Conditions: Mucositis
Keywords: Mucositis Methotrexate Uridine Phosphorylase Inhibitor Head and Neck Cancer
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 22
Healthy volunteers: no

Brief summary:
Patients will receive methotrexate at a dose of 45 mg/m2 administered weekly for 4 consecutive weeks as an iv infusion along with a nutritional supplement administered two hours before the methotrexate. One hour before the methotrexate treatment the patients will be administered the first infusion of the day of either TK112690 or placebo depending on randomization. Five hours after the methotrexate treatment the patients will be administered the second treatment of either TK112690 or placebo depending on randomization. The TK112690 dose will be 45 mg/kg.

Detailed description:
Patients will receive methotrexate at a dose of 45 mg/m2 administered weekly for 4 consecutive weeks as an iv infusion along with a nutritional supplement administered two hours before the methotrexate. One hour before the methotrexate treatment the patients will be administered the first infusion of the day of either TK112690 or placebo depending on randomization infusion. Five hours after the methotrexate treatment the patients will be administered the second treatment of either TK112690 or placebo depending on randomization. The TK112690 dose will be 45 mg/kg.

* A total of 22 patients will be enrolled into one of 2 different dose groups: TK-112690 treated or placebo treated.
* Screening must be within 15 days of subject enrollment.
* Patients will remain for observation at the clinical site for a minimum of 25 hours post initial TK112690 or placebo dose.
* Study follow-up will occur on Week 6, two weeks after the last dosing of methotrexate.
* Blinding: The study will be partially blinded. The patient and investigator will be blinded as to whether TK112690 or placebo is administered. The CRO, sponsor, and site pharmacist will know whether the patient was administered active drug or placebo.

Arms:
arm 1: TK112690 treatment arm 2: TK112690 formulation

Interventions: intervention 1: TK-112690 intervention 2: Placebo TK-112690
Intervention descriptions: intervention 1: TK112690 treatment pre-methotrexate treatment intervention 2: Placebo

Protocol document:
Prot_SAP_000.pdf: 
Confidential 
 
TOSK, INC. 
2672 Bayshore Parkway, #507 
Mountain View, CA 94043 USA 
+1 408-245-6838 
 
 
PROTOCOL TITLE:                                        A Phase 2a, Multi-center, Placebo-controlled,  
                                                                              Randomized Partially Blinded, Study of Infused  
                                                                              METREXASSIST™ (Parenteral TK-112690) or  
                                                                              Metrexassist™ Placebo Administered Along with  
                                                                              Methotrexate Weekly for Four Consecutive Weeks to  
                                                                              Patients with Recurrent or Residual SCCHN. 
 
PROTOCOL NUMBER: 
 
 
CLP-2690-0003 
 
VERSION 
 
 
 
 
2.0 
 
DRUG: 
 
 
 
 
METREXASSISTTM 
 
SPONSOR NAME: 
 
 
 
Tosk, Inc. 
 
SPONSOR ADDRESS: 
 
 
2672 Bayshore Parkway, Suite 507 
Mountain View, CA  94043 USA 
 
 
 
 
 
 
CONTRACT RESEARCH 
Crystal Life Sciences 
ORGANIZATION  
Office Number: 812, 8th Floor 
Global Business Hub,Near Eon Free Zone 
 
 
 
 
 
 
Kharadi, Pune  
 
 
 
 
 
 
Maharashtra -411014 
 
 
 
 
 
 
INDIA 
 
MEDICAL WRITER 
MrsSoumiDattagupta 
 
 
 
 
 
SPONSOR MEDICAL EXPERT: 
 
Shanna Stopatschinskaja, MD 
 
 
 
 
 
 
Dolores Medical Services  
1073 Dolores St, San Francisco, CA 94110  
(908)-230-9327 (cell) 
 
 
 
 
 
 
stopats@gmx.net 
 
SAE CONTACT DETAILS:  
 
William Garland, PhD  
` 
 
 
 
 
 
 
 
FAX SAE REPORTS:  
 
 
+1 408-245-6808 
 
CONTACT NUMBER: 
 
 
+1 408-348-5164 
 
 
 
 
 
 
wgarland@tosk.com 
 
INSURANCE  
 
 
 
The New India Assurance Co. Ltd. 
                                                                               201, 202, 203, Trade Square, Beside Parishkar Flats, 
Khokhra, Maninagar (East) 380008 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 2 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
CONFIDENTIAL 
Tosk, Inc 
Confidentiality Statement 
 
Contains confidential/trade secret information subject to 18 USC § 1905, and all claims of privilege and 
confidentiality in both statutory and common law are asserted. Further dissemination may only be made 
with the written permission of Tosk, Inc. 
 
The information contained in this document, particularly unpublished data, is the property of Tosk, Inc. and 
is provided to you in confidence as Principal Investigator (PI), potential PI, or Consultant, for review by 
you, your staff, and an applicable Institutional Review Board or Independent Ethics Committee. The 
information is only to be used by you in connection with authorized clinical studies of the investigational 
drug described in the protocol. By accepting this document, you agree that you will not disclose any of this 
information to others without prior written authorization from Tosk. Inc. except to the extent necessary to 
obtain informed consent from those persons to whom the drug may be administered. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 3 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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METREXASSISTTM (Parenteral TK-112690)                                                                         Page 4 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Tosk, Inc 
 
 
INVESTIGATOR AND SITE DETAILS 
 
Investigator Names 
Site Names 
Dr. Anupam Datta 
Netaji Subash Chandra Bose Cancer Research Institute, 
3081, Nayabad Ave, New Garia, Pancha Sayar, Kolkata, 
West Bengal 700094 
Dr. Anil Kumar MR 
Bangalore Cancer Centre, 118/1-2 , Machohalli forest gate, 
Magadi Main Rd, Bengaluru, Karnataka 560091 
Dr. Kiran Ashok Kattimani 
Karnataka Cancer Therapy & Research Institute, Navanagar, 
Hubli, Karnataka 580025 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 5 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Tosk, Inc 
STUDY ACKNOWLEDGMENT / DISCLOSURE 
 
Protocol number: 
CLP-2690-0003 
 
Protocol title:              A Phase 2a, Multi-center, Placebo-controlled, Randomized, Partially                                         
Blinded, Study of Infused METREXASSIST™ (Parenteral TK-112690) or Metrexassist™  Placebo 
Administered Along with Methotrexate Weekly for Four Consecutive Weeks to Patients with Recurrent or 
Residual  SCCHN. 
 
I have carefully read and understand the foregoing protocol and agree that it contains all the necessary 
information for conducting this study safely. I will conduct this study in strict accordance with this 
protocol, ICH guidelines for Good Clinical Practice, the Code of Federal Regulations, the Health Insurance 
Portability and Accountability Act (HIPAA), if applicable, the World Medical Association Declaration of 
Helsinki (Appendix I), and local regulatory guidelines. I will attempt to complete the study within the time 
designated.   
 
I will ensure that the rights, safety and welfare, of study subjects under my care are protected. I will ensure 
control of the drugs under investigation in this study.   
 
I will provide copies of the protocol and all other study-related information supplied by the Sponsor to all 
personnel responsible to me who participate in the study. I will discuss this information with them to assure 
that they are adequately informed regarding the drug and conduct of the study.   
 
I agree to keep records on all study subject information (case report forms, shipment and drug return forms 
and all other information collected during the study) and drug disposition in accordance with DCGI and 
FDA regulations. I agree to retain and maintain strict accountability of the Investigational Products supplied 
to the study site.  
 
I will not enroll any subjects into this study until applicable Regulatory approval, IEC/IRB approval and 
Sponsor approval are obtained. 
 
 
 
 
 
 
 
 
 
 
 
 
 
Principal Investigator’s Signature 
 
 
 
Date_____________ 
 
 
 
 
 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 6 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
CONFIDENTIAL 
Tosk, Inc 
CONTACT DETAILS 
 
CRO 
Crystal Life Sciences 
Office Number : 812, 8th Floor 
Global Business Hub, Near Eon Free Zone 
Kharadi ,  Pune  
Maharashtra -411014 
INDIA 
Mobile no. +91 9850435298 
Email: vidyadharpujari@gmail.com 
DATA MANAGEMENT  
Crystal Life Sciences 
Office Number : 812, 8th Floor 
Global Business Hub, Near Eon Free Zone 
Kharadi ,  Pune  
Maharashtra -411014 
INDIA 
Mobile no. +91 9850435298 
Email: vidyadharpujari@gmail.com 
CLINICAL LABORATORY  
Oncquest Laboratories Ltd 
3, Factory Road 
Adj.Safdarjung Hospital 
New Delhi 110029 
Landline No: +91 11 26101240 
Fax: +91 11 26182231 
SPONSOR LABORATORY 
Tosk, Inc. 
725 San Aleso Ave. 
Suite 4 
Sunnyvale, California 94085 USA 
Landline No.: +1 408-245-6838 
Fax: +1 408-245-6808 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 7 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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TABLE OF CONTENTS 
 
SPONSOR/CRO SIGNATURE PAGE .......................................................................................... 3 
STUDY ACKNOWLEDGMENT / DISCLOSURE ...................................................................... 5 
Contact details ................................................................................................................................. 6 
TABLE OF CONTENTS ................................................................................................................ 7 
FIGURES ...................................................................................................................................... 12 
TABLES ....................................................................................................................................... 14 
LIST OF ABBREVIATIONS AND DEFINITIONS OF TERMS ............................................... 15 
PROTOCOL REVISION HISTORY ........................................................................................... 17 
Study Synopsis .............................................................................................................................. 18 
INTRODUCTION ........................................................................................................................ 23 
Rationale for the Clinical Development of TK-112690 ............................................................... 27 
1.0 SUPPORTING INFORMATION ........................................................................................... 27 
1.1. Name And Description Of The Investigational Drug ........................................................ 31 
1.2. Summary Pre-Clinical Efficacy Results ................................................................................ 31 
1.3. Pharmacology ........................................................................................................................ 31 
1.3.1. 
In vitro ........................................................................................................................ 31 
1.3.2 
In vivo ......................................................................................................................... 33 
1.3.3. Preclinical Pharmacokinetic (PK)/ADME Studies ......................................................... 35 
1.4. Toxicology/Safety .................................................................................................................. 37 
1.4.1. Pre-Clinical Toxicology. ................................................................................................. 37 
1.4.2 Clinical Toxicology ......................................................................................................... 38 
1.5. Summary of Clinical Data ..................................................................................................... 38 
1.5.1 Phase 1a Study ............................................................................................................. 39 
1.5.2 Phase 1b Study ............................................................................................................. 42 
1.6. Purpose of Study ................................................................................................................ 63 
1.7. Rationale for Dosage .......................................................................................................... 63 
1.7.1. TK-112690 .................................................................................................................. 63 
1.7.2. Placebo ........................................................................................................................ 63 
1.7.3. MTX ............................................................................................................................ 64 
1.8. Conduct of Trial ................................................................................................................. 64 
2.0. STUDY OBJECTIVES .......................................................................................................... 64 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 8 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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2.1. Primary Objective .............................................................................................................. 64 
2.2. Secondary Objectives ......................................................................................................... 64 
3.0. STUDY DESIGN AND TREATMENT ................................................................................ 64 
3.1 Study Outcomes/Endpoints ................................................................................................. 64 
3.1.2. Dose Modifications ......................................................................................................... 65 
3.2. Overview of Study Design and Dosing Regimen .............................................................. 65 
3.3 Concomitant Medication and Treatment ............................................................................ 65 
3.3.1. Palliative and Supportive Care .................................................................................... 66 
3.4. Restrictions ........................................................................................................................ 66 
3.4.1. Prior Therapy .............................................................................................................. 66 
3.4.2. Fluid and Food Intake ................................................................................................. 66 
3.4.3. Subject Activities and Restrictions ............................................................................. 66 
3.5. Randomization and Blinding ............................................................................................. 66 
3.6. Number of Subjects in the Study ....................................................................................... 67 
3.7. Centers ............................................................................................................................... 67 
4.1. Target Population ............................................................................................................... 67 
4.2. Inclusion Criteria ............................................................................................................... 67 
4.3. Exclusion Criteria .............................................................................................................. 68 
4.4. Waivers .............................................................................................................................. 68 
5.0. STUDY TREATMENT ......................................................................................................... 68 
5.1. Description of Treatment ................................................................................................... 68 
5.1.1. Study Drug .................................................................................................................. 68 
5.1.2. Study Drug Placebo .................................................................................................... 69 
5.1.3. MTX ............................................................................................................................ 69 
5.1.4. Nutritional Supplement ............................................................................................... 69 
5.2. Study Therapy Administration ........................................................................................... 69 
5.3. Selection and Timing of Dose for Each Subject ................................................................ 70 
5.4. Packaging and Labeling ..................................................................................................... 70 
5.5. Blind\Code Break ............................................................................................................... 71 
5.6. Storage and Accountability ................................................................................................ 71 
5.7. Investigational Product Retention at Study Site and destruction ....................................... 72 
5.8. Duration ............................................................................................................................. 72 
6.0. STUDY PROCEDURES ....................................................................................................... 72 
6.1. Informed Consent ............................................................................................................... 72 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 9 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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6.2. Subject Identification ......................................................................................................... 72 
6.2.1. Subject Registration .................................................................................................... 72 
6.2.2. Subject Number .......................................................................................................... 73 
6.3. Medical History ................................................................................................................. 73 
6.4. Physical Examination ......................................................................................................... 73 
6.5. Vital Signs, Weight Determinations and cardiovascular assessments ............................... 73 
6.6. Dispensing Study Drug ...................................................................................................... 73 
6.7. Clinical Laboratory Tests ................................................................................................... 74 
6.7.1. Laboratory Parameters ................................................................................................ 74 
6.7.2. Pharmacokinetics (PK) ............................................................................................... 75 
6.7.3. Surrogate Markers ....................................................................................................... 75 
6.7.4. ANC Blood Samples ................................................................................................... 75 
6.7.5 Summary of Blood Samples to be Obtained. ............................................................... 75 
6.7.6 Processing Blood Samples. .......................................................................................... 76 
6.6 Mucositis Assessment ......................................................................................................... 76 
7.0. STUDY Activities .................................................................................................................. 76 
7.1. Schedule of events ............................................................................................................. 76 
7.1.1 Screening Visit ............................................................................................................. 77 
7.1.2 Day before start of study (Day 0) ................................................................................ 78 
7.1.3. Days 1 and 2 (Weeks 1-4) ........................................................................................... 78 
7.1.4. Follow-Up Evaluations ............................................................................................... 79 
8.0. SELECTION AND WITHDRAWAL OF SUBJECTS ......................................................... 79 
8.1. Pregnancy ........................................................................................................................... 79 
8.2. Subject Withdrawal Criteria .............................................................................................. 79 
9.0. ASSESSMENT OF SAFETY ................................................................................................ 80 
9.1. Specification of Safety Parameters .................................................................................... 80 
9.1.1. Adverse Events ........................................................................................................... 80 
9.1.2. Laboratory Test Abnormalities ................................................................................... 81 
9.1.3. Serious Adverse Event ................................................................................................ 81 
9.1.4. Follow-up of Adverse Events ..................................................................................... 81 
9.1.5. Follow-up of Abnormal Laboratory Values ............................................................... 81 
9.1.6. Pregnancy .................................................................................................................... 82 
9.2. Assessing, Recording, and Analyzing Safety Parameters ................................................. 82 
9.2.1. ECG Parameters .......................................................................................................... 83 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 10 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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9.3. Recording and Reporting Adverse Events/Intercurrent Illnesses ...................................... 83 
9.3.1. Relationship of AE to Study Medication .................................................................... 83 
9.3.2. Unexpected Adverse Event ......................................................................................... 84 
9.3.3. Reporting of Serious Adverse Events ......................................................................... 84 
9.4. Warnings and Precautions .................................................................................................. 86 
9.4.1. Precautions .................................................................................................................. 86 
9.4.2. Treatment Failure ........................................................................................................ 86 
9.5 Efficacy Assessments .......................................................................................................... 86 
9.5.1 Mucositis Assessment Scales ....................................................................................... 86 
9.5.3. Surrogate Markers ....................................................................................................... 88 
9.5.4. Surrogate Markers ....................................................................................................... 88 
9.6 
Appropriateness of Measurements ................................................................................. 88 
10.0. STATISTICAL CONSIDERATIONS................................................................................. 88 
10.1. General Considerations .................................................................................................... 88 
10.1.1. Sample Size and Associated Power .......................................................................... 88 
10.1.2. Randomization of the Trial ....................................................................................... 89 
10.2. Populations ....................................................................................................................... 89 
10.2.1. Efficacy and Safety Population ................................................................................. 89 
10.3. Analysis of Safety ............................................................................................................ 89 
10.3.1. Incidence of Adverse Events .................................................................................... 89 
10.3.2. Laboratory Data ........................................................................................................ 90 
10.4. Subject Accountability and Missing Data ........................................................................ 90 
10.5. Interim Analysis ............................................................................................................... 90 
11.0. DIRECT ACCESS TO SOURCE DATA / DOCUMENTS AND INVESTIGATOR 
RESPONSIBILITY ...................................................................................................................... 90 
11.1. Subject Information and Consent ..................................................................................... 91 
11.2. Subject Confidentiality .................................................................................................... 91 
11.3. Source Data ...................................................................................................................... 91 
11.4. Source documents ............................................................................................................ 92 
11.5. Direct Access ................................................................................................................... 92 
11.6. Study Monitoring ............................................................................................................. 92 
12.0. QUALITY CONTROL/ QUALITY ASSURANCE ........................................................... 92 
12.1. Quality Control ................................................................................................................ 92 
12.2. Quality Assurance ............................................................................................................ 92 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 11 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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12.3. Inspection ......................................................................................................................... 93 
12.4. Audit ................................................................................................................................ 93 
13.0. ETHICS APPROVALS ....................................................................................................... 93 
13.1. Independent Ethics Committee (IEC) .............................................................................. 93 
13.2. Institutional Review Board (IRB) .................................................................................... 93 
14.0. MODIFICATION OF PROTOCOL .................................................................................... 94 
15.0. DATA HANDLING AND RECORD KEEPING ............................................................... 94 
15.1. Completion of Case Report Forms .................................................................................. 94 
15.2. Archiving ......................................................................................................................... 94 
16.0. Financial Disclosure ............................................................................................................. 95 
17.0. FINANCING AND INSURANCE ...................................................................................... 95 
18.0. PUBLICATION POLICY ................................................................................................... 95 
18.1. Publication Policy ............................................................................................................ 95 
18.2. Confidentiality ................................................................................................................. 96 
19.0. REFERENCE LIST ............................................................................................................. 96 
20.0. appendices: ........................................................................................................................... 97 
20.1. Appendix 1: World Medical Association Declaration Of Helsinki ................................. 97 
20.2. Appendix 2: ECOG Performance Status ........................................................................ 101 
20.3. APPENDIX 3: METREXASSISTTM (TK-112690 for Injection) Dose Preparation ..... 102 
20.4. appendix 4: Infusion reaction criteria ............................................................................ 104 
20.5. Appendix 5: ICH Guidelines, Topic E2 ......................................................................... 105 
20.6. Appendix 6: Mucositis Scoring ..................................................................................... 107 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 12 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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FIGURES 
 
Figure 1. Box plots showing prevention of weight loss by TK-112690 in a mouse model for MTX-
induced mucositis .......................................................................................................................... 30 
Figure 2. Plasma glucose concentrations ± SE in subjects providing a blood sample pre-dose 
and at Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined). Week1=Pre-dose, 
Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. ....... 46 
Figure 3. Plasma creatinine concentrations ± SE in subjects providing a blood sample pre-dose 
and at Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined). Week1=Pre-dose, 
Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. ....... 46 
Figure 4.Plasma AP (alkaline phosphatase) concentrations ± SE in subjects providing a blood 
sample pre-dose and at Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined). 
Week1=Pre-dose, Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, Week5= 
Study Week4. ................................................................................................................................. 47 
Figure 5. Plasma AST concentrations ± SE in subjects providing a blood sample pre-dose and at 
Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined). Week1=Pre-dose, Week2=Study 
Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. .............................. 48 
Figure 6.Plasma ALT concentrations ± SE in subjects providing a blood sample pre-dose and at 
Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined).Week1=Pre-dose, Week2=Study 
Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. .............................. 48 
Figure 7. WBC concentrations ± SE in subjects providing a blood sample pre-dose and at Weeks 
1, 2, 3, and 4 (24-hour and 48-hour values combined). Week1=Pre-dose, Week2=Study Week1, 
Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. ........................................... 49 
Figure 8. WBC concentrations for every subject providing a blood sample pre-dose and at 
Weeks 1, 2, 3, and 4 (24-hour and 48-hour samples combined).Week1=Pre-dose, Week2=Study 
Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. .............................. 50 
Figure 9.WBC concentrations for every subject providing a blood sample pre-dose and at Weeks 
1, 2, 3, and 4 (24-hour and 48-hour samples combined).Week1=Pre-dose, Week2=Study Week1, 
Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. ........................................... 50 
Figure 10. Lymphocyte concentrations for every subject providing a blood sample pre-dose and 
at Weeks 1, 2, 3, and 4 (24-hour and 48-hour samples combined). Week1=Pre-dose, 
Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. ....... 51 
Figure 11. Hematocrits for every subject providing a blood sample pre-dose and at Weeks 1, 2, 
3, and 4 (24-hour and 48-hour samples combined). Week1=Pre-dose, Week2=Study Week1, 
Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. ........................................... 51 
Figure 12. Bar chart showing mean concentration of TK-112690, pg/mL ± SE, for individual 
dosing intervals at 5 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes 
data from all patients who completed 4 doses.Interval 1=Study Week 1, Interval 2=Study Week 
2, Interval 3=Study Week 3, and Interval 4=Study Week 4. ......................................................... 57 
Figure 13. Bar chart showing mean concentration of TK-112690, pg/mL ± SE, for individual 
dosing intervals at 24 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690.Analysis includes 
data from all patients who completed 4 doses.Interval 1=Study Week 1, Interval 2=Study Week 
2, Interval 3=Study Week 3, and Interval 4=Study Week 4. ......................................................... 57 
Figure 14.Bar chart showing mean concentration of uridine, pg/mL ± SE, for individual dosing 
intervals at 5 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690.Analysis includes data from 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 13 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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all patients who completed 4 doses. Interval 1=Study Week 1, Interval 2=Study Week 2, Interval 
3=Study Week 3, and Interval 4=Study Week 4. .......................................................................... 58 
Figure 15. Bar chart showing mean score NCI mucositis scale for individual dosing intervals at 
24 and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes data from all 
patients evaluated. ........................................................................................................................ 60 
Figure 16. Bar chart showing mean score WHO oral mucositis scale for individual dosing 
intervals at 24 and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes 
data from all patients evaluated. .................................................................................................. 60 
Figure 17. Bar chart showing mean score PROMS scale for individual dosing intervals at 24 
and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes data from all 
patients evaluated. ........................................................................................................................ 61 
Figure 18. Bar chart showing mean OMAS mouth pain score for individual dosing intervals at 
24 and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes data from all 
patients evaluated. ........................................................................................................................ 62 
Figure 19. Bar chart showing mean OMAS difficulty swallowing score for individual dosing 
intervals at 24 and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes 
data from all patients evaluated. .................................................................................................. 62 
Figure 20. Overview of Study Design and Dosing Regimen. ....................................................... 65 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 14 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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TABLES 
 
Table 1.Mean plasma concentrations of TK-112690 and uridine for 0.08 and 0.5 time points ... 33 
Table 2. Selected findings preclinical pharmacokinetic studies with TK-112690 ....................... 36 
Table 3. Safety studies with TK-112690 ...................................................................................... 37 
Table 4. Mean plasma concentrations TK-112690 in volunteers (3 volunteers/dose group). ...... 40 
Table 5. Mean pharmacokinetic parameter estimates derived from plasma concentrations for 15-
45 mg/kg doses ............................................................................................................................. 41 
Table 6. Patient characteristics, Dropouts and Reason for Dropouts ........................................... 43 
Table 7.Reported SAEs in Study. ................................................................................................. 44 
Table 8. CTCAE Grade 3/4 Adverse events ................................................................................. 45 
Table 9. Other Safety Tests ........................................................................................................... 52 
Table 10. Central Laboratory Tests .............................................................................................. 74 
Table 11. Nature and total volume of blood samples ................................................................... 75 
Table 12. Schedule of events (weekly cycle for 4 weeks and follow up at 6 week) .................... 76 
Table 13. Tumor response criteria ................................................................................................ 87 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 15 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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LIST OF ABBREVIATIONS AND DEFINITIONS OF TERMS 
AE 
 
Adverse event 
ADME 
 
Absorption, Distribution, Metabolism and Excretion 
ALB 
 
Albumin 
ALT 
 
Alanine transaminase (SGPT) 
ANC 
 
Absolute neutrophil count 
AP 
 
Alkaline phosphatase 
AST 
 
Aspartate transaminase (SGOT) 
AUCLast 
 
AUC calculated using last concentration measured  
AUCInf 
 
AUCLast + last measured concentration/terminal elimination rate 
constant   
AUMC 
 
Area under moment curve 
BMI 
 
Body mass index 
BUN 
 
Blood urea nitrogen 
CFR 
 
Code of Federal Regulations 
CD40 
 
Cluster of differentiation 40, CD40 is a costimulatory protein 
found on antigen presenting cells and is required for their 
activation. 
CD40L 
 
Ligand for CD40 
CLS 
 
Crystal Life Sciences (a clinical CRO) 
CNS 
 
Central nervous system 
CR 
 
Creatinine 
CRF 
 
Case report form 
CRO 
 
Contract Research Organization 
CT 
 
Computerized tomography 
CTCAE 
      Common terminology criteria adverse events 
dL 
 
Deciliter 
DLT 
 
Dose limiting toxicity 
ECG/EKG 
      Electrocardiogram 
ECOG 
 
Eastern Cooperative Oncology Group 
ESF  
 
Eligibility Screening Form 
FDA 
 
Food and Drug Administration 
FGF-9 
 
FGF-9 (fibroblast growth factor-9) is an approximately 26 kDa 
secreted glycoprotein of the FGF family. FGF family members 
possess broad mitogenic and cell survival activities 
GCP 
 
Good Clinical Practices 
GLP 
 
Good Laboratory Practice 
GGT 
 
Gamma-glutamyltransferase 
GI 
 
Gastrointestinal 
Hct 
 
Hematocrit 
Hb 
 
Hemoglobin 
HBsAg 
 
Hepatitis B surface antigen 
HCV 
 
Hepatitis C virus 
HIV 
 
Human immunodeficiency virus 
HPLC 
 
High performance liquid chromatography 
ICH 
 
International Conference on Harmonization 
IEC 
 
Independent Ethics Committee 
IL 
 
Interleukin 
IND 
 
Investigational New Drug 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 16 of 110 
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IEC 
 
Independent Ethics Committee 
IRB 
 
Institutional Review Board 
iv 
 
Intravenous 
ip 
 
Intraperitoneal 
LC/MS 
 
Liquid chromatography/mass spectrometry 
LC/MS/MS 
      Liquid chromatography/mass spectrometry/mass spectrometry  
LDH 
 
Lactic Acid Dehydrogenase 
LEU 
 
Leucovorin 
LLN 
 
Lower limit of normal 
LPS 
 
Lipopolysaccharide 
MedDRA 
      Medical Dictionary for Regulatory Activities 
MCH 
 
Mean corpuscular hemoglobin 
MCHC 
 
Mean corpuscular hemoglobin concentration 
MCV 
 
Mean corpuscular volume 
mL 
 
Milliliter 
MRI 
      Magnetic resonance imaging 
MRT 
 
Mean residence time 
MRTLast 
 
MRT calculated using last concentration measured 
MRTInf 
 
MRT calculated using last measured concentrationt 
MTD 
 
Maximum tolerated dose 
MTX 
 
Methotrexate 
OMAS 
 
Oral mucositis assessment scale 
PBS 
 
Phosphate buffered saline 
PI 
 
Principal Invesatigator 
PK 
 
Pharmacokinetics 
PD 
 
Pharmacodynamics 
PROMS 
 
Patient-reported oral mucositis symptom scale 
PT 
 
Prothrombin time 
PTT 
 
Partial thromboplastin time 
RBC 
 
Red blood cell 
Rsq 
 
Regression square 
RECIST 
      Response Evaluation Criteria in Solid Tumors 
SAE 
 
Serious adverse event 
SCCHN 
      Squamous cell carcinoma of the head and neck 
SD 
 
Standard deviation 
SE 
 
Standard Error 
SGOT 
 
Serum glutamic oxaloacetic transaminase (AST) 
SGPT 
 
Serum glutamic pyruvic transaminase (ALT) 
TEAE 
 
Treatment emergent adverse event 
TK-112690 
      Tosk’s anti-mucositis adjuvant 
TNF 
 
Tumor necrosis factor 
ULN 
 
Upper limit of normal 
USP 
 
United States Pharmacopoeia 
WBC 
 
White blood cell 
WHO 
 
World Health Organization 
WMA 
 
World Medical Association 
µg 
 
Micrograms 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 17 of 110 
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PROTOCOL REVISION HISTORY 
 
Sr. 
No.  
Revised version.  
Revision date 
Revision Summary  
2 
V2— 
10 February 2019 
1. Title of protocol simplified. 
2. MTX dose reduced to 45 
mg/m2 
3. Inclusion criteria modified to 
specifically 
include 
only 
patients who have failed at 
least one round of non-MTX 
chemotherapy 
4. Exclusion criteria modified to 
specifically exclude patients 
who have not failed at least 
one 
round 
of 
non-MTX 
chemotherapy 
5. Labels for placebo vials and 
the placebo storage carton 
updated 
 
 
 
 
 
 
 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 18 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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STUDY SYNOPSIS 
 
Study 
CLP-2690-0003 
 
Title of the Study 
A Phase 2a, Multi-center, Placebo-controlled, Randomized, Partially Blinded, Study of Infused 
METREXASSIST™ (Parenteral TK-112690) or Metrexassist™  Placebo Administered Along with 
Methotrexate Weekly for Four Consecutive Weeks to Patients with recurrent or residual  SCCHN. 
 
 
Principal Investigators  
Approximately 3 
 
Study Centers  
Approximately 3 
 
Clinical Phase 
Phase 2a 
 
 
Number of Subjects 
The total number of individuals enrolled will be 22, 11 dosed TK-112690 and methotrexate and 11 
patients dosed methotrexate and placebo. All patients will be dosed a nutritional supplement to assure 
adequate basal levels of uridine and uridine-related biochemicals.  
 
Study Drug:TK-112690, an anhydrouridine inhibitor of uridine phosphorylase 
 
Projected Subject Enrollment Duration  
10 months  
 
Objectives 
Primary 
Determine pilot efficacy of an iv infusion of TK-112690 to placebo as a mucositis preventive in subjects 
with locally advanced, residual, or recurrent or metastatic SCCHN scheduled to receive MTX as 
chemotherapy. 
 
Secondary 
Confirmation of the safety/tolerability of a continuous administered weekly for 4 weeks and lowering of 
plasma concentrations of surrogate markers of mucositis, e.g., CD40/CD40L, post TK-112690 in patients 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 19 of 110 
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suffering from local, advanced, residual or  recurrent, metastatic SCCHN receiving sequential continuous 
iv infusions of TK-112690 and MTX or TK-112690 placebo and MTX. 
 
Study Design 
A Phase 2a, Multi-center, Placebo-controlled, Randomized, Partially Blinded, Study in Patients with 
recurrent or residual SCCHN. 
 
Patients will receive MTX at a dose of 45 mg/m2 administered weekly for 4 consecutive weeks as an iv 
infusion along with a nutritional supplement containing uridine monophosphate (Fortasyn Connect™ / 
SouvenaidTM, Nutricia NV) administered two hours before the MTX. One hour before the MTX treatment 
the patients will be administered the first infusion of the day of either TK-112690 or placebo depending 
on randomization infusion. Five hours after the MTX treatment the patients will be administered the 
second treatment of either TK-112690 or placebo depending on randomization. The TK-112690 dose will 
be 45 mg/kg.  
 
● A total of 22 patients will be enrolled into one of 2 different dose groups: TK-112690 treated or 
placebo treated.  
● Screening must be within 15 days of subject enrollment. 
● Patients will remain for observation at the clinical site for a minimum of 25 hours post initial TK-
112690 or placebo dose. 
● Study follow-up will occur on Week 6, two weeks after the last dosing of MTX. 
● Blinding: The study will be partially blinded. The patient and investigator will be blinded as to 
whether TK-112690 or placebo is administered. The CRO,sponsor, and site pharmacist will 
know whether the patient was administered active drug or placebo. 
 
Main Study Endpoints/Outcomes 
● Mucositis Outcomes 
Mucositis status in the patients will be evaluated using 4 different published and validated mucosit
scales: OMAS/Sonis, PROMS, WHO, and CTCAE/mucositis. 
 
● Surrogate Marker Outcomes 
Plasma samples will be obtained to determine surrogate markers of mucositis, eg, CD40/CD40L
TNF-α, etc. 
 
● Safety Outcomes 
Adverse events will be assessed throughout the study. Incidents of toxicity will be determined to
at least possibly related to the study drug and graded according to CTCAE Version 4.0.  
 
Study Procedures and Study Assessments  
● A review of a patient’s medical history including a detailed history of the patient’s cancer and 
concomitant medications will be performed at screening. 
● Screening for drugs of abuse will be performed at the time of patient screening and Day 0 (the 
day before start of study). 
● Vital sign measurements will be performed at patient screening, on Day 0, and at 24 and 48 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 20 of 110 
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hours post each initial infusion of TK-112690/placebo as well as on Day 1 of Week 6. 
● Physical examinations will be performed at screening, on Day 0, and 24 and 48 hours post each 
initial infusion of TK-112690/ placebo as well as on Day 1 of Week 6. 
● ECOG performance status will be determined at patient screening, on Day 0, and at Day 1 of 
Weeks 6. 
● For pre-menopausal females, a urine pregnancy test will be performed at screening, on Day 0, 
and at Day 1 of Week 6. 
● 12-Lead ECG at screening and 24 hours post each initial infusion of TK-112690/ Placebo. 
● CBC, Liver function test, Kidney function test  determination at the clinical site prior to 
methotrexate treatment to ensure patient fit to dose. 
● Serum chemistry, hematology, coagulation and urinalysis at screening, Day 0, and at 24 and 48 
hours post each initial infusion of TK-112690/ placebo as well as on Day 1 of Week 6. 
● Adverse events will be evaluated 5, 24 and 48 hours post each initial infusion of TK-112690/ 
Placebo as well as on Day 1 of Week 6.  
● Blood samples will be obtained pre-initial infusion of TK-112690/ placebo and 5, 24 and 48 
hours post each initial infusion as well as on Day 1 of Week 6. Plasma will be obtained from the 
blood samples in order to determine   surrogate markers of mucositis, e.g., CD40/CD40L, TNF-
α, etc. 
● Patients will be evaluated for extent and severity of mucositis using established mucositis rating 
scales, e.g., OMAS/Sonis, PROMS, WHO, and CTCAE/mucositis on the day prior to study start 
(Day 0), and 24 and 48 hours post each initial infusion of TK-112690/ placebo as well as on 
Day 1 of Week 6. Examination will assess the lining of the mouth, throat, and other linings of 
the digestive tract. Incidence of oral mucositis, duration of severe oral mucositis, throat 
soreness, severity of pain and use of parenteral or transdermal opioid analgesics will be 
assessed. 
 
Study Population  
Patients at least 18 years old, diagnosed with locally advanced or residual or recurrent or metastatic 
SCCHN and scheduled to receive 45 mg/m2 MTX to treat their cancer. The diagnosis must be confirmed 
by histopathology or cytology. 
 
Inclusion Criteria  
● Male and female subjects over 18 years old with a histologically or cytological confirmed 
diagnosis of locally residual, recurrent or metastatic SCCHN. 
● Subject must have failed at least onecourses of non-MTX chemotherapy, orone course of non-
MTX chemotherapyand chemo radiation for treating their SCCHN. 
● No prior systemic treatments for cancer (chemotherapy and/or radiotherapy) 4 weeks prior to 
screening. 
● No other concurrent, active, invasive malignancies.   
● An Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. 
● Must have a life expectancy of at least 6 months. 
● History of brain metastases allowed if disease has stabilized or improved after radiation and/or 
craniotomy. 
● No active angina or uncontrolled arrhythmia. 
● No detectable infection including hepatitis B/C and HIV. 
● Not pregnant or nursing. Women of childbearing potential must have a negative urine pregnancy 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 21 of 110 
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test at screening and on the day before dosing and must use medically acceptable methods of 
birth control. Acceptable methods of birth control include oral or transdermal contraceptives, 
condoms, spermicidal foam, IUD, progestin implant or injection, abstinence, vaginal ring, or 
sterilization of partner. The reason for non-childbearing potential, such as bilateral tubal 
ligation, bilateral oophorectomy, hysterectomy, or post-menopausal for ≥ 1 year, must be 
specified in the patient’s medical history file and CRF. 
● Must have adequate organ and immune function as indicated by the following laboratory values: 
 
Parameter Laboratory Values 
Serum creatinine 
    ≤1.5 x ULN 
Est. creatinine clearance ≥45 mL/min 
Total bilirubin 
≤2.0 mg/dL (≤34.2 µmol/L) 
AST & ALT  
≤3 x ULN  
Absolute granulocytes    ≥1.5 x 109 cells/L 
Platelets  
 
≥100,000/µL  
● Be able to read orunderstand, and provide a signature or thumb impression on the Informed 
Consent Form (ICF) before entering the study. 
 
Exclusion Criteria  
● Subject has not failed at least one courses of non-MTX chemotherapy or one course of non-
MTX chemotherapy and chemo radiation for treating their SCCHN. 
● Uncontrolled active infection. 
● Current mucositis (>Grade 1).  
● Pregnant or nursing mother. 
● Prior history of a cerebrovascular accident or hemorrhage.  
● Congestive heart failure, as defined by New York Heart Association class III or IV. 
● Uncontrolled hypertension. 
● Active psychiatric/mental illness making informed consent or useful clinical follow-up unlikely. 
● Subjects who have previously been enrolled into this study and subsequently withdrew. 
● Subject receiving other investigational agent(s). 
● Any systemic immunosuppressive medication/therapy (eg, other chemotherapy, steroids). 
● Any significant systemic illness, unstable or severe medical condition(s) that could put the 
subject at risk during the study, interfere with outcome measures, or affect compliance with the 
protocol procedures such as intercurrent infection and/or autoimmune disease, ie, any condition 
that compromises the immune system. 
● Known or suspected intolerance or hypersensitivity to the study materials (TK-112690 and/or 
excipients or closely related compounds). 
● Subjects, who have received, or plan to receive, radiation or chemotherapy within 4 weeks of 
screening. 
● Subjects that have a history of poor compliance in clinical research studies. 
● Subjects that have participated in any other investigative clinical trial in the past 4 weeks. 
 
Dose and Dosing Regimen 
The dose of METREXASSISTTM (TK-112690) will be 45 mg/kg administered parenterally over one 
hour in a clear, neutral, aqueous formulation (no organic chemical excipients). METREXASSISTTM will 
be given one hour before and 5 hours after the MTX treatment. The nutrient drink will be given one hour 
before METREXASSISTTM infusion. The MTX formulation will that traditionally used as standard-of-


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 22 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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care at a study site. 
 
Test Product, Dose and Mode of Administration 
● METREXASSISTTM (TK-112690 for Infusion) is a clear, sterile, neutral (pH=7.4), aqueous 
solution containing 5 mL of 100 mg/mL TK-112690. 
● METREXASSISTTM is packaged as a 5 mL solution in a 10 mL flint glass vial with an 
elastomeric stopper held in place by an aluminum seal and flip-off cap. The concentration of 
TK-112690 in the solution is 100 mg/mL 
● METREXASSISTTM will be administered as a continuous iv infusion over a duration of one 
hour in a volume of 250 mL normal saline. 
● The nutrient drink, Fortasyn Connect™ / SouvenaidTM, is commercially available as a 125 mL, 
125 kcal solution. The drink is administered orally. 
● The placebo is isotonic saline.  
 
Reference Therapy or Comparator 
 Placebo-Isotonic saline  
Follow-up  
Subjects need to return at Day 1 of Week 6, which is two weeks from the last dose of the study drug. 
 
Statistical Methods 
● Safety: AEs, vital signs, physical examination data and clinical laboratory data will be analyzed 
using descriptive statistics with safety outcomes for patients in a dose group pooled & compared 
with patients in other groups. 
● Mucositis: Scale data from individual doses groups will be analyzed using descriptive statistics. 
● Surrogate Markers: Plasma concentration data evaluated for individual doses groups using 
descriptive statistics as well as compared with Surrogate marker data from the completed Phase 
1bstudy.  
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 23 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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INTRODUCTION 
 
Methotrexate (MTX, structure below) was introduced in the early 1950s and remains the main 
antifolate in widespread use despite numerous attempts to replace or complement this 
chemotherapeutic.1,2,3,4MTX is used to treat a variety of cancers, such as head and neck cancer, 
leukemia, osteosarcoma, breast cancer, acute lymphoblastic, lymphocytic/meningeal leukemia, 
and non-Hodgkin lymphoma. It is also used to treat cancer of the uterus, breast, lung, gestational 
choriocarcinoma, chorioadenoma destruens, and hydatidiform mole. In these applications, MTX 
limits the metabolism of the cancer cell by inhibiting the enzyme responsible for folic acid 
metabolism, resulting in cellular folic acid deficiency,causingcell death. A particularly attractive 
application of MTX is as a relatively inexpensive, but useful, palliative treatment for advanced 
head and neck cancer.5 
 
 
 
MTX is also used clinically in a variety of other pathogenic conditions, including rheumatoid 
arthritis, psoriasis, uveitis, and graft-versus-host disease.6 In these applications, lower doses of 
MTX are used and the effect is generally attributed to an immunosuppression phenomenon. 
 
Besides affecting cancerous tissue, MTX often produces unintended adverse effects in normal, 
non-cancerous, tissues, particularly tissues that have a high rate of proliferation, such as gut and 
bone marrow.7 The side effects of MTX can threaten survival. Gastrointestinal mucosa, bone 
marrow, liver and hair are particularly vulnerable to the effects of MTX. Renal toxicity is also 
frequent with high doses of MTX. 
                                               
1Mager DR, Methotrexate, Home Health Now. 2015; 33:139-41. 
2 McGuire JJ. Anticancer antifolates: Current status and future directions. Curr Pharm Des. 2003; 9:2593-613. 
3 Visentin M, Zhao R, Goldman ID. The antifolates. Hematol Oncol Clin North Am. 2012; 26:629-48. 
4 Jolivet J, Cowan KW, Curt GA, Clendeninn NJ, Chabner BA. The pharmacology and clinical use of MTX. N Engl 
J Med. 1983; 309:1094–1104. 
5 Chakraborty S, Geetha M, Sujith KM, Biji MS, Sateeshan B. Palliative low dose fortnightly methotrexate in oral 
cancers: Experience at a rural cancer centre from India. South Asian J Cancer. 2014; 3:166-170. 
6Hashkes PJ, Becker ML, Cabral DA, Laxer RM, Paller AS, Rabinovich CE, Turner D, Zulian F. 
Methotrexate: new uses for an old drug. J Pediatr. 2014; 164: 231-6. 
7Gaies E, Jebabli N, Trabelsi S, Salouage I, Charfi R, Lakhal M, Klouz A, Methotrexate Side Effects: Review 
Article. J Drug MetabToxicol 2012. 3:125-129.  


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Mucositis describes the inflammation, lesions, and ulcers that develop in the oral and 
gastrointestinal tract because of treatment with chemotherapeutics such as MTX.8 An effective 
adjuvant treatment that ameliorates MTX-induced mucositis would provide important relief to 
cancer patients undergoing chemotherapy. 
 
Mucositis can affect up to 100% of people receiving high doses of chemotherapy.9 The 
frequency of mucositis is responsible for increased patient hospitalization, resulting in a 
substantial financial burden for both patients and hospitals10,11 In addition, mucosal damage 
increases the susceptibility of infection and sepsis in neutropenic patients. Pain, discomfort and 
the inability to eat or drink are the most frequent occurrences for patients undergoing 
chemotherapy. As a result, delays and suspensions in chemotherapy regimens are common for 
patients experiencing severe mucositis. The frequency, financial burden, and disruptions of 
effective cancer therapy all underscore the need for treatments that can mitigate mucositis. 
 
To date, no product is available to effectively treat MTX-induced mucositis, especially mucositis 
outside the oral cavity: 
 
● Several publications from animal studies have revealed evidence for compounds that can 
protect against MTX induced small intestinal damage. These potentially therapeutic 
compounds include various nutraceuticals, α-lipoic acid, lactoferrin, taurine, 
docosahexaenoic acid, prostaglandin E1, N-acetylcysteine.12,13,14,15,16[,17,18] To date, none 
of these compounds are being widely explored in the clinic as potential side-effect 
reducing adjuvants for MTX-induced mucositis. 
 
                                               
8 Villa A, Sonis ST. Mucositis: pathobiology and management. CurrOpin Oncol. 2015; 27:159-64. 
9 Sonis ST, Perspectives on Cancer Therapy-Induced Mucosal Injury. Cancer. 2004;100:1995-2025. 
10 Carlotto A, Hogsett VL, Maiorini EM, Razulis JG, Sonis ST. The economic burden of toxicities associated with 
cancer treatment: review of the literature and analysis of nausea and vomiting, diarrhoea, oral mucositis and fatigue. 
Pharmacoeconomics. 2013; 31: 753-66. 
11Elting, LS, The Burdens of Cancer Therapy. Cancer. 2003;98:1531-1539. 
12 Thomsen M, Vitetta L Adjunctive Treatments for the Prevention of Chemotherapy- and Radiotherapy-Induced 
Mucositis. Integr Cancer Ther. 2018 Aug 23:1534735418794885 (ePub prior to publication) 
13 Ahmed AA, Selim MA, El-Sayed NM. α-Lipoic acid ameliorates oral mucositis and oxidative stress induced by 
methotrexate in rats. Histological and immunohistochemical study. Life Sci. 2017;171: 51-59. 
14Van’T Land B. Lactoferrin reduces MTX-induced small intestinal damage possibly through inhibition of GLP-2 
mediated epithelial cell proliferation. Digestive Diseases and Sciences. 2004;49:425-433. 
15Cetiner M. Taurine protects against MTX induced toxicity and inhibits leukocyte death. Toxicology and Applied 
Pharmacology. 2005;209;39-50. 
16Horie T. Docosahexaenoic acid exhibits a potent protection of small intestine from MTX-induced damage in mice. 
1998; 62(15):1333-1338. 
17 Gao F. Protective effect of a synthetic analog of prostaglandin E1 on the small intestinal damage induced by the 
administration of MTX to rats. Journal of Pharmaceutical Sciences. 2001; 90:1040-1048. 
18Ciralik H. Effects of N-Acetylcysteine on MTX-induced small intestinal damage in rats. The Mount Sinai Journal 
of Medicine. 2006;73:1086-1092. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 25 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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● Epidermal growth factors are candidates for reducing radiation and chemotherapy 
induced mucositis. Palifermin (human recombinant keratinocyte growth factor-1) is 
approved by the FDA to decrease the incidence and duration of severe oral mucositis in 
patients with hematologic malignancies receiving myelotoxic therapy requiring 
hematopoietic stem cell support. Palifermin is thought to maintain mucosal barrier 
integrity by stimulating basal cell proliferation and differentiation in the oral epithelia19,20 
The use of a protein that stimulates growth in cancer patients is problematic and 
concerning. 
 
Preliminary preclinical data demonstrates the 
potential of TK-112690 (structure on the right) as 
a cytoprotectant against MTX induced mucositis.  
 
● In a mouse model of human MTX-
induced mucositis, TK-112690 protects 
from weight loss,21 one of the cardinal 
features of human mucositis using a 
published weight model that mimics many of the features of “natural” mucositis.22 
● TK-112690 limits the increase in systemic WBC concentration observed in mice post-
MTX treatment,23 and 
● TK-112690 limits the increase in mucosal permeability observed in mice post-MTX 
treatment.24 
 
Finally, TK-112690 appears unusually safe for clinical use. The compound does not affect the 
cytotoxicity of MTX toward three different cancer cell lines25, 26 and two xenograft studies..27, 28 
                                               
19 Nguyen DT, Shayani S, Palmer J, Dagis A, Forman SJ, Epstein J, Spielberger R. 
Palifermin for prevention of oral mucositis in allogeneic hematopoietic stem cell transplantation: a single-institution 
retrospective evaluation. Support Care Cancer. 2015; 23: 3141-7. 
20Blijlevens N and Sonis ST. Palifermin(recombinant keratinocyte growth factor-1): a pleiotropic growth factor with 
multiple biological activities in preventing chemotherapy and radiotherapy induced mucositis. Annals of Oncology. 
2007;18:817-826 
21 Tosk Report: In vivo Response of Methotrexate (200 mg/kg Day 2, 100 mg/kg Day 3) and/or Dose Range of TK-
112690 (15, 30, 45, 60, or 90 mg/kg) ip 3 Hours Before and After Methotrexate in Female C57Bl/6 Mice Pre-dosed 
with  LPS (5 µg, Day 1, ip), FSR-PC-2690-0002 
22deKoning BAE, Contributions of mucosal immune cells to MTX-induced mucositis. International Immunology. 
2006;18: 941-949. 
23 Tosk Report: In vivo Measurement of Leukocytosis in Female C57Bl/6 Mice Treated with Methotrexate (50 
mg/kg Days 1, 2, 3, 4, 6, and 8, ip) with or without TK-112690 (60 mg/kg 3 Hours Before and After Methotrexate, 
ip), FSR-PC-2690-0012 
24 Tosk Report: In Vivo Effect of 60 mg/kg TK-112690 (ip) on Increased Intestinal Permeability Induced by 
Methotrexate (100 mg/kg ip Days 2, 3 and 4) in C57Bl/6 Mice, FSR-PC-2690-0043 
25 Tosk Report: In Vitro Evaluation in U-937 and CCRF-CEM Cells of the Effect of a 72 Hour Treatment with TK-
112690 (1.0, 10, 100 µM) or Leucovorin (1.0, 10, 100 µM) on the Antiproliferative Activity of Methotrexate (0.03 
µM), FSR-PC-2690-0004. 
26 Tosk Report: In Vitro Effect of TK-112690 (1.0, 10, 100 µM) on the Cytotoxicty of Methotrexate (0, 0.01, 0.03, 
0.1, 0.3, 1.0, 3.0, 10, 100 µM) in AS283 Human Lymphoma Cells using CellTiter-Glo Assay, FSR-PC-2690-0014. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 26 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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No untoward events were noted in studies in rats and dogs administered high doses of TK-
112690 every day29 for 28-days.30,31 No CV effects were observed in a study with TK-11290 in 
instrumented monkeys. Further, no effects on the most common cytochrome p-450s were 
observed with TK-112690.32 A study in human volunteers dosed once with up to 45 mg/kg of 
TK-112690 produced no untoward events,33 and a predictable PK profile.34 Recently, a Phase 1b 
study completed in 25 patients with head and neck cancer. No unanticipated safety findings were 
observed and promising anti-mucosal activity was found.  
 
TK-112690 is an inhibitor of uridine phosphorylase (UPase). The clearance of uridine is 
controlled by UPase, and the inhibition of UPase leads to an increase of uridine (↑ uridine 
salvage).35 In this regard, increased uridine is associated with protection from drug-induced 
toxicity in many situations, eg, zidovudine-induced mitochondrial myopathy/hyperlactatemia in 
mice,36 cortical neuron damage from glucose deprivation-induced death,37 glucose deprivation-
induced death of immune-stimulated astrocytes,38 zalcitabine-induced micro-vesicular 
steatohepatitis in mice,39 in an animal model of lung inflammation,40 cardinal features of 
asthmatic airway inflammation,41 protective effect on cornea in a rabbit dry eye model,42 
                                                                                                                                                       
27 Tosk Study: In vivo Response of Subcutaneously Planted AS283 Human Lymphoma Xenografts in Male C.B.-17 
SCID Mice to Treatment with Methotrexate (5.0 mg/kg q1d x 5, ip) and/or TK-112690 (30 mg/kg, 3 Hours Before 
and After Methotrexate, ip), FSR-PC-2690-0020 
 
28 Tosk Report: In Vivo Response of Subcutaneously Planted CCRF-CEM Leukemia Xenografts in Male Athymic 
NCr-nu/nu Mice to Treatment with Methotrexate (7.5 mg/kg for 5 Days, ip) and/or TK-112690 (30 mg/kg 3 Hours 
Before and After Methotrexate, ip), FSR-PC-2690-0003 
 
29 Tosk Report: A Cardiovascular Safety Pharmacology Study Using Radiotelemetry in Conscious Cynomolgus 
Monkeys  Following Intravenous Injection, FSR-PC-2690-0028. 
30 Tosk Report: Toxicokinetics 0, 20, 60 and 180 mg/kg TK-112690 Administered iv Daily in a 28-day General 
Toxicity Study in Sprague-Dawley Rats, FSR-PC-2690-0009. 
31 Tosk Report: Toxicokinetics 0, 20, 60 or 180 mg/kg TK-112690 Administered iv Daily in a 28-Day General 
Toxicity Study in Beagle Dog, FSR-PC-2690-0010. 
32 Tosk Report: Determination of the Potential for TK-112690 to Inhibit the Enzyme Activities of CYP1A2, 
CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4 in Human Liver Microsomes, 
FSR-PC-2690-0026 
33 Tosk Report: TK90Clinical_Phase1a, FSR-CL-2690-0002 
34 Tosk Report: TK90PKPDUE_Phase1a FSR-CL-2690-0001. 
35 Pizzorno G, Cao D, Leffert JJ, Russell RL, Zhang D, Handschumacher RE. 
Homeostatic control of uridine and the role of uridine phosphorylase: a biological and clinical update. 
BiochimBiophys Acta. 2002 Jul 18;1587(2-3):133-44. 
36Lebrecht D et al., Uridine Supplementation Antagonizes Zidovudine-induced mitochondrial myopathy & 
hyperlactatemia in mice, Arthritis Rheum 2008; 58: 318.  
37 Choi JW et al., Uridine Protects Cortical Neurons from Glucose Deprivation-Induced Death: Possible Role of 
Uridine Phosphorylase. J Neurotrauma 2008; 25: 695. 
38 Choi JW et al., Uridine prevents the glucose deprivation-induced death of immune-stimulated astrocytes via the 
action of UPase. Neurosci Res. 2006; 56: 111. 
39Lebrecht D et al., Uridine Supplementation Antagonizes Zalcitabine-induced Microvesicular Steatohepatitis in 
Mice. Hepatology 2007, 45:72. 
40Evaldsson C et al., Anti-inflammatory effects of exogenous uridine in an animal model of lung inflammation. 
International Immunopharmacology 2007; 7: 1025. 
41 Muller et al., Local administration of uridine suppresses the cardinal features of asthmatic airway inflammation. 
Clinical & Experimental Allergy 2010; 40: 1552. 


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development of antigen-induced arthritis,43 etc. Uridine is anti-apoptotic.44 Significant with 
respect to mucosal toxicity, uridine protects from mucosal damage produced by dextran sulfate, 
an established IBD model.45 Finally, uridine triacetate (VISTOGARD), an orally active prodrug 
of UR, recently received marketing approval by US FDA to treat an overdose of 5-FU. 46 
RATIONALE FOR THE CLINICAL DEVELOPMENT OF TK-112690 
 
MTX, a structural analogue of folic acid, is widely used as a chemotherapeutic agent for various 
malignancies including head and neck cancer. One of the major toxic effects of MTX is intestinal 
injury, apparently mediated by both a direct effect of MTX, and an indirect effect produced by 
infiltration of gut bacteria and gut bacteria-associated toxins into the systemic circulation through 
the impaired mucosal barrier.  
 
METREXASSISTTM, TK-112690 for parenteral use, is a novel, non-toxic and specific therapy to 
treat mucositis caused by MTX treatment. In mouse models of human MTX-induced mucositis, 
TK-112690 protects from weight loss, one of the cardinal features of human mucositis, as well as 
limits the increase in systemic WBC concentration and mucosal permeability observed in mice 
post-MTX treatment. TK-112690 does not affect the cytotoxicity of MTX toward cancer 
cellsinin vitro and in vivo studies. Various other preclinical studies and a single dose study in 
human volunteers suggest no safety concerns with TK-112690.  
 
The protocol provided in this document was designed further determine the tolerability of TK-
112690 when administered weekly along with MTX as an intravenous infusion in patients with 
local, advanced, recurrent, metastatic SCCHN. Relevant mucositis endpoints will also be 
collected in the study. To increase the reliability of the results, the study is partially blinded- The 
patient and investigator will be blinded as to whether TK-112690 or placebo is 
administeredonlythe CRO, sponsor and site pharmacist will know whether the patient was 
administered active drug or placebo.  
1.0 SUPPORTING INFORMATION 
Methotrexate (MTX) is used to treat a wide range of cancers.47In addition to affecting cancerous tissue, 
MTX often produces unintended adverse effects in normal, non-cancerous, tissues, particularly tissues 
that have a high rate of proliferation, such as bone marrow and gut47. 
                                                                                                                                                       
42 Ob et al., Protective Effect Uridine on Cornea in a Rabbit Dry Eye Model. Investigative Ophthalmology & Visual 
Science, 48; 1102. 
43 Narendra et al., Local but Not Systemic Administration of Uridine Prevents Development of Antigen- Induced 
Arthritis. PLos One 2015. 10: e0141863. 
44Cansev M, Minbay Z, Goren B, Yaylagul EO, Cetinkaya M, Koksal N, Alkan T. Neuroprotective effects of 
uridine in a rat model of neonatal hypoxic-ischemic encephalopathy. Neurosci Lett. 2013;542:65-70. 
45Jeengar MK, Thummuri D, Magnusson M, Naidu VGM, Uppugunduri S. Uridine Ameliorates Dextran Sulfate 
Sodium (DSS)-Induced Colitis in Mice. Sci Rep. 2017; 7:3924.. 
46 https://www.vistogard.com/Vistogard/media/Main-Media/final-labeling-text-vistogard.pdf 
47 Jolivet J, Cowan KW, Curt GA, Clendeninn NJ, Chabner BA, The pharmacology and clinical use of 
MTX, N Engl J Med 1983; 309:1094–1104. 


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Mucositis describes the inflammation, lesions, and ulcers that develop in the oral and gastrointestinal tract 
because of treatment with chemotherapeutics such as MTX48,49 An effective adjuvant treatment that 
ameliorates chemotherapeutic-induced mucositis would provide important relief to cancer patients 
undergoing chemotherapy with MTX. 
Mucositis can affect up to 100% of people receiving high doses of chemotherapy.50 The frequency of 
mucositis is responsible for increased patient hospitalization, resulting in a substantial financial burden for 
both subjects and hospitals.51 In addition, mucosal damage increases the susceptibility of infection and 
sepsis in neutropenic subjects52,53,54 Pain, discomfort and the inability to eat or drink are the most frequent 
occurrences for subjects undergoing chemotherapy. As a result, delays and suspensions in chemotherapy 
regimens are common for subjects experiencing severe mucositis.3, 4 The frequency, financial burden, and 
disruptions of effective cancer therapy all underscore the need for treatments that can mitigate mucositis. 
 
● Several publications from animal studies have revealed evidence for compounds that can protect 
against MTX-induced small intestinal damage. These potentially therapeutic compounds include 
lactoferrin, taurine, docosahexaenoic acid, prostaglandin E1, N-acetylcysteine.55,56,57,58,59 To date, 
none of these compounds are being widely explored in the clinic as potential side-effect-reducing 
adjuvants for MTX-induced mucositis. 
● Epidermal growth factors have become candidates for reducing radiation and chemotherapy 
induced mucositis. Palifermin (human recombinant keratinocyte growth factor-1) is approved by 
the FDA to decrease the incidence and duration of severe oral mucositis in subjects with 
hematologic malignancies receiving myelotoxic therapy requiring hematopoietic stem cell 
                                               
48 McGuire, DB, Mucosal Tissue Injury in Cancer Therapy, Cancer Practice 2002; 10: 170-191. 
49 Rubenstein EB, Clinical practice guidelines for the prevention and treatment of cancer therapy – 
induced oral and gastrointestinal mucositis, Cancer Supplement 2004; 100: 2026-2046. 
50Sonis ST, Perspectives on Cancer Therapy-Induced Mucosal Injury, Cancer 2004; 100: 1995-2025. 
51Elting, LS, The Burdens of Cancer Therapy Cancer 2003; 98: 1531-1539. 
52Sonis, ST, Oral mucositis and the clinical and economic outcomes of hematopoietic stem-cell 
transplantation Journal of Clinical Oncology 2001; 19: 2201-2205. 
53Wardley, AM, Prospective evaluation of oral mucositis in patients receiving myeloablative conditioning 
regimens and haemopoietic progenitor rescue, British Journal of Haematology 2001; 110: 292-299. 
54Yuen, KY, Unique risk factors for bacteraemia in allogenic bone marrow transplant recipients before 
and after engraftment, Bone Marrow Transplantation 1998; 21: 1137-1143. 
55Van’T Land, B, Lactoferrin reduces MTX-induced small intestinal damage possibly through inhibition 
of GLP-2 mediated epithelial cell proliferation. Digestive Diseases and Sciences 2004; 49: 425-433. 
56Cetiner, M, Taurine protects against MTX induced toxicity and inhibits leukocyte death, Toxicology 
and Applied Pharmacology 2005; 209; 39-50. 
57Horie, T., Docosahexaenoic acid exhibits a potent protection of small intestine from MTX-induced 
damage in mice. 1998 62(15) p. 1333-1338. 
58Gao, F., Protective effect of a synthetic analog of prostaglandin E1 on the small intestinal 
damageinduced by the administration of MTX to rats. Journal of Pharmaceutical Sciences. 2001. 90:p. 
1040-1048. 
59Ciralik, H., Effects of N-Acetylcysteine on MTX-induced small intestinal damage in rats. The Mount 
Sinai Journal of Medicine. 2006.73; 1086-1092. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 29 of 110 
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support. Palifermin is thought to maintain mucosal barrier integrity by stimulating basal cell 
proliferation and differentiation in the oral epithelia60,61 
 
One reason mucositis has remained a significant problem and limitation for the use of chemotherapy has 
been the lack of insight into the pathogenesis of the disease. In January 2002, the Multinational 
Association of Supportive Care in Cancer and the International Society for Oral Oncology assembled an 
expert panel to set guidelines for the evaluation, prevention, and treatment of mucositis.3,4 From this 
meeting,2 a five-step model emerged to explain the development and progress of mucositis:  
 
Step 1: Initiation,  
Step 2: Up-regulation of “message,”  
Step 3: Signaling and amplification,  
Step 4: Ulceration and inflammation, and  
Step 5: Healing.  
 
Using this model, arealistic animal model can be used to examine potential cytoprotectants for 
chemotherapeutic-induced mucositis. 
 
TK-112690 Preliminary data demonstrating the potential of TK-112690 as a cytoprotectant against MTX 
induced mucositis was demonstrated at Tosk using a published weight model that mimics virtually all of 
the features of “natural” mucositis.62 In this model, GI toxicity is induced in C57BL/6 mice by pre-dosing 
with lipopolysaccharide (LPS) on Day 1 followed by MTX injections on Days 2 and 3. 
 
Typical results using this model are provided in the following Figure. 
 
 
 
 
 
 
 
 
 
 
 
                                               
60Blijlevens, N and Sonis, S.T., Palifermin(recombinant keratinocyte growth factor-1): a pleiotropic 
growth factor with multiple biological activities in preventing chemotherapy and radiotherapy induced 
mucositis Annals of Oncology. 2007 18: 817-826. 
61 Duncan, M and Grant, G, Review article: oral and gastrointestinal mucositis-causes and possible 
treatments. Aliment PharmacolTher 2003; 18: p.853-874. 
62deKoning, BAE, Contributions of mucosal immune cells to MTX-induced mucositis, International 
Immunology 2006, 18: 941-949. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 30 of 110 
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Figure 1. Box plots showing prevention of weight loss by TK-112690 in a mouse model for MTX-
induced mucositis 
 
Animal weight change was calculated by subtracting Day 8-Day 1, and ten C57BL/6 mice per dose group 
were evaluated. Group 1=saline treatment, Group 2=MTX alone, Group 3=LPS alone, Group 4=MTX + 
LPS alone, Group 5=60 mg/kg TK-112690 qd with MTX or Group 6=60 mg/kg TK-112690 qd with 
MTX + LPS. 
 
Why combine LPS and MTX in the model?  
 
LPS, or endotoxin, is a polysaccharide that covers the outer membrane of most gram-negative 
bacteria63,64. The use of MTX as a chemotherapeutic agent is known to cause severe damage to the rapidly 
dividing crypt cells of the intestinal epithelium.65 Diminished cell renewal and breakdown of the mucosal 
barrier can expose macrophages, CD4+T cells and other mucosal immune cells to the vast amounts of 
microbial pathogens within the intestinal lumen resulting in three of the hallmarks of mucositis: GI 
inflammation, weight loss, and sepsis.66,67,68,69 Toll-like-receptors (TLR4) on the surface of innate immune 
cells, such as macrophages and monocytes, recognize the conserved patterns of endotoxins during the 
                                               
63Raetz, CRH, Lipopolysaccharide Endotoxins, Annu. Rev. Biochem 2002; 71: 635-700. 
64Beutler, B and Rietschel, ET, Innate immune sensing and its roots: the story of endotoxin, Nature 
Reviews Immunology, 2003; 3: 169-176 
65deKoning, BAE, MTX-induced mucositis in mucin-2 deficient mice, Journal of Cellular Physiology 
2007; 210; 144-152. 
66Blijlevens, NMA, Mucosal barrier injury: biology, pathology, clinical counterparts and consequences of 
intensive treatment for haematological malignancy: an overview, Bone Marrow Transplantation 2000; 25: 
1269-1278. 
67 Macdonald, TT, The mucosal immune system, Parasite Immunology 2003; 25: 235-246. 
68Cheroutre, H, IELs: enforcing law and order in the court of the intestinal epithelium, Immunologic 
Reviews 2005; 206: 114-131. 
69Strober, W, The immunology of mucosal models of inflammation.Annu Rev Immunol 2002; 20: 495-
549 


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course of a bacterial infection.70 Binding of LPS to TLR4 is the critical event that results in the activation 
of immune cells leading to their release of the pro-inflammatory cytokines TNF-α, IL-1 and IL-6.71,72 
Because LPS plays a central role in the inflammatory response and is a natural part of the intestinal 
microflora, its artificial injection prior to MTX treatment is meant to exacerbate the development of 
mucositis in the same way that bacteria perform this function in the pathology of natural mucositis. 
 
1.1. NAME AND DESCRIPTION OF THE INVESTIGATIONAL DRUG 
 
TK-112690 is a highly water soluble anhydrouridine that inhibits human and murine uridine 
phosphorylase (EC 2.4.2.3), an enzyme that catalyzes the chemical reaction of uridine + phosphate → 
uracil + α-D-ribose 1-phosphate. In this reaction, the two substrates are uridine and phosphate and the two 
products are uracil and α-D-ribose 1-phosphate. 
 
METREXASSISTTM is TK-112690 for parenteral use provided as a 5 mL solution containing 100 mg/mL 
sterile TK-112690 packaged in a 10 mL glass vial sealed with an elastomeric stopper held in place with 
an aluminum seal.  
1.2. SUMMARY PRE-CLINICAL EFFICACY RESULTS 
 
In animal models of the human condition of mucositis, TK-112690 protects from three cardinal features 
associated with MTX-induced mucositis: weight loss, WBC increase (likely caused by infection), and 
increased mucosal permeability. The efficacy of TK-112690 in the weight loss model parallels the 
elevation in plasma uridine induced by inhibition of uridine phosphorylase. Findings in three in vitro 
studies and two in vivo studies with MTX and TK-112690 in human cancer cells suggest no effect of TK-
112690 on the chemotherapeutic effect of MTX. Overall, the efficacy data suggest that treatment with 
TK-112690 may provide an innovative and useful approach to MTX-associated mucositis in man.  
 
1.3. PHARMACOLOGY 
 
1.3.1. IN VITRO 
 
1. Effect of TK-112690 on U-937 and CCRF-CEM Human Cancer Cells.  
An in vitro study in CCRF-CEM and U-937 human cancer cells was performed to evaluate whether 
TK-112690 (1-100 µM) diminished the cytotoxicity of 0.03 µM MTX. Cell viability was measured 
using alamarBlue® and Leucovorin (LEU) was used as a positive control. The incubation was 
performed for 72 hours.  For the study with U-937 cells, there was no statistical difference between 
cell viability in MTX (0.03 µM) test wells and test wells with MTX (0.03 µM) + TK-112690 (1, 10, 
100 µM.). Therefore, the antiproliferative activity of MTX in this cancer cell line is not altered by the 
addition of TK-112690. In addition, the findings with the U-937 cells demonstrate that (i) TK-112690 
does not interfere with MTX cytotoxicity, (ii) TK-112690 is not cytotoxic, and (iii) LEU (positive 
                                               
70Beutler, B, Defective LPS signaling in C3H/HeJ and C57Bl/10 ScCr mice: Mutations in Tlr4 gene, 
Science 1998; 282: 2085-2088. 
71Sonis, S.T. Mucositis as a biological process: a new hypothesis for the development of chemotherapy-
induced stomatotoxicity, Oral Oncology 1998; 34: 39-43 
72Tracey, KJ, and Cerami, A, Tumor Necrosis Factor, Other Cytokine and Disease,Annu.Rev. Cell Biol 
1993 9: 317-343. 


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control) rescued cells from MTX cytotoxicity at concentrations equivalent to those studied with TK-
112690. 
 
For the study with CCRF-CEM cells, no statistical difference was noted between cell viability in MTX 
(0.03 µM) test wells and test wells with MTX + TK-112690 (1, 10, 100 µM). Therefore, the 
antiproliferative activity of MTX is not altered by the addition of TK-112690. In addition, there was 
no statistical difference between cell viability in untreated cells and cells treated with TK-112690 (1, 
10, 100 µM) demonstrating that TK-112690 has no anti-proliferative activity in this cell line. Further, 
there was no statistical difference between cell viability in untreated cells and cells treated with MTX 
+ LEU (1, 10, 100 µM). Therefore, LEU (positive control) completely rescued cells from MTX anti-
proliferative activity at concentrations equivalent to those studied with TK-112690. 
 
2. Effect of TK-112690 (1.0, 10, 100 µM) on the Cytotoxicity of MTX (0, 0.01, 0.03, 0.1, 0.3, 1.0, 3.0, 
10, 100 µM) in AS283 Human Lymphoma Cells using CellTiter-Glo Assay.  
An in vitro study in AS283 human cancer cells was performed to evaluate whether TK-112690 (1, 10, 
100 µM) diminished the cytotoxicity of MTX (0.01, 0.03, 0.1, 0.3, 1.0, 3.0, 10, 100 µM). Cell 
viability was measured using CellTiter-Glo and DOX (10 µM) was used as a reference standard. The 
incubation was performed for 72 hours. There was no statistical difference between cell viability in 
MTX test wells and test wells with MTX + TK-112690 (1, 10, 100 µM). Therefore, the 
antiproliferative activity of MTX is not altered by the addition of TK-112690. Results from the study 
demonstrated that in the AS283 human lymphoma cancer cell line TK-112690 (1, 10, 100 µM) does 
not alter the IC50 of MTX (0.01-0.02 µM). In addition, TK-112690 is not cytotoxic in the AS283 cell 
line. 
 
3. Effect of TK-112690 on the Inhibition of Uridine Phosphorylase Derived from Mouse and Human 
Intestinal Mucosa.  
Uridine phosphorylase (UPase) plays a key role in the regulation of pyrimidine metabolism by 
catalyzing the reversible phosphorolysis of uridine into uracil. 2, 2’Anhydrouridines such as TK-
112690 are reported as potent inhibitors of UPase in both in vitro and in vivo systems73,74 Inhibition of 
UPase can lead to the increased concentration of cellular uridine which is known to be a significant 
cell protectant.75 Increasing the bioavailability of uridine by either UPase inhibition or exogenous 
uridine supplementation reduces adverse events associated with the use of fluropyrimidines76,77 
Additional animal studies have shown the ability of uridine to reduce the lethal effects of endotoxins. 
                                               
73Veres Z, Szabolcs A, Szinai I, Dénes G, Kajtár-Peredy M, Otvös L. 5-Substituted-2,2'-anhydrouridines, 
potent inhibitors of uridine phosphorylase ,BiochemPharmacol. 1985; 34: 1737-40. 
74Drabikowska AK, Lissowska L, Veres Z, Shugar D. Inhibitor properties of some 5-substituted uracil 
acyclonucleosides, and 2,2'-anhydrouridines versus uridine phosphorylase from E. coli and mammalian 
sources. BiochemPharmacol. 1987; 36: 4125-8 
75Mazzola A, Amoruso E, Beltrami E, Lecca D, Ferrario S, Cosentino S, Tremoli E, Ceruti S, Abbracchio 
MP. 
Opposite effects of uracil and adenine nucleotides on the survival of murine cardiomyocytes.J Cell Mol 
Med. 2008 Mar-Apr;12(2):522-36 
76Pizzorno G, YeeL, Burtness BA, Marsh JC, Darnowski JW, Chu M, Chu SH, Chu E, Leffert JJ, 
Handschumacher RE, Calabresi P. Phase I clinical and pharmacological studies of benzylacycluridine, a 
uridine phosphorylase inhibitor. Clinical Cancer Research. 1998; 4: 1165-1160 
77 Martin DS, Stolfi RL, Sawyer RC, Spiegelman S, Young CW. High dose 5-flurouracil with delayed 
uridine “rescue” in mice. Cancer Research. 1982; 42; 3964-3970 


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78, 79 To detect the activity of UPase, the reaction system was designed to measure the amount of 
uracil produced by the enzyme in the presence of uridine and phosphate. 
 
Fresh mouse small intestine was obtained from sacrificed mice. The human intestine was 
commercially purchased and thawed at room temperature prior to use. The tissues were prepared in 
PBS fortified with EDTA and DTT. TK-112690 was added concentrations of 0, 0.1, 0.5, 1, 5, 10, 50, 
100, 500, 1000, 5000 and 10000 µM. The uridine phosphorylase preparation was 10% (w/v) with the 
precise concentration not determined. Uracil was measured by HPLC.  
 
The activities of the enzyme decreased in the presence of TK-112690 demonstrating the inhibitory 
effect of the compound on the activity of human uridine phosphorylase. The IC50 was 20 µM. In 
summary, TK-112690 showed an inhibitory effect on the activity of uridine phosphorylases derived 
from both mouse and human tissues. 
 
1.3.2 
IN VIVO 
 
Uridine Increase in Mice Post-TK-112690.  
CD-1 female mice (n=3/treatment group) were injected ip with a range of TK-112690 doses (0, 15, 30 
and 60 mg/kg) and plasma from the animals analyzed for concentration of uridine. Plasma uridine and 
TK-112690 concentrations were determined by HPLC from plasma samples collected 0.08, 0.50, 1, 2, 4 
or 12 hours post TK-112690 injection. The HPLC assay used 5-fluorouracil as the internal standard for 
both uridine and TK-112690. 
 
Results from the study at the two time points where uridine and TK-112690 were greatest are provided in 
Table 1 The concentration of endogenous plasma uridine determined by the HPLC method described in 
this report is approximately 0.5 µg/mL. 
Table 1.Mean plasma concentrations of TK-112690 and uridine for 0.08 and 0.5 time points 
 
 
Concentration (µg/mL) 
 
15 mg/kg Dose 
30 mg/kg Dose 
60 mg/kg Dose 
 
Mean 
SD 
Mean 
SD 
Mean 
SD 
TK-112690 
10.33 
7.66 
38.27 
14.70 
77.88 
49.52 
Uridine 
1.57 
1.00 
1.53 
0.93 
2.28 
1.16 
 
As expected, plasma concentrations of TK-112690 increased with increasing doses of TK-112690 
administered either by ip or continuous infusion, which expected to be elevated through UPase inhibition 
by TK-112690. 
 
                                               
78Galanos C, Freudenberg MA, Reutter W. Galactosamine-induced sensitization to the lethal effects of 
endotoxin.Proc. Natl. Acad. Sc. USA. 1979; 76: 5939-5943 
79 Rosenthal GJ, Lebetkin E, Thigpen JE, Wilson R, Tucker AN, Luster, MI. Characteristics of 2,3,7,8-
teterachlorodibenzo-P-dioxin Induced Endotoxin Hypersensitivity: Association with 
Hepatotoxicity.Toxicology. 1989; 251: 239-251 


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1. LPS/MTX Weight Loss Model (See Figure 1).  
A published weight model80 was employed to determine the ability of TK-112690 to protect against 
MTX-induced mucositis. Mice injected with MTX/LPS alone showed a severe, highly significant 
weight loss from day 5 to day 8 compared to animals treated only with saline. A significant reduction 
in MTX/LPS weight loss occurred in animals treated with 60 mg/kg TK-112690. In addition, dose 
ranging studies with TK-112690 in this model demonstrated that TK-112690 prevented MTX-induced 
weight loss at a dose as low as 15 mg/kg. The protection was dose-dependent. 
 
2. Effect of TK-112690 on MTX-induced Intestinal Permeability of Iodixanol.  
A published model81 was employed to determine the ability of TK-112690 to protect against MTX- 
induced intestinal permeability. Saline alone injected animals maintained a healthy mucosal barrier 
demonstrated by trace concentrations of plasma iodixanol. The MTX treatment produced a statistically 
significant (p<0.005) increase in plasma iodixanol compared to saline alone treated animals. Co-
administration of TK-112690 with MTX provided plasma concentration similar (p=1.00) to those 
found in the saline treated animals supporting the hypothesis that TK-112690 protects from MTX-
induced GI damage. 
 
3. Effect of TK-112690 on Elevated Systemic WBC Concentration Produced in Mice by Treatment with 
MTX.  
A published model82 was employed to determine the ability of TK-112690 to protect against MTX 
induced WBC elevation. MTX can have a cytotoxic effect on the rapidly-dividing cells of the mucosal 
lining leading to damage and increased permeability. This increase in intestinal permeability can lead 
to bacterial infiltration and infection. An elevation in the WBC of the MTX alone group is an 
indication of this bacterial infection and inflammation, possibly due to the MTX-induced intestinal 
damage. The MTX+TK-112690 did not exhibit this WBC increase supporting the hypothesis that TK-
112690 protects against MTX-induced mucositis. 
 
4. Effect of TK-112690 on in vivo Response to Treatment with MTX of Subcutaneously Planted CCRF-
CEM Leukemia Xenografts in Male AthymicNCr-nu/nu Mice.  
An in vivo study of CCRF-CEM xenografts was performed to evaluate whether TK-112690 (30 mg/kg 
3 hours before and after MTX, ip) diminished the antitumor efficacy of MTX (7.5 mg/kg for 5 Days, 
ip). The number of nonspecific deaths, the number of partial and complete tumor regressions, the 
number of tumor-free survivors, and the median number of days for the tumors in each group to reach 
two tumor mass doublings were calculated. The median time to reach two tumor mass doublings was 
used in the calculation of the overall delay in the growth of the median tumor. The study was 
terminated forty-eight days after tumor implantation. 
 
● Tumors in the vehicle-treated control group grew to the evaluation point in all ten mice. The 
median tumor reached two tumor mass doublings in approximately 10 days. There was an 
average body weight loss of 3% (0.8 g).  
                                               
80 de Koning BA, van Dieren JM, Lindenbergh-Kortleve DJ, van der Sluis M, Matsumoto T, Yamaguchi 
K, Einerhand AW, Samsom JN, Pieters R, Nieuwenhuis EE. Contributions of mucosal immune cells to 
methotrexate-induced mucositis, IntImmunol. 2006;18(6):941-9. 
81Leblond J, Le Pessot F, Hubert-Buron A, Duclos C, Vuichoud J, Faure M, Breuillé D, Déchelotte P, 
Coëffier M. Chemotherapy-induced mucositis is associated with changes in proteolytic pathways.ExpBiol 
Med. 2008; 233: 219-28 
82 T. Robbins, D. Bowen, Q. Bui, M. Tran, Modulation of High-dose Methotrexate Toxicity by a Non-
toxic Level of 5-Flourouracil. Toxicology1986; 41; 61-73 


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● Treatment with MTX was tolerated with a maximum average body weight loss of 9% (2.5 g). The 
MTX treatment delayed the growth of CCRF-CEM leukemia xenografts with a tumor doubling 
time of approximately 20 days. 
● There was a single drug-related euthanasia out of ten animals following administration of TK-
112690 at a dosage of 30 mg/kg/injection combined with MTX at a dosage of 7.5 mg/kg/injection 
with a corresponding maximum average body weight loss of 8% (2.3 g). Administration of TK-
112690 combined with MTX delayed the growth of CCRF-CEM leukemia xenografts with a 
tumor doubling time of approximately 26 days. There was one complete tumor regression out of 
10 animals which remained tumor-free at the conclusion of the study from the combined 
treatment. 
 
Results from this study suggested that TK-112690 does not alter the antitumor efficacy of MTX against 
sc implanted CCRF-CEM human leukemia xenografts in male athymicNCr-nu/nu mice. 
 
5. In vivo Response of Subcutaneously Planted AS283 Human Lymphoma Xenografts in Male C.B.-17 
SCID Mice to Treatment with MTX (5.0 mg/kg q1d x 5, ip) and/or TK-112690 (30 mg/kg, 3 Hours 
Before and After MTX, ip).  
The purpose of this study was to determine whether TK-112690 effects MTX anti-tumor efficacy 
against subcutaneously (sc) implanted AS283 human lymphoma xenografts in male C.B.-17 SCID 
mice. MTX administered alone was used as a reference compound. 
 
Growth of AS283 human lymphoma xenografts was delayed by treatment with MTX (5.0 
mg/kg/injected q1d x 5) alone or in combination with TK-112690 (30 mg/kg 3 hours before and after 
MTX). Groups receiving MTX with or without TK-112690 were statistically identical (p = 1.00). 
AS283 Xenograft Data Demonstrates that TK-112690 does not Interfere with MTX Anti-Tumor 
Efficacy. Growth of AS283 human lymphoma xenografts was delayed by treatment with MTX (5.0 
mg/kg/injected q1d x 5) alone or in combination with TK-112690 (30 mg/kg 3 hours before and after 
MTX). Groups receiving MTX with or without TK-112690 were statistically identical (p = 1.00). 
 
AS283 Xenograft Data demonstrates that TK-112690 does not interfere with MTX anti-tumor efficacy. 
● Tumors in the vehicle-treated control group grew to the evaluation point in all ten mice. The 
median tumor reached 4,387 mg in 21 days. There was an average body weight gain of 14% (3.5 
g) which correlates with tumor weight. 
● Treatment with MTX was tolerated with a maximum average body weight loss of 0.4 % (0.1 g). 
The MTX treatment delayed the growth of AS283 lymphoma xenografts with a median tumor 
weight value 2.8% of the control on Day 21 and a median tumor weight value 24.7% (40.0 mg) 
smaller than the median tumor weight value at the start of treatment (162 mg). 
● Treatment with TK-112690 at a dosage of 30 mg/kg/injection combined with MTX at a dosage of 
5.0 mg/kg/injection was well tolerated with no average body weight (0.0 g). Administration of 
TK-112690 combined with MTX delayed the growth with a median tumor weight value 3.5% of 
the control on Day 21 and a median tumor weight value 5.6% (9.0 mg) smaller than the median 
tumor weight value at start of treatment (162 mg). 
 
1.3.3. PRECLINICAL PHARMACOKINETIC (PK)/ADME STUDIES 
 
Results from preclinical PK studies with TK-112690 can be found in Table 2 below.  
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 36 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Tosk, Inc 
 
Table 2. Selected findings preclinical pharmacokinetic studies with TK-112690 
Species  
Sex 
iv Treatment 
Term. 
t1/2 (h) 
aMaxConc. 
(µg/mL) 
bVss 
(L/kg) 
cCL 
(L/h/kg) 
AUC 
(µg∗h/mL
) 
Duration 
Route 
mg/kg 
Cynomolgus 
monkey 
2M 
2F 
Single 
dose 
iv 
100 
13 
220 
0.64 
0.19 
540d 
Beagle dog 
2M 
2F 
28 days, 
qd  
iv 
60 
36 
240 
2.20 
0.25 
253e 
Sprague-
Dawley rat 
3M 
3F 
28 days, 
qd 
iv 
60 
13 
520 
0.99 
0.50 
227f 
CD-1 mice 
F 
Single 
dose 
iv 
50 
21 
221 
1.72 
1.2 
43f 
CD-1 mice 
F 
Single 
dose 
ip 
50 
― 
65 
― 
― 
40f 
CD-1 mice 
F 
Single 
dose 
po 
50 
― 
3 
― 
― 
9f 
a0 to 1 hours post-initiation of infusion, bVss: volume distribution steady-state, cCL: clearance; d0 to 48 hours; e0 to 
120 hours; f0 to72 hours; M=male, F=female;  
 
In addition, TK-112690 at concentrations up to 300 µg/mL did not inhibit CYP1A2, CYP2A6, CYP2B6, 
CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, or CYP3A4 in human liver microsomes and TK-
112690 at concentrations ranging from 30-300 µg/mL did not induce CYP1A2, CYP2B6, or CYP3A4 
enzyme activities. 
 
Finally, the potential drug interaction of TK-112690 and MTX was assessed in vivo by pre-treating CD-1 
mice for 3 days with 50 mg/kg TK-112690 prior to administration of MTX (50 mg/kg). Due to sensitivity 
limits in the HPLC analytical test method used, only MTX plasma concentrations 30 minutes post-
initiation of infusion were measurable, and a complete pharmacokinetic evaluation was not possible 
because of this limitation. However, the limited data obtained suggested no difference as determined by 
an independent sample t-test (p>0.5) in the MTX plasma concentrations with the TK-112690 pre-
treatment compared to plasma concentrations from the MTX control group.  
 
These studies demonstrated that TK-112690: 
● Exhibited approximate dose proportional increases in systemic exposure in animals following iv 
administration. 
● Has an elimination half-life of approximately 13, 35 and 13 hours in rats, dogs and monkeys, 
respectively. 
● Has a volume of distribution in all animals that greatly exceeds vascular volume suggesting 
considerable tissue distribution.  
● Neither inhibits or induces the most common CYP450s. 
● Appears to not affect the clearance of MTX in mice. 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 37 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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1.4. TOXICOLOGY/SAFETY 
1.4.1. PRE-CLINICAL TOXICOLOGY. 
 
Findings from the principal safety studies performed with TK-112690 are provided in Table 3.  
 
Table 3. Safety studies with TK-112690 
 
Study 
Description 
GLP 
Species 
Route 
Treatment Duration 
Dosing 
Regimen 
Results 
Acute Safety in 
Mice 
No 
Female CD-1 
Mice 
ip 
Single dose  
Observation up to 7 
days post-initiation 
of infusion 
0, 500, 
1000 and 
2000 mg/kg 
qd 
No significant 
findings re weight 
&clinical 
chemistry 
measures  
Exploratory 
Safety in Mice 
No 
Female 
C57BL/6 
Mice 
ip 
7 Days 
0, 10, 30 & 
100 mg/kg 
q7d 
No significant 
findings with 
weight, clinical 
chemistry and 
hematology 
measures 
14-Day Dose 
Ranging Rodent 
No 
Male/Female 
Sprague-
Dawley Rats  
iv 
14 Days 
0, 10, 30, 
90 or 270 
mg/kg q14d 
No significant 
findings with 
animal weight, 
organ weight, 
gross pathology, 
clinical chemistry 
and hematology; 
treatment related 
increases in TBIL 
in male and 
female animals at 
30, 90 and 270 
mg/kg/day, but all 
values still within 
normal range  
14-Day Dose 
Ranging Canine 
No 
Male/Female 
Beagle Dogs 
iv 
14 Days 
0, 3.3, 10, 
30 or 90 
mg/kg 
No significant 
findings with 
animal weight, 
organ weight, 
gross pathology, 
clinical chemistry 
and hematology 
28-Day Safety + 
14-Day 
Recovery 
Rodent 
Yes 
Male/Female 
Sprague-
Dawley Rats 
iv 
28 Days + 14-Day 
Recovery 
0, 20, 60 or 
180 mg/kg 
q28d 
NOAEL=180 
mg/kg/day  


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 38 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Study 
Description 
GLP 
Species 
Route 
Treatment Duration 
Dosing 
Regimen 
Results 
28-Day Safety + 
14-Day 
Recovery 
Canine 
Yes 
Male/Female 
Beagle Dogs  
iv 
28 Days + 14-Day 
Recovery 
0, 20, 60 or 
180 mg/kg 
q28d 
NOAEL=180 
mg/kg/day 
Cardiovascular 
Safety in 
Telemetered 
Non-human 
primate  
Yes 
Cynomolgus 
Monkeys 
iv 
Single dose 
0, 10, 30 
and 
100mg/kg 
qd 
No effect on body 
temperature, 
respiratory rate, 
arterial blood 
gases and Lead II 
ECG variables 
(RP, PR, QT, 
QTcF, QTcQ and 
QRS intervals). 
Ames 
Genotoxicity 
Yes 
In vitro;S.typhimuriumstrains TA97, TA98, 
TA100, TA1535 and E. colistrain uvrA-pKM101 
8-5000 
µg/plate 
with, and 
without, 
metabolic 
activation. 
No revertants 
 
These studies demonstrated that TK-112690: 
● Does not produce toxic effects at doses of up to 180 mg/kg delivered iv for 28-days to rats and 
dogs. 
● An iv dose of 100 mg/kg of TK-112690 to male, telemetered, Cynomolgus monkeys, produces no 
effects on cardiac function. 
● No apparent effect of gender on disposition. 
 
1.4.2 CLINICAL TOXICOLOGY 
 
As further described in the following sections, single and multiple doses of METREXASSISTTM (TK-
112690) for parenteral use have been studied in healthy human volunteers (Study CLP-2690-0001) and 
cancer patients (Study CLP-2690-0002) without any apparent drug-related adverse effects. 
 
1.5. SUMMARY OF CLINICAL DATA 
 
METREXASSISTTM was studied in a single escalating dose, Phase 1a study in normal, healthy, male 
volunteers (dose levels of 5, 15, 25, 35 or 45 mg/kg administered as an intravenous infusion over 4 
hours). METREXASSISTTM was also studied in a multiple escalating dose, Phase 1b study in SCCHN 
patients (dose levels of 15, 30, 45, or 60 mg/kg, bid, administered as an intravenous infusion over 1 
hours) weekly for 4 weeks. The Phase 1a study was performed under GCP conditions in South Africa. 
The Phase 1b studies was performed under GCP conditions in India. 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 39 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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1.5.1 Phase 1a Study83 
 
1.5.1.1 Study Design 
 
Subjects (3 subjects/cohort/15 subjects total) were admitted to the study center the day prior to dosing 
(Day 0). Study drug was administered iv over 4 hours on the morning of Day 1. Subjects remained 
confined for 48 hours and returned for a follow-up visit at Day 7 (± 24 hours) post dosing. Blood samples 
were obtained for determination of plasma concentrations of TK-112690 and uridine prior to dosing 
(baseline, and specified hours post-initiation of infusion). No subject participated in more than one cohort. 
Dose escalation was permitted if no dose-limiting toxicity (DLT) was observed by Day 7 post-infusion to 
the last subject in the previous dose cohort. Safety was assessed by monitoring adverse events (AEs), 
conducting physical examinations and 12-lead electrocardiograms (ECGs), measuring vital signs (blood 
pressure, heart rate, respiratory rate, and oral body temperature) and conducting laboratory tests (clinical 
chemistry, hematology and coagulation) and physical examinations before dosing, specified time post-
dosing, and at Day 7 ± 1 day post dosing. 
 
1.5.1.2 Overall Safety 
 
Administration of METREXASSISTTM to the volunteers was well tolerated. Only two adverse events 
were reported as either possibly (headache in Subject 2, 5 mg/kg dose group) or definitely (burning at 
infusion site experienced by Subject 3, 5 mg/kg dose group) drug related. In the 15 subjects receiving 
METREXASSISTTM, there were no ≥ Grade 3 AEs which were considered related to study drug. There 
were no serious adverse events (SAEs) and therefore no IND Safety Reports. No actions were taken for 
safety reasons, and there were no protocol modifications based on safety concerns associated with the 
TK-112690 administration. Apparent polyuria was noted in Subjects 1, 3-8 and 10-15. However, the 
greater than expected urine volumes were not considered excessive given the relatively large volume of 
fluids concurrently consumed by the volunteers and was, therefore, considered not drug related. 
 
1.5.1.3 Clinical Chemistry 
 
Blood samples were obtained from the volunteers at Screening, Day 0, Pre-Dose (Day 1), 4 hour (Day 1), 
12 hours (Day 1), 24 hours (Day1), 48 hours (Day 2) and 7 Days post-dose. The blood was analyzed for 
electrolytes such as sodium, potassium, chloride, and calcium (total), enzymes such as aspartate 
aminotransferase, alkaline phosphatase, gamma glutamyl transferase, alanine aminotransferase, lactate 
dehydrogenase, creatine kinase, and biochemical such as CO2, urea, creatinine, uric acid, phosphate, 
protein (total), albumin, globulin, bilirubin (total), bilirubin (direct), cholesterol, triglyceride, glucose, and 
C- reactive protein. Values for all analytes were within the normal laboratory range at all 
METREXASSISTTM doses. 
 
1.5.1.4 Hematology 
 
Blood samples were obtained from the volunteers at Screening, Day 0, Pre-Dose (Day 1), 4 hours (Day 
1), 12 hours (Day 1), 24 hours (Day1), 48 hours (Day 2) and 7 Days post-dose. The blood was analyzed 
for hemoglobin, erythrocyte count, hematocrit, mean cell volume, MCH, MCHC, platelet count, 
leucocyte count, neutrophils, neutrophils (absolute), lymphocytes, lymphocytes (absolute), monocytes, 
monocytes (absolute), eosinophils, eosinophils (absolute), basophils and basophils (absolute). Values for 
all analytes were within the normal laboratory range at all METREXASSISTTM doses. 
 
                                               
83 Tosk FSR-CL-2690-0002: TK90 Clinical_Phase1a 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 40 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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1.5.1.5 Coagulation 
 
Blood samples were obtained from the volunteers at Screening, Day 0, Pre-Dose (Day 1), 4 hours (Day 
1), 12 hours (Day 1), 24 hours (Day1), 48 hours (Day 2) and 7 Days post-dose. The samples were 
analyzed for coagulation times. No effects at any METREXASSISTTM dose on PT or PTT coagulation 
times were observed.  
 
1.5.1.6 Urinalysis 
 
Urine samples were collected from each volunteer on Day 0, and on Days 1-2. No effect at any 
METREXASSISTTM dose was noted on urine appearance, color, or concentration of glucose, ketones, 
proteins or occult blood.   
 
1.5.1.7 Physical Examination 
 
Physical examinations, including assessments of the skin, head, eyes, ears, nose, throat, neck, thyroid, 
lungs, heart, abdomen, lymph nodes, extremities, and body weight were performed at screening, Day0, 
pre-dose and at 4, 12, 24, 48 hours, and 7 Days post-dose. 
 
1.5.1.8 Vital Signs 
 
Vital signs [supine blood pressure (systolic and diastolic), heart rate, respiratory rate and oral body 
temperature] were performed at screening, Day0, pre-dose and 4, 6, 8, 12, 24, 48 hours, and 7 Days post-
dose. No effect of the drug at any METREXASSISTTM dose was observed on any vital sign measurement. 
 
1.5.1.9 EKGs 
 
12-Lead EKGs were obtained at screening and at 4, 12, and 24 hours post-dose. No drug-induced changes 
were noted.  
 
1.5.1.10 Pharmacokinetics 
 
Mean TK-112690 measured plasma concentrations are provided in Table 4 below. Mean 
pharmacokinetic parameter estimates derived from plasma concentrations for 15-45 mg/kg doses are 
provided in Table 5. 
Table 4. Mean plasma concentrations TK-112690 in volunteers (3 volunteers/dose group). 
 
 
 
Hours Post Initiation of 4 Hour Infusion 
Dose 
(mg/kg) 
#Values 
4 
6 
8 
12 
24 
Mean 
SD 
Mean 
SD 
Mean 
SD 
Mean 
SD 
Mean 
SD 
5 
3 
13.16 
3.27 
5.53 
0.91 
2.95 
0.76 
0.71 
0.19 
nm 
⎯ 
15 
3 
24.22 
1.94 
17.06 
3.95 
8.81 
2.32 
2.57 
0.01 
0.26 
0.05 
25 
3 
38.40 
0.58 
18.48 
3.80 
10.49 
2.77 
4.60 
1.42 
1.37 
1.54 
35 
3 
58.69 
2.50 
21.51 
2.06 
12.01 
1.34 
4.60 
0.54 
0.60 
0.24 
45 
3 
79.60 
4.59 
29.31 
1.79 
16.08 
1.36 
6.40 
0.72 
1.17 
0.05 
Mean=µg/mL ± SD 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 41 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Table 5. Mean pharmacokinetic parameter estimates derived from plasma concentrations for 15-45 
mg/kg doses 
 
Parameter Estimates 
Mean 
SD 
Dosing time 
0 
0 
Rsq 
0.97 
0.04 
Peak Concentration 
50.27 
22.03 
No._points_Lambda_z 
4.00 
0.00 
Tlast 
24.00 
0.00 
Clast 
0.89 
0.80 
AUClast 
257.02 
93.10 
Lambda_z 
0.19 
0.04 
t1/2_Lambda_z 
3.92 
1.06 
AUCall 
257.02 
93.10 
AUCINF(observed) 
263.13 
95.62 
AUCINF(observed)/D 
0.0091 
0.0012 
AUC_%Extrap(observed) 
2.13 
2.84 
Vz(observed) 
632.28 
129.70 
Cl(observed) 
113.32 
14.21 
AUMClast 
1678.50 
598.78 
AUMCINF(observed) 
1871.16 
765.97 
AUMC_%Extrap(obs.) 
8.14 
8.53 
MRTlast 
4.55 
0.50 
MRTINF(observed) 
5.07 
1.23 
Vss(observed) 
563.87 
81.97 
Units: Dosing time=Hours , Rsq=Dimensionless, Tmax=Hours, Cmax=µg/mL, 
Points_Lambda_z=Number, Tlast= Hours, Clast= µg/mL, 
AUClast=µgxHour/mL; Lambda_z=Hour-1, t1/2_Lambda_z=Hours, AUCall, 
µg∗Hour/mL, UCINF(observed), AUCINF(observed)/D=Dimensionless, 
AUC_%Extrap(obs.), %, Vz(observed), mL/kg, Cl(observed), mL∗hour/kg, 
AUMClast, ng x hour2 /mL,  AUMCINF(observed) , ng x hour2 /mL, 
AUMC_%Extrap(obs.), %, MRTlast, Hours,  MRTINF(observed), Vss(observed), 
mL/kg 
 
Measurement of intact TK-112690 and uridine in blood and urine samples obtained during the Phase 1 
study demonstrated that: 
 
● The LC/MS/stable isotope dilution assay developed to measure both TK-112690 and uridine in 
plasma and urine appears adequate to measure relevant concentrations of both analytes in plasma 
and urine of humans treated with METREXASSISTTM. 
● Peak TK-112690 concentrations achieved at doses of 35 or 45 mg/kg were approximately 50 
µg/mL 
● The terminal elimination half-life of TK-112690 appears to be approximately 4 hours based on 
alambda_Z calculation and approximately 5 hours based on medium residence time (MRT) 
calculation.  
● The volume of distribution appears to be approximately 600 mL/kg. 
● Excellent proportionality of systemic exposure with dose was observed (plasma AUC increased 
from approximately 70 µg∗h/mL at a 5 mg/kg dose to approximately 40 µg∗h/mL at the 45 
mg/kg dose). 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 42 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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● At doses ≥15 mg/kg, the increase in uridine at 6 hours post start of the infusion over pre-dose 
values appears to be approximately 50%. 
● The mean amount of TK-112690 excreted into urine as intact drug was approximately 41% at the 
lowest dose evaluated, 5 mg/kg, and 17% at the highest dose evaluated, 45 mg/kg. 
 
1.5.1.11 Overall Summary 
 
The findings above suggest: 
● No safety concerns are apparent. 
● Variability in blood levels for TK-112690 is modest, ≤25%. 
● The MRT for TK-112690 is consistent with bid dosing. 
● The AUC0-24h for TK-112690 at a 25 mg/kg dose of TK-112690, approximately 200 µg∗h/mL, is 
more than twice that needed to achieve efficacy in the MTX-induced weight loss model, 80 
µg∗h/mL, (Figure 1, bid dosing). 
 
1.5.2 Phase 1b Study 
 
1.5.2.1 Study Design 
 
Patients were admitted to the study center the day prior to dosing (Day 0). Study drug was administered iv 
over 1 hour on the morning of Day 1 one hour after the patients drank a nutritional supplement. MTX was 
administered 45 mg/m2 by iv infusion over one hour one hour after the TK-112690 treatment. A second 
TK-11690 dose was administered 6 hours after the first. Subjects remained confined for 48 hours. This 
sequence was repeated for three additional weeks. Patients returned for a follow-up visits 5 and 8 weeks 
(± 24 hours) post TK-112690 treatment. Blood samples were obtained for determination of uridine 
(Biomarker) prior to dosing (baseline, and 5 and 24 hours post TK-112690 treatment). Blood samples for 
Surrogate Marker measurements were obtained pre-dose of TK-112690, and 5, 24, 48 hours and 5 and 8 
weeks post the TK-112690 dose. Dose cohorts were 15, 30, 45 and 60 mg/kg, bid. Each of the cohorts 
(cohorts 1-5) consisted of three patients. An additional 9 patients were dosed at 60 mg/kg bid, the MTD 
determined from dosing to cohorts 1-5.  
 
No subject participated in more than one cohort. All patients histologically confirmed SCCHN. Safety 
was assessed by monitoring adverse events (AEs), conducting physical examinations and 12-lead 
electrocardiograms (ECGs), measuring vital signs (blood pressure, heart rate, respiratory rate, and oral 
body temperature) and conducting laboratory tests (clinical chemistry, hematology and coagulation) and 
physical examinations before dosing, at specified time post-dosing, and at weeks 5 and 8 (± 1 day) post 
dosing. Mucositis status was evaluated pre-dose, at 24 and 48 hours post dose, and at weeks 5 and 8 post 
dose.   
 
1.5.2.2 Patient Characteristics, Dropouts, and Reason for Dropouts 
 
 
A total of 25 patients at 5 centers signed the informed consent and were enrolled in the study. 06 
females were enrolled and 19 males. ECOG scores ranged from 0 to 1 except for a score of 2 for 
patient 12. Sixteen patients completed the protocol. Eighteen patients completed 4 weeks of 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 43 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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dosing. Of the nine patients who did not complete the protocol two died. Following 
investigation, both deaths were attributed to causes other than dosing with TK-112690.84,85 
 
Patient characteristics along with dropouts are listed in the following Table.  
 
 
Table 6. Patient characteristics, Dropouts and Reason for Dropouts 
Patient 
Gende
r 
Dose 
(mg/kg
) 
Cohor
t 
Ag
e 
BMI 
(kg/m2) 
Initial 
ECOG 
Disposition 
1 
Male 
15 
1 
37 
16.40 
1 
Completed 
2 
Male 
15 
1 
52 
15.20 
1 
Completed 
3 
Male 
15 
1 
52 
20.10 
1 
Completed 
4 
Male 
30 
2 
62 
22.50 
1 
Completed 
5 
Male 
30 
2 
31 
23.20 
1 
Completed 
6 
Male 
30 
2 
63 
14.70 
1 
Completed 
7 
Male 
45 
3 
55 
15.60 
0 
Completed 
8 
Male 
45 
3 
80 
15.80 
0 
Completed 
9 
Female 
45 
3 
83 
19.00 
0 
Dead 
10 
Male 
45 
3 
66 
19.20 
0 
Weeks 1, 2, 3 and 4 
completed, Patient did not 
report for week 5. Lost to 
Follow up 
11 
Male 
60 
4 
45 
15.97 
1 
Completed 
12 
Male 
60 
4 
38 
14.60 
2 
Week 1, 2 and 3 completed.  
Consent self-withdrawal. 
13 
Female 
60 
4 
72 
15.20 
1 
Completed 
14 
Female 
60 
5 
49 
25.60 
1 
Week 1 Completed. 
Withdrawal following SAE. 
15 
Female 
60 
5 
47 
20.70 
0 
Completed 
16 
Female 
60 
5 
70 
17.50 
0 
Dead 
17 
Female 
60 
5 
60 
16.20 
0 
Week 3 completed followed 
by self-withdrawal. 
18 
Male 
60 
5 
52 
25.10 
1 
Completed 
19 
Male 
60 
5 
45 
25.30 
0 
Completed 
20 
Male 
60 
5 
32 
17.14 
0 
Completed 
                                               
84 Government of India Directorate General of Health Services Central Drugs Standard Control Organization 
(Medicines Safety Monitoring Division), Order re CT/SAE-D-334/2017, Patient DDR/TK/004/009, 9 September 
2018. ` 
85 Government of India Directorate General of Health Services Central Drugs Standard Control Organization  
(Medicines Safety Monitoring Division), Order re CT/SAE-O-90/2018),  Patient MNB/TK/005/016, 5 October 
2018.  


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 44 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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21 
Male 
60 
5 
56 
15.82 
0 
Week 3 completed followed 
by self-withdrawal 
22 
Male 
60 
5 
49 
17.40 
1 
Completed 
23 
Male 
60 
5 
67 
28.20 
0 
Week 2 completed followed 
by withdrawal due to an 
SAE 
24 
Male 
60 
5 
41 
18.10 
0 
Week 5 completed followed 
by self-withdrawal 
25 
Male 
60 
5 
50 
19.30 
1 
Completed 
 
No relationship among dose, age, BMI, or ECOG and disposition is apparent. Male patients 
completed the trial at a higher rate (14 of 19) than female patients (2 of 6).   
 
1.5.2.3 Overall Safety 
 
Administration of METREXASSISTTM plus a relatively high dose of methotrexate to the cancer patients 
resulted in a total of 35 treatment-emergent adverse events (TEAEs) were reported in 21 (84.0%) patients; 
the majority were mild to moderate in severity and resolved with or without treatment. However, all 
events were assessed to be not related to study drug but attributed to the disease under study and/or 
concomitant disease conditions. A total of 6 CTCAE Grade 3/4 were reported in 5 (20%) patients. 
 
Treatment-emergent serious adverse events (TESAEs) were reported in 5 (20%) patients. All TESAEs 
were assessed to be not related to the study drug but attributed to the disease under study and/co-
morbidities. A total of 4 (16.0%) patients discontinued the study due to AEs. All were cases of anemia 
(n=4). A total of 2 (8%) patients died due to AEs. Febrile neutropenia caused one death (n=1) and 
pancytopenia the other (n=1). 
 
No actions were taken for safety reasons, and there were no protocol modifications based on safety 
concerns associated with the TK-112690 administration. No dose limiting toxicity (DLT) was reported in 
any of the patients. The observed AEs, SAEs, and deaths are described or listed in the sections below. 
 
1.5.2.4 SAEs 
 
SAEs in the study are provided in the following Table. 
Table 7.Reported SAEs in Study. 
 
Patient 
SAE 
TK-112690 
(mg/kg) 
Causality by PI 
Outcome 
9 
Febrile neutropenia resulting in 
to death 
45 
Not related 
Death 
14 
Stomatitis 
60 
Not related 
Recovered 
15 
Upper respiratory tract infection 
60 
Not related 
Recovered 
16 
Pancytopenia 
60 
Not related 
Death 
23 
Febrile neutropenia converted 
into pancytopenia 
60 
Not related 
Recovered 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 45 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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No SAEs occurred in 15 or 30 mg/kg, bid, dose groups. No increase in SAEs with increase in 
TK-112690 dose from 45 to 60 mg/kg, bid, is apparent. An SAE occurred in 25% (1/4) of the 
patients administered 45 mg/kg, bid, and 26% (4/15) of the patients dosed 60 mg/kg TK-112690, 
bid.  
 
1.5.2.5 CTCAE Grade 3/4 AEs 
 
Table 8. CTCAE Grade 3/4 Adverse events 
 
A total of 5 CTCAE Grade 3/4 were reported in 5 (20%) patients. These events included Increase 
WBC count (n=1), Increase Absolute neutrophils count (ANC, n=1), febrile neutropenia (n=1), 
pancytopenia (n=1), febrile neutropenia converted into pancytopenia (n=1), and anemia (n=1). 
All events were assessed to be not related to METREXASSISTTM but attributed to the disease 
under study and/ or concomitant disease conditions. 
 
Patien
t 
AEs Grade 3/4 
Severity  
TK-112690 
(mg/kg) 
Causality Determined 
by PI 
Outcome 
3 
Increased WBC 
15 
Unrelated to TK-112690 
Recovered 
3 
Increase ANC 
15 
Unrelated to TK-112690 
Recovered 
9 
Febrile neutropenia 
45 
Unrelated to TK-112690 
Death 
16 
Pancytopenia 
60 
Unrelated to TK-112690 
Death 
23 
Pancytopenia 
60 
Not related 
Recovered 
24 
Anemia 
60 
Not related 
Lost to follow-
up 
 
1.5.2.6 Clinical Chemistry 
 
Blood samples were obtained from each patient at Screening, Day 024 hour (Day1), 48 hours (Day 2), at 
equivalent times on weeks 2, 3 and 4, and at weeks 5 and 8 post-dose. The blood was analyzed for 
electrolytes such as sodium, potassium, chloride, and calcium (total), enzymes such as aspartate 
aminotransferase, alkaline phosphatase, gamma glutamyl transferase, alanine aminotransferase, lactate 
dehydrogenase, creatine kinase, and biochemical such as creatinine, uric acid, phosphate, protein (total), 
albumin, globulin, bilirubin (total), bilirubin (direct), cholesterol, triglyceride, glucose, and C- reactive 
protein.  
 
Selected, but typical, hematology findings from the study are provided in the Figures below. 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 46 of 110 
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Figure 2. Plasma glucose concentrations ± SE in subjects providing a blood sample pre-dose 
and at Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined). Week1=Pre-dose, 
Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 3.Plasma creatinine concentrations ± SE in subjects providing a blood sample pre-dose 
and at Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined). Week1=Pre-dose, 
Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 47 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Figure 4.Plasma AP (alkaline phosphatase) concentrations ± SE in subjects providing a blood 
sample pre-dose and at Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined). 
Week1=Pre-dose, Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, 
Week5= Study Week4. 
. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 48 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Figure 5. Plasma AST concentrations ± SE in subjects providing a blood sample pre-dose and 
at Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined). Week1=Pre-dose, 
Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 6.Plasma ALT concentrations ± SE in subjects providing a blood sample pre-dose and at 
Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined).Week1=Pre-dose, Week2=Study 
Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Like the glucose measurements and creatinine measurements (Figures 2 and 3), the 
measurement of albumin, sodium, potassium, chloride, calcium, phosphorus, triglyceride, 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 49 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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creatine kinase, total protein, uric acid, BUN. and cholesterol showed no clinically significant 
changes across treatment groups. One liver-related measures, alkaline phosphatase (Figures 4, 
respectively), show a potentially protective effect of TK-112690 treatment. Other liver function 
measurements such as AST/ALT (Figures 5 and 6), bilirubin and direct bilirubin show much 
less change with TK-112690 treatment compared to pre-dose.  
 
CRP levels, Positive or Negative determination only, provided no useful information’s 
. 
1.5.2.7 Hematology 
 
Blood samples were obtained from each patient at Screening, Day 0, 24 and 48 hours Week1, and at 
equivalent times on weeks 2, 3 and 4, and at weeks 5 and 8 post-dose. The blood was analyzed for 
hemoglobin, erythrocyte count, hematocrit, mean cell volume, MCH, MCHC, platelet count, leucocyte 
count, neutrophils, neutrophils (absolute), lymphocytes, lymphocytes (absolute), monocytes, monocytes 
(absolute), eosinophils, eosinophils (absolute), basophils and basophils (absolute).  
 
Selected, but typical, hematology findings from the study are provided below. 
 
Figure 7.WBC concentrations ± SE in subjects providing a blood sample pre-dose and at 
Weeks 1, 2, 3, and 4 (24-hour and 48-hour values combined). Week1=Pre-dose, Week2=Study 
Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 50 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Figure 8.WBC concentrations for every subject providing a blood sample pre-dose and at 
Weeks 1, 2, 3, and 4 (24-hour and 48-hour samples combined).Week1=Pre-dose, 
Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 9.WBC concentrations for every subject providing a blood sample pre-dose and at 
Weeks 1, 2, 3, and 4 (24-hour and 48-hour samples combined).Week1=Pre-dose, 
Week2=Study 
Week1, 
Week3=Study 
Week2, 
Week4=Study 
Week3, 
Week5= Study 
Week4. 
 
 
 
 
 
 
 
 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 51 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Figure 10. Lymphocyte concentrations for every subject providing a blood sample pre-dose and 
at Weeks 1, 2, 3, and 4 (24-hour and 48-hour samples combined). Week1=Pre-dose, 
Week2=Study Week1, Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 11. Hematocrits for every subject providing a blood sample pre-dose and at Weeks 1, 2, 
3, and 4 (24-hour and 48-hour samples combined). Week1=Pre-dose, Week2=Study Week1, 
Week3=Study Week2, Week4=Study Week3, Week5= Study Week4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 52 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Although Table 8 reports five, CTCAE Grade 3/4 hematology-related adverse events, a more 
general evaluation of hematology findings for all patients, do not suggest an overall concern. 
 
Table 9. Other Safety Tests 
 
Measure 
Test 
Results 
Coagulation 
Prothrombin (PT) tests 
performed at screening, 
Day0, 24 and 48 hours 
post-dosed on Weeks 1-4, 
and 5 and 8 Weeks post-
dose. 
Prothombrin (PT). 
No apparent effect of TK-112690 on PT. All mean values at 
pre-dose and at Week1, 2, 3, 4, 5 and 8 between 13 and 15 
seconds. 
Partial Thromboplastin Time (PTT). No apparent effect of 
TK-112690 on PTT. All mean values at pre-dose and at 
Week1, 2, 3, 4, 5 and 8 between 29 and 40 seconds. 
Urinalysis 
Urine 
analyses 
tests 
performed at screening, 
Day0, 24 and 48 hours 
post-dosed on Weeks 1-4, 
and 5 and 8 Weeks post-
dose.. 
pH 
No apparent effect of TK-112690 on urine pH. Mean values 
for dose cohorts ranged from 5.8 to 7.2.  
Positive/Negative Nitrite 
No apparent effect of TK-112690 on urinary nitrite. Vast 
majority of sample either negative, or, in some cases, no 
measurement. Positive finding for only two samples: One 
patient in 15 mg/kg, bid, dose group at 24 hours/Week 1, and 
one patient in 15 mg/kg, bid, dose group at 48 hours/Week 4. 
Occult Blood 
No apparent effect of TK-112690 on urinary occult blood. 
All samples either negative for occult blood, or, in some 
cases, no measurement. No positive findings for occult 
blood. 
Appearance (Clear/Hazy) 
Data too variable for any conclusion, but no apparent effect 
of TK-112690 on urine appearance.  
Color (Pale Yellow/Yellow) 
Data too variable for any conclusion, but no apparent effect 
of TK-112690 on urine color. 
Glucose (+++, ++, +, None) 
No apparent effect of TK-112690 on urine glucose. Some 
scattered findings. Single +++ finding in 30 mg/kg, bid, dose 
cohort at Week 3/48 hours. Single ++ findings in 30 mg/kg, 
bid, dose cohort pre-dose, 30 mg/kg, bid, dose group at Week 
5, and 60 mg/kg, bid, dose cohort at Week 3/24 hours. Single 
+ findings in 60 mg/kg, bid, dose cohort, at Week 1/24 hours, 
Week 3/ 48 hours, and Week 4/48 hours. All other findings 
none, or no measurements. 
Protein (+++, ++, +, Trace or None) 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 53 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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No apparent, consistent effect of TK-112690 on urinary 
protein. Some scattered findings. Single +++ findings in 60 
mg/kg, bid, dose cohort at Week 4/48 hours and Week 5. 
Single ++ findings in 30 mg/kg, bid, dose cohort at Week 
2/24 hours, Week 2/48 hours and Week 8, and 60 mg/kg, bid, 
dosed cohort at Week 8. Single + findings in 15 mg/kg, bid, 
dose cohort pre-dose, 30 mg/kg, bid, dose cohort at 
Week3/24 hours, Week 3/48 hours, and Week 5 (two 
findings), 45 mg/kg, bid, dose cohort at Week 5, and 60 
mg/kg, bid, at Week 2/ 24 hours, Week 2/48 hours, Week 
3/48 hours (two findings), Week 4/48 hours, and Week 5. All 
other findings none, trace or no measurements. 
Vital Signs 
Vital signs measurements 
were performed on each 
patient at Screening, Day 
0, 12 hours (Day 1), 24 
hour (Day1), 48 hours 
(Day 2), at equivalent 
times on weeks 2, 3 and 
4, and at weeks 5 and 8 
post-dose. 
Vital 
signs 
measured included supine 
blood pressure (systolic 
and diastolic), heart rate, 
respiratory rate and oral 
body temperature. were 
performed at screening, 
Day 0, pre-dose and 4, 6, 
8, 12, 24, 48 hours and 5 
and 8 Days post-dose. 
No apparent effect of TK-112690 dosing on blood pressure, 
pulse, respiratory rate, body temperature, or BMI 
 
Diastolic BP (mmHg) 
      Week         Dose           Mean             n            SD 
Pre-dose 
15 
115 
3 
13 
 
30 
115 
3 
8 
 
45 
123 
4 
10 
 
60 
119 
15 
8 
1 
15 
122 
6 
2 
 
30 
124 
6 
8 
 
45 
117 
8 
8 
 
60 
117 
30 
7 
2 
15 
122 
6 
5 
 
30 
127 
6 
6 
 
45 
114 
6 
5 
 
60 
118 
28 
7 
3 
15 
122 
6 
7 
 
30 
125 
6 
3 
 
45 
113 
4 
5 
 
60 
118 
26 
8 
4 
15 
121 
6 
1 
 
30 
127 
6 
4 
 
45 
114 
4 
5 
 
60 
118 
20 
7 
Diastolic BP (mmHg) 
       Week              Dose         Mean           n              SD 
Pre-dose 
15 
75 
3 
14 
 
30 
79 
3 
3 
 
45 
78 
4 
5 
 
60 
80 
15 
5 
1 
15 
78 
6 
4 
 
30 
79 
6 
5 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 54 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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45 
75 
8 
4 
 
60 
78 
30 
4 
2 
15 
77 
6 
4 
 
30 
79 
6 
3 
 
45 
74 
6 
5 
 
60 
76 
28 
7 
3 
15 
80 
6 
6 
 
30 
82 
6 
2 
 
45 
73 
4 
5 
 
60 
78 
26 
5 
4 
15 
79 
6 
3 
 
30 
81 
6 
2 
 
45 
73 
4 
5 
 
60 
76 
20 
4 
Respiratory Rate (Per-minute) 
       Week         Dose         Mean             n              SD 
Pre-dose 
15 
17 
3 
1 
 
30 
17 
3 
1 
 
45 
17 
4 
1 
 
60 
17 
15 
2 
1 
15 
18 
6 
2 
 
30 
15 
6 
3 
 
45 
17 
8 
1 
 
60 
17 
30 
2 
 
Total 
17 
50 
2 
2 
15 
18 
6 
1 
 
30 
17 
6 
1 
 
45 
17 
6 
1 
 
60 
17 
28 
2 
3 
15 
18 
6 
2 
 
30 
17 
6 
2 
 
45 
17 
4 
1 
 
60 
17 
26 
2 
4 
15 
17 
6 
1 
 
30 
18 
6 
1 
 
45 
17 
4 
1 
 
60 
18 
20 
2 
Heart Rate (Per Minute) 
       Week          Dose        Mean             n              SD 
Pre-dose 
15 
76 
3 
2 
 
30 
87 
3 
10 
 
45 
80 
4 
2 
 
60 
80 
15 
4 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 55 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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1 
15 
80 
6 
7 
 
30 
85 
6 
10 
 
45 
79 
8 
2 
 
60 
80 
30 
5 
2 
15 
81 
6 
7 
 
30 
85 
6 
5 
 
45 
78 
6 
2 
 
60 
79 
28 
5 
3 
15 
80 
6 
6 
 
30 
79 
6 
3 
 
45 
78 
4 
2 
 
60 
80 
26 
4 
4 
15 
77 
6 
6 
 
30 
78 
6 
2 
 
45 
80 
4 
2 
 
60 
79 
20 
4 
BMI (kg/m2) 
       Week         Dose         Mean             n              SD 
0 
15 
18 
3 
2 
 
30 
20 
3 
5 
 
45 
17 
4 
2 
 
60 
19 
15 
4 
1 
15 
18 
3 
2 
 
30 
20 
3 
5 
 
45 
17 
4 
2 
 
60 
19 
15 
5 
2 
15 
18 
3 
2 
 
30 
20 
3 
5 
 
45 
18 
3 
2 
 
60 
19 
14 
4 
3 
15 
18 
3 
1 
 
30 
20 
3 
5 
 
45 
17 
2 
2 
 
60 
18 
13 
3 
4 
15 
18 
3 
2 
 
30 
20 
3 
5 
 
45 
17 
2 
2 
 
60 
19 
10 
4 
Body Temperature (°C) 
       Week           Dose       Mean         n              SD 
0 
15 
115 
3 
13 
 
30 
115 
3 
8 
 
45 
123 
4 
10 
 
60 
119 
15 
8 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 56 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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1 
15 
98 
6 
0 
 
30 
98 
6 
0 
 
45 
98 
8 
0 
 
60 
98 
30 
1 
2 
15 
98 
6 
0 
 
30 
98 
6 
0 
 
45 
98 
6 
0 
 
60 
98 
28 
1 
3 
15 
98 
6 
0 
 
30 
98 
6 
0 
 
45 
98 
4 
0 
 
60 
98 
26 
1 
4 
15 
98 
6 
0 
 
30 
98 
6 
0 
 
45 
98 
4 
0 
 
60 
98 
20 
1 
Physical 
Examination 
A physical examination 
was performed on each 
patient at Screening, Day 
0, 12 hours (Day 1), 24 
hours (Day1), 48 hours 
(Day 2), at equivalent 
times on weeks 2, 3 and 
4, and at weeks 5 and 8 
post-dose. The physical 
examinations 
included 
assessments of the skin, 
head, eyes, ears, nose, 
throat, 
neck, 
thyroid, 
lungs, heart, abdomen, 
lymph 
nodes, 
and 
extremities. 
Overall no apparent effect of TK-112690 dosing on findings 
from the Physical Examination.  
 
Physical exam results were scored as either change (C) or no 
change 
(NC). 
NC 
was 
recorded 
for 
all 
eye, 
head/neck/thyroid, 
blood/lymphatics, 
immune 
system, 
nervous/psychiatric, general and site of administration, 
respiratory, 
cardiovascular, 
GI/Hepatobiliary, 
musculoskeletal, 
infections/infestations, 
renal, 
and 
reproductive.  
 
C was noted: 
● In skin of Patient 7 at Week1/48 hours.  
● In ears/nose/throat of Patient 1 at Week 3/24 hours, 
Week 4/24 hours, Week 4/48 hours, and Week 8. 
● In ears/nose/throat of Patient 14 at Week1/24 hours, and 
Week 1/48 hours. 
● In ears/nose/throat of Patient 19 at Week 5 and Week 8. 
● In ears/nose/throat of Patient 19 at Week 8. 
● In endocrine/metabolism/nutrition at Week 5, and Week 
8.  
EKG 
A 12-Lead ECG was 
performed 
on 
each 
patient at Screening and 
at 24 hours on Day1 as 
well as at equivalent 
times on Weeks 2, 3 and 
4. 
No apparent effect of TK-112690 dosing on ECG. All ECGs 
normal except for Patient 1 (15 mg/kg TK-112690, bid) at 
Weeks 1, 2, 3 and 4, and Patient 3 (15 mg/kg TK-112690, 
bid) at Weeks 1 and 4.  
Disease 
Progression 
CT scan for size of target 
lesion at screening and 
Week 8. 
Complete data available only for Patients 1, 2, 3, 5, 6, 8, 11, 
19, 20, and 22. Given the limited data no analysis by 
RECIST criteria was possible. However, for the sum of 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 57 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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longest tumor diameter measure, 7 lesions decreased and 3 
increased, although the changes were not large. 
 
1.5.2.11 TK-112690 Pharmacokinetics (PK) 
 
Blood samples for PK were obtained on each patient at Pre-dose (Day 1), 5 hours (Day 1), and 
24 hour (Day1) post-dose, and TK-112690 measured by LC/MSMS in the harvested plasma. 
Reports on the PK86 and LC/MS/MS assay87 are available. Except for a few scattered 
measurements, TK-112690 concentrations in pre-dose samples were nm. The two following 
Figures provide the mean TK-112690 concentration data observed with dose and dosing 
interval.  
 
Figure 12. Bar chart showing mean concentration of TK-112690, pg/mL ± SE, for individual 
dosing intervals at 5 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes 
data from all patients who completed 4 doses.Interval 1=Study Week 1, Interval 2=Study Week 
2, Interval 3=Study Week 3, and Interval 4=Study Week 4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 13.Bar chart showing mean concentration of TK-112690, pg/mL ± SE, for individual 
dosing intervals at 24 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690.Analysis 
includesdata from all patients who completed 4 doses.Interval 1=Study Week 1, Interval 
2=Study Week 2, Interval 3=Study Week 3, and Interval 4=Study Week 4. 
                                               
86 Tosk FSR-CL-2690 0015: PK/PD of TK-11290 Administrated to Cancer Patients in Clinical Study CLP-2690-
0002. 
87 Tosk FSR-CL-2690-0014: Method Validation for “Determination of TK-112690 in Human Plasma by 
LC/MS/MS” 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 58 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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The TK-112690 blood level data suggests: 
 
● Plasma concentrations increase with increasing dose. 
● The increase in concentration observed with the 60 mg/kg dose is somewhat less than expected.  
● Comparing the 5-hour and 24-hour data, the terminal elimination half-life appears to be 
somewhat longer than the approximately 4 hours observed in the Phase 1a study. The estimated 
terminal elimination half-life in this study is approximately 6 hours. 
 
1.5.2.12 Biomarker (Uridine) 
 
Uridine was also measured in the same samples used for PK measurement using a pilot 
LC/MS/MS assay.88 The uridine data can be found in the same report providing the TK-112690 
concentration data.86 
 
Uridine data from the study are provided in the Figure below.  
 
Figure 14.Bar chart showing mean concentration of uridine, pg/mL ± SE, for individual dosing 
intervals at 5 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690.Analysis includes data from 
all patients who completed 4 doses. Interval 1=Study Week 1, Interval 2=Study Week 2, Interval 
3=Study Week 3, and Interval 4=Study Week 4. 
                                               
88 Tosk ATM-2690-0002: An LC/MS/MS Test Method for Uridine in Human Plasma Post Administration of TK-
112690. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 59 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Compared to the 15 mg/kg dose,89 the 30 and 45 mg/kg, bid, doses of TK-112690 provided the 
expected increase in uridine (TK-112690 is an inhibitor of an enzyme responsible for the 
clearance of uridine, uridine phosphorylase. The reason for the less than expected increase in 
uridine with the 60 mg/kg, bid, dose of TK-112690 is unknown.  
 
1.5.2.13 Surrogate Markers (CD40, CD40L, TNF-α, FGF-9) 
 
Blood samples were obtained from each patient for surrogate marker determination at, pre-dose 
(Day 1), and 5-hours (Day 1), 24-hour (Day1), 48-hours (Day 2) post dosing with TK-112690 as 
well as at equivalent times on weeks 2, 3 and 4. Complete data for the Surrogate Markers are 
available in a Tosk report.90 
 
 
No specific trend emerged as no dose related changes has been observed on scheduled time 
points in these biomarkers. This could be due to the high variability in the marker levels and few 
subjects per group. FGF9 measurements were almost all non- measurable. 
 
Virtually all FGF9 concentrations were found non-measurable. 
                                               
89Pre-dose uridine measurements in the study were found very variable and unreliable likely because of a 
mistake in the protocol positioning the pre-dose sample one hour before the TK-112690 dose which was 
after treatment with the nutraceutical containing uridine monophosphate. The nutraceutical treatment 
would be expected to initially disturb the many components of the “uridine” biochemical system. This 
disturbance would not be expected to measurements taken at 5 and 24 hours post the TK-112690. 
90 Tosk FSR-CL-2690-0016: Plasma Concentrations CD40, CD40L, FGF9, and TNF-〈 Post TK-11290 
Administration to Cancer Patients in Clinical Study CLP-2690-0002. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 60 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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1.5.2.14 Mucositis Status 
 
Patients were evaluated for mucositis status on Day 0, pre-dose (Day 1), 24 hours (Day1), 48 hours (Day 
2), at equivalent times on 2, 3, and 4 weeks post-dose. The mucositis evaluation included four standard 
scales: CTCAE/mucositis, WHO/Oral Mucositis, PROMS, and OMAS/Sonis. 
 
Data for the scales are provided below. In general, the mucositis experience experienced by the patients 
was low, and many low values were recorded by the Scales. Much higher values would be expected in 
patients dosed with methotrexate but with no TK-112690. 
 
Figure 15. Bar chart showing mean score NCI mucositis scale for individual dosing intervals at 
24 and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes data from all 
patients evaluated. 
 
 
 
Figure 16. Bar chart showing mean score WHO oral mucositis scale for individual dosing 
intervals at 24 and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes 
data from all patients evaluated. 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 61 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Figure 17. Bar chart showing mean score PROMS scale for individual dosing intervals at 24 
and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes data from all 
patients evaluated. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 62 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Figure 18. Bar chart showing mean OMAS mouth pain score for individual dosing intervals at 24 
and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes data from all 
patients evaluated. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 19. Bar chart showing mean OMAS difficulty swallowing score for individual dosing 
intervals at 24 and 48 hours post 15, 30, 45 or 60 mg/kg dose of TK-112690. Analysis includes 
data from all patients evaluated. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 63 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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The scores in the mucositis scale tests suggest that TK-11290 at doses of 45 and 60 mg/kg, bid, mitigated 
mucositis produced by a relatively high methotrexate dose of 45 mg/m2.  
 
1.5.2.15 Overall Summary 
 
The findings above from the Phase 1b study suggest: 
● Although numerous adverse events, some serious including two deaths, occurred during the 
study, none appear associated with the TK-112690 treatment. Instead, the adverse events appear 
associated with the methotrexate treatment or the patient’s illness. None of the adverse events 
appears related to the dose of TK-112690 employed. All the PIs in the study agree that none of 
the adverse events can be attributed to the TK-11290 treatment. 
● The PK of TK-112690 in patients appears like that observed in the Phase 1a study in volunteers, 
except the terminal elimination half-life in patients appears slightly longer. Plasma concentrations 
of TK-112690 increased with increasing dose of drug, although the increase at 60 mg/kg, bid, was 
somewhat less than expected.  
● The increase in plasma uridine compared to the lowest dose administered expected by the TK-
122690 treatment was achieved with the 30 mg/k, bid, and 45 mg/kg, bid, doses but not the 60 
mg/kg, bid, dose.. 
● The suppression of CD40 levels, a measure of immune activation, with TK-112690 doses > 15 
mg/kg, bid, supports the notion that TK-112690 acts to diminish the immune response which 
Sponsorbelieves underlies chemotherapy-induced mucositis  
● The finding that TK-112690 treatment at doses > 15 mg/kg, bid, appears to decrease two liver 
damage markers, GGT and alkaline phosphatase needs further clinical verification and study in 
animals.  
● The protective effect of TK-112690 on mucositis post methotrexate observed in animal studies 
was confirmed in the Phase 1b study. but this confirmation needs further verification in a placebo 
controlled clinical trial. 
 
1.6. PURPOSE OF STUDY 
 
METREXASSISTTM, TK-112690 for parenteral use, is a novel, non-toxic and specific therapy to treat 
mucositis, a major side-effect of MTX. This study is designed primarily to establish, in a placebo- 
controlled trial, pilot efficacy compared to placebo and secondarily to confirm the safety and tolerability 
of TK-112690 when administered weekly for 4 weeks along with MTX as an intravenous infusion in 
subjects with local, advanced, recurrent, metastatic SCCHN. 
 
1.7. RATIONALE FOR DOSAGE 
 
1.7.1. TK-112690 
 
The dose of TK-112690 to be tested in patients in this study will be 45 mg/kg, bid. This dose was found 
tolerable and likely efficacious in the Phase 1b study in patients with SCCHN. The drug will be given iv 
over one hour. 
 
 
 
1.7.2. Placebo 
 
Placebo would be an identical a volume of isotonic saline in 10 mL vials as used for the TK-112690 dose. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 64 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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1.7.3. MTX 
 
The dose of MTX will be 45 mg/m2. This dose was used in the Phase 1b study in patients with SCCHN.  
 
1.7.4 Nutritional Supplement 
 
TK-112690 is a uridine phosphorylase (UPase) inhibitor. Inhibition of UPase leads to increased uridine 
which is hypothesized to be the active protecting agent. The nutritional supplement, Fortasyn Connect™ 
(Nutricia NV), contains uridine monophosphate and is being dosed to ensure that all the cancer patients 
have enough uridine in the body for TK-112690 to have the desired effect. In multiple preclinical studies 
at Tosk, uridine alone, without TK-112690, had no protective effect on MTX-induced mucositis.  
 
1.8. CONDUCT OF TRIAL 
 
This clinical trial will be conducted according to the current revision which has its origin in the 
Declaration of Helsinki (Revised 59th WMA General Assembly, Seoul, October 2008 -Appendix 1). The 
study will be conducted in compliance with this protocol, CFR parts 50, 56 and 3112, Good Clinical 
Practice (CPMP/ICH/135/95), Schedule Y of the Indian Drugs and Cosmetics Act, and designated 
standard operating procedures. 
2.0. STUDY OBJECTIVES 
 
2.1. PRIMARY OBJECTIVE 
 
The primary objective of this study is to establish pilot efficacy compared to placebo for TK-112690 as an 
anti-mucositis agent when administered weekly for 4 weeks by iv infusion to subjects with locally 
advanced, residual or recurrent or metastatic SCCHN scheduled to receive MTX as chemotherapy.  
 
2.2. SECONDARY OBJECTIVES 
 
The secondary objective of this study is to confirm the safety and tolerability of a continuous iv infusion 
of TK-112690 demonstrated in the Phase 1b study in patients suffering from local, advanced, residual 
recurrent, metastatic SCCHN receiving sequential continuous iv infusions of TK-112690 and MTX. 
3.0. STUDY DESIGN AND TREATMENT 
 
3.1 STUDY OUTCOMES/ENDPOINTS 
 
Key study outcomes/endpoints are listed below: 
 
● Efficacy. Mucositis scores in 4 standard mucositis scales. 
● PD: Evaluation potential relationships among TK-112690 dose, mucositis scores, and surrogate 
markers of mucositis, e.g., CD40/CD40Land TNF-α. 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 65 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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3.1.2. DOSE MODIFICATIONS 
 
Treatment will be withheld following grade 3 or 4 adverse events. Treatment may be restarted when the 
adverse events have recovered to ≤ grade 2. Subjects in whom treatment is withheld for > 2 weeks will 
have treatment discontinued permanently. 
 
3.2. OVERVIEW OF STUDY DESIGN AND DOSING REGIMEN 
 
This is a multi-center, randomized, partially blinded, placebo controlled, Phase 2a, pilot efficacy/safety 
study of METREXASSISTTM (parenteral TK-112690) administered weekly for 4 weeks in combination 
with MTX in subjects with SCCHN.  
 
Figure 20 below provide, respectively, an overview of the study design. 
 
Figure 20. Overview of Study Design and Dosing Regimen. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3.3 CONCOMITANT MEDICATION AND TREATMENT 
Subjects should continue at study initiation with their concomitant medications, as directed by their 
physicians. Any medication or therapy received by the patient within 4 weeks of baseline, during the 
study, including: over-the-counter, herbal preparations, supplements, prescription and non-prescription 
drugs, vaccinations or discontinued medications must be reported on the appropriate concomitant 
1
Weeks          1                          2                          3                            4                           5 
  6  
Screening/Baseline: 
• 
 Patient Evaluation 
• 
 Overall Health 
• 
 Disease Status 
• 
 Mucositis History 
• 
 Baseline Vitals, Clin Chems, Hematology, 
etc. 
• 
  Surrogate Markers of Mucositis 
• 
  
Dose2 
Dose3
Dose4 
Follow-up
4 
• 
 Mucositis Status 
• 
 Safety 
• 
 Disease Status 
• 
 Surrogate 
Markers 
Placebo vs. Treated: 
• 
Mucositis  
• 
Safety,  
• 
Surrogate 
Markers 
• 
Disease Status  
1Nutritional supplement orally 1 hour before TK-112690, or TK-112690 
placebo. 
2TK-112690 (45 mg/kg) or TK-112690 placebo 1 hour before, and 5 hours 
after, MTX (45 mg/m
2). 
3Patient can continue treatment after fourth dose with agreement of the PI. 
Dose1
1-3 
CBC 
Liver/Kidney Function 
Mucositis 
Safety 
Surrogate markers 
CBC 
Liver/Kidney Function 
Mucositis  
Safety 
Surrogate markers 
CBC 
Liver/Kidney Function 
Mucositis 
Safety 
Surrogate markers 
CBC 
Liver/Kidney Function 
Mucositis 
Safety 
Surrogate markers 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 66 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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medication page(s) of the case report form (CRF). The information on the concomitant 
medication/therapy CRFs will include the name of the medication/therapy, dose, frequency, route of 
administration, dates of use (start and finish date), and indication for use. Subjects should be instructed 
not to take any medications including over-the-counter products, without first consulting with the PI. Any 
adverse event that results from taking a concomitant medication/therapy should be recorded on the CRF 
adverse event page. Additionally, any diagnostic, therapeutic or surgical procedure performed during the 
study period, should be recorded including date, indication, description of the procedure and any clinical 
findings. 
 
3.3.1. Palliative and Supportive Care 
 
Palliative and supportive care for disease-related symptoms will be offered as needed to all subjects in 
this study per the caring physician’s judgment. These may be anti-emetics, anti-diarrhea agents, anti-
abdominal cramping agents and blood products and blood transfusions as appropriate. Stomatitis may be 
treated at the PI’s discretion  
 
3.4. RESTRICTIONS 
 
3.4.1. Prior Therapy 
 
Participation in another clinical trial within 4 weeks of dosing is not allowed. 
 
3.4.2. Fluid and Food Intake 
 
There are no protocol-mandated restrictions with respect to ingested fluids and food.  
 
3.4.3. Subject Activities and Restrictions 
 
There are no specific restrictions in physical activities. 
 
3.5. RANDOMIZATION AND BLINDING 
 
The Phase 2a study will be partially blinded. The patient and investigator will be blinded as to whether 
TK-112690 or placebo is administered. The CRO, sponsor, and site pharmacist will know whether the 
patient was administered active drug or placebo.  
 
A list providing randomization, active drug and placebo, for each of the 22 subjects will be prepared (List 
A). Another list will provide randomization for 8 additional subjects if additional subjects are enrolled 
(List B). Both lists will be kept by the CRO.  
 
A designated person or Pharmacist will prepare the TK-112690 treatments by adding either active drug or 
placebo into 250 ml 0.9% sodium chloride iv bottle (Appendix 3). Whether active drug or placebo is 
added will reflect the subject number and the randomization suggestion made in the Randomization List 
for that subject number. The CRO will provide the designated person or pharmacist with vials re-labelled 
to maintain the partial blind. The randomization will be done by the CRO or a third-party vendor.  
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 67 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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3.6. NUMBER OF SUBJECTS IN THE STUDY 
 
A total of 22 subjects will be recruited over a period of 10 months. 
 
3.7. CENTERS 
 
This is a multi-center study conducted within India across various geographical regions in India. At least 
3 centers are planned.  
 
4.0. STUDY POPULATION 
 
4.1. TARGET POPULATION 
 
Subjects considered for enrollment will be selected from subjects presenting with a confirmed diagnosis 
of local, advanced, recurrent, metastatic SCCHN for which MTX at a dose of 45 mg/m2 is the scheduled 
therapy. 
 
4.2. INCLUSION CRITERIA 
 
● Male and female subjects over 18 years old with a histologically or cytologically confirmed 
diagnosis of locally residual, recurrent or metastatic SCCHN. 
● Subjects must have a histologically confirmed diagnosis SCCHN (any stage). 
● Subject must have failed at least onecourses of non-MTX chemotherapy or one coursenon-
MTX chemotherapy and chemo radiation for treating their SCCHN. 
● No prior systemic treatments for cancer (chemotherapy and/or radiotherapy) within 4 weeks 
of dosing. 
● Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2. 
● Must have a life expectancy of at least 6 months. 
● History of brain metastases allowed if disease has stabilized or improved after radiation 
and/or craniotomy. 
● No active angina or uncontrolled arrhythmia. 
● No other concurrent, active, invasive malignancies. 
● No detectable infection including hepatitis B/C and HIV. 
● No pregnant or nursing females. Women of childbearing potential must have a negative 
serum ß-hCG pregnancy test at screening and must use medically acceptable methods of birth 
control. Acceptable methods of birth control include oral or transdermal contraceptives, 
condoms, spermicidal foam, IUD, progestin implant or injection, abstinence, vaginal ring, or 
sterilization of partner. The reason for non-childbearing potential, such as bilateral tubal 
ligation, bilateral oophorectomy, hysterectomy, or post-menopausal for ≥ 1 year, must be 
specified on patient’s source documents (medical history file) and CRF. 
● Must have adequate organ and immune function as indicated by the following laboratory 
values: 
 
Parameter 
Laboratory Values 
Serum creatinine 
 
 
≤1.5 x ULN 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 68 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Estimated creatinine clearance             ≥45 mL/min 
Total bilirubin 
 
 
≤2.0 mg/dL (≤34.2 µmol/L) 
AST (SGOT) & ALT (SGPT) 
 
≤3 x ULN  
Absolute granulocyte count 
 
≥1.5 x 109 cells/L 
Platelets  
 
 
 
≥ 100,000/µL 
 
● Be able to read or understand, and provide a signature/thumb impression on the Informed 
Consent Form (ICF) before entering into the study. 
 
4.3. EXCLUSION CRITERIA 
● Subject has not failed at least one courses of non-MTX chemotherapy or one course of non-
MTX chemotherapy and chemoradiation for treating their SCCHN. 
● Uncontrolled active infection. 
● Current mucositis (> Grade 1). 
● Pregnancy or nursing mother. 
● Prior history of a cerebrovascular accident or hemorrhage. 
● Congestive heart failure as defined by New York Heart Association class III or IV. 
● Uncontrolled hypertension. 
● Active psychiatric or mental illness making informed consent or careful clinical follow-up 
unlikely. 
● Subjects who have previously been enrolled into this study and subsequently withdrew. 
● Subject receiving other investigational agent(s). 
● Any systemic immunosuppressive medication/therapy (eg, chemotherapy, steroids). 
● Any significant systemic illness, unstable or severe medical condition(s) that could put the 
subject at risk during the study, interfere with outcome measures or affect compliance with 
the protocol procedures such as autoimmune disease, ie, any condition that compromises the 
immune system and/or intercurrent infection 
● Known or suspected intolerance or hypersensitivity to the study materials [TK-112690 and/or 
excipients or closely related compounds]. 
● Subjects who have received radiation or chemotherapy within 4 weeks of projected 
enrollment. 
●   Subjects that have a history of poor compliance in clinical research studies. 
●   Subjects who have participated in any other investigative clinical trial in the past 4 weeks. 
 
4.4. WAIVERS 
 
No waivers can be granted for inclusion in the study. 
 
5.0. STUDY TREATMENT 
 
5.1. DESCRIPTION OF TREATMENT 
 
5.1.1. Study Drug 
 
METREXASSISTTM (TK-112690 for Injection) is a clear, sterile, neutral, aqueous solution containing 
100 mg/mL TK-112690. TK-112690 is a water soluble anhydrouridine that inhibits uridine 
phosphorylase. METREXASSISTTM is an aqueous 5 mL solution, pH 7.4 in 50 mM sodium phosphate, 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 69 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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packaged in a 10 mL flint glass vial with an elastomeric stopper held in place by an aluminum seal and 
flip-off cap. METREXASSISTTM is supplied for administration by continuous iv infusion over one hour 
in a final of volume of 250 mL Saline for Injection (USP). METREXASSISTTM is to be re-suspended for 
infusion in Saline for Injection (USP). The vials must be stored frozen (-15 to -25°C).. Once opened, 
solution for infusion containing must be used within 8 hours of preparation. 
 
5.1.2. Study Drug Placebo 
 
10 mL glass vials of isotonic saline equipped with an elastomeric stopper held in place by an aluminum 
seal and flip-off cap.  
 
5.1.3. MTX 
 
MTX drug product traditionally used at the clinical site,  
 
5.1.4. Nutritional Supplement 
 
The nutritional supplement containing uridine monophosphate (Fortasyn Connect™ / SouvenaidTM) is a 
commercial, over the counter, product available from Nutricia NV. The supplement will be given to all 
dosed patients one hour prior to the TK-112690/placebo infusion (2 hours before the MTX infusion).  
 
5.2. STUDY THERAPY ADMINISTRATION 
 
The study therapy will be administered as an infusion via a peripheral vein in the forearm delivered using 
a catheter. This access vein for the infusion must not be used for blood sampling. Replacement of the 
intravenous catheter will be done according to local practice and the discretion of PI or designee, e.g., in 
the event of phlebitis. If a catheter is replaced, it should be flushed with saline prior to removal unless 
there are signs of phlebitis. TK-112690/placebo will initially be administered as a one-hour infusion. In 
case of immediate adverse reaction to the infusion, please follow management of reaction 
(Appendix 4: Infusion Reaction Criteria). 
 
Epinephrine (1:1000) for subcutaneous injection, diphenhydramine (12.5 mg to 50 mg) for iv 
injection, and any other medications and resuscitation equipment for the emergency management 
of anaphylactic reactions must be available in the room where the infusions are being performed. 
 
All patients will be evaluated at a follow-up visit on Day 1 of Week 6 post after initial drug treatments.  
 
METREXASSISTTM (TK-112690 for Injection) should be prepared for infusion by a healthcare 
professional using aseptic technique. METREXASSISTTM will be diluted into 250 mL of 0.9% sodium 
chloride in a iv bag/bottle. Please refer to Appendix 3 for the directions on how to calculate and dilute for 
the different doses to be administered to the subjects.  
 
For the  placebo will be prepared as described above for the TK-112690 except isotonic saline in 10 mL 
glass vials will be substituted for the 10 mL METREXASSISTTM vials. 
 
Dosing will be calculated on a mg/kg basis and rounded to the closest 10 mg. The TK-112690/placebo 
dose will be 45 mg/kg. 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 70 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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5.3. SELECTION AND TIMING OF DOSE FOR EACH SUBJECT 
 
Dosage will be administered to enrolled subjects as defined in the protocol ± one day 
 
 
5.4. PACKAGING AND LABELING 
 
METREXASSISTTM and placebo will be supplied by Tosk in labeled, sealed 10 ml vials. 
 
The vials will be labeled as follows: 
 
 
 
 
 
 
 
 
 
 
 
 
 
The boxes will be labeled as follows: 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 71 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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5.5. BLIND\CODE BREAK 
 
Phase 2a is a partially blinded study. The patient and investigator will be blinded as to whether TK-
112690 or placebo is administered, and the CRO, Sponsor,and site pharmacist (unblinded) will know 
whether TK-112690 or placebo. was administered. The Pharmacist will be receiving all the vials from 
CRO, on randomization to a particular group the unblinded pharmacist will take the IP\Placebo and mask 
it with a white sticker so that the blind is maintained at all times. At the request of the investigator, the 
code can be broken. A Subject’s treatment assignment will not be broken until the end of the study, unless 
medical treatment of the subject depends on knowing the study treatment the subject received. In the 
event that the blind needs to be broken because of a medical emergency, the investigator may unblind an 
individual subject’s treatment allocation. As soon as possible, the investigator should first contact the 
medical monitor to discuss the medical emergency and the reason for revealing the actual treatment 
received by that subject. It should be documented in the case record form. For unblinding, investigator 
may also ask the medical monitor, who will in turn ask the unblinded statistician to provide the code to 
the investigator for the particular subject. The date on which the code was broken, together with the 
identity of the person responsible, must also be documented. When the investigator unblinds a patient 
treatment for emergency reasons, he/she must note the date, time, and reason for doing it and record this 
information in the source notes.  
 
5.6. STORAGE AND ACCOUNTABILITY 
 
All study therapy must be kept in a secure place under adequate storage conditions. The TK-
112690infusion concentrate must be frozen (-20˚C ±5˚C) and protected from light. 
Placebo must be stored between 15 ˚C to 30 ˚C. 
 
The PI has overall responsibility for ensuring that study therapy is stored in a safe limited access location 
under the specified appropriate storage conditions. Limited responsibility may be delegated to a 
nominated pharmacy representative, but this delegation must be documented.  
 
Study therapy will be dispensed by the pharmacist or designated member of the study team. The PI or 
designee will record dispensing of the study medication on a study medication accountability record. 
These records should include dates, quantities, batch/serial numbers, updated expiration dates (if 
applicable), and the unique code number assigned to the investigational product and trial subject. This 
record will be made available to clinical monitoring personnel for the purpose of accounting for the 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 72 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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clinical study medication supply. A study medication supply inspection for inventory purposes and 
assurance of proper storage will be conducted as necessary. Any significant discrepancy will be recorded 
and reported to the sponsor and a plan for resolution will be documented.  
 
5.7. INVESTIGATIONAL PRODUCT RETENTION AT STUDY SITE AND DESTRUCTION 
 
All study therapy required for completion of this study will be provided by Tosk (MetrexassistTM, placebo 
and the nutritional supplement,).  
 
The recipient will acknowledge receipt of the drug indicating shipment content and condition. Damaged 
supplies will be replaced. Accurate records of all study drug dispensed, used, and returned will be 
maintained. At the conclusion of the trial, all unused and used vials of will be returned to the sponsor or 
designee. Alternately, drug may be destroyed on site as dictated by the standard operating procedures at 
the participating institution (if appropriate). Vials should only be destroyed or returned after drug 
accountability has been performed by the clinical research associate and all vials were accounted for. If 
there is an error or perceived error, vials should be returned to Tosk. 
 
5.8. DURATION  
 
Phase 2a:  
 
Start Date: 
 
First Quarter 2019 
End of Recruitment:  
3rd Quarter 2019 
End of Treatment:  
Fourth Quarter 2019 
 
 
6.0. STUDY PROCEDURES 
 
6.1. INFORMED CONSENT 
 
All subjects are to give informed consent in accordance with the origins of the Declaration of Helsinki 
(Appendix 1) and CFR part 50. The informed consent form as well as any advertisements used to recruit 
patients must be approved by the IRB/IEC. 
 
The subject will provide the sign/thumb impression on the Informed Consent Form (ICF) before 
she/he enters the study, ie, before screening blood samples, screening assessments or any other 
study-related activity. The subject will be given sufficient time to consider the study’s implications 
before deciding whether to participate. The informed consent form as well as any advertisements used to 
recruit patients must be approved by the IRB/IEC. Participants must sign/thumb impression the IRB/IEC-
approved informed consent form prior to participation in any study specific procedure. The participant 
must receive a copy of the signed and dated consent document. The original signed copy of the consent 
document must be retained in the research file. 
 
Should there be any amendments to the final protocol, the subject must agree to sign/thumb impression 
the amended ICF indicating that they re-consent to participate in the trial. 
 
6.2. SUBJECT IDENTIFICATION 
 
6.2.1. Subject Registration 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 73 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Prior to registration and any study-specific evaluations being performed, all subjects must have given 
written informed consent for the trial and must have completed the screening evaluations (see Section 
7.1). Subjects must meet all of the eligibility requirements listed in Section 4.0.  
 
6.2.2. Subject Number 
 
When the subject has completed the screening process and enters into the trial, he/she will be assigned a 
unique subject number composed of a site identification number and unique subject identification 
sequence number. The subject number and the subject’s initials will be used as identification for the 
whole duration of the study. 
 
6.3. MEDICAL HISTORY 
 
Medical history will be performed at screening and will establishing age, sex, race, history of 
smoking/alcohol consumption/drugs and including subject’s disease history. The review of 
previous/ongoing medications should cover a period of time that is 180 days prior to enrollment.  
 
6.4. PHYSICAL EXAMINATION 
 
A complete physical examination will be conducted at screening, on Day 0, 24 and 48 hours post each 
TK-112690/placebo dosing and on Day 1 of Week 6. Physical examination will be performed by site 
personnel who are experienced and routinely conduct physical examinations. 
 
6.5. VITAL SIGNS, WEIGHT DETERMINATIONS AND CARDIOVASCULAR ASSESSMENTS 
 
Body temperature will be recorded by the oral, rectal or tympanic route at screening and during weekly 
visits. The same route should be used for all measurements, if possiblesupine blood pressure (systolic and 
diastolic), respiratory rate and pulse will be recorded at screening (defined as baseline) and at Day 0, and 
24 and 48 hours post TK-112690 /placebo infusions as well as on Day 1 of Week6. The time of the 
measurements will be noted. All measurements will be made with the subject in the supine position. 
Blood pressure should be determined by cuff (manual or automated is acceptable, although the same 
method should be used throughout the study).  
 
Weight will be determined concurrent with vital sign measurements.  
 
A standard 12 lead ECG will be recorded at screening (defined as baseline) and at 24 post each TK-
112690/placebo dosing. The PI will provide an overall judgment of the ECG.  
 
6.6. DISPENSING STUDY DRUG 
 
Study drugs must be used only as directed in the protocol. The PI will be provided with forms to enable 
accurate, written records of all medication received from Tosk. These records will be kept by the PI or 
pharmacist/nominated person. The PI or pharmacist/nominated person will also keep accurate records of 
the quantities dispensed and used of the investigational product.  
 
At the end of the study, all unused trial medication (ie, vials) will be returned by the pharmacist/ 
nominated person to a nominated contractor on behalf of Tosk. All certificates of delivery and returns 
must be signed by the pharmacist/nominated person. Based on entries in the drug accountability forms, at 
the end of the trial, it must be possible to reconcile delivery records with those of usage and returned 
stocks. All study medication must be accounted for and all discrepancies documented appropriately. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 74 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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6.7. CLINICAL LABORATORY TESTS 
 
6.7.1. Laboratory Parameters 
 
Besides the Central Laboratory Tests, an in-house (at site) CBC, Kidney function test, Liver function test   
will be performed to qualify the subject for dosing with MTX, .Coagulation: (prothrombin time, PT, and 
activated partial thromboplastin time, PTT,tests will be performed at the Local laboratory associated 
with the clinical site as per schedule of events. 
 
Subjects will be in a seated or supine position during blood collection. Clinical laboratory tests to be 
performed are included in Table 10.  
Table 10. Central Laboratory Tests 
Hematology: 
 
 
 
 
Serum Chemistry: 
Hematocrit (Hct) 
 
 
 
 
Albumin (ALB) 
Hemoglobin (Hb) 
 
 
 
 
Alkaline phosphatase (ALK-P) 
Mean corpuscular hemoglobin (MCH)  
 
Alanine aminotransferase (ALT or SGPT) 
Mean corpuscular hemoglobin concentration (MCHC) Aspartate aminotransferase (AST or SGOT) 
Mean corpuscular volume (MCV)  
 
 
Blood urea nitrogen (BUN) 
Platelet count 
 
 
 
 
 
C-reactive protein 
Red blood cell (RBC) count  
 
 
 
Calcium (Ca) 
White blood cell (WBC) count with differential   
Chloride (Cl) 
Creatinine 
 
 
 
 
 
 
 
Creatinine kinase  
 
 
 
 
 
 
 
Direct bilirubin 
 
 
 
 
 
 
 
Total bilirubin 
Total cholesterol (non-fasting) 
 
 
 
 
 
 
 
Total protein 
 
 
 
 
 
 
 
Triglycerides (non-fasting) 
 
 
 
 
 
 
 
Uric acid 
Gamma-glutamyltransferase (GGT) 
Globulin 
 
 
 
Glucose (Random) 
Lactate dehydrogenase (LDH) 
Phosphorus 
Potassium (K) 
Sodium (Na) 
 
Urinalysis :( will be performed by dipstick) 
 
Appearance 
 
 
 
 
 
Color  
 
 
 
 
 
Glucose 
 
 
 
 
 
Protein  
 
 
 
 
 
Occult blood 
 
 
 
 
 
Nitrite 
pH 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 75 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Urine human chorionic gonadotropin: Females of childbearing potential only 
 
Coagulation: 
 
● Prothrombin time (PT) 
● Activated partial thromboplastin time (PTT) 
 
The laboratory measurements of clinical chemistry, hematology and urinalysis will be performed during 
screening (defined as baseline), on Day 0 and at 24 and 48 hours post each initial infusion of TK-112690 
or  Placeboas well as on Day 1 of Week6.  
 
All laboratory measurements will be performed at a central laboratory. The laboratory will provide the PI 
and Tosk with test results including units, relevant reference ranges and updates as necessary. Laboratory 
measurements can also be performed at local sites for medical or informational reasons However; these 
measurements will not be considered part of the study record.  
 
6.7.2. Pharmacokinetics (PK) 
 
No blood samples will be collected for PK. If necessary, to establish correct dosing of an individual 
patient at a particular time, an aliquot of blood sample relevant to the suspect dosing from either the 
(6.7.3) surrogate marker (6.7.4) blood samples obtained from the patient.   
 
6.7.3. Surrogate Markers 
 
Blood samples will be collected for the surrogate marker measurements which shall include relevant 
inflammatory and immune markers, e.g., CD40/CD40L. Note: these samples must be collected from 
the arm not used for drug infusion. A total of17 blood samples will be collected for surrogate marker 
measurements: Pre-initial infusion of TK-112690 or placebo, at 5 and 24 hours and 48 hours post each 
initial infusion of TK-112690 or placebo as well as on Day 1 of Week 6. The blood samples will be 
collected in a 10 mL heparinized Vacutainers. 
 
6.7.4. Blood Samples 
 
A blood sample for CBC, Kidney function test, Liver Function test determination will be 
obtained 24 hours or so before each MTX dose to assure the patient is suitable for treatment with 
this chemotherapeutic. The sample will be processed at the local laboratory associated with the 
clinical site, and the data provided to the PI, the CRO and Tosk. 
 
6.7.5 Summary of Blood Samples to be obtained. 
 
A summary of the blood samples to be obtained in the study is provided in Table 11.  
 
Table 11. Nature and total volume of blood samples 
 
Purpose 
Size 
(mL) 
Time 
Total Volume (mL) / Patient 
CBC, Kidney function 
test, Liver Function test 
7 
Pre-dose Weeks 1-4 
28 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 76 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Laboratory Test 
14 
Screening 
Day 0 
Weeks 1-4 (24 and 48 hours) 
Week 6 
 
154 
Surrogate Markers 
5 
Weeks 1-4 (pre-dose, 5, 24 and 
48 hours) 
Week 6 
85 
 
 
Total 
267 
 
6.7.6 Processing Blood Samples. 
 
Blood sample each will be collected per Table 11 above and Schedule of Events (Table 12) for 
Laboratory, Surrogate Marker measurements in a heparinized tube and immediately placed on ice. Within 
30 minutes of collection, plasma will be isolated by centrifugation at 4°C/1000∗g for 10 minutes. 
 
● CBC, Kidney function test, Liver Function test (7 mL): This is a test prior to dosing to 
demonstrate that the patient can safely be treated with methotrexate. The test will be performed at 
the laboratory used by the clinical site. 
● Laboratory Test samples (14 mL): The plasma for the laboratory tests will be split into two equal 
parts, transferred into polypropylene freezer vials and then frozen at -20°C to -70°C. One of the 
two vials will be used for the Laboratory Tests performed at the site and the other vial will be sent 
to the central laboratory. 
● Surrogate Marker samples (5mL). The plasma for sample) will be transferred to a polypropylene 
freezer vial and then frozen at -20°C to -70°C.  
 
Specific shipping instructions will be issued by the analytical laboratory performing the analyses. The 
heparinized tube and freezer vial will be labeled with study code, subject number, subject initials, date 
and sampling time points. The plasma samples will be stored at the center until the study coordinator 
arranges transport to the analytical sites. 
 
Laboratory test will be performed both at the central laboratory except . Assays used to measure surrogate 
markers will be performed at Tosk, or a CRO engaged by Tosk.  
 
6.6 MUCOSITIS ASSESSMENT 
 
Mucositis status in subjects will be assessed using scoring systems described in more detail in Appendix 
20.6.  
 
7.0. STUDY ACTIVITIES 
 
Study visits should occur on the indicated visit day.  
 
7.1. SCHEDULE OF EVENTS 
 
Schedule of events are provided in Table 12 below. 
Table 12. Schedule of events (weekly cycle for 4 weeks and follow up at 6 week) 
Evaluation 
Screening 
Day 0 
Weeks 1, 2, 3,  and 4 
Week 6 
Follow-up 
0h 
5h 
6h 
24h 
48h 


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Informed Consent1 
X 
 
 
 
 
 
 
 
I/E Criteria 
X 
 
 
 
 
 
 
 
Medical history2 
X 
 
 
 
 
 
 
 
Test for drugs of abuse 
X 
X 
 
 
 
 
 
 
Physical examination3,4 
X 
X 
 
 
 
X5 
X5 
X 
Vital signs and weight 
X 
X 
 
 
 
X6 
X6 
X6 
ECOG 
X 
X 
 
 
 
 
 
X 
Pregnancy test (females) 
X 
X 
 
 
 
 
 
X 
12-Lead ECG 
X 
 
 
 
 
X 
 
 
Laboratory tests7 
X 
X 
 
 
 
X 
X 
X 
Randomization 
 
X 
 
 
 
 
 
 
CBC, Kidney function 
test, Liver Function test 
 
X8 
 
 
 
 
 
 
Nutritional supplement 
 
 
X9 
 
 
 
 
 
TK-112690/placebo 
treatments10 
 
 
X10 
 
X13 
 
 
 
MTX treatment 
 
 
X11 
 
 
 
 
 
Surrogate marker sample 
 
 
X12 
X 
 
X 
X 
X 
Mucositis evaluation14 
 
X 
 
 
 
X 
X 
X 
Disease Status 
X 
 
 
 
 
 
 
X 
AEs assessment 
 
 
 
X 
 
X 
X 
X 
1 To be obtained before any study-related activities are performed. 
2 Include a review of previous/ongoing medications for 180 days prior to enrollment. 
3 Complete examination, including assessments of the skin, head, eyes, ears, nose, throat, neck, thyroid, lungs, 
heart, abdomen, lymph nodes, extremities, and body weight. 
4 Height will be measured at screening only. 
5 Partial examinations to update findings from the examination performed at screening. 
6 Include blood pressure, pulse, respiratory rate and temperature. 
7 Includes serum chemistry, hematology (including coagulation), urinalysis; Hepatitis B/C & HIV only at 
screening 
8 CBC, Kidney function test, Liver Function test at clinical site can be performed anytime within 24 hours of a 
methotrexate treatment (NEEDED FOR ALL MTX TREATMENTS, EG, TREATMENTS ON WEEKS 1, 2, 3, 
AND 4, TO VERIFY OK TO DOSE MTX)  
9 One hour before TK infusion/placebo 
10 Beginning of TK-112690/placebo infusions is 0 hours. Dose is 45 mg/kg. 
11 45 mg/m2 one hour after TK-112690/placebo infusion. 
12 Pre-dose control samples for surrogate marker measurements. 
136 hours after TK-112690/placebo treatment, ie, 5 hours post MTX treatment 
14See Section 20.6 for mucositis assessment scales. 
   
7.1.1 Screening Visit 
 
To be accomplished within 15 days of expected initial dosing and ONLY AFTER THE ICF IS SIGNED. 
 
An Eligibility Screening Form (ESF) documenting the subject’s fulfillment of the entry criteria for all 
subjects considered for the study is to be completed by the PI. Subjects who are considered for study 
entry, but who fail to meet the eligibility requirements, will also have an ESF completed with the reason 
for ineligibility. These subjects will not be entered into the trial database. The ESFs for subjects who fail 
to meet the eligibility criteria requirements should be kept in the files at the sites.  
 
During this visit the following activities will be performed: 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 78 of 110 
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● Eligible subjects meeting the inclusion/exclusion criteria for this study will be asked to read, 
comprehend, and sign/thumb impression an informed consent form. 
● The subject medical history and concomitant medication use will be recorded as well as a history 
of drug abuse, alcohol consumption, and tobacco use. 
● Perform a urine screen for drugs of abuse.  
● A complete physical examination will be performed assessing the following: Skin, eyes, ear, 
nose, throat, neck, thyroid, lungs, heart, abdomen, lymph nodes, extremities, and body weight. 
● Vital signs and weight will be measured as well as an AE assessment. 
● ECOG performance status (Section 20.2 Appendix 2) 
● A pregnancy test will be performed on women of childbearing potential.  
● A 12-lead ECG will be performed. 
● The following laboratory test will be performed: hematological panel, infective agent panel, 
serum chemistry, coagulation and urinalysis (Laboratory tests, see Table 10 for complete list of 
tests).  
● Disease (tumor) assessment by CT scanning will be performed within 7 days post screening but 
before the first dosing. 
 
7.1.2 Day before start of study (Day 0) 
 
Prior to study start, all subjects will undergo the following: 
 
● Randomization 
● Perform urine screen for drugs of abuse. 
● A physical examination to update findings from the examination performed at screening. 
● Perform vital sign and weight measurements. 
● ECOG performance status. 
● A pregnancy test will be performed on women of childbearing potential. 
● Perform laboratory tests (hematology, chemistry, coagulation and urinalysis). 
● Perform a mucositis assessment (Section 20.6, Appendix 6). 
 
7.1.3. Days 1 and 2 (Weeks 1-4) 
 
Patients will be hospitalized on Day 1 and observed until after the 25-hour evaluations and plasma sample 
collection are obtained. All subjects will undergo the following on Days 1 and 2 of Weeks 1-4: 
 
● An in-house CBC, Kidney function test, Liver Function test to be performed within 24 hours of 
expected methotrexate dosing to verify patient Fit to receive methotrexate.  
● The nutritional supplement is ingested 2 hours prior to initiation of the MTX treatment, one hour 
prior to the TK-112690/placebo infusion.  
● TK-112690/placebo is administered as a one hour infusion pre-MTX and 5 hours post-MTX 
(±15mins window period). 
● One hour after the initial infusion of TK-112690 or placebo, MTX will be administered by 
continuous infusion for one hour (±15mins window period). 
● Physical examination, vital signs, weight, mucositis evaluation at 24 and 48 hours post the 
initialTK-112690/placebo infusion. 
● 12-lead ECG at 24 hours post initial TK-112690/placebo infusion.  
● Laboratory tests (hematology, chemistry, coagulation and urinalysis) 24 and 48 hours post initial 
TK-112690/placebo infusion. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 79 of 110 
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● Plasma samples will be collected for surrogate marker measurements pre-dose of the 
nutraceutical and 5, 24 and 48 hours initial infusion of TK-112690 orplacebo. 
● Mucositis assessments (Section 20.6, Appendix 6) at 24 and 48 hours post initial infusion TK-
112690 or placebo. 
● AEs to be recorded at 5, 24 and 48 hours post initial infusion of TK-112690 or placebo. 
● ±15mins of window period is considered acceptable for schedule of events. 
 
 
7.1.4. Follow-Up Evaluations 
 
All patients will undergo the following on Day 1 of Week 6: 
 
● Perform a physical examination and determine vital signs, weight, and AE assessment. 
● Determine ECOG performance status. 
● For females of childbearing age, a pregnancy test will be performed. 
● Perform laboratory tests (hematology, chemistry, coagulation and urinalysis). 
● Obtain a blood sample for surrogate marker evaluation. 
● Disease (tumor) assessment by CT scanning will be performed. 
● Mucositis assessment (Section 20.6, Appendix 6). 
8.0. SELECTION AND WITHDRAWAL OF SUBJECTS 
 
8.1. PREGNANCY 
 
Subjects who become pregnant during the study should discontinue the study immediately. Subjects 
should be instructed to notify the PI if it is determined after completion of the study that they became 
pregnant during the treatment phase of the study. 
 
Whenever possible, a pregnancy should be followed to term, any premature terminations reported, and the 
status of the mother and the child should be reported to Tosk after delivery. 
 
8.2. SUBJECT WITHDRAWAL CRITERIA 
 
A subject may voluntarily discontinue study participation at any time. At any time, the PI may also at 
his/her discretion discontinue a subject’s study participation. Subjects may be withdrawn from this study 
for the following reasons: 
 
● At the PI’s discretion in situations where the subject is unable to comply, or complies poorly with 
the protocol. 
● Disease progression and/or experiences intolerable toxicity. 
● Major protocol violation. 
● Lost to follow-up. 
● If TK-112690/placebo treatment is delayed due to toxicity for more than 2 weeks. 
● Inter-current event preventing administration of study medication for more than 2 weeks. 
● Subject withdraws consent. 
● Subject becomes pregnant. 
● Subject starts any other chemotherapy agent or anti-cancer treatment other than study therapy for 
refractory solid tumor, e.g., radiation therapy. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 80 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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● Death. 
 
If there is an ongoing toxicity due to the study agent, subjects must be followed with appropriate medical 
management until resolution or stabilization, regardless of evidence of progressive disease. 
 
The subject will be advised in the Informed Consent Forms that he/she has the right to withdraw from the 
study at any time without prejudice and may be withdrawn at the discretion of the PI or Tosk at any time. 
In the event that the subject drops out of the study or is withdrawn from the study, the withdrawal CRF 
should be completed. On the withdrawal page the PI should record the date of the withdrawal, the person 
who initiated withdrawal and the reason for withdrawal. 
 
Reasonable effort should be made to contact any subject lost to follow-up during the course of the study 
in order to complete assessments and retrieve any outstanding data. 
 
At the time of study withdrawal, following will be recorded for these premature removals: 
 
● Update medical history including any additional cancer therapies, including starting date 
(immunotherapy, targeted therapy, radiation and surgical interventions) if known. 
● Physical examination and determination of vital signs, weight and AEs. 
● Laboratory tests (hematology, chemistry, coagulation and urinalysis). 
● Mucositis assessment (Section 20.6, Appendix 6). 
 
Subjects with an ongoing apparently drug-induced toxicity will continue to be seen at monthly intervals 
until the toxicity resolves or stabilizes to a level acceptable to the medical monitor and the PI. If the 
subject starts new cancer therapy, the relationship to study drug should be re-assessed.  
9.0. ASSESSMENT OF SAFETY 
 
9.1. SPECIFICATION OF SAFETY PARAMETERS 
 
9.1.1. Adverse Events 
 
An adverse event (AE) is any untoward medical occurrence in a patient or clinical Investigational subject 
administered a pharmaceutical product and which does not necessarily have a causal relationship with this 
treatment. An AE can be any unfavorable and unintended sign (including an abnormal laboratory 
finding), symptom, or disease temporally associated with the use of an Investigational product, whether or 
not related to the Investigational product. Pre-existing conditions which worsen during a study are to be 
reported as adverse events. 
 
All adverse events, regardless of causal relationship, encountered during the clinical study will be 
reported on the AE page of the CRF (please see section 9.3). Intensity of AEs will be graded using the 
National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE, version 4.0) and 
reported in detail as indicated on the CRF. If an adverse event occurs which is not contained in the NCI-
CTCAE, the four-point scale (mild, moderate, severe, life-threatening) below will be used.  
 
Mild 
 
discomfort noticed but no disruption of normal daily activity 
Moderate 
 
discomfort sufficient to reduce or affect daily activity 
Severe 
 
severe discomfort, inability to work or perform normal daily activity 
Life threatening 
represents an immediate threat to life 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 81 of 110 
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9.1.2. Laboratory Test Abnormalities 
 
Laboratory test results will be recorded on the laboratory results pages of the CRF. Laboratory test value 
abnormalities as such should not be reported on the AE page of the CRF as adverse events, unless there is 
an associated clinical condition for which the subject is given treatment or concomitant treatment is 
altered, study treatment is interrupted/delayed or the dose of study drug is modified, or the subject is 
permanently discontinued from the study drug because of the abnormal test value. 
 
9.1.3. Serious Adverse Event 
 
A serious adverse event (SAE) is any untoward medical occurrence that at any dose: 
 
● Results in death. 
● Is life-threatening (subject is at immediate risk of death from the event as it occurred). 
● Requires subject hospitalization or prolongation of existing hospitalization. 
● Results in persistent or significant disability/incapacity. 
● Is a congenital anomaly/birth defect. 
● Other medically important condition. 
 
All of the above criteria apply to the case as a whole and should not be confused with the outcomes of 
individual reactions/events. More than one of the above criteria can be applicable to the one event. 
 
Important medical events that may not be immediately life-threatening or result in death or hospitalization 
may be considered an SAE when, based upon appropriate medical judgment, they may jeopardize the 
subject or require medical or surgical intervention to prevent one of the outcomes listed in the definition 
above. 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 hospitalization, or 
development of drug dependency or drug abuse.  
 
The definition and reporting requirements of the ICH Guideline for Clinical Safety Data management, 
Definitions and Standards for Expedited Reporting Topic E2 will be adhered to (see Appendix 5). 
 
All SAEs, whether or not deemed drug-related or expected, must be reported to Tosk and to the trial 
clinical research associate (clinical monitor).  
 
9.1.4. Follow-up of Adverse Events 
 
All adverse events (and treatments for them) must be documented throughout the Study Treatment Phase 
starting after the administration of the first dose of study medication and for 28 days after the last intake 
of study medication, and followed up/medically managed until the event is either resolved or adequately 
explained, even after the subject has completed his/her study treatment. Unrelated, mild or moderate 
events must be followed for 28 days after the last study drug administration. Serious, life threatening or 
related events must be followed until resolution, the subject’s death, the start of a new cancer therapy or 
the relationship is re-assessed. 
 
9.1.5. Follow-up of Abnormal Laboratory Values 
 
In the events of unexplained abnormal laboratory test values, the tests should be repeated and followed up 
until they have returned to normal range or to the baseline value, and/or an adequate explanation of the 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 82 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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abnormality is found. If a clear explanation is established it should be recorded on the CRF.  
 
9.1.6. Pregnancy 
 
Pregnancy, in and of itself, is not regarded as an adverse event, unless there is suspicion that study 
medication may have interfered with the effectiveness of a contraceptive medication or method. The 
procedures that will be followed based on whether a pregnancy is confirmed by a positive serum or urine 
test result are listed below: 
 
● 
Pregnancy confirmed by a positive serum test result, then: 
- PI and subject must notify each other immediately 
- PI must notify the sponsor immediately  
- Discontinue study medication immediately 
- Withdraw the subject from the study 
- Perform the required Early Termination visit study evaluations 
 
PI must complete and submit the initial and follow-up report to the sponsor 
● Pregnancy confirmed by a positive urine test result, then: 
- PI and subject must notify each other immediately 
- PI must notify the sponsor immediately  
- Study medication must be discontinued immediately 
- A serum pregnancy test must be performed to confirm the urine test result. (The serum test 
should be performed at the investigative site to ensure the test will be performed promptly 
and the result available immediately for review) 
● If a positive serum test confirms the urine test result, then: 
- 
Withdraw the subject from the study 
- 
Perform the required Early Termination visit study evaluations 
- 
PI must complete and submit the required initial and follow-up report to the sponsor 
● If a negative serum test does not confirm the urine test result, then: 
- 
The PI will use his/her expert judgment, based on an assessment of the potential 
benefit/risk to the subject, to determine if it is in the subject’s best interest to resume study 
medication and continue participation in the study 
 
Any pregnancy diagnosed during the study, or that occurs within 28 days after stopping study medication, 
must be reported immediately to the PI. The PI will notify the sponsor or designee. The outcome of all 
such pregnancies (i.e., spontaneous miscarriage, elective termination, normal birth, or congenital 
abnormality) must be documented and followed-up on a form that will be provided by the sponsor. The 
pregnancy will be followed to term and the outcome, including any premature termination, must be 
reported to the sponsor. All live births must be followed for a minimum of 30 days or to the first well-
baby visit. All reports of congenital abnormalities/birth defects and spontaneous abortions/miscarriages 
should be reported as an SAE for this study. Elective abortion procedures, without complications, should 
not be considered as adverse events. 
 
9.2. ASSESSING, RECORDING, AND ANALYZING SAFETY PARAMETERS 
 
Safety lab assessments will be performed by the central laboratory and will be collected and processed 
according to standard investigative site procedures. Normal value ranges and laboratory certification will 
be collected from all laboratories prior to study initiation.  
 
Safety laboratory assessments will include: 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 83 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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● Complete Blood Count with differential  
● Enzyme panel including AST, ALT, LDH, creatinine kinase, alkaline phosphatase 
● Chemistry panel including total protein, albumin, total bilirubin, uric acid, phosphate, 
triglycerides, cholesterol, calcium, BUN, creatinine, sodium, potassium, chloride, 
bicarbonate, glucose, and phosphorus; and  
● Urinalysis including pH, glucose, protein, ketones and blood 
 
9.2.1. ECG Parameters 
 
ECG parameters will be analyzed including ECG abnormalities and PI’s assessment of clinical 
significance analyzing above parameters, rhythm abnormalities, and conduction abnormalities. Any 
abnormalities will be reported on the CRF with a copy of the ECG recording. 
 
9.3. RECORDING AND REPORTING ADVERSE EVENTS/INTERCURRENT ILLNESSES 
 
The PI will probe, via discussion with the subject, for the occurrence of AEs during each subject visit and 
record the information in the site’s source documents. For each AE, the PI should note the start and 
resolution dates, the severity, whether it meets the definition of an SAE, the relationship of the event to 
the study drug, the action taken regarding study drug, and the outcome of the event. Data should be 
transcribed from the source documents to the case report forms as per the case report form instructions, so 
that all changes in intensity and seriousness will be captured on the AE case report form. 
 
The PI must report in detail all adverse signs and symptoms which are either volunteered by subjects or 
observed during or following the course of Investigational product administration on the appropriate CRF 
page.  
 
All AEs will be monitored until resolution or, if the AE is determined to be chronic, a cause is identified. 
If an AE is considered possibly related to study treatment and remains unresolved at the conclusion of the 
study, this event will be followed until resolution, stabilization, or initiation of treatment that confounds 
the ability to assess the event. 
 
9.3.1. Relationship of AE to Study Medication 
 
The relationship of an adverse event to study medication is to be assessed according to the following 
definitions:  
 
Definitely Related: 
Strong evidence exists that the study drug caused the adverse event. There is 
a temporal relationship between the event onset and administration of the 
study drug. There is strong therapeutic and pharmacologic evidence that the 
event was caused by the study drug. The subject’s clinical state or 
concomitant therapies have been ruled out as a cause. In the case of 
cessation or reduction of the dose, the event abates or resolves, and 
reappears upon re-challenge. 
 
Probably Related: 
A temporal relationship exists between the event onset and the 
administration of study drug, and appears with some degree of certainty to 
be related based on the known therapeutic and pharmacologic actions of the 
study drug. It cannot be readily explained by the subject’s clinical state or 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 84 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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concomitant therapies. In the case of cessation or reduction of the dose, the 
event abates or resolves. 
 
Possibly Related: 
A temporal relationship exists between the event onset and the 
administration of study drug. Although the adverse event may appear 
unlikely to be related to the study drug, it cannot be ruled out with certainty; 
and/or the event cannot be readily explained by the subject’s clinical state or 
concomitant therapies. 
 
Not Related: 
Evidence exists that the adverse event definitely has an etiology other than 
the study drug (eg, pre-existing condition or underlying disease, intercurrent 
illness, or concomitant medication) and does not meet any criteria listed 
above. 
 
Included in the description should be the nature of the sign or symptom; the date of onset; date of 
resolution (duration); the severity; the relationship to study treatment or other therapy; the action taken (if 
any), and the outcome.  
 
9.3.2. Unexpected Adverse Event 
 
An unexpected adverse event is one not previously reported (in nature, severity or incidence) in the 
current PI’s Brochure, in the clinical plan, or elsewhere. Unexpected, as used in this definition, refers to 
an adverse drug experience that has not been previously observed (eg, included in the PI Brochure) rather 
than from the perspective of such experience not being anticipated from the pharmacological properties of 
the pharmaceutical product. 
 
9.3.3. Reporting of Serious Adverse Events 
 
Adverse events classified as serious require expeditious handling and reporting to Dr. Shanna 
Stopatschinskaja at Tosk to comply with regulatory requirements. For any serious adverse event (SAE) 
that occurs while a subject is on-study; within 30 days of the last study drug administration, regardless of 
any opinion as to the relationship of the SAE to the study drug; or if any SAE that the PI feels is related to 
the study drug occurs later than 30 days after the last study drug administration, Tosk must be notified by 
telephone within 24 hours of becoming aware of the event. During both business and non-business hours, 
the telephone number listed below should be used to notify Tosk.  
 
All SAEs require that, in addition to telephone notification, a Serious Adverse Event Report Form be 
completed and forwarded via facsimile to Tosk at the number listed below within 24 hours of becoming 
aware of the event.  
 
All SAES (not clearly related to disease progression) whether considered to be drug-related or not should 
be considered unexpected in this first-in-human study, and must rapidly be communicated to the 
institutional review board (s) and all other investigators.  
 
SAEs will be reported to: 
 
 
Sponsor:   
 
William Garland, Ph.D. 
VP R&D, TOSK, INC. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 85 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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2672 Bayshore Parkway, #507 
Mountain View, CA 94043 
+1 408-348-5164 (Cell) 
+1 408-245-6838 (Landline) 
+1 408-245-6808 (Fax) 
 
All SAEs will be reviewed by both Dr. Garland and the Tosk Safety Monitor: 
 
Shanna Stopatschinskaja, MD 
Dolores Medical Services  
1073 Dolores St, San Francisco, CA 94110  
+1 908-230-9327 (cell) 
stopats@gmx.net 
 
CRO: 
 
Dr.L.Krishnamurthy 
Consultant Medical Monitor  
+91 9603662465 
dr_murthy130475@yahoo.com 
 
Intuitions / Hospital as applicable. 
 
Drug Control General of India 
 
FDA Bhavan, ITO, Kotla Road, New Delhi -
110002 
Phone: +91-11-23216367(CDSCO)/ 23236960 
Fax: +91-11-23236973 
E-mail:- dci@nic.in 
 
All adverse events must be recorded in the case report form (CRF). To avoid colloquial expressions, the 
adverse event should be reported in standard medical terminology and will be coded in MedDRA. 
Whenever possible, the adverse event should be evaluated and reported as a diagnosis rather than as 
individual signs or symptoms. If a definitive diagnosis is not possible, the individual symptoms and signs 
should be recorded. Any laboratory abnormalities deemed clinically significant by the PI should be 
reported on the adverse event CRF. Whenever possible, the etiology of the abnormal findings will be 
documented on the CRF. Any additional relevant laboratory results obtained by the PI during the course 
of this study will be supplied to the sponsor and recorded on the CRF. The required SAE information 
should also be completed on the CRFs and the data reported within 24 hours from the time that the event 
was identified. This will ensure that the written documentation is transmitted to the appropriate 
pharmacovigilance contact person within the required reporting time period. 
 
The IRB/regulatory authority must be informed if the SAE or AE, in the opinion of Tosk or the PI, is 
likely to affect the safety of the subjects or the conduct of the study. 
 
All Investigators participating in the trial will also be notified of any unexpected SAEs determined to be 
related to study treatment. 
 
For any questions about adverse events or serious adverse events contact Sponsor’s medical monitor 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 86 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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9.4. WARNINGS AND PRECAUTIONS 
 
Subjects receiving study therapy (TK-112690) should be monitored by a physician experienced in the use 
of cancer chemotherapy agents. Use of these agents in pregnant or breast-feeding women is 
contraindicated.  
 
9.4.1. Precautions 
 
Infusion reactions with the first dose of TK-112690 may be observed. TK-112690 administration should 
be interrupted in all subjects with severe infusion reactions and appropriate medical therapy administered. 
 
9.4.2. Treatment Failure 
 
In case of treatment failure, patients will be treated using the Standard Guidelines for Management of 
Mucositis.91 
 
9.5 EFFICACY ASSESSMENTS 
 
9.5.1 Mucositis Assessment Scales 
 
The scales described in Section 20.6 of this protocol will be used to assess/rate mucositis. The scales are 
OMAS/Sonis,92,93 PROMS,94 WHO and CTCAE/mucositis. 
 
Response 
 
Response will be determined according to the RECIST methodology. It will be the best response recorded 
from the start of the treatment until disease progression/recurrence. To be assigned a status of partial 
response or complete response, changes in tumor measurements must be confirmed by repeat assessments 
performed at least 4 weeks after the criteria of response are first met. 
 
Target lesions 
 
● Complete response is defined as the disappearance of all target lesions.  
                                               
91Rubenstein EB, Peterson DE, Schubert M, Keefe D,McGuire D, Epstein J, EltingLS,Fox PC, Cooksley 
C, Sonis ST. Clinical Practice Guidelines for Mucositis. Cancer 2004;100 (9 Suppl):2026–2046. 
92Sonis ST, Eilers JP, Epstein JB, LeVeque FG, Liggett WH Jr, Mulagha MT, Peterson DE, Rose AH, 
Schubert MM, Spijkervet FK, Wittes JP. Validation of a new scoring system for the assessment of clinical 
trial research of oral mucositis induced by radiation or chemotherapy. Mucositis Study Group. 
Cancer.1999; 85: 2103-13. 
93Oral mucositis and the clinical and economic outcomes of hematopoietic stem-cell transplantation. 
Sonis ST, Oster G, Fuchs H, Bellm L, Bradford WZ, Edelsberg J, Hayden V, Eilers J, Epstein JB, 
LeVeque FG, Miller C, Peterson DE, Schubert MM, Spijkervet FK, Horowitz M. 
J ClinOncol.2001 ;19:2201-5. 
94 Kushner JA, Lawrence HP, Shoval I, Kiss TL, Devins GM, Lee L, Tenenbaum HC, Development and 
validation of a Patient-Reported Oral Mucositis Symptom (PROMS) scale. J Can Dent Assoc. 2008; 74: 
59. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 87 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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● Partial response is defined as at least a 30% decrease in the sum of the longest diameter of the 
target lesions, taking as a reference the baseline sum longest diameter.  
● Progressive disease is defined at least a 20% increase in the sum of the longest diameter of target 
lesions, taking as a reference the smallest sum longest diameter recorded since the treatment 
started or the appearance of one or more new lesions.  
● Stable disease is defined as shrinkage insufficient to qualify for partial response or insufficiently 
increased to qualify for progressive disease, taking as a reference the smallest sum longest 
diameter since the treatment started. 
 
Non-target lesions 
 
● Complete response is defined as the disappearance of all non-target lesions. 
● Non-complete response /non-progressive disease is defined as persistence of 1 or more non-target 
lesion. 
● Progressive disease is defined as the appearance of 1 or more new lesions and/or unequivocal 
progression of existing non-target lesions. 
● The cytological confirmation of the neoplastic origin of any effusion that appears or worsens 
during treatment when the measurable tumor has met criteria for response or stable disease is 
mandatory to differentiate between response or stable disease and progressive disease.  
 
Confirmation of No Response on Tumor 
 
To be assigned a best tumor response status of partial response or complete response, changes in tumor 
measurements in subjects with responding tumors must be confirmed by repeat studies that should be 
performed no less than 4 weeks after the criteria for response are first met. In the case of stable disease, 
follow-up measurements must have met the stable disease criteria at least once after study entry at a 
minimum interval of 8 weeks.  
 
Determination of Overall Best Tumor Response by RECIST (Version 1.1) Methodology 
 
The overall assessment of best tumor response will involve all parameters as depicted in Table 13below. 
 
Table 13. Tumor response criteria 
 
Target lesions* 
Non-Target lesions** 
New Lesions*** 
Overall Response  
Complete Response 
Complete Response 
No  
Complete response 
Complete Response 
Non-complete Response 
/Non-progressive disease 
No  
Partial response 
Partial Response 
Non-progressive disease 
No  
Partial response 
Stable disease 
Non-progressive disease 
No  
Stable disease 
Partial disease 
Any response  
Yes or No  
Progressive disease  
Any response  
Progressive disease 
Yes or No  
Progressive disease  
Any response  
Any response  
Yes  
Progressive disease  
*Measurable lesions only  
**May include measurable lesions not followed as target lesions or non-measurable lesions  
***Measurable or non-measurable lesions 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 88 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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The overall best tumor response is the best response recorded from the start of the treatment until disease 
progression/recurrence, taking as reference for tumor progression the smallest measurements recorded 
since the treatment started. The subject’s best tumor response assignment will depend on the achievement 
of both measurement and confirmation criteria. 
 
Subjects will be defined as being not evaluable for response (NE) if there is no post-baseline lesion 
assessment, unless the subject terminates from the study for disease progression.  
 
Subjects with a global deterioration of health status requiring discontinuation of treatment without 
objective evidence of disease progression at that time should be reported as “symptomatic deterioration” 
on the Study Termination CRF. Every effort should be made to document the objective progression even 
after discontinuation of treatment. It should also be noted that a tumor marker increase does not constitute 
adequate objective evidence of tumor progression. However, such a tumor marker increase should prompt 
a repeat radiographic evaluation to document whether or not objective tumor progression has occurred. In 
some circumstances, it may be difficult to distinguish residual disease from normal tissue. When the 
evaluation of a CR depends upon this determination, it is recommended that the residual lesion be 
investigated by fine needle aspirate or biopsy before confirming the CR status.  
 
9.5.3. Surrogate Markers 
 
The effect of TK-112690 treatment on mucositis-related inflammatory markers such as CD40/CD40L will 
be studied. The results of the exploratory assessments will not be recorded in the CRF but will be reported 
separately in an addendum. 
 
9.5.4. Surrogate Markers 
 
Plasma samples for establishing the surrogate marker profiles will be obtained at times specified in the 
protocol. The results of the exploratory assessments will not be recorded in the CRF but will be reported 
separately in an addendum. 
 
9.6 APPROPRIATENESS OF MEASUREMENTS 
 
Study measurements are those associated with a standard evaluation of a new modality for modifying 
side-effects associated with chemotherapy.  
10.0. STATISTICAL CONSIDERATIONS 
 
10.1. GENERAL CONSIDERATIONS 
 
All analyses will be performed. and all Tables, Figures, and data listings will be prepared using a 
validated statistical program. Summary statistics for continuous variables will include the mean, standard 
deviation, median, minimum, and maximum value; categorical variables will be presented as counts and 
percentage. 
 
10.1.1. Sample Size and Associated Power 
 
The primary objective of this Phase 2a trial is to evaluate the pilot efficacy and the safety/tolerability of 
MetrexassistTM administered intravenously to subjects with cancer also receiving 45 mg/m2 MTX. This is 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 89 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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an exploratory study and is may not be powered to demonstrate statistical significance. The sample size is 
based not on statistical calculations but on the outcome in the Phase 1b study where all patients received 
TK-112690 experienced relatively little mucositis. Without the TK-112690 considerably more mucositis 
is expected, perhaps enough to achieve statistical significance. At a minimum, sufficient data will be 
obtained to accurately power the next study with TK-112690 and MTX.  
 
10.1.2. Randomization of the Trial 
 
The clinical CRO or a third-party provider will alternatively assign patients as per the randomization list. 
If a patient drops out of the study before completing first dosing, he/she will be replaced by someone with 
the same assigned treatment.  
 
10.2. POPULATIONS 
 
10.2.1. Efficacy and Safety Population 
 
The efficacy population will consist of all subjects who received at least four doses of TK-112690. The 
safety population will consist of all subjects who receive at least one dose of TK-112690.  
 
 
10.3. ANALYSIS OF SAFETY 
 
Subjects in study will be evaluated for safety at Week 1 and 2. Subjects with tolerable toxicity will be 
allowed to continue study therapy for an additional 2 weekly treatments and possibly more at the 
discretion of the investigator. 
 
Vital signs (systolic and diastolic blood pressure, and pulse), weight determinations and physical 
examination results will be summarized by treatment group using appropriate descriptive statistics. 
Continuous variables will be summarized using the number of observations, mean, standard deviation, 
minimum, median and maximum values. Categorical values will be summarized using number of 
observations and percentages. 
 
Withdrawals from the study will be summarized by dose group.  
 
10.3.1. Incidence of Adverse Events 
 
Adverse events will be classified and graded according to the NCI Common Terminology Criteria for 
Adverse Events (CTCAE), version 3.0.  
 
The primary safety analysis using descriptive statistics will include summaries of incidence rates, 
severity, and type of adverse events; summary of changes in subjects’ clinical laboratory results; and 
summaries of the number of toxicity grades for laboratory and non-laboratory data. 
 
Adverse events will be coded using the MedDRA adverse event dictionary. Frequency of treatment 
emergent adverse events will be calculated for each body system, by preferred term, by treatment group, 
for number of subjects and proportion reporting the event. The severity of the adverse events and the 
relationship to study medication will be summarized for each body system and preferred term by 
treatment group. Withdrawals due to adverse events will be summarized for each body system and 
preferred term by treatment group. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 90 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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10.3.2. Laboratory Data 
 
The number and percentage of subjects with laboratory abnormalities at the screening visit and the final 
visit (or early withdrawal) will be tabulated.  
 
Descriptive statistics (number of observations, mean, standard deviation, minimum, median and 
maximum values) will be calculated for clinical laboratory tests (hematology, serum chemistry, and 
urinalysis) at applicable visits. 
 
10.4. SUBJECT ACCOUNTABILITY AND MISSING DATA 
 
Data from subjects lost to follow-up will be tabulated and any difference between those subjects and 
subjects not lost to follow-up will be noted.  
 
10.5. INTERIM ANALYSIS 
No interim analyses will be performed. 
 
11.0. DIRECT ACCESS TO SOURCE DATA / DOCUMENTS AND INVESTIGATOR 
RESPONSIBILITY 
 
It is understood that the term “PI” as used in this protocol and on case report forms refers to the Principal 
PI or a member of the staff that the Principal PI designates to perform a certain duty. However, on 
specific CRFs the investigator him/herself is required to sign where indicated. The Principal PI is 
ultimately responsible for the conduct of all aspects of the study. 
 
The PI will ensure that this study is conducted in full conformance with the principles of the “Declaration 
of Helsinki” (as amended in Tokyo, Venice, Hong Kong, Somerset West, and Edinburgh) and with the 
laws and regulations of the country in which the research is conducted, whichever affords the greater 
protection to the individual. 
 
It is the responsibility of the PI to obtain written informed consent from each individual participating in 
this study, after adequate explanation of the aims, methods, objectives and potential hazards of the study. 
The PI must also explain to the subjects that they are completely free to refuse to enter the study or to 
withdraw from it at any time. The document must contain all the elements described in 21 CFR, Part 50 
and ICH Guidelines. 
 
The PI shall make accurate and adequate reports to Tosk and/or its representative and to the EC/IRB on 
the progress of the study at appropriate intervals. Additionally, the PI shall make accurate and adequate 
final status reports, through completed CRFs, to the monitors and to the IRB within three weeks after the 
completion, termination, or discontinuation of the study. The final report must include all case report 
forms that were not previously provided to the monitors. 
 
Qualified representatives of the sponsor or sponsor designees (“study monitors”) will monitor the study 
according to a predetermined monitoring plan. Monitoring visits provide the sponsor with the opportunity 
to: 
● Evaluate the progress of the study. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 91 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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● Verify the accuracy and completeness of CRFs. 
● Assure that all protocol requirements, applicable laws and/or regulations, and PI’s obligations are 
being fulfilled. 
● Resolve any inconsistencies in the study records. 
 
The PI must allow the study monitors to periodically review, at mutually convenient times during the 
study and after the study has been completed, all CRFs and office, hospital, and laboratory records 
supporting the participation of each subject in the study. The CRFs and other documentation supporting 
the study must be kept up-to-date by the PI and the research staff at the investigative site. These study 
materials must be available for review by the study monitor, and/or other qualified representatives of the 
sponsor, at each monitoring visit. 
 
The study monitor will regularly inspect the various records of the study (CRFs, subject medical and 
laboratory records, and other pertinent data) provided that subject confidentiality is maintained in 
accordance with local institution, state, country, and federal requirements. The study monitor will verify 
the data against other source documentation in order to verify its accuracy and completeness. The study 
monitor will identify data discrepancies and collaborate with the PI and research staff to resolve the 
discrepancies in the CRF in a timely manner. The study monitor will generate queries as required using 
the CRF system. Protocol deviations will also be identified and recorded on a “Protocol Deviation Log”. 
The study monitor will follow an “Issue Escalation” plan in order to ensure that each issue identified 
during a monitoring visit is appropriately documented, reported, and resolved in a timely manner in 
accordance with the plan’s requirements.  
 
11.1. SUBJECT INFORMATION AND CONSENT 
 
The PI will ensure that the subject is given full and adequate verbal and written information about the 
nature, purpose, possible risk and benefit of the study. Subjects, legal guardian or responsible relative 
must also be notified that they are free to discontinue their participation in the study at any time. The 
subject legal guardian or responsible relative should be given the opportunity to ask questions and, when 
possible, time for consideration. The PI is responsible for obtaining signed informed consent from all 
subjects before enrollment. In subjects unable to consent to treatment, consent must be obtained from a 
close family member or legal guardian in writing before enrollment. 
 
A copy of the subject information including the signed Consent Form should be retained by the subject. 
 
11.2. SUBJECT CONFIDENTIALITY 
 
All data computer-processed at Tosk or by its designee will be identified by subject number only, thereby 
ensuring that the subject’s identity remains unknown to the sponsor. The subjects should be informed in 
writing that the data will be stored and analyzed in a computer, maintaining confidentiality in accordance 
with national data legislation. The subjects should also be informed in writing that authorized 
representatives of the company and/or Regulatory Authorities, may require access to those parts of the 
hospital/practice records relevant to the study, including medical history, for verification of data. The 
Principal PI is responsible for keeping a subject identification list or form of all subjects enrolled, 
including enrollment code, subject number, full name and address. 
 
11.3. SOURCE DATA 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 92 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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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 trial necessary for the reconstruction and 
evaluation of the trial. Source data are contained in source documents (original records or certified 
copies). 
 
11.4. SOURCE DOCUMENTS 
 
Source documents are defined as original documents, data and records (eg, hospital records, clinical and 
office charts, laboratory notes, memoranda, subject diaries or evaluation check lists, pharmacy dispensing 
records, recorded data from automated instruments, copies or manuscripts certified after verification as 
being accurate copies, microfiches, photographic negatives, microfilm or magnetic media, x-rays, subject 
files, records kept at pharmacy, at the laboratories and at medico technical departments involved in the 
clinical trial).  
 
11.5. DIRECT ACCESS 
 
Direct access is defined as the permission to examine, analyze, verify and reproduce any records and 
reports that are important to evaluation of a clinical trial. Any party (eg, domestic and foreign regulatory 
authorities, Tosk monitors and auditors) with direct access should take all reasonable precautions within 
the constraints of the applicable regulatory requirements to maintain the confidentiality of subject 
identities and sponsor proprietary information. 
 
11.6. STUDY MONITORING 
 
In accordance with applicable regulations and Good Clinical Practice, Tosk / CRO monitors will 
periodically contact the site, including conducting on-site visits. During these contacts, the monitor will 
check and assess the progress of the study, review the data collected, conduct source document 
verification, and identify any issues and address their resolution. These activities are performed in order 
to verify that the data are authentic, accurate, and complete; the safety and rights of the subjects are being 
protected; and the study is conducted in accordance with the currently approved protocol (and any 
amendments), GCP, and all applicable regulatory requirements. 
12.0. QUALITY CONTROL/ QUALITY ASSURANCE 
 
An independent audit at the study site may take place at any time during or after the trial. The 
independent audit can be conducted by the Quality Assurance (QA) Department at of Tosk or a regulatory 
authority.  
 
12.1. QUALITY CONTROL 
 
Quality Control is defined as the operational techniques and activities undertaken within the quality 
assurance system to verify that the requirements for quality of the trial related activities have been 
fulfilled. Quality Control should be applied to each stage of data handling to ensure that all data are 
reliable and have been processed correctly. 
 
12.2. QUALITY ASSURANCE 
 
Quality Assurance is defined as the planned and systematic actions that are established to ensure that the 
trial is performed and the data are generated, documented (recorded) and reported in compliance with 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 93 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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Good Clinical Practice (GCP) and the applicable regulatory requirements. 
 
12.3. INSPECTION 
 
An Inspection is defined as the act by a regulatory authority of conducting an official review of 
documents, facilities, records and any other resources that are deemed by the authorities to be related to 
the clinical trial and that may be located at the site of the trial, or at the sponsor’s and/ or clinical research 
organization facilities or at any other establishments deemed appropriate by the regulatory authorities. 
 
12.4. AUDIT 
 
An audit is a systematic and independent review of trial-related activities and documents to determine 
whether the validated trial-related activities were conducted and the data were recorded, analyzed and 
accurately reported according to the protocol, designated Standard Operating Procedure (SOPs), Good 
Clinical Practice (GCP) and the applicable regulatory requirements.   
13.0. ETHICS APPROVALS 
 
Before initiating a trial, the PI should have written and dated approval/favorable opinion from the relevant 
IRB or IEC for the trial protocol (and any amendments), written informed consent form, consent form 
updates, subject recruitment procedures (eg, advertisements), and any other written information to be 
provided to subjects. Approval will be indicated in writing with reference to the final protocol number 
and date. Details of the IRB’s or IEC’s constitution including names of its members and what function 
they perform on the committee (eg, chairman, specialist, lay-member) should be made available to Tosk. 
During the trial the PI should provide to the IRB all documents that are subject to review. 
 
The protocol, the proposed informed consent form, and all forms of participant information related to the 
study (e.g. advertisements used to recruit participants) will be reviewed and approved by the IRB/IEC. 
Prior to obtaining approval, the protocol must be approved by the Sponsor. The initial protocol and all 
protocol amendments must be approved by the IRB/IEC prior to implementation.  
 
13.1. INDEPENDENT ETHICS COMMITTEE (IEC) 
 
An independent body (a review board or a committee, institutional, regional, national, or supranational), 
constituted of medical professionals and non-medical members, whose responsibility it is to ensure the 
protection of the rights, safety and well-being of human subjects involved in a trial and to provide public 
assurance of that protection, by, among other things, reviewing and approving/providing favorable 
opinion on, the trial protocol, the suitability of the investigator(s), facilities, and the methods and material 
to be used in obtaining and documenting informed consent of the trial subjects.  
 
13.2. INSTITUTIONAL REVIEW BOARD (IRB) 
 
This is an independent body constituted of medical, scientific, and non-scientific members, whose 
responsibilities are to ensure the protection of the rights, safety and well-being of human subjects 
involved in a trial by, among other things, reviewing, approving, and providing continued review of trial 
protocol and amendments and of the methods and material used in obtaining and documenting informed 
consent of the trial subjects.  


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 94 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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14.0. MODIFICATION OF PROTOCOL 
 
Once the protocol has been approved by the IRB/IEC, any changes to the protocol must be documented in 
the form of an amendment. The amendment must be signed by the PI and approved by Tosk and the 
IRB/IEC prior to implementation. 
 
The PI should not implement any deviation from, or changes to, the protocol without agreement by Tosk. 
Any changes which may affect a subject’s treatment or informed consent, especially those increasing 
potential risks, must receive prior review and documented approval/favorable opinion from the IRB or 
IEC. The only exceptions are when necessary to eliminate an immediate hazard(s) to trial subjects, or 
when the change(s) involves only logistical or administrative aspects of the trial [eg, change in 
monitor(s), change of telephone number(s)]. 
 
As soon as possible, the implemented deviation or change, the reasons for it, and, if appropriate, the 
proposed protocol amendment(s) should be submitted: 
 
● To the IRB or IEC for review and approval/favorable opinion. 
● To the sponsor for agreement and, if required. 
● To the regulatory authority (ies). 
 
The party initiating an amendment must confirm it clearly in writing and it must be signed and dated by 
Tosk and the Principal PI. Tosk will ensure that the Investigators submit necessary protocol amendments 
to the appropriate IRBs or IECs. 
 
All agreed protocol amendments must be clearly documented using standard procedures as defined by 
Tosk, and must be signed and dated by Tosk and the PI. 
 
15.0. DATA HANDLING AND RECORD KEEPING 
 
15.1. COMPLETION OF CASE REPORT FORMS 
 
Site personnel will collect study data using CRFs compliant with FDA 21 CFR Stage 11 regulations. The 
PI must sign and date a declaration on the CRF attesting to his/her responsibility for the quality of all data 
recorded and that the data represents a complete and accurate record for each subject’s participation in the 
study. 
 
Data reported on the CRF that are derived from source documents should be consistent with the source 
documents or the discrepancies should be explained. Any data to be recorded directly on the CRFs (to be 
considered as source data) will be identified at the start of the trial. 
 
15.2. ARCHIVING 
 
As described in the ICH GCP Guidelines, “essential documents,” including CRFs, source documents, 
consent forms, laboratory test results, and medication inventory records, should be retained by the PI until 
at least 2 years after the last approval of a marketing application in an ICH region and until there are no 
pending or contemplated marketing applications in an ICH region or at least 2 years have elapsed since 
the formal discontinuation of clinical development of the investigational product. These documents 
should be retained for a longer period however if required by the applicable regulatory requirements or by 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 95 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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an agreement with Tosk. The PI should obtain written permission from Tosk prior to the destruction of 
any study document. 
 
These records will be made available at reasonable times for inspection and duplication, if required, by a 
properly authorized representative of the US FDA in accordance with 21 CFR 312.68 or other National 
Regulatory Authorities. 
16.0. FINANCIAL DISCLOSURE 
 
The PI will be required to disclose any financial arrangement whereby the value of the compensation for 
conducting the study could be influenced by the outcome of the study following information; any 
significant payments of other sorts from Tosk such as a grant to fund ongoing research, compensation in 
the form of equipment, retainer for ongoing consultation, or honoria; any proprietary interest in 
METREXASSISTTM [parenteral (TK-112690)] or any significant equity interest in Tosk as defined in the 
US Code of Federal Regulations [21 CFR 54 2(b)]. 
 
In consideration of participation in the study, Tosk will reimburse the PI or nominated payee according to 
schedule attached to the PI Agreement. 
 
17.0. FINANCING AND INSURANCE 
 
The costs necessary to perform the study will be agreed to with each PI and will be documented in a 
separate financial agreement that will be signed by the PI and Crystal Life Science prior to the trial 
commencing. 
 
Subjects will be reimbursed for reasonable study-related travel expenses. 
 
With respect to any liability directly or indirectly caused by the study drugs in connection with this 
Clinical Trial, Tosk assumes liability by law on behalf of the PI and his/her assistants for possible injury 
to the subject provided the PI and his/her assistants have followed the instructions of Tosk in accordance 
with this protocol and any amendments thereto, that supplied by Tosk, and that the PI and his/her 
assistants have in general performed this Clinical Trial in accordance with scientific practice and currently 
acceptable techniques and know-how.  
18.0. PUBLICATION POLICY 
 
18.1. PUBLICATION POLICY 
 
It is intended that the results of the study may be published as scientific literature. Results may also be 
used in submissions to regulatory authorities. The following conditions are to protect commercial 
confidential materials (patents, etc.), not to restrict publication. However, any proposed oral or written use 
of such results must be submitted to Tosk for review and written approval at least 60 days prior 
submission for publication, presentation, or use.  
 
All information concerning TK-112690―such as patent applications, formulae, manufacturing processes, 
basic scientific data, or formulation information supplied to the PI by Tosk and not previously 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 96 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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published―is considered confidential by Tosk and shall remain the sole property of Tosk. The PI agrees 
not to use it for other purposes without the written consent of Tosk. 
 
It is understood by the PI that Tosk will use the information developed in this clinical study in connection 
with the development of TK-112690 and therefore may be disclosed as required to other Tosk 
Investigators or any appropriate international Regulatory Authorities. In order to allow for the use of 
information derived from this clinical study, the PI understands that he/she has an obligation to provide 
Tosk with complete test results and all data developed during this study. In accordance with generally 
recognized principles of scientific collaboration, co-authorship with any Tosk personnel will be discussed 
and mutually agreed upon before submission of a manuscript to a publisher. 
 
18.2. CONFIDENTIALITY 
 
The principal PI and any other study personnel involved in this study shall not disclose, or use for any 
purposes (other than for the performance of this study), any data, records, or other information 
(hereinafter collectively “Information”) disclosed to the Principal PI or other study personnel. Such 
information shall remain the confidential and proprietary property of Tosk and shall be disclosed only to 
the Principal PI or other designated personnel. The obligation of non-disclosure shall not apply to the 
following: 
 
● Information after such time that it is or becomes publicly available through no fault of the PI or 
other study personnel. 
● Information after such time that it is disclosed to the Principal PI by a third party entitled to 
disclose such information. 
 
The PI must assure that subject anonymity will be maintained and that identities are protected from 
unauthorized parties. Subjects should not be identified by their names but by their initials and an 
identification code on CRFs or other documents submitted to the sponsor. Documents that will not be 
submitted to Tosk (eg, written informed consent form), should be maintained by the PI in strict 
confidence. 
 
 
19.0. REFERENCE LIST 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 97 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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20.0. APPENDICES: 
20.1. APPENDIX 1: WORLD MEDICAL ASSOCIATION DECLARATION OF HELSINKI 
 
Ethical Principles for Medical Research Involving Human Subjects  
 
Adopted by the 18th WMA General Assembly, Helsinki, Finland, June 1964, and amended by the: 
29th WMA General Assembly, Tokyo, Japan, October 1960 
35th WMA General Assembly, Venice, Italy, October 1983 
41st WMA General Assembly, Hong Kong, September 1989 
48th WMA General Assembly, Somerset West, Republic of South Africa, October 1996 
52nd WMA General Assembly, Edinburgh, Scotland, October 2000 
53th WMA General Assembly, Washington 2002 (Note of Clarification on paragraph 29 added) 55th 
WMA General Assembly, Tokyo 2004 (Note of Clarification on Paragraph 30 added) 
59th WMA General Assembly, Seoul, October 2008 
 
A. INTRODUCTION 
 
1. The World Medical Association (WMA) has developed the Declaration of Helsinki as a statement of 
ethical principles for medical research involving human subjects, including research on identifiable 
human material and data. The Declaration is intended to be read as a whole and each of its constituent 
paragraphs should not be applied without consideration of all other relevant paragraphs. 
2. Although the Declaration is addressed primarily to physicians, the WMA encourages other participants 
in medical research involving human subjects to adopt these principles. 
3. It is the duty of the physician to promote and safeguard the health of patients, including those who are 
involved in medical research. The physician's knowledge and conscience are dedicated to the 
fulfillment of this duty.  
4. The Declaration of Geneva of the WMA binds the physician with the words, “The health of my patient 
will be my first consideration,” and the International Code of Medical Ethics declares that, “A 
physician shall act in the patient's best interest when providing medical care.” 
5. Medical progress is based on research that ultimately must include studies involving human subjects. 
Populations that are underrepresented in medical research should be provided appropriate access to 
participation in research. 
6. In medical research involving human subjects, the well-being of the individual research subject must 
take precedence over all other interests. 
7. The primary purpose of medical research involving human subjects is to understand the causes, 
development and effects of diseases and improve preventive, diagnostic and therapeutic interventions 
(methods, procedures and treatments). Even the best current interventions must be evaluated continually 
through research for their safety, effectiveness, efficiency, accessibility and quality. 
8. In medical practice and in medical research, most interventions involve risks and burdens.  
9. Medical research is subject to ethical standards that promote respect for all human subjects and protect 
their health and rights. Some research populations are particularly vulnerable and need special 
protection. These include those who cannot give or refuse consent for themselves and those who may 
be vulnerable to coercion or undue influence. 
10. Physicians should consider the ethical, legal and regulatory norms and standards for research involving 
human subjects in their own countries as well as applicable international norms and standards. No 
national or international ethical, legal or regulatory requirement should reduce or eliminate any of the 
protections for research subjects set forth in this Declaration. 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 98 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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B. PRINCIPLES FOR ALL MEDICAL RESEARCH 
 
11. It is the duty of physicians who participate in medical research to protect the life, health, dignity, 
integrity, right to self-determination, privacy, and confidentiality of personal information of research 
subjects. 
12. Medical research involving human subjects must conform to generally accepted scientific principles, 
be based on a thorough knowledge of the scientific literature, other relevant sources of information, 
and adequate laboratory and, as appropriate, animal experimentation. The welfare of animals used for 
research must be respected. 
13. Appropriate caution must be exercised in the conduct of medical research that may harm the 
environment. 
14. The design and performance of each research study involving human subjects must be clearly 
described in a research protocol. The protocol should contain a statement of the ethical considerations 
involved and should indicate how the principles in this Declaration have been addressed. The protocol 
should include information regarding funding, sponsors, institutional affiliations, other potential 
conflicts of interest, incentives for subjects and provisions for treating and/or compensating subjects 
who are harmed as a consequence of participation in the research study. The protocol should describe 
arrangements for post-study access by study subjects to interventions identified as beneficial in the 
study or access to other appropriate care or benefits. 
15. The research protocol must be submitted for consideration, comment, guidance and approval to a 
research ethics committee before the study begins. This committee must be independent of the 
researcher, the sponsor and any other undue influence. It must take into consideration the laws and 
regulations of the country or countries in which the research is to be performed as well as applicable 
international norms and standards but these must not be allowed to reduce or eliminate any of the 
protections for research subjects set forth in this Declaration. The committee must have the right to 
monitor ongoing studies. The researcher must provide monitoring information to the committee, 
especially information about any serious adverse events. No change to the protocol may be made 
without consideration and approval by the committee. 
16. Medical research involving human subjects must be conducted only by individuals with the appropriate 
scientific training and qualifications. Research on patients or healthy volunteers requires the 
supervision of a competent and appropriately qualified physician or other health care professional. The 
responsibility for the protection of research subjects must always rest with the physician or other 
health care professional and never the research subjects, even though they have given consent. 
17. Medical research involving a disadvantaged or vulnerable population or community is only justified if 
the research is responsive to the health needs and priorities of this population or community and if 
there is a reasonable likelihood that this population or community stands to benefit from the results of 
the research. 
18. Every medical research study involving human subjects must be preceded by careful assessment of 
predictable risks and burdens to the individuals and communities involved in the research in 
comparison with foreseeable benefits to them and to other individuals or communities affected by the 
condition under investigation. 
19. Every clinical trial must be registered in a publicly accessible database before recruitment of the first 
subject.  
20. Physicians may not participate in a research study involving human subjects unless they are confident 
that the risks involved have been adequately assessed and can be satisfactorily managed. Physicians 
must immediately stop a study when the risks are found to outweigh the potential benefits or when 
there is conclusive proof of positive and beneficial results. 
21. Medical research involving human subjects may only be conducted if the importance of the objective 
outweighs the inherent risks and burdens to the research subjects.  


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 99 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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22. Participation by competent individuals as subjects in medical research must be voluntary. Although it 
may be appropriate to consult family members or community leaders, no competent individual may be 
enrolled in a research study unless he or she freely agrees. 
23. Every precaution must be taken to protect the privacy of research subjects and the confidentiality of 
their personal information and to minimize the impact of the study on their physical, mental and social 
integrity.  
24. In medical research involving competent human subjects, each potential subject must be adequately 
informed of the aims, methods, sources of funding, any possible conflicts of interest, institutional 
affiliations of the researcher, the anticipated benefits and potential risks of the study and the 
discomfort it may entail, and any other relevant aspects of the study. The potential subject must be 
informed of the right to refuse to participate in the study or to withdraw consent to participate at any 
time without reprisal. Special attention should be given to the specific information needs of individual 
potential subjects as well as to the methods used to deliver the information. After ensuring that the 
potential subject has understood the information, the physician or another appropriately qualified 
individual must then seek the potential subject’s freely-given informed consent, preferably in writing. 
If the consent cannot be expressed in writing, the non-written consent must be formally documented 
and witnessed.  
25. For medical research using identifiable human material or data, physicians must normally seek consent 
for the collection, analysis, storage and/or reuse. There may be situations where consent would be 
impossible or impractical to obtain for such research or would pose a threat to the validity of the 
research. In such situations, the research may be done only after consideration and approval of a 
research ethics committee. 
26. When seeking informed consent for participation in a research study the physician should be 
particularly cautious if the potential subject is in a dependent relationship with the physician or may 
consent under duress. In such situations the informed consent should be sought by an appropriately 
qualified individual who is completely independent of this relationship.  
27. For a potential research subject who is incompetent, the physician must seek informed consent from 
the legally authorized representative. These individuals must not be included in a research study that 
has no likelihood of benefit for them unless it is intended to promote the health of the population 
represented by the potential subject, the research cannot instead be performed with competent persons, 
and the research entails only minimal risk and minimal burden. 
28. When a potential research subject who is deemed incompetent is able to give assent to decisions about 
participation in research, the physician must seek that assent in addition to the consent of the legally 
authorized representative. The potential subject’s dissent should be respected. 
29. Research involving subjects who are physically or mentally incapable of giving consent, for example, 
unconscious patients, may be done only if the physical or mental condition that prevents giving 
informed consent is a necessary characteristic of the research population. In such circumstances the 
physician should seek informed consent from the legally authorized representative. If no such 
representative is available and if the research cannot be delayed, the study may proceed without 
informed consent provided that the specific reasons for involving subjects with a condition that renders 
them unable to give informed consent have been stated in the research protocol and the study has been 
approved by a research ethics committee. Consent to remain in the research should be obtained as soon 
as possible from the subject or a legally authorized representative. 
30. Authors, editors and publishers all have ethical obligations with regard to the publication of the results 
of research. Authors have a duty to make publicly available the results of their research on human 
subjects and are accountable for the completeness and accuracy of their reports. They should adhere to 
accepted guidelines for ethical reporting. Negative and inconclusive as well as positive results should 
be published or otherwise made publicly available. Sources of funding, institutional affiliations and 
conflicts of interest should be declared in the publication. Reports of research not in accordance with 
the principles of this Declaration should not be accepted for publication. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 100 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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C. ADDITIONAL PRINCIPLES FOR MEDICAL RESEARCH COMBINED WITH 
MEDICAL CARE 
 
31. The physician may combine medical research with medical care only to the extent that the research is 
justified by its potential preventive, diagnostic or therapeutic value and if the physician has good 
reason to believe that participation in the research study will not adversely affect the health of the 
patients who serve as research subjects.  
32. The benefits, risks, burdens and effectiveness of a new intervention must be tested against those of the 
best current proven intervention, except in the following circumstances: 
• The use of placebo, or no treatment, is acceptable in studies where no current proven intervention 
exists; or  
• Where for compelling and scientifically sound methodological reasons the use of placebo is 
necessary to determine the efficacy or safety of an intervention and the patients who receive 
placebo or no treatment will not be subject to any risk of serious or irreversible harm. Extreme 
care must be taken to avoid abuse of this option. 
33. At the conclusion of the study, patients entered into the study are entitled to be informed about the 
outcome of the study and to share any benefits that result from it, for example, access to interventions 
identified as beneficial in the study or to other appropriate care or benefits.  
34. The physician must fully inform the patient which aspects of the care are related to the research. The 
refusal of a patient to participate in a study or the patient’s decision to withdraw from the study must 
never interfere with the patient-physician relationship.  
35. In the treatment of a patient, where proven interventions do not exist or have been ineffective, the 
physician, after seeking expert advice, with informed consent from the patient or a legally authorized 
representative, may use an unproven intervention if in the physician's judgment it offers hope of saving 
life, re-establishing health or alleviating suffering. Where possible, this intervention should be made 
the object of research, designed to evaluate its safety and efficacy. In all cases, new information should 
be recorded and, where appropriate, made publicly available.  
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 101 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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20.2. APPENDIX 2: ECOG PERFORMANCE STATUS 
 
ECOG PERFORMANCE STATUS 
 
0 
Fully active, able to carry on all pre-disease performance without restriction. 
 
 
1 
Restricted in physically strenuous activity but ambulatory and able to carry out work of 
a light or sedentary nature (eg, light housework, office work). 
 
 
2 
Ambulatory and capable of all self-care but unable to carry out any work activities. Up 
and about more than 50% of waking hours. 
 
 
3 
Capable of only limited self-care, confined to bed or chair more than 50% of waking 
hours. 
 
 
4 
Completely disabled. Cannot carry on any self-care. Totally confined to bed or chair. 
 
 
5 
Dead. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 102 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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20.3. APPENDIX 3: METREXASSISTTM (TK-112690 FOR INJECTION) DOSE PREPARATION 
 
OVERVIEW  
 
TK-112690 must be administered under the supervision of a physician experienced in the use of anti-
neoplastic medicinal products. Solutions of formulated TK-112690 should not be co-administered or 
mixed with any other solution. 
 
TK-112690 is provided as a concentrate for solution for infusion in a single-use vial, which contains a 
nominal amount of 500 mg of TK-112690 in 5 mL (concentration of 100mg/mL).  
METREXASSIST (TK-112690) is formulated with 50 mM sodium phosphate pH 7.4. The drug product 
is a clear, colorless, sterile liquid solution that has to be diluted in 0.9 % sodium chloride solution prior to 
administration.TK-112690IS NOT TO BE ADMINISTERED AS AN IV PUSH OR BOLUS. TK-
112690 should be administered as a one-hour iv infusion.  
HOW SUPPLIED 
TK-112690 is supplied as 5 mL of a sterile solution in single-use glass vials to deliver 500 mg of 
METREXASSIST per vial as follows: 
● 
Single unit 500 mg vial: Contains 5 mL of TK-112690 (100 mg/mL).  
METREXASSISTTM vials must be stored frozen (-15 to -25°C). TK-112690 vials should be protected 
from light. Store in the original carton until time of use. 
DOSE PREPARATION 
TK-112690 should be diluted for infusion by a healthcare professional using aseptic technique. Withdraw 
the necessary amount of TK-112690 to obtain the required dose and dilute in a total volume of 250 mL of 
0.9% Sodium Chloride Injection, USP.  
Calculation for the amount ofTK-112690 for dilution into the iv bag is presented on the following page. 
Calculation is based on patient’s weight (in kilograms) and desired Dose Level.  
The parenteral drug products should be inspected visually for particulate matter and discoloration prior to 
administration. 
Diluted TK-112690 solutions for infusion may be stored at 2-8°C (36-46°F) for up to 8 hours. No 
incompatibilities between TK-112690 and polyvinylchloride bags have been observed. 
 
 
 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 103 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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CALCULATION OF METREXASSIST FOR DILUTION INTO 250 ML 0.9% SODIUM CHLORIDE IV BAG 
Part A. Calculation of mL (milliliters) needed to dilute into iv bag for dose level based on patient’s 
weight in kg (kilograms) 
For Dose Levels 45 mg/kg, use supplied 100 mg/mL METREXASSIST (TK-112690 for injection): 
Dose Level 
Multipl
y 
Weight 
Patient 
Divide 
Concentration 
of TK-112690 
Equals 
Total mL for Dose 
Level 
45 mg/kg 
x 
____kg 
/ 
100 mg/mL 
= 
_____mL 
 
 
 
 
 
 
 
 
Example : 85 kg patient 
 
Dose Level 
Multipl
y 
Weight of 
Patient 
Divide 
Concentration 
of TK-112690 
 
Equals 
Total mL for Dose 
Level 
45 mg/kg 
x 
85 kg 
/ 
100 mg/mL 
= 
38.25 mL 
 
Part B. Calculation of number of vials needed to obtain required mL for 45 mg/kg dose levels 
mL Required 
Divide 
mL/ 
vial 
Equals 
Number of Vials 
Required  
_mL 
/ 
5 mL 
= 
____ # Vials 
 
Example:  85 kg patient 
 
38.25 mL 
/ 
5 mL 
= 
7.65 Vials 
 
DOSE ADMINISTRATION 
DO NOT ADMINISTER AS AN IV PUSH OR BOLUS. TK-112690 dose should be delivered over 1 
hour by IV infusion. 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 104 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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20.4. APPENDIX 4: INFUSION REACTION CRITERIA 
 
Epinephrine (1:1000) for subcutaneous injection, diphenhydramine (12.5 mg to 50 mg) for iv injection, 
and any other medications and resuscitation equipment for the emergency management of anaphylactic 
reactions must be available in the room where the infusions are being performed. 
 
Section 1 
The subject’s study treatment must be discontinued immediately if a Grade 4 AE occurs during the 
infusion of TK-112690, and the subject must be withdrawn from the study. The subject’s study treatment 
must be discontinued immediately if a Grade 3 AE occurs during the infusion of TK-112690 and should 
not be completed even if the subject recovers. Subsequent administration of TK-112690should be 
preceded by prophylactic premedication as outlined in Section 2. If another Grade 3 infusion reaction 
occurs during a subsequent treatment day, treatment will again be discontinued for the rest of that 
infusion. If the investigator wishes to continue treatment in this subject, there should be discussion 
with the medical monitor about the possibility of reduced infusion rates for subsequent infusions. 
 
If Grade 1 or 2 AEs occur during infusion of TK-112690, the subject may complete the treatment at half 
the previous infusion rate (180 minutes or shorter based on the acceleration of the infusion allowed after 
the first dose). Subsequent administration of TK-112690 should be preceded with prophylactic treatment 
as outlined in Section 2. To assess the events, please refer to the NCI CTCAE in the Study Reference 
Manual. 
 
Treatment Recommendations Prior to, During, and Immediately After Infusion 
Section 2 Prophylactic Treatment Prior to Infusion 
 
Prophylactic measures prior to the administration of should not be initiated unless a previous infusion 
reaction has occurred. Subjects who have previously experienced a reaction to must receive prophylactic 
treatment prior to subsequent infusions. Prophylactic treatment with acetaminophen (1 g) and 
diphenhydramine HCl (12.5 to 50 mg; or equivalent dose of a similar agent) by mouth 30 to 60 minutes 
prior to the start of the infusion is recommended. Steroids should not be used as pre-medication in this 
study. 
 
Section 3 Treatment of Infusion Reactions 
The use of acetaminophen plus an antihistamine, such as diphenhydramine (or similar agent), is 
recommended for the treatment of an infusion reaction. For adjustment to the subject’s infusion see 
Section 1. 
 
Modification of the Subject’s Treatment during Therapy 
 
Acetaminophen and diphenhydramine should be repeated as clinically indicated for the infusion reaction. 
Vital sign measurements will be recorded on the appropriate CRF. Any infusion reaction will be recorded 
as an AE on the AE CRF. Management of Grade 3 or Grade 4 infusion reaction is outlined in Section  
 
These recommendations do not address life-threatening events, including anaphylaxis, for which study 
treatment should be discontinued and all appropriate standard measures, including full resuscitation 
medicine and equipment, must be available and should be used as clinically indicated. 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 105 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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20.5. APPENDIX 5: ICH GUIDELINES, TOPIC E2 
 
ICH Guidelines for Clinical Safety Data Management, Definitions and Standards for Expedited 
Reporting, Topic E2 
 
A serious adverse event is any experience that suggests a significant hazard, contraindications, side effect 
or precaution. It is any adverse event that at any dose fulfils at least one of the following criteria: 
 
● Is fatal (results in death).  
(Note: death is an outcome, not an event). 
● Is life-threatening.  
(Note: the term “life-threatening” refers to an event in which the subject was at immediate risk of 
death at the time of the event, it does not refer to an event which could hypothetically have 
caused a death it been more severe). 
● Required in subject hospitalization or prolongation of existing hospitalization. 
● Results in persistent or significant disability/incapacity. 
● Is a congenital anomaly/birth defect. 
● Is medically significant or requires intervention to prevent one or more of the outcomes listed 
above. 
 
Medical and scientific judgment should be exercised in deciding whether expedited reporting to the 
sponsor is appropriate on other situations, such as important medical events that may not be immediately 
life-threatening or result in death or hospitalization but may jeopardize the subject or may require 
intervention to prevent one of the outcomes listed in the definitions above. These situations should also 
usually be considered serious. 
 
Examples of such events are intensive treatment in an emergency room or at home for allergic 
bronchospasm, blood dyscrasias or convulsions that do not result in hospitalization, or development of 
drug dependency or drug abuse. 
 
An unexpected adverse event is one, the nature or severity of which is not consistent with the applicable 
product information. 
 
Causality is initially assessed by the investigator. For SAEs, causality can be one of the two possibilities: 
 
● No (unrelated, equals not drug related) 
● Yes (possibly, probably or definitely drug related; or relationship not provided) 
 
The term severe is a measure of intensity, thus a severe adverse event is not necessarily serious. For 
example, nausea of several hours duration may be rated as severe, but may not be clinically serious. 
 
A serious adverse event occurring during the study or which comes to the attention of the investigator 
within 28 days after stopping the treatment or during the protocol defined follow-up period, if this is 
longer, whether considered treatment related or not, must be reported. In addition, a SAE that occurs after 
this time, if considered related to test “drug,” should be reported.  
 
Progression of neoplasia should not be reported as an AE or SAE. Findings that are clearly consistent 
with the expected progression of the underlying cancer should not be reported as an AE, and 
hospitalizations due to the progression of cancer do not necessarily qualify for a SAE. If there is any 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 106 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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uncertainty about a finding being due solely to progression of neoplasia, the finding should be reported as 
an AE or SAE as appropriate. 
 
Such preliminary reports will be followed by detailed descriptions later, which will include copies of 
hospital case reports, autopsy reports and other documents when requested and applicable. 
 
For SAEs, the following must be assessed and recorded on the adverse event page of the CRF: intensity, 
relationship to test substance, action taken, and outcome. 
 
The investigator must notify the Ethics Review Committee/Institutional Review Board of a SAE in 
writing as soon as is practical and in accordance with international and local laws and regulations. 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 107 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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20.6. APPENDIX 6: MUCOSITIS SCORING 
 
Mucositis scoring will be performed using the following scales and other determinations. 
 
OMAS Scale 
 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 108 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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PROMS Scale 
 
Questionnaire for Patient-reported Oral Mucositis Symptom Scale 


METREXASSISTTM (Parenteral TK-112690)                                                                         Page 109 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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METREXASSISTTM (Parenteral TK-112690)                                                                         Page 110 of 110 
CLP-2690-0003                                                                                                         25 February 2019 
 
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WHO Scale for Oral Mucositis 
 
Grade 0 = No oral mucositis 
Grade 1 = Erythema and soreness 
Grade 2 = Ulcers, able to eat solids 
Grade 3 = Ulcers, requires liquid diet (due to mucositis) 
Grade 4 = Ulcers, alimentation not possible (due to mucositis) 
 
Mucositis per CTCAE version 4.0 
 
             Grade 1 = Asymptomatic or mild symptoms; intervention not indicated. 
             Grade 2 = Moderate pain; not interfering with oral intake; modified diet indicated 
             Grade 3 = Severe pain; interfering with oral intake 
             Grade 4 = Life-threatening consequences; urgent intervention indicated 
             Grade 5 = Death