and 
audit trail will be provided at the close of the study to each Investigator. AmMax or designee will 
retain the eCRF archive and audit trail for all investigative sites. 
11.2. 
Study Monitoring 
Before an investigational site can enter a subject into the study, a representative of AmMax will 
visit the investigational study site to: 
• Determine the adequacy of the facilities 
• Discuss with the investigator(s) and other personnel their responsibilities regarding 
protocol adherence, and the responsibilities of AmMax or its representatives. This 
will be documented in a Clinical Study Agreement between AmMax and the 
investigator. 
During the study, a monitor from AmMax or representative will have regular contacts with the 
investigational site, for the following: 
• Provide information and support to the investigator(s) 
• Confirm that facilities remain acceptable 
• Confirm that the investigational team is adhering to the protocol, that data are being 
accurately recorded in the case report forms, and that investigational product 
accountability checks are being performed 
• Perform source data verification. This includes a comparison of the data in the case 
report forms with the subject’s medical records at the hospital or practice, and other 
records relevant to the study. This will require direct access to all original records for 
each subject (e.g. clinic charts). 
• Record and report any protocol deviations not previously sent to AmMax. 
• Confirm AEs and SAEs have been properly documented on CRFs and confirm any 
SAEs have been forwarded to AmMax and those SAEs that met criteria for reporting 
have been forwarded to the IRB. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 59 
 
 
The monitor will be available between visits if the investigator(s) or other staff needs 
information or advice. 
11.3. 
Audits and Inspections 
Authorized representatives of AmMax, a regulatory authority, an Independent Ethics Committee 
or an Institutional Review Board may visit the site to perform audits or inspections, including 
source data verification; the Investigator agrees to allow the auditor direct access to all relevant 
documents and to allocate his or her time, and that of site personnel, to the auditor to discuss 
findings and any relevant issues. Sufficient prior notice will be provided to allow the Investigator 
to prepare properly for the audit. 
The purpose of a AmMax audit or inspection is to systematically and independently examine all 
study-related activities and documents to determine whether these activities were conducted, and 
data were recorded, analyzed, and accurately reported according to the protocol, Good Clinical 
Practice guidelines of the International Conference on Harmonization, and any applicable 
regulatory requirements.  
Other regulatory agencies may also conduct similar auditing procedures. The Investigator should 
immediately notify the AmMax study monitor of any upcoming regulatory inspection. 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 60 
 
 
12. 
ADMINISTRATIVE PROCEDURES 
12.1. 
Ethics Review 
The protocol and the ICF must be reviewed and approved by a properly constituted IRB/IEC 
before study start.  
A signed and dated statement that the protocol and ICF have been approved by the IRB/IEC 
and/or national competent authorities must be given to AmMax or designee before study 
initiation.  
Prior to study start, the investigator is required to sign a protocol signature page confirming 
agreement to conduct the study in accordance with these documents and all of the instructions 
and procedures found in this protocol and to give access to all relevant data and records to 
AmMax monitors, auditors, AmMax’ Quality Assurance representatives, IRBs/IECs/REBs, and 
regulatory authorities as required.  
The Principal Investigator is responsible for informing the IRB or IEC of any amendment to the 
protocol in accordance with local requirements. In addition, the IRB or IEC must approve all 
advertising used to recruit subjects for the study. The protocol must be re-approved by the IRB 
or IEC upon receipt of amendments and annually, as local regulations require. 
The Principal Investigator is also responsible for providing the IRB or IEC with reports of any 
reportable serious adverse drug reactions from any other study conducted with the investigational 
product. AmMax will provide this information to the Principal Investigator. 
At the completion of the study, the Investigator must provide AmMax a copy of the final conduct 
report that was submitted to their IRB/IEC, including a review of AEs, as described by CFR, 
Title 21, Part 312.64. 
12.2. 
Good Clinical Practice 
This study will be conducted in accordance with principles of GCP as promulgated by the ICH, 
the FDA and applicable local regulations. Good Clinical Practice is an international ethical and 
scientific quality standard for designing, conducting, recording and reporting trials that involve 
the participation of human subjects. Compliance with this standard provides public assurance 
that the rights, safety, and well-being of human subjects are protected under current ethical 
principles and that the clinical study data are credible.  
Current CGP standards may be found in ICH Guidance E6 [R2] (Good Clinical Practice: 
Consolidated Guidance). This guidance describes the principles of GCP and the obligations of 
the IRB/IEC, the Investigator and the AmMax in conducting this study in accordance with those 
principles. 
12.3. 
Written Informed Consent 
A complete description of the study is to be presented to each potential study subject and a 
signed and dated (and witnessed, where required by law or regulation) ICF that has been 
approved by the IRB/IEC will be obtained before any study-specific procedures are performed.  

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 61 
 
 
The subject must be able to communicate well with study staff, understand and comply with the 
requirements of the study, and read and voluntarily sign ICF and the HIPAA authorization, if 
applicable, prior to the conduct of any study-specific procedures.  
All consent documents and procedures must comply with national laws, respective regulations, 
and IRBs/ECs relevant to the country where the subject participates. 
All reasonable efforts should be taken by the study staff to ensure the subject is able to 
comprehend what participation means. All consent/assent documents will be provided in the 
subject’s native language and in a form the subject is able to comprehend. Whenever possible, 
written informed consent should be sought from the subject as soon as he/she becomes capable 
of comprehending the scope of the study. 
The process of obtaining informed consent must be documented in the subject source documents. 
AmMax will provide to investigators in a separate document a proposed ICF that complies with 
the ICH GCP guideline and regulatory requirements and is considered appropriate for this study. 
Any changes to the proposed consent form suggested by the investigator must be agreed to by 
AmMax before submission to the IRB/IEC, and a copy of the approved version must be provided 
to the AmMax monitor after IRB/IEC approval. 
Females of childbearing potential should be informed that taking the study drug may involve 
unknown risks to the fetus if pregnancy were to occur during the study and agree that in order to 
participate in the study, they must adhere to the contraception requirement for the duration of the 
study. If there is any concern the subject will not reliably comply, they should not be entered in 
the study. 
Male subjects must be informed of potential risks to the fetus of a partner if conception occurs 
during the study period. 
The Principal Investigator(s) must maintain the original, signed ICF. A copy of the signed ICF 
must be given to the subject. 
12.4. 
Subject Confidentiality  
In order to maintain subject privacy, all eCRFs, study drug accountability records, and study 
reports and communications will use the 6-digit assigned Subject ID. The Investigator will grant 
the monitor and auditor from AmMax or its designee and any regulatory authority access to the 
subject’s original medical records for verification of data gathered on the eCRFs and to audit the 
data collection process. The subject’s confidentiality will be maintained and will not be made 
publicly available to the extent permitted by the applicable laws and regulations. 
AmMax will comply with the requirements of the US HIPPA regulations, and the EU General 
Data Protection Regulation. 
12.5. 
Protocol Deviation 
Investigators will apply due diligence to avoid a protocol deviation. Unless there is a safety 
concern, there should be no deviations from the study protocol. In the event of a safety concern, 
the investigator/designee must document and explain the reason for any deviation from the 
approved protocol. The investigator may implement a deviation from or a change to the protocol 
to eliminate an immediate hazard to subjects without prior IRB/IEC or regulatory authority 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 62 
 
 
approval. Immediately after the implemented deviation or change, the investigator must submit a 
report explaining the reason for protocol deviation to AmMax or its designee and to the IRB/IEC 
(if required). 
12.6. 
Protocol Amendment 
All amendments to the protocol must be documented in writing, reviewed and approved by 
AmMax, the controlling regulatory authority, and each Investigator, and submitted to the 
IRB/IEC for approval prior to implementation.  
If the protocol amendment substantially alters the study design or potential risk to the subject, 
new written informed consent for continued participation in the study must be obtained from 
each subject who is affected by the change. 
12.7. 
Protocol Termination 
AmMax has the right to terminate this study and remove all study material from the site at any 
time for medical or administrative reasons. AmMax will endeavor to give adequate notice to 
allow safe withdrawal of subjects from the study. 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 63 
 
 
13. 
DATA HANDLING AND RECORDKEEPING 
13.1. 
Case Report Forms 
The study site staff should collect and record data for the study in the source documents, and 
transcribe into the Electronic Case Report Forms (eCRF) which uses fully validated software that 
conforms to 21 CFR Part 11 requirements. Site staff will not be given access to the EDC system 
until they have been trained.  
The Investigator must ensure that complete data for the clinical study are collected and 
accurately documented in the appropriate sections of the eCRF and adequately supported by 
appropriate source documentation. In addition, it is the Investigator's responsibility to provide 
electronic signatures where requested indicating concurrence with data in the eCRF. 
Data should be entered into the eCRF within three (3) working days of each visit. 
13.2. 
Inspection of Records 
AmMax or designee will be allowed to conduct site visits to the investigation facilities for the 
purpose of monitoring any aspect of the study. The Investigator agrees to allow the monitor to 
inspect the drug storage area, study drug stocks, drug accountability records, subject charts and 
study source documents, and other records relative to study conduct. 
13.3. 
Retention of Records 
Records of subjects, source documents, monitoring visit logs, eCRFs, inventories of study 
product, regulatory documents, and other correspondence pertaining to the study must be kept in 
the appropriate study files at the site.  
The Investigator will maintain all study records according to ICH GCP and applicable local 
regulatory requirements. At a minimum, records will be retained for at least 2 years after the last 
marketing application approval or 2 years after formal discontinuation of the clinical 
development of the investigational product or according to applicable local regulatory 
requirements. However, the essential documents should be retained for a longer period if 
required by the applicable regulatory requirements or by an agreement with AmMax. 
If the Investigator withdraws from the responsibility of keeping the study records, custody must 
be transferred to a person willing to accept the responsibility. The Sponsor must be notified in 
writing if a custodial change occurs. 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 64 
 
 
14. 
PUBLICATION POLICY 
14.1. 
Clinical Trial Database  
AmMax will post key design elements of this protocol in a publicly accessible database such as 
clinicaltrials.gov. In addition, upon study completion and finalization of the study report, the 
results of this study will be posted in a publicly accessible database of clinical trial results and 
may be submitted for publication. 
14.2. 
Publishing Study Results 
All information from the study will be regarded as confidential. The Investigator agrees not to 
publicly disclose such information in any way without prior written permission from AmMax. 
AmMax must be notified of and be allowed to review and approve any potential publication of 
the results, either in part or in total, including articles in journals or newspapers, oral 
presentations, or abstracts, by the Investigator(s) or their representative(s), within a reasonable 
time frame. Study results cannot be published in violation of AmMax confidentiality restrictions 
or to the detriment of AmMax’s intellectual property rights. 
It is anticipated that the results of this study will be presented at scientific meetings and/or 
published in a peer-reviewed scientific or medical journal. A Publications Committee comprising 
the Investigators participating in the study and representatives from the Sponsor will be formed 
to oversee the publication of study results, which will reflect the experience of all participating 
study centers.  
Subsequently, individual Investigators may publish results from the study in compliance with 
their agreement with AmMax. A pre-publication manuscript is to be provided to AmMax at least 
90 days prior to submission of the manuscript to a publisher. Similarly, AmMax will provide any 
AmMax-prepared manuscript to Investigators for review at least 30 days prior to submission to a 
publisher. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 65 
 
 
15. 
LIST OF REFERENCES 
Benner B, Good L, Quiroga D, et al. Pexidartinib, a novel small molecule CSF-1R inhibitor is 
use for tenosynovial giant cell tumor: a systemiatic review of pre-clinical and clinical 
development. Drug Des Devel Therapy. 2020:14;1693-1704. 
Brahmi M, Vinceneux A, Cassier PA. Current systemic treatment options for tenosynovial giant 
cell tumor/pigmented villonodular synovitis: targeting the CSF1/CSF1R Axis. Curr Treat 
Options Oncol. 2016;17(2):10. 
Cassier PA, Italiano A, Gomez-Roca CA, et al. CSF1R inhibition with emactuzumab in locally 
advanced diffuse-type tenosynovial giant cell tumours of the soft tissue: a dose-escalation and 
dose-expansion phase 1 study. Lancet Oncol. 2015;16(8):949-956. 
Cupp JS, Miller MA, Montgomery KD, et al. Translocation and expression of CSF1 in 
pigmented villonodular synovitis, tenosynovial giant cell tumor, rheumatoid arthritis and other 
reactive synovitides. Am J Surg Pathol. 2007;31(6):970-976. 
de Saint Aubain Somerhausen N, van de Rijn M. Tenosynovial giant cell tumor: localized type / 
diffuse type. In: Fletcher CDM, Bridge JA, Hogendoorn PCW, Mertens F, eds. World Health 
Organization Classification of Tumours of Soft Tissue and Bone. 4th ed. IARC Press; 2013:100-
103. 
Ehrenstein V, Andersen SL, Qazi I, et al. Tenosynovial giant cell tumor: incidence, prevalence, 
patient characteristics, and recurrence. A registry-based cohort study in Denmark. J Rheumatol. 
2017;44(10):1476-1483. 
Eisenhauer EA, Therasse P, Bogaerts J, et al. New response evaluation criteria in solid tumours: 
revised RECIST guideline (version 1.1). Eur J Cancer. 2009;45(2):228-247. 
Evans CH, Kraus VB, Setton LA. Progress in intra-articular therapy. Nat Rev Rheumatol. 
2014;10(1):11-22. 
Gelderblom H, van de Sande M. Pexidartinib: first approved systemic therapy for patients with 
tenosynovial giant cell tumor. Future Oncol. 2020;16(29):2345-2356. 
Giustini N, Bernthal NM, Bukata SV, Singh AS. Tenosynovial giant cell tumor: case report of a 
patient effectively treated with pexidartinib (PLX3397) and review of the literature. Clin 
Sarcoma Res. 2018;8:14. 
Granowitz S, D’Antonio J, Mankin HL. The pathogenesis and long-term end results of 
pigmented villonodular synovitis. Clin Orthop Relat Res. 1976;(114):335-351. 
Heads of Medicines Agencies. Clinical Trials Facilitation and Coordination Group. 
Recommendations related to contraception and pregnancy testing in clinical trials. 2014. 
https://www.hma.eu/fileadmin/dateien/Human_Medicines/01-
About_HMA/Working_Groups/CTFG/2014_09_HMA_CTFG_Contraception.pdf 
Mastboom MJL, Verspoor FGM, Verschoor AJ, et al. Higher incidence rates than previously 
known in tenosynovial giant cell tumors. Acta Orthop. 2017;88(6):688-694. 
Mertens F, Orndal C, Mandahl N, et al. Chromosome aberrations in tenosynovial giant cell 
tumors and nontumorous synovial tissue. Genes Chromosomes Cancer. 1993;6:212-217. 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 66 
 
 
Murphey MD, Rhee JH, Lewis RB, Fanburg-Smith JC, Flemming DJ, Walker EA. Pigmented 
villonodular synovitis: radiologic-pathologic correlation. Radiographics. 2008;28(5):1493-1518. 
Nissen MJ, Boucher A, Brulhart L, Menetrey J, Gabay C. Efficacy of intra-articular 
bevacizumab for relapsing diffuse-type giant cell tumour. Ann Rheum Dis. 2014;73(5):947-948. 
Ohjimi Y, Iwasaki H, Ishiguro M, et al. Short arm of chromosome 1 aberration recurrently found 
in pigmented villonodular synovitis. Cancer Genet Cytogenet. 1996;90:80-85. 
Ostuni R, Kratochvill F, Murray PJ, Natoli G. Macrophages and cancer: from mechanisms to 
therapeutic implications. Trends Immunol. 2015;36(4):229-239. 
Palmerini E, Staals EL, Maki RG, et al. Tenosynovial giant cell tumour/pigmented villonodular 
synovitis: outcome of 294 patients before the era of kinase inhibitors. Eur J Cancer. 
2015;51(2):210-217. 
Papadopoulos KP, Gluck L, Martin LP, et al. First-in-human study of AMG 820, a monoclonal 
anti-colony-stimulating factor 1 receptor antibody, in patients with advanced solid tumors. Clin 
Cancer Res. 2017;23(19):5703-5710. 
Ponce R, Abad L, Amaravadi L, et al. Immunogenicity of biologically-derived therapeutics: 
assessment and interpretation of nonclinical safety studies. Regul Toxicol Pharmacol. 
2009;54(2):164-182. 
Radi ZA, Koza-Taylor PH, Bell RR, et al. Increased serum enzyme levels associated with 
Kuppfer cell reduction with no signs of hepatic or skeletal muscle injury. Am J Pathol. 
2011;179(1):240-247. 
Staals EL, Ferrari S, Donati DM, Palmerini E. Diffuse-type tenosynovial giant cell tumour: 
current treatment concepts and future perspectives. Eur J Cancer. 2016;63:34-40. 
Stepensky D. Local versus systemic anti-tumor necrosis factor-α effects of adalimumab in 
rheumatoid arthritis: pharmacokinetic modelling analysis of interaction between a soluble target 
and a drug. Clin Pharmacokinet. 2012;51(7):443-455. 
Tap WD, Gelderblom H, Palmerini E, et al. Pexidartinib versus placebo for advanced 
tenosynovial giant cell tumour (ENLIVEN): a randomised phase 3 trial. Lancet. 
2019;394(10197):478-487. 
Turalio [package insert]. Daiichi Sankyo, Inc; 2020. 
Verspoor F, van der Geest I, Vegt E, Veth R, van der Graaf WT, Schreuder B. Pigmented 
villonodular synovitis: current concepts about diagnosis and management. Future Oncol. 
2013;9:1515-1531. 
Wang J. Efficacy and safety of adalimumab by intra-articular injection for moderate to severe 
knee osteoarthritis: An open-label randomized controlled trial. J Int Med Res. 2018;46:326-334. 
West RB, Rubin BP, Miller MA, et al. A landscape effect in tenosynovial giant-cell tumor from 
activation of CSF1 expression by a translocation in a minority of tumor cells. Proc Natl Acad Sci 
USA. 2006;103(3):690-695. 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 67 
 
 
 
Worst Stiffness NRS 
Stiffness of the affected joint will be assessed using a self-administered NRS to assess the 
“worst” stiffness in the last 24 hours. The NRS for this item ranges from 0 (no stiffness) to 10 
(stiffness as bad as you can imagine). 
 
 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 68 
 
 
 
PROMIS PHYSICAL FUNCTION SCALE 
 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 69 
 
 
 
BPI (Short Form) 
 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 70 
 
 
 
EQ-5D-5L Assessment 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 71 
 
 
 

AmMax Bio, Inc. 
Protocol AMB-051-01  
Confidential 
Version 2.1 
 
 
Page 72 
 
 
 
COVID-19 CONTINGENCY PLAN 
COVID-19 Risk Mitigation 
To mitigate any risk of COVID-19 infection that might be associated with study participation, 
study conduct will be modified in the following ways in regions with COVID-19–related 
shelter-in-place orders, shutdown of clinical trial sites, or other restrictions that would prevent 
subjects from going to study sites.  
• The study will not screen or enroll new subjects in such regions.  
• If enrollment has already begun in a region and such restrictions are issued, remote study 
visits consisting of a combination of home health visits and telemedicine may be 
conducted in place of certain in-clinic visits. 
• The Investigator must consult with the Medical Monitor to determine the best course of 
action, particularly for situations not delineated here or for further clarification. 
If clinic visits are no longer possible, activities categorized as in-clinic–only activities will not be 
conducted. Once COVID-19–related restrictions are lifted, sites should attempt to conduct any 
missed in-clinic–only activities via an unscheduled visit. 
If a subject or a member of the subject’s household is suspected or confirmed to have 
COVID-19, only telemedicine activities can proceed. Once the subject or member of his/her 
household no longer has suspected or confirmed COVID-19, missed study activities should be 
conducted as an unscheduled visit via home health nurse visit or clinic visit, as the situation 
allows. 
Subject Disposition in the Event of COVID-19 Infection 
If a subject is suspected or confirmed to have COVID-19, the Investigator will consider AE and 
SAE guidelines (Section 9.6) and work with the subject and Medical Monitor to assess safety 
and determine whether it is in the best interest of the subject to discontinue study drug / 
withdraw from the study or to continue study drug. If a subject discontinues study drug / 
withdraws from the study because of COVID-19, the reason for early termination will be 
captured as such. 
Regulatory and Study Oversight Considerations 
If onsite monitoring visits are not possible because of COVID-19, remote monitoring may occur, 
if allowed by local and federal laws and regulations. Home healthcare staff will transfer any 
source documents collected at a home health visit to the trial site as soon as the situation allows. 
If a protocol deviation is the result of COVID-19–related circumstances, this information should 
be captured.