Clinical trial NCT04294472
Conditions: BK Virus Infection
Sponsor: Vera Therapeutics, Inc.
Start date: 2020-08-05; Completion date: 2022-02-10
Enrollment: 30 participants; Allocation: RANDOMIZED; Intervention model: PARALLEL

Brief summary:
This clinical research study will test the safety and efficacy of the investigational medication MAU868, compared to a placebo, in patients who have had a kidney transplant who have active BK virus.

Detailed description:

Arms: arm 1: Cohort 1: MAU868 1350 mg IV approximately every 28 days for a total of 4 doses arm 2: Cohort 2: MAU868 6750 mg IV on Study Day 1 and then 1350 mg IV approximately every 28 days for a total of 4 doses arm 3: Cohort 3: MAU868 6750 mg IV approximately every 28 days for a total of 4 doses arm 4: 5% dextrose in water \[D5W\] IV delivered every 28 days for a total of 4 doses
Interventions: intervention 1: MAU868 intervention 2: Placebo
Intervention descriptions: intervention 1: MAU868 is a human monoclonal antibody (IgG1) that binds the viral capsid protein, VP1, that is responsible for binding to the surface of host cells intervention 2: 250 mL D5W placebo IV to be labeled to match that of MAU868

Protocol documents:
Prot_000.pdf: 
Page 1 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
CLINICAL STUDY PROTOCOL 
 
A Randomized, Double-blind, Placebo-controlled Study to 
Assess the Safety, Pharmacokinetics and Efficacy of 
MAU868 for the Treatment of BK Viremia in Kidney 
Transplant Recipients 
 
Investigational Product: MAU868 
Protocol Number: MAU868-201 
 
 
 
Sponsor: 
Amplyx Pharmaceuticals, Inc. 
12730 High Bluff Drive, Suite 160 
San Diego, CA 92130 
United States 
Telephone: +1-858-345-1755 
Fax: +1-858-345-1346 
 
 
Version Number: 2.0 
Date: 15Apr2020 
 
 
 
Confidentiality Statement 
The information in this document is confidential and is not to be disclosed without the written 
consent of Amplyx Pharmaceuticals, Inc. except to the extent that disclosure would be required 
by law and for the purpose of evaluating and/or conducting a clinical study for 
Amplyx Pharmaceuticals, Inc. You are allowed to disclose the contents of this document only to 
your Institutional Review Board or Independent Ethics Committee and study personnel directly 
involved with conducting this protocol. Persons to whom the information is disclosed must be 
informed that the information is confidential and proprietary to Amplyx Pharmaceuticals, Inc. 
and that it may not be further disclosed to third parties. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 2 of 94 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
SIGNATURE PAGE 
STUDY TITLE: A Randomized, Double-blind, Placebo-controlled Study to 
Assess the Safety, Pharmacokinetics and Efficacy of MAU868 for the 
Treatment of BK Viremia in Kidney Transplant Recipients 
 
I, the undersigned, have read this protocol and agree that it contains all necessary information 
required to conduct the study. 
Signature 
 
 
 
 
 
 
 
Date 
 
 
 
 
Michael R. Hodges, MD 
Chief Medical Officer 
Amplyx Pharmaceutical, Inc.  
 
 
16th April 2020


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 3 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
INVESTIGATOR AGREEMENT 
By signing below, I agree that: 
I have read this protocol. I approve this document and I agree that it contains all necessary details 
for carrying out the study as described. I will conduct this study in accordance with the design and 
specific provision of this protocol and will make a reasonable effort to complete the study within 
the time designated. I will provide copies of this protocol and access to all information furnished 
by Amplyx Pharmaceuticals, Inc. (Amplyx) to study personnel under my supervision. I will 
discuss this material with them to ensure they are fully informed about the study product and study 
procedures. I will let them know that this information is confidential and proprietary to Amplyx 
and that it may not be further disclosed to third parties. I understand that the study may be 
terminated, or enrollment suspended at any time by Amplyx, with or without cause. 
I agree to conduct this study in full accordance with United States Food and Drug Administration 
(FDA) Regulations, Institutional Review Board/Ethic Committee Regulations and International 
Council for Harmonization Guidelines for Good Clinical Practices. 
 
 
 
 
 
 
______________________________________________  
____________________ 
Investigator’s Signature 
 
 
 
 
 
Date 
 
 
 
______________________________________________ 
Investigator’s Printed Name 
 
 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 4 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
SYNOPSIS 
TITLE:  A randomized, double-blind, placebo-controlled study to assess the safety, 
pharmacokinetics and efficacy of MAU868 for the treatment of BK viremia in kidney transplant 
recipients 
PROTOCOL NUMBER: MAU868-201 
INVESTIGATIONAL PRODUCT: MAU868 
PHASE: 2 
INDICATION: Treatment of BK viremia 
OBJECTIVES: 
The primary objective of this study is: 
• To assess the safety and tolerability of MAU868 
Secondary objectives of this study are: 
• To assess the impact of MAU868 on BK virus related outcomes including viruria, 
viremia, BK virus nephropathy, graft function and rejection among renal transplant 
recipients with BK viremia 
• To assess the pharmacokinetics of MAU868 
BACKGROUND: 
Infection with BK virus (BKV) is essentially ubiquitous, with estimates ranging between 80 and 
90% of the population globally. Primary infection occurs in childhood (usually by 10 years of 
age) and is either a mild, non-specific, self-limited illness or asymptomatic. Persistent infection 
is established in the epithelial cells of the renal tubules, ureters, and bladder, and is effectively 
controlled, though never eliminated by the immune system. Compromised immune function can 
lead to uncontrolled viral replication and development of disease. The two best-characterized 
BKV-associated diseases are a nephropathy that affects kidney transplant recipients  
(i.e., a disease of the allograft) and hemorrhagic cystitis, with or without renal involvement, that 
affects hematopoietic stem cell transplant (HSCT) recipients. BKV nephropathy (BKVN) is a 
leading cause of premature allograft loss, second only to allograft rejection. Patients who 
develop BK viremia irrespective of whether biopsy confirms BKVN have been reported to have 
significantly lower allograft survival at 10 years (24.8% vs 85.6%, P <0.001; Moura et al 2017). 
BKV-associated hemorrhagic cystitis prolongs hospitalizations, often requires administration of 
blood products and urologic intervention, can involve the native kidneys and can lead to death 
in the most severe cases. BKV has four major genotypes, but genotype is not linked with the 
risk or severity of disease. 
MAU868 is a human monoclonal antibody (IgG1) that binds the viral capsid protein, VP1, that 
is responsible for binding to the surface of host cells (i.e., the first step in the infection of new 
cells; Tsai and Qian 2010). MAU868 neutralizes all four BKV genotypes at sub-nanomolar 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 5 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
concentrations in vitro. It binds to an epitope on VP1 that is highly conserved. Resistance-
associated BKV variants were not identified in two independent long-term in vitro selection 
studies, demonstrating that MAU868 has a high in vitro barrier-to-resistance. It is being 
developed for the treatment of clinically significant BKV infection in immunosuppressed 
populations, notably solid organ and hemopoietic stem cell transplant (HSCT) recipients. 
The results of the non-clinical studies identify no specific risk for investigation of MAU868 in 
human subjects, as expected for a human monoclonal antibody that recognizes a foreign 
(i.e., non-human) antigen. No MAU868-related effects were observed in rats after once weekly 
dosing (5 doses total) of MAU868 up to 750 mg/kg IV and 150 mg/kg SC. In addition, MAU868 
did not bind human tissues (42 normal tissues) or blood smears as assessed by 
immunohistochemistry.  
To date, a total of 27 subjects (26 healthy volunteers and 1 subject with BKV nephropathy) have 
received MAU868. A first-in-human, randomized, blinded, placebo-controlled, single 
ascending dose study to assess the safety, tolerability and pharmacokinetics of MAU868 
following IV or SC administration to healthy adult subjects was performed. Twenty-six subjects 
received doses of MAU868 up to 100 mg/kg IV or 3 mg/kg SC; all doses were safe and well 
tolerated. No deaths or SAEs were reported, and there were no AEs that led to the 
discontinuation of dosing or the study. After single doses, serum concentrations of MAU868 
declined in a biphasic manner with a terminal half-life of 23 to 30 days. The estimated relative 
bioavailability of MAU868 following SC administration was 57.6%. Administration of 
MAU868 increased anti-BKV antibody titers and the neutralizing potency of the serum, while 
administration of placebo had no effect. 
One adult female kidney transplant recipient was treated with MAU868 1350 mg IV for 
refractory BKV nephropathy (i.e., preceding persistent BK viremia for ~7 months with biopsy 
confirmation) as part of an individual patient managed access program requested and initiated 
by the treating physician. She received a total of 11 doses over 6 months, most of which were 
administered every two weeks. The treating physician elected to pre-treat the patient with 
steroids, antihistamines, and acetaminophen for each infusion. MAU868 was considered safe 
and well tolerated by the patient with no adverse events related to MAU868 or the infusion. 
Further details of non-clinical and clinical studies conducted to date with MAU868 can be found 
in the Investigator’s Brochure (IB). 
To date, there are no effective antiviral therapies directed at BKV. MAU868 has the potential to 
be a safe and well-tolerated therapy that can eliminate a threat to the survival of the renal 
allograft and greatly simplify the post-transplantation care of kidney transplant recipients.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 6 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
POPULATION: 
Inclusion Criteria: 
Subjects must meet all of the following criteria to be eligible for study entry: 
1. Be a male or female 18 years of age or older.  
2. Recipient of a kidney (or kidney-pancreas) transplant within the year prior to enrollment.  
3. Documented BKV viremia based on local or central laboratory testing within 10 days 
prior to randomization of either 
a) 104 copies/mL OR 
b) a detectable viral load in 2 consecutive plasma samples (collected between 
1 and 3 weeks apart) where the most recent sample demonstrates a BK viral 
load of 103 copies/mL.  (Note: only the second, most recent sample must be 
collected within 10 days prior to randomization)  
4. Have a functioning graft that is producing urine. 
5. Females of childbearing potential (i.e., not postmenopausal or surgically sterilized) with 
male partners, and males with female partner(s) of childbearing potential, must agree to 
use two forms of highly effective contraception, 1 of which must be a barrier method, 
throughout the duration of the study and for 90 days following the last study drug  
administration. Acceptable barrier forms of contraception are condom and diaphragm. 
Acceptable non-barrier forms of contraception for this study are oral birth control pill, 
depot, patch, implants or injectable, abstinence, intrauterine device, and/or spermicide. 
6. Females of childbearing potential must have a negative urine or serum pregnancy test 
result within 96 hours prior to Baseline (i.e., pre-dose on Study Day 1). 
7. Be willing to participate in the study, to give written informed consent and to comply 
with the study restrictions. 
Exclusion Criteria: 
Subjects who meet any of the following criteria will not be eligible for study entry: 
1. A BKV plasma viral load which has exceeded 103 copies/mL for >4 months. 
2. A BKV plasma viral load of 107 copies/mL. 
3. Are receiving, at the time of informed consent, systemic mTOR inhibitors. 
4. Kidney transplant recipients who are anticipated to require Intravenous Immune 
Globulin (IVIG) treatment during the study period or who have received IVIG in the 
previous 9 months. 
5. Kidney transplant recipients who, in the opinion of the Investigator, are likely to require 
antibody-depletion. Antibody-depleting therapies include but are not necessarily limited 
to hemodialysis, plasmapheresis and immunoadsorption. 
6. Treatment within the previous month with the following medications:  cidofovir, 
leflunomide.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 7 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
7. History of hypersensitivity or intolerance to intravenous or subcutaneous administration 
of biologic medications or to any of the excipients included in the formulation of 
MAU868. 
8. Platelet count <50,000/mm3 at the time of informed consent, as determined by local 
laboratory.  
9. History of splenectomy or asplenia.  
10. Are lactating and/or pregnant. 
11. Use of other investigational drugs at the time of enrollment, or within 5 half-lives of 
enrollment, or until the expected PD effect has returned to baseline, whichever is longer; 
or longer than 5 half-lives if required by local regulations. 
12. Prior exposure to MAU868. 
13. Any other condition or laboratory abnormality that, in the opinion of the Investigator or 
the Sponsor, would put the patient at unacceptable risk for participation in the study or 
would interfere with the assessments included in the study. 
STUDY DESIGN AND DURATION: 
This is a randomized, placebo-controlled, double-blinded, proof-of-concept study in kidney 
transplant recipients. Up to 36 subjects with BK viremia will participate in 1 of 3 sequential 
cohorts.  Each cohort will randomize approximately 12 subjects (8 MAU868 and 4 placebo).  
The study will consist of a screening period, a 12-week treatment period and a 24-week 
follow-up period.  
Protocol-specific procedures should not be performed until the patient has consented to 
participation in the study.  However, assessments and procedures performed as part of standard 
of care prior to informed consent, including determination of BK viral load in plasma may be 
used to qualify a patient for the study.  Once qualifying BK viremia has been confirmed, subjects 
should be randomized as soon as possible and no more than 10 days after the sample 
documenting the viremia was collected.   
During the treatment period, subjects will receive MAU868 or placebo approximately every 
28 days (every 4 weeks) for 12 weeks (4 doses total). Urine and blood will be monitored for 
BKV DNA by PCR weekly for the first 6 weeks after initiation of treatment. For the remainder 
of the treatment period, urine and blood must be collected for BKV DNA by PCR at least every 
other week. However, the Investigator may also request testing more frequently (i.e., weekly) 
than mandated by the protocol after the first 6 weeks of treatment and when clinically indicated. 
During the study, BKV DNA by PCR will be tested at the central laboratory.  Pharmacokinetics 
(PK), viral resistance, and anti-drug antibodies (ADA) will also be monitored. Subjects should 
continue study drug until the last scheduled dose, regardless of changes in plasma BK viral load, 
use of rescue therapy, and/or need for change in immunosuppressive regimen for any reason.  
During the 24-week follow-up period, 3 follow-up visits will be scheduled. At each visit, urine 
and blood samples for BKV DNA and samples for PK will be collected. Investigators may 
collect samples for BKV DNA more often as clinically indicated. During the follow-up period, 
BKV DNA by PCR will be tested at the central laboratory.   


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 8 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Routine post-transplantation care is to be guided by the Investigator’s discretion and site 
standard of care.  This includes decisions to change the immunosuppressive regimen for a 
subject for any reason except for changes in immunosuppression in response to BK viremia. 
In order to treat BK viremia, prior to randomization, (i.e., prior to screening, during the 
screening period and at the Baseline Visit) Investigators are permitted to decrease or alter 
immunosuppressive therapy at their discretion and/or per standard of care at their site.  
However, in the first 4 weeks after randomization, Investigators should refrain from additional 
changes in immunosuppressive regimen in response to BKV unless the viral load has increased 
by >1 log and the Investigator determines that a change is in the best interest of the subject. 
Use of other antiviral agents including cidofovir and leflunomide as well as IVIG are not 
permitted during the first 4 weeks of therapy and are strongly discouraged thereafter.   
Use of fluoroquinolones for reasons other than treatment of BKV is permitted.  
Between screening and the last visit, subjects will attend a total of 14 planned visits. 
Unscheduled visits are permitted at the Investigator’s discretion. 
A schematic representing the study’s design is included below: 
 
 
 
Progression from Cohort 1 to Cohort 2  
Approximately 12 weeks after the 9th subject in Cohort 1 has been randomized, blinded safety 
data will be reviewed by the Sponsor Study Review Committee (SSRC). Members of this 
committee will include a Sponsor medical representative, the Medical Monitor and the study’s 
Principal Investigator.  Cohort 2 will be opened for screening once the following criteria have 
been met: 
1. All 12 subjects from Cohort 1 have been randomized, 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 9 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
2. No significant safety issues related to the administration of MAU868 have been 
identified by the SSRC based on the blinded safety review described above as well as an 
assessment of any new SAEs reported after the SSRC review and before randomization 
of the 12th subject in Cohort 1.  
3. No significant safety issues related to the administration of MAU868 have been 
identified by the independent Data Safety Monitoring Board (DSMB) (see below). 
The Chair of the DSMB will be notified of the SSRC’s decision to open Cohort 2. 
Accordingly, some subjects enrolled in Cohort 1 will continue participation in the study 
through the 24-week follow-up period while new subjects are screened and enrolled into 
Cohort 2.  
Progression from Cohort 2 to Cohort 3 
Cohort 3 will not be opened for screening and enrollment until an evaluation of unblinded safety, 
efficacy and pharmacokinetics findings from both Cohorts 1 and 2 through the 12-week 
treatment period has been completed by the SSRC. 
DOSAGE FORMS AND DOSE REGIMEN: 
The following treatment arms and dosing regimens are planned.  
Treatment Arms:   
• Cohort 1: MAU868 1350 mg IV approximately every 28 days for a total of 4 doses 
• Cohort 2: MAU868 6750 mg IV on Study Day 1 and then 1350 mg IV approximately 
every 28 days for a total of 4 doses 
• Cohort 3: MAU868 6750 mg IV approximately every 28 days for a total of 4 doses 
Cohorts 1, 2, and 3 Placebo Arms: 
• 5% dextrose in water [D5W] IV delivered every 28 days for a total of 4 doses   
MAU868 
MAU868 450 mg/3 mL (150 mg/mL) solution for infusion and injection is a slightly opalescent 
and colorless to slightly colored aqueous solution packaged in a 6 mL clear glass vial with a 
grey rubber stopper, which is sealed with an aluminum cap with plastic flip-off disk. The vial is 
overfilled by 10% (containing a total volume of 3.3 mL) to allow for the complete removal of 
the dose (450 mg).  
MAU868 450 mg/3 mL solution for infusion and injection contains, in addition to MAU868 
drug substance, L-histidine, L-histidine-hydrochloride monohydrate, sucrose and polysorbate 
20. The excipients utilized are standard pharmacopeial grade excipients that are commonly used 
in antibody parenteral products. The formulation does not contain any preservative; it is to be 
used for single-dose administration only. 
Placebo 
Placebo solution D5W will be supplied by the clinical site.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 10 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
RATIONALE FOR DOSE AND SCHEDULE SELECTION:  
In Cohort 1, MAU868 will be administered as an IV infusion of 1350 mg in 250 mL D5W over 
a period of at least 60 minutes. In Cohort 2, MAU868 will be administered as an IV infusion of 
6750 mg in 250 mL D5W over a period of at least 180 minutes on Study Day 1 and at 1350 mg 
in 250 mL D5W over a period of at least 60 minutes for subsequent doses. In Cohort 3, MAU868 
will be administered as an IV infusion of 6750 mg in 250 mL D5W over a period of at least 
180 minutes. All infusions will be followed by at least a 25 mL D5W flush to run at the same 
infusion rate as the dose of IP. 
There are no rigorous clinical studies that identify target exposures required for BKV antiviral 
efficacy and no robust animal model of BKV infection or disease; therefore, the most robust 
estimate of the clinical dose considers the following parameters 1) MAU868 BKV neutralizing 
activity in vitro, 2) simulation of serum concentrations based on a model created from Phase 1 
data in healthy volunteers, and 3) published literature on the extravascular distribution of 
immunoglobulin (renal 13.7%). For clinical efficacy, our therapeutic approach is to maintain the 
Ctrough in target tissues ≥10-fold the 50% effective concentration (EC50) of the least susceptible 
BKV genotype (genotype III).  A review of the information is as follows: 
A high-content imaging-based in vitro neutralization assay in RPTE cells was used to 
characterize the antiviral activity of MAU868 determined against representative isolates from 
the four major genotypes of BKV (genotypes I, II, III, and IV, respectively); genotypes I and IV 
account for approximately 95% of the global seroprevalence, while genotypes II and III account 
for the remaining 5% (Zheng et al 2007; Zhong et al 2009).  
Table 1. 
MAU868 In Vitro Neutralization Activity 
Genotype 
EC50 (µg/mL) 
EC90 (µg/mL) 
BKV Genotype I 
0.009 + 0.010 
0.102 + 0.028 
BKV Genotype II 
0.040 + 0.025 
4.160 + 6.076 
BKV Genotype III 
0.093 + 0.057 
2.662 + 2.805 
BKV Genotype IV 
0.020 + 0.020 
0.465 + 0.318 
 
A first-in-human study explored single ascending doses of MAU868 (1, 3, 10, 30, and 
100 mg/kg IV) and the serum concentration data was used to develop a PK model.  The model 
was then used to estimate Ctrough concentrations for a series of 3 treatment regimens. To have a 
treatment effect on BK viremia, MAU868 would need to curtail BKV replication in the target 
tissue (i.e., kidney). Based on an in vivo radiolabeled study in animals and physiologically based 
pharmacokinetic (PBPK) modeling estimates, the antibody biodistribution coefficient in kidney 
is 13.7% (Shah and Betts 2013). The estimated trough levels for each treatment arm were 
compared directly to in vitro-determined antiviral activity (EC50 and EC90) for each BKV 
genotype and corrected for the assumed antibody distributions in kidney.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 11 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
These data show that the planned dose regimens of MAU868 for each treatment arm provides 
high virus neutralizing tissue levels with kidney exposures at Ctrough ≥10-fold the EC50 of the 
least susceptible BKV genotype (III). Specifically, kidney exposures at Ctrough range from 253 to 
2618-fold (Cohort 1), 365 to 3775-fold (Cohort 2), and 1264 to 13,061-fold (Cohort 3) above 
the EC50 at the end of treatment (12 weeks, range = least to most susceptible BKV genotype). 
Using EC90 determinations, kidney exposures at Ctrough range from 6 to 231-fold (Cohort 1), 
8 to 33-fold (Cohort 2), and 28 to 1152-fold (Cohort 3) above the EC90 at the end of treatment.  
A 12-week treatment period was selected to ensure sustained levels of MAU868 to inhibit virus 
replication and promote virus clearance. The subsequent 24-week follow-up period will allow 
evaluation of the durability of effect and additional safety and PK observations. 
From a safety perspective, the highest administered dose of MAU868 expected in this study 
(6750 mg = 100 mg/kg for a 67.5 kg patient) was also the highest administered dose (MAU868 
100 mg/kg) investigated in the first-in-human study and below the no observed adverse effect 
level (NOAEL) exposure (750 mg/kg) in the 4-week repeat-dose toxicity study in rats. 
Specifically, human steady-state AUC exposure at the proposed dose of MAU868 1350 mg 
(20 mg/kg for a 67.5 kg patient) once monthly (206231 µg·hr/mL) provides safety margins of 
6.9X and 5.0X, respectively, compared to the NOAEL (750 mg/kg; 1420000 µg·hr/mL) in the 
4-week rat study and to the AUC at the highest human dose (100 mg/kg; 1031155 µg·hr/mL) 
tested to date. Likewise, human steady-state AUC exposure at the proposed dose of MAU868 
6750 mg once monthly (1031155 µg·hr/mL) provides a safety margin of 1.4X compared to the 
NOAEL (750 mg/kg; 1420000 µg·hr/mL) in the 4-week rat study. 
EFFICACY OBJECTIVES: 
Efficacy objectives of this study are secondary and include: 
• To assess the impact of MAU868 on BKV related outcomes including viremia, BKV 
nephropathy, graft function and rejection among renal transplant patients with BK 
viremia 
• To assess the pharmacokinetics of MAU868 
Exploratory: 
• To investigate the potential immunogenicity of MAU868 
• To investigate genotypic resistance 
• To investigate viral kinetics 
EFFICACY ENDPOINTS: 
• Time (weeks) to decrease of BKV plasma viral load by 1 log 
• Time (weeks) to first decrease of BKV plasma viral load to <lower limit of quantification 
• Proportion of subjects with >1 log decrease of BKV plasma viral load by 1 week, 
2 weeks, 4 weeks, 8 weeks, 12 weeks, and 36 weeks  
• Proportion of subjects with decrease of BKV plasma viral load to <lower limit of 
quantification by 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 36 weeks  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 12 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
• Rate of decrease in BKV plasma viral load by 1 week, 2 weeks, 4 weeks, 8 weeks, 
12 weeks and 36 weeks  
• Change in eGFR from baseline to week 12 and from Baseline to week 36 
• Proportion of subjects with BKV nephropathy during the study 
• Proportion of subjects with graft failure during the study 
• Proportion of subjects with acute rejection during the study 
• Mortality rate during the study 
Exploratory: 
• Proportion of subjects with presence of anti-drug antibodies (ADA) at any time during 
the study 
• Presence of genotypic resistance 
• Viral kinetics of BKV in plasma and urine 
SAFETY ENDPOINTS: 
• Physical examinations, vital signs, clinical safety laboratory parameters, 12-lead ECGs, 
and adverse events. 
PHARMACOKINETIC ENDPOINTS: 
• MAU868 serum concentrations 
DISCONTINUATION OF STUDY DRUG OR STUDY PARTICIPATION: 
Study drug for an individual subject must be discontinued for any of the following reasons: 
• The subject withdraws consent or requests discontinuation for any reason. 
• Occurrence of any medical condition or circumstance that exposes the subject to 
substantial risk and/or does not allow the subject to adhere to the requirements of the 
protocol. 
• Any SAE, clinically significant adverse event, severe laboratory abnormality, 
intercurrent illness, or other medical condition which indicates to the Investigator or 
Sponsor that continued participation is not in the best interest of the subject. Specifically, 
study drug must be discontinued in subjects with development of a treatment-related 
SAE, a treatment-related AE Grade 3 or higher, or a clinically significant treatment-
related laboratory abnormality Grade 3 or higher.  
• Pregnancy during treatment period. 
• Subject failure to comply with protocol requirements or study-related procedures. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 13 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
• Subject experiences study drug related symptoms that the Investigator determines are 
consistent with any of the following: 
o Anaphylaxis or severe allergic reaction.  
o An infusion reaction determined to be Grade 3 or higher based on Common 
Terminology Criteria for Adverse Events (CTCAE) version 5. 
o Cytokine release syndrome determined to be Grade 2 or higher based on 
CTCAE version 5. 
o Serum sickness determined to be Grade 2 or higher based on CTCAE version 5. 
Changes in BKV plasma viral load, use of rescue therapy, and/or need for change in 
immunosuppressive regimen for any reason should not prompt early discontinuation of therapy. 
If a subject is discontinued from study drug treatment administration the subject will still be 
encouraged to complete follow-up visits and assessments necessary for appropriate safety 
follow-up. 
Study participation by an individual subject must be prematurely discontinued for any of the 
following reasons: 
• The subject withdraws consent or requests discontinuation for any reason. 
• Occurrence of any medical condition or circumstance that exposes the subject to 
substantial risk and/or does not allow the subject to adhere to the requirements of the 
protocol. 
• Any SAE, clinically significant adverse event, severe laboratory abnormality, 
intercurrent illness, or other medical condition which indicates to the Investigator or 
Sponsor that continued participation is not in the best interest of the subject. 
• Subject failure to comply with protocol requirements or study-related procedures. 
If a subject withdraws prematurely from the study, study staff should make every effort to 
contact the Sponsor prior to discontinuation, if possible, and to complete the full panel of 
assessments scheduled for the Early Termination Visit. The reason for subject withdrawal must 
be documented in the electronic Case Report Form.  
In the case of subjects lost to follow-up, attempts to contact the subject must be made and 
documented in the subject’s medical records.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 14 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
STUDY STOPPING RULES: 
The study may be discontinued, or paused, for reasons that may include (but are not limited to): 
reasons of safety, lack of study drug availability, inability to enroll the study, or decision by a 
regulatory authority or the Sponsor (see Appendix D). 
In the event that a dosing cohort shows efficacy and it is not anticipated that additional dosing 
would show added efficacy, the sponsor may choose to stop and not complete the study.  
Further, in the instance of 2 or more treatment-related SAEs, 2 or more treatment related AEs 
Grade 3 or higher or 2 or more clinically significant treatment-related Grade 3 or higher 
laboratory abnormalities, the study will be paused pending an SSRC review of the safety events. 
The Sponsor will inform the applicable regulatory authority(ies) of any safety-related pause in 
the study.    
 In the case that the study is discontinued, the Sponsor will promptly inform the Investigators 
and applicable regulatory authority(ies) of the termination of the study and the reason(s) for the 
termination. The Investigators are responsible for promptly informing subjects that they must 
discontinue study drug. The Institutional Review Board (IRB)/Independent Ethics Committee 
(IEC) will also be informed promptly and provided the reason(s) for the termination, as specified 
by the applicable regulatory requirement(s). 
DATA SAFETY MONITORING BOARD: 
An independent data safety monitoring board (DSMB) will review cumulative unblinded safety 
data as outlined in the DSMB charter. 
STATISTICAL CONSIDERATIONS: 
Analysis Populations: 
The primary efficacy analysis will be performed in the modified ITT (MITT) analysis 
population. The MITT includes subjects who meet all of the following criteria: 
• Received at least 1 dose of study drug  
• Has at least 1 post-baseline plasma BK viral load result available 
Additional analyses will be performed in the Intent-To-Treat (ITT) analysis population 
(all subjects randomized). 
The safety population will include all subjects who received at least 1 dose of study drug.  
The PK population will include all subjects with at least 1 post-baseline PK sample available.   


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 15 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Efficacy Analyses 
In all efficacy analyses, the placebo subjects from the cohorts will be combined. Thus, the 
analysis models will include treatment group (four levels: placebo, low dose, medium dose, high 
dose) as a factor. Time-to-event endpoints will be analyzed using Cox proportional hazards 
regression models. Proportion endpoints will be analyzed using logistic regression models.  
Quantitative endpoints will be analyzed using one-way analysis of variance (ANOVA) models. 
In all analyses, pairwise contrasts comparing each of the three active groups to the combined 
placebo group will be tested. All efficacy and exploratory analyses will be conducted using 
two-sided tests at the alpha=0.05 level of significance, with no adjustment for multiplicity. 
Additional efficacy analyses will be conducted using the data from each cohort.  Quantitative 
endpoints will be analysed using the two-sample t test and proportion endpoints will be analysed 
using Fisher’s exact test. Due to the small sample sizes, time-to-event variables will be 
summarized descriptively. 
Safety Analyses 
All safety analyses will be performed on data from the Safety Analysis Population. Adverse 
events (AEs), vital signs, ECGs and clinical laboratory evaluations will be summarized by 
appropriate descriptive statistics.  
Pharmacokinetic Analysis 
MAU868 levels in serum will be determined by a validated ELISA-based method. A detailed 
description of the method used will be included in the PK bioanalytical data report. 
The anticipated Lower Limit of Quantification (LLOQ) is 50.0 ng/mL. Concentrations will be 
expressed in mass per volume units (e.g., ng/mL). Missing values or those concentrations below 
the LLOQ will be labeled as such in the data listings and reported as “zero” in data presentations 
and calculations. 
MAU868 serum concentration data will be listed by subject and visit/sampling time point. 
Descriptive summary statistics of trough levels will be provided by visit/sampling time point, 
including the frequency (n, %) of concentrations below the LLOQ and reported as zero. 
Summary statistics will include mean (arithmetic and geometric), SD, CV (arithmetic and 
geometric), median, minimum and maximum. Concentrations below LLOQ will be treated as 
zero in summary statistics.  
Summary statistics (e.g., mean, standard deviation) and individual subject listing of serum 
concentration measurements of MAU868 at the assigned time points will be provided as 
surrogates of systemic exposure. 
Interim Analyses 
Separate from the blinded safety review by the SSRC which will enable enrollment of subjects 
into Cohort 2, unblinded safety and tolerability data (adverse events, clinical laboratories, 
vitals/physical exams and ECGs), efficacy data (BK viral load in the plasma) and PK (MAU868 
plasma levels) will be reviewed by the SSRC once all 12 subjects in Cohort 1 have completed 
the treatment period. The treatment assignment in Cohort 1 will be unblinded; however, these 
data will not include associated subject or site identifiers. The objectives of this interim analysis 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 16 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
are to evaluate whether four doses MAU868 1350 mg IV administered every 28 days for a total 
of 4 doses demonstrate: 
• 
safety and tolerability signals compared to placebo 
• 
a decrease in BK viral load in plasma compared to placebo 
• 
predicted MAU868 plasma levels 
The conclusions from this first analysis will be used by the Sponsor to evaluate the safety and 
efficacy of MAU868 early-on in this first-in-patient study. Unless a significant safety issue 
related to administration of MAU868 has been identified, the conclusions will have no impact 
on Cohort 2 or the study’s design. 
Following completion of the 12-week treatment periods for Cohorts 1 and 2, cumulative 
unblinded data from both cohorts will be reviewed for safety and tolerability (adverse events, 
clinical laboratories, vitals/physical exams and ECGs), efficacy (BK viral load in the plasma) 
and PK (MAU868 plasma levels). The treatment assignments will be unblinded; however, these 
data will not include associated subject or site identifiers. The objectives of this second interim 
analysis are to evaluate whether four doses MAU868 1350 mg IV administered every 28 days 
or MAU868 6750 mg IV administered as a first dose followed by 3 more doses of MAU868 
1350 mg IV administered every 28 days demonstrate: 
• 
safety and tolerability signals compared to placebo 
• 
a decrease in BK viral load compared to placebo 
• 
predicted MAU868 plasma levels 
Based on the SSRC’s safety, efficacy and PK conclusions for Cohorts 1 and 2, the dosing 
regimen for Cohort 3 may be adjusted in dosage and/or duration; however, the dosage and 
duration for Cohort 3 will not exceed the dose already specified in the protocol. Cohort 3 will 
not be opened for screening and enrollment until this evaluation has been completed. 
Sample Size Determinations: 
This study will randomize approximately 36 subjects (12 per cohort) to MAU868 and placebo 
in a 2:1 ratio (24 MAU868 and 12 placebo; 8 MAU868 and 4 placebo per cohort).  This study 
is not powered to an efficacy endpoint.  The number of subjects chosen will provide data useful 
in determining proof of concept. 
SITES:  Approximately 20 sites 
SPONSOR: 
Amplyx Pharmaceuticals, Inc. 
12730 High Bluff Drive, Suite 160 
San Diego, CA 92130 
United States 
Telephone: +1-858-345-1755 
Fax: +1-858-345-1346 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 17 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
TABLE OF CONTENTS 
1 
INTRODUCTION AND BACKGROUND INFORMATION ..................................... 25 
1.1 
BKV Infection and Nephropathy .......................................................................... 25 
1.2 
MAU868 ............................................................................................................... 26 
1.3 
Non-clinical Data .................................................................................................. 26 
1.4 
Clinical Data ......................................................................................................... 27 
1.4.1 Human Safety and Tolerability Data ........................................................ 28 
1.4.2 Human Pharmacokinetic Data .................................................................. 28 
1.4.3 Human Pharmacodynamic Data ............................................................... 28 
1.5 
Study Rationale ..................................................................................................... 28 
1.6 
Rationale for Dose and Schedule Selection .......................................................... 28 
1.7 
Rationale for Choice of Comparator and Background Therapy ........................... 30 
1.8 
Assessment of Potential Risks and Benefits ......................................................... 30 
1.9 
Blood Sample Volumes ........................................................................................ 31 
2 
STUDY OBJECTIVES AND ENDPOINTS .................................................................. 31 
2.1 
Study Objectives ................................................................................................... 31 
2.2 
Safety Endpoints ................................................................................................... 31 
2.3 
Efficacy Endpoints ................................................................................................ 31 
2.4 
Exploratory ........................................................................................................... 32 
2.5 
Pharmacokinetic Endpoints .................................................................................. 32 
3 
STUDY DESCRIPTION ................................................................................................. 32 
3.1 
Summary of Study Design .................................................................................... 32 
3.2 
Selection and Withdrawal of Subjects .................................................................. 34 
3.2.1 Inclusion Criteria ...................................................................................... 34 
3.2.2 Exclusion Criteria ..................................................................................... 35 
3.3 
Discontinuation Rules ........................................................................................... 36 
3.3.1 Study Stopping Rules ................................................................................ 36 
3.3.2 Discontinuation from Study Drug ............................................................. 36 
3.3.3 Discontinuation from Study Participation ................................................ 37 
3.4 
Early Termination Visit and Withdrawal Procedures ........................................... 38 
4 
TREATMENTS ARMS ................................................................................................... 38 
4.1 
Treatment Groups ................................................................................................. 38 
4.2 
Randomization ...................................................................................................... 39 
4.3 
Treatment Arm Blinding ....................................................................................... 39 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 18 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
4.3.1 Breaking the Treatment Blind ................................................................... 39 
5 
DRUG SUPPLIES ............................................................................................................ 40 
5.1 
Formulation and Packaging .................................................................................. 40 
5.2 
Study Drug Preparation and Dispensing ............................................................... 40 
5.3 
Study Drug Administration ................................................................................... 41 
5.3.1 Dose Adjustments and Interruption of Study Drug .................................. 41 
5.3.2 Study Drug Compliance ............................................................................ 42 
5.4 
Storage and Accountability ................................................................................... 42 
6 
PRIOR AND CONCOMITANT MEDICATIONS AND/OR PROCEDURES ......... 42 
6.1 
Excluded Medications and/or Procedures ............................................................. 42 
6.2 
Rescue Medication ................................................................................................ 43 
6.3 
Documentation of Prior and Concomitant Medication Use .................................. 43 
6.4 
Infusion Reactions ................................................................................................ 43 
7 
STUDY PROCEDURES ................................................................................................. 44 
7.1 
Informed Consent.................................................................................................. 44 
7.2 
Screening Period ................................................................................................... 44 
7.3 
Treatment Period (Day 1 to Day 84) ..................................................................... 45 
7.3.1 Day 1 (Baseline; Study Drug Infusion 1) ................................................. 46 
7.3.2 Day 7 ......................................................................................................... 47 
7.3.3 Day 14 ....................................................................................................... 48 
7.3.4 Day 21 ....................................................................................................... 48 
7.3.5 Day 28 (Study Drug Infusion 2) ............................................................... 48 
7.3.6 Day 35 ....................................................................................................... 49 
7.3.7 Day 42 ....................................................................................................... 50 
7.3.8 Day 56 (Study Drug Infusion 3) ............................................................... 50 
7.3.9 Day 70 ....................................................................................................... 51 
7.3.10 Day 84 (Study Drug Infusion 4) ............................................................... 51 
7.4 
Follow-up Period (Day 112 to Day 252) .............................................................. 53 
7.4.1 Day 112 (Follow Up 1) ............................................................................. 53 
7.4.2 Day 140 (Follow Up 2) ............................................................................. 53 
7.4.3 Day 252 (Last Follow Up) ........................................................................ 53 
7.4.4 Early Termination Visits ........................................................................... 54 
8 
STUDY PROCEDURES AND ASSESSMENTS .......................................................... 54 
8.1 
Schedule of Events ................................................................................................ 54 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 19 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
8.2 
Subject Demographics/Other Baseline Characteristics ........................................ 55 
8.3 
Efficacy / Pharmacodynamics ............................................................................... 55 
8.4 
Clinical Outcome Assessments (COAs) ............................................................... 55 
8.5 
Safety .................................................................................................................... 56 
8.5.1 Pregnancy .................................................................................................. 56 
8.5.2 Physical Examination................................................................................ 56 
8.5.3 Vital Signs ................................................................................................. 56 
8.5.4 Laboratory Evaluations ............................................................................. 56 
8.5.5 Electrocardiogram ..................................................................................... 57 
8.5.6 Pharmacokinetics ...................................................................................... 57 
8.5.7 BKV by PCR Sample Collection .............................................................. 57 
8.5.8 Other Assessments: Viral Resistance and Immunogenicity ..................... 57 
8.6 
Other Samples ....................................................................................................... 58 
8.6.1 Use of Residual Biological Samples ......................................................... 58 
9 
SAFETY ASSESSMENTS .............................................................................................. 58 
9.1 
Adverse Events ..................................................................................................... 58 
9.1.1 Adverse (Drug) Reaction .......................................................................... 59 
9.1.2 Unexpected Adverse Drug Reaction ......................................................... 60 
9.1.3 Assessment of Adverse Events by the Investigator .................................. 60 
9.1.4 AEs of Special Interest.............................................................................. 61 
9.2 
Serious Adverse Events ........................................................................................ 61 
9.3 
Serious Adverse Event Reporting − Procedures for Investigators ........................ 62 
9.3.1 Initial Reports ............................................................................................ 62 
9.3.2 Follow-up Reports .................................................................................... 63 
9.4 
Pregnancy Reporting ............................................................................................. 63 
9.5 
Expedited Reporting ............................................................................................. 64 
9.6 
Special Situation Reports ...................................................................................... 64 
9.7 
Data Safety Monitoring Board .............................................................................. 65 
9.8 
Evaluations for Safety ........................................................................................... 65 
10 
STATISTICS .................................................................................................................... 65 
10.1 
General Design and Analysis ................................................................................ 65 
10.2 
Determination of Sample Size .............................................................................. 66 
10.3 
Analysis Populations ............................................................................................. 66 
10.4 
Safety Analysis ..................................................................................................... 66 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 20 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
10.5 
Efficacy Analysis .................................................................................................. 66 
10.5.1 Efficacy Endpoints .................................................................................... 67 
10.6 
Disposition, Demographics and Baseline Characteristics .................................... 68 
10.7 
Concomitant Medications ..................................................................................... 68 
10.8 
Safety .................................................................................................................... 68 
10.8.1 Vital Signs ................................................................................................. 69 
10.8.2 ECG Evaluations ....................................................................................... 69 
10.8.3 Clinical Laboratory Evaluations ............................................................... 69 
10.8.4 Adverse Events ......................................................................................... 69 
10.8.5 Pharmacokinetics ...................................................................................... 69 
10.8.6 Interim Analysis ........................................................................................ 70 
11 
DATA MANAGEMENT AND RECORD KEEPING ................................................. 71 
11.1 
Data Management ................................................................................................. 71 
11.1.1 Data Handling ........................................................................................... 71 
11.1.2 Computer Systems .................................................................................... 71 
11.1.3 Data Entry ................................................................................................. 71 
11.1.4 Medical Information Coding ..................................................................... 71 
11.1.5 Data Validation ......................................................................................... 71 
11.2 
Record Keeping .................................................................................................... 71 
12 
INVESTIGATOR REQUIREMENTS AND QUALITY CONTROL ........................ 72 
12.1 
Ethical Conduct of the Study ................................................................................ 72 
12.2 
Institutional Review Board/Independent Ethics Committee ................................. 72 
12.3 
Informed Consent.................................................................................................. 72 
12.4 
Subject Card .......................................................................................................... 73 
12.5 
Study Monitoring Requirements ........................................................................... 73 
12.6 
Disclosure of Data ................................................................................................. 73 
12.7 
Retention of Records ............................................................................................. 73 
12.8 
Publication Policy ................................................................................................. 74 
12.9 
Financial Disclosure .............................................................................................. 74 
12.10 Insurance and Indemnity ....................................................................................... 74 
12.11 Legal Aspects ........................................................................................................ 74 
13 
STUDY ADMINISTRATIVE INFORMATION .......................................................... 75 
13.1 
Protocol Amendments ........................................................................................... 75 
13.2 
Address List .......................................................................................................... 75 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 21 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
13.2.1 Sponsor ..................................................................................................... 75 
13.2.2 Contract Research Organization ............................................................... 75 
13.2.3 Clinical Safety ........................................................................................... 75 
14 
REFERENCES ................................................................................................................. 76 
 
LIST OF TABLES 
Table 1. 
MAU868 In Vitro Neutralization Activity .............................................................10 
Table 2. 
MAU868 Binding Affinity and Neutralizing Activity...........................................26 
Table 3. 
MAU868 In Vitro Neutralization Activity .............................................................29 
 
LIST OF APPENDICES 
Appendix A: Schedule of Events .................................................................................................78 
Appendix B: Clinical Safety Laboratory Analytes ......................................................................81 
Appendix C: PK Sample Schedule ..............................................................................................82 
Appendix D: CTCAE 5 ...............................................................................................................83 
 
 
 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 22 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
LIST OF ABBREVIATIONS AND DEFINITION OF TERMS 
Abbreviation 
Definition 
AE 
adverse event 
ADA 
ALP 
antidrug antibody 
alkaline phosphatase 
ALT 
alanine aminotransferase 
ANOVA 
analyzed using one-way analysis of variance  
AST 
BKV 
aspartate aminotransferase 
BK virus 
BUN 
blood urea nitrogen 
CFR 
U.S. Code of Federal Regulation 
CK 
creatinine kinase 
CO2 
carbon dioxide 
CRF 
case report/record form (paper or electronic) 
CRO 
contract research organization 
CTA 
clinical trial authorization 
CTC 
common toxicity criteria 
CTCAE 
Common Terminology Criteria for Adverse Events 
CV 
coefficient of variation 
D5W 
5% dextrose in water 
DNA 
Deoxyribonucleic acid 
DSMB 
Data Safety Monitoring Board 
EC50 
effective concentration 
ECG 
electrocardiogram 
EDC 
electronic data capture 
eGFR 
estimated glomerular filtration rate 
ELISA 
enzyme-linked immunosorbent assay 
FDA 
Food and Drug Administration 
GCP 
Good Clinical Practice 
GGT 
gamma-glutamyl transferase 
H2 Blocker 
histamine receptor antagonist 
HBsAg 
hepatitis B surface antigen 
HCT 
hematopoietic cell transplant  
Hr 
Hour 
IV 
Intravenous 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 23 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Abbreviation 
Definition 
IB 
Investigator’s Brochure 
ICF 
Informed Consent Form 
ICH 
International Conference on Harmonization of Technical 
Requirements for Registration of Pharmaceuticals for Human Use 
I/E 
Inclusion and Exclusion 
INR 
international normalized ratio 
IRB 
Institutional Review Board 
ITT 
intent-to-treat 
IVIG 
intravenous immunoglobulin 
IWRS 
Interactive Web Response System 
KDPI 
Kidney Donor Profile Index 
LDH 
lactate dehydrogenase 
LFT 
liver function test 
LLN 
lower limit of normal 
LLOQ 
lower limit of quantification 
MedDRA 
medical dictionary for regulatory activities 
Mg 
milligram(s) 
mITT 
modified intent-to-treat 
mL 
milliliter(s) 
mTOR 
mammalian target of rapamycin 
NOAEL 
No observed adverse effect level 
PBPK 
physiologically based pharmacokinetics 
PD 
pharmacodynamic(s) 
PK 
pharmacokinetic(s) 
PT 
prothrombin time 
RAV 
resistance-associated variance 
RBC 
red blood cell(s) 
SC 
Subcutaneous 
SAE 
SAP 
serious adverse event 
statistical analysis plan 
sCR 
serum creatinine 
SD 
standard deviation 
SGOT 
serum glutamic oxaloacetic transaminase 
SGPT 
serum glutamic pyruvic transaminase 
SSRC 
Sponsor Study Review Committee 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 24 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Abbreviation 
Definition 
SUSAR 
suspected unexpected serious adverse reaction 
TEAE 
treatment emergent adverse event 
ULN 
upper limit of normal 
ULQ 
upper limit of quantification 
VP 
viral protein 
WBC 
white blood cell(s) 
WHO 
World Health Organization 
 
 
 


Amplyx Pharmaceuticals, Inc. 
Clinical Study Protocol MAU868-201 
Page 25 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
1 
INTRODUCTION AND BACKGROUND INFORMATION 
1.1 
BKV Infection and Nephropathy 
The human polyomavirus BK (BK virus or BKV) is a DNA virus that infects 80-90% of the world's 
population (Kean 2009; Boothpur and Brennan 2010; Egli et al 2009). It is generally acquired 
during childhood and, subsequently, establishes a lifelong infection in renal tubular and 
uroepithelial cells (Antonsson 2010).  Although the primary and persistent infections are generally 
clinically silent, BKV reactivation may occur in the setting of organ transplantation when innate 
immune T cell immunity is compromised by immunosuppressive drugs (Ambalathingal 2017). 
In particular, recipients of kidney transplant may develop nephropathy and recipients of 
hematopoietic stem cell transplants may develop hemorrhagic cystitis. 
BKV replication in immunosuppressed kidney transplant recipients follows a well-established 
clinical course from viruria (~35% of all kidney transplant recipients) to viremia (~11%) to 
nephropathy (3-5%; Sawinski and Goral 2015; Hirsch et al 2013; Dharnidharka et al 2011). 
The median onset of detectable viruria is 5 weeks post-transplantation (range 2 to 41 weeks), and 
the median onset of viremia is 10 weeks (range 5 to 51 weeks; Babel et al 2009). The median onset 
of BKV nephropathy is 42 weeks post-transplantation (range 7 to 113 weeks; 
Hirsch and Steiger 2003).  
Patients who develop BK viremia irrespective of whether biopsy confirms BKV nephropathy have 
been reported to have significantly lower allograft survival at 10 years (24.8% vs 85.6%, P <0.001; 
Moura et al 2017). By contrast, patients without viruria do not develop viremia; likewise, patients 
without viremia do not develop nephropathy (Babel et al 2009).  
The main risk factor for BKV replication and the development of disease is the level of 
immunosuppression, including the type of induction therapy used prior to transplantation. 
A number of other risk factors including recipient age, male sex, allograft rejection, degree of 
human leukocyte antigen mismatching, length of cold ischemia time, and recipient and donor BKV 
serostatus 
(e.g., 
donor 
positive-recipient 
negative) 
have 
also 
been 
implicated 
(Sawinski and Goral 2015). No single risk factor is reliably predictive. 
Current treatment guidelines recommend reduction of immunosuppression to control the infection, 
typically when BK viremia is >104 copies/mL (KDIGO Clinical Practice Guideline 2009). Clearance 
of the viremia takes months and often requires multiple stepwise reductions in the 
immunosuppression. Subjects for whom immunosuppression is reduced have an increased risk of 
acute allograft rejection (Bohl and Brennan 2007; Sood et al 2012).  
There are no specific or effective anti-BKV therapies. These data underscore the need for more 
effective means to control or prevent BKV reactivation. MAU868 has the potential to be a safe 
and well-tolerated therapy that can eliminate a threat to the survival of the renal allograft and 
greatly simplify the post-transplantation care of kidney transplant recipients. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 26 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
1.2 
MAU868 
BKV encodes only seven proteins and lacks the traditional targets for antiviral drugs 
(e.g., protease, polymerase). The non-enveloped icosahedral virion of BKV is composed of three 
different viral proteins (VP1, VP2, VP3), but only VP1 (the major viral capsid protein) is exposed 
on the virion surface.  
MAU868 is a human monoclonal antibody (IgG1) that binds the viral capsid protein, VP1, that is 
responsible for binding to the surface of host cells (i.e., the first step in the infection of new cells; 
Tsai and Qian 2010). MAU868 neutralizes all four BKV genotypes at sub-nanomolar 
concentrations in vitro. It recognizes a conformational epitope on VP1 that is highly conserved, 
resulting in a high barrier to resistance in vitro. It is being developed for the prevention of clinically 
significant BKV infection in immunosuppressed populations, notably solid organ and HCT 
recipients. 
The most relevant data for the present study are summarized in the sections below. For detailed 
information, please refer to the MAU868 Investigator's Brochure. 
1.3 
Non-clinical Data 
The non-clinical evaluation of MAU868, a human monoclonal antibody recognizing a non-human 
antigen, was performed according to the ICH S6(R1) guidelines. Details regarding all non-clinical 
studies conducted to date with MAU868 are provided in the Investigator’s Brochure. 
No genotoxicity or reproductive toxicology studies were conducted because MAU868 1) is a fully 
human monoclonal IgG1 antibody comprising native non-modified amino acids, 2) does not 
contain any chemical linkers or chelators, 3) is highly specific for an epitope unique to human 
polyomaviruses BK and JC, and 4) there are no pharmacologically relevant animal models. 
Because MAU868 is a protein comprised of native amino acids and because if its pharmacological 
mechanism of action it is considered to be non-genotoxic.  
BKV VP1 is the major viral capsid protein and the only protein exposed on the virion surface. 
Binding of VP1 to ganglioside receptors on the host cell surface initiates internalization of the 
virus (Tsai and Qian 2010). Binding of MAU868 to VP1 blocks these interactions and prevents 
infection of new cells. 
MAU868 has picomolar affinity for BKV VP1 and sub-nanomolar neutralization potency against 
all four BKV genotypes. 
Table 2. 
MAU868 Binding Affinity and Neutralizing Activity 
GENOTYPE 
Kd (pM) 
EC50 (nM) 
EC50 (μg/mL) 
Genotype I 
5.8 ± 1.8 
0.062 ± 0.068 
0.009 ± 0.010 
Genotype II 
2.8 ± 0.6 
0.278 ± 0.175 
0.040 ± 0.025 
Genotype III 
8.4 ± 3.7 
0.645 ± 0.397 
0.093 ± 0.057 
Genotype IV 
4.1 ± 1.3 
0.143 ± 0.135 
0.021 ± 0.020 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 27 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
MAU868 binds to a conformation-dependent epitope on VP1. The key contact residues (Y169, 
R170, and K172), all located within the VP1 EF loop, are 100% conserved among reference 
isolates and 156 (genotype I) and 66 (genotype IV) GenBank sequences analyzed. Mutations at 
these locations confer either a loss of viral fitness (i.e., inability to replicate) or no change in 
susceptibility to MAU868. 
Resistance selection experiments in renal proximal tubule epithelial cells infected with BKV 
genotype I and genotype IV, which comprise 95% of global seroprevalence, failed to generate 
virus with genotypic resistance to MAU868 after six serial passages (>84 days in cell culture). 
Mutant BK viruses harboring a series of VP1 polymorphisms at other locations in VP1 that were 
identified through analyses of available sequences in GenBank also confer no reduced 
susceptibility to MAU868 in vitro. The available non-clinical data demonstrate a high barrier to 
the development of resistance to MAU868 in vitro. 
Repeated dose-toxicity studies were conducted in rats. Once weekly IV or SC administration for 
4-weeks (5 doses total) of MAU868 up to 750 mg/kg IV and 150 mg/kg SC to rats was well 
tolerated. The NOAEL for IV administration was 750 mg/kg/week; the NOAEL for SC 
administration was 150 mg/kg/week. 
1.4 
Clinical Data 
To date, a total of 27 subjects (26 healthy volunteers and 1 subject with BKV nephropathy) have 
received MAU868.  
A first-in-human, randomized, blinded, placebo-controlled, single ascending dose study to assess 
the safety, tolerability and pharmacokinetics of MAU868 following IV or SC administration to 
healthy adult subjects was performed. A total of 33 subjects participated in the study; 26 subjects 
received MAU868 and 7 received placebo. MAU868 doses of 1, 3, 10, 30 and 100 mg/kg 
(4 subjects received each dose) were administered IV as 1-hr infusions. Six subjects received 
MAU868 3 mg/kg as a bolus SC injection. Administration of study drug was followed by 
assessments for safety, pharmacokinetics, and testing for anti-drug antibodies up to 105 days 
post-dose. Ex vivo assessments of neutralizing serostatus were also performed prior to and 28 days 
after administration of MAU868 or placebo. No deaths or SAEs were reported, and there were no 
AEs that led to the discontinuation of the infusion or the study. 
One adult female kidney transplant recipient was treated with MAU868 1350 mg IV for refractory 
BKV nephropathy (i.e., preceding persistent BK viremia for ~6 months with biopsy confirmation) 
as part of an individual patient managed access program requested and initiated by the treating 
physician. She received a total of 11 doses over 7 months, most of which were administered every 
two weeks. The treating physician elected to pretreat the patient with steroids, antihistamines, and 
acetaminophen for each infusion. MAU868 was safe and well tolerated by the patient with no 
adverse events considered related to MAU868 or the infusion. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 28 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
1.4.1 
Human Safety and Tolerability Data 
Single doses up to 100 mg/kg MAU868 were safe and well tolerated. Eleven (11) of 26 subjects 
exposed to MAU868 (42%) and one of seven subjects exposed to placebo (14%) reported adverse 
events. Events occurring in more than one subject included nasal congestion (3), oropharyngeal 
pain (3), and injection site hemorrhage (2) - all in subjects who received MAU868. 
1.4.2 
Human Pharmacokinetic Data 
The time course of exposure to MAU868 following IV administration was consistent with that of 
a typical monoclonal IgG1 and therefore dose-proportional and predictable. The observed C28d 
("trough") concentrations of MAU868 (mean ± SD) were 4.9 ± 1.4, 19.4 ± 5.0, 59.9 ± 11.0, 
171.3 ± 12.7 and 509.8 ± 145.9 ug/mL following administration of 1, 3, 10, 30 and 100 mg/kg 
doses, respectively. Consistent with predictions of population PK, these observed systemic 
exposures on Day 28 for all doses of MAU868 were 50- to 5000-fold higher than the highest EC50 
of 0.093 ug/mL in vitro (versus BKV). 
1.4.3 
Human Pharmacodynamic Data 
Administration of MAU868 increased the BKV neutralizing potency of the serum from 
participating subjects in a manner that was proportional to the dose. No increase was observed for 
the subjects who received placebo. 
1.5 
Study Rationale 
The purpose of this study is to determine whether MAU868 warrants further clinical development 
for the treatment of renal allograft threatening BKV infection in kidney transplant recipients. 
1.6 
Rationale for Dose and Schedule Selection 
In Cohort 1, MAU868 will be administered as an IV infusion of 1350 mg in 250 mL D5W over a 
period at least 60 minutes. In Cohort 2, MAU868 will be administered as an IV infusion of 
6750 mg in 250 D5W over a period of at least 180 minutes on Study Day 1 and at 1350 mg in 
250 mL D5W over a period of at least 60 minutes for subsequent doses. In Cohort 3, MAU868 
will be administered as an IV infusion of 6750 mg in 250 mL D5W over a period of at least 
180 minutes. 
There are no rigorous clinical studies that identify target exposures required for BKV antiviral 
efficacy and no robust animal model of BKV infection or disease; therefore, the most robust 
estimate of the clinical dose considers the following parameters 1) MAU868 BKV neutralizing 
activity in vitro, 2) simulation of serum concentrations based on a model created from Phase 1 data 
in healthy volunteers, and 3) published literature on the extravascular distribution of 
immunoglobulin (renal 13.7%). For clinical efficacy, our therapeutic approach is to maintain the 
Ctrough in target tissues ≥10-fold the EC50 of the least susceptible BKV genotype (genotype III).  
A review of the information is as follows: 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 29 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
A high-content imaging-based in vitro neutralization assay in RPTE cells was used to characterize 
the antiviral activity of MAU868 was determined against  representative isolates from the four 
major genotypes of BKV (genotypes I, II, III, and IV, respectively); genotypes I and IV account 
for approximately 95% of the global seroprevalence, while genotypes II and III account for the 
remaining 5% (Zheng et al 2007; Zhong et al 2009).  
Table 3. 
MAU868 In Vitro Neutralization Activity 
Genotype 
EC50 (µg/mL) 
EC90 (µg/mL) 
BKV Genotype I 
0.009 + 0.010 
0.102 + 0.028 
BKV Genotype II 
0.040 + 0.025 
4.160 + 6.076 
BKV Genotype III 
0.093 + 0.057 
2.662 + 2.805 
BKV Genotype IV 
0.020 + 0.020 
0.465 + 0.318 
 
A first-in-human study explored single ascending doses of MAU868 (1, 3, 10, 30, and 100 mg/kg 
IV) and the serum concentration data was used to develop a PK model.  The model was then used 
to estimate Ctrough concentrations for a series of 3 treatment regimens. To have a treatment effect 
on BK viremia, MAU868 would need to curtail BKV replication in the target tissue (i.e., kidney). 
Based on an in vivo radiolabeled study in animals and PBPK modeling estimates, the antibody 
biodistribution coefficient in kidney is 13.7% (Shah and Betts 2013). The estimated trough levels 
for each treatment arm were compared directly to in vitro-determined antiviral activity (EC50 and 
EC90) for each BKV genotype and corrected for the assumed antibody distributions in kidney.  
These data show that the planned dose regimens of MAU868 for each treatment arm provides high 
virus neutralizing tissue levels with kidney exposures at Ctrough ≥10-fold the EC50 of the least 
susceptible BKV genotype (genotype III). Specifically, kidney exposures at Ctrough range from 
253 to 2618-fold (Cohort 1), 365 to 3775-fold (Cohort 2), and 1264 to 13,061-fold (Cohort 3) 
above the EC50 at the end of treatment (12 weeks, range = least to most susceptible BKV genotype). 
Using EC90 determinations, kidney exposures at Ctrough range from 6 to 231-fold (Cohort 1), 
8 to 333-fold (Cohort 2), and 28 to 1152-fold (Cohort 3) above the EC90 at the end of treatment.  
A 12-week treatment period was selected to ensure sustained levels of MAU868 to inhibit virus 
replication and promote virus clearance. The subsequent 24-week follow-up period will allow 
evaluation of the durability of effect and additional safety and PK observations. 
From a safety perspective, the highest administered dose of MAU868 expected in this study 
(6750 mg = 100 mg/kg for a 67.5 kg patient) was also the highest administered dose 
(MAU868 100 mg/kg) investigated in the first-in-human study and below the no observed adverse 
effect level (NOAEL) exposure (750 mg/kg) in the 4-week repeat-dose toxicity study in rats. 
Specifically, human steady-state AUC exposure at the proposed dose of MAU868 1350 mg 
(20 mg/kg for a 67.5 kg patient) once monthly (206231 µg·hr/mL) provides safety margins of 6.9X 
and 5.0X, respectively, compared to the NOAEL (750 mg/kg; 1420000 µg·hr/mL) in the 4-week 
rat study and to the AUC at the highest human dose (100 mg/kg; 1031155 µg·hr/mL) tested to 
date. Likewise, human steady-state AUC exposure at the proposed dose of MAU868 6750 mg 
once monthly (1031155 µg·hr/mL) provides a safety margin of 1.4X compared to the NOAEL 
(750 mg/kg; 1420000 µg·hr/mL) in the 4-week rat study. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 30 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
1.7 
Rationale for Choice of Comparator and Background Therapy 
Placebo is the comparator because there are no therapies available for treating BKV reactivation 
following kidney transplantation. 
Induction and maintenance immunosuppression is to be determined at the discretion of the 
attending physician(s). 
1.8 
Assessment of Potential Risks and Benefits 
MAU868 may prevent progression of BKV infection to irreversible renal allograft injury. Since 
current management of BKV reactivation involves reduction of immunosuppressive regimens 
(with accompanying increased risk for rejection), if MAU868 is effective in preventing BKV 
nephropathy in the post-kidney transplant setting, post-transplant care could be simplified with 
improved clinical outcomes.   
To date, no MAU868-specific risks have been identified. The overall adverse event profile from 
the first-in human study was quite satisfactory. Based on clinical data from pooled 
immunoglobulin preparations and a monoclonal antibody active against respiratory syncytial 
virus, potential risks of MAU868 include infusion-related reactions, including allergic 
(e.g., hypersensitivity, anaphylaxis) and non-allergic (e.g., cytokine release syndrome) reactions, 
renal dysfunction, and thromboembolic events.  
The excipients and their respective concentrations in the formulation of MAU868 have been safely 
used in humans.  However, since this is the first study in which renal transplant recipients 
specifically will be exposed, there may be unknown risks associated with either the excipients or 
the dosing of MAU868 that may be unanticipated and serious.  
Risks associated with participation in a clinical trial include risks associated with venipuncture and 
placement of intravenous cannulas, including infection, erythema, and pain or tenderness at the 
site. The safety of MAU868 during pregnancy has not been investigated and the potential risks of 
MAU868 during pregnancy are unknown. Women of child-bearing potential who may participate 
will be required to follow contraceptive measures to avoid becoming pregnant during the study. 
Potential risks to the study participants will be minimized by adherence to the eligibility criteria 
and protocol provisions, diligent clinical monitoring, and appropriate management of participating 
subjects. In addition, the doses MAU868 used in this study are well below doses of 
immunoglobulin typically associated with renal or thromboembolic risk. 
There are no specific or effective anti-BKV therapies. The risks of BKV reactivation and 
associated nephropathy in the post-renal transplant setting are potentially catastrophic. Thus, there 
is a critical unmet need for effective means to treat the consequences of BKV reactivation in the 
post-transplant setting. MAU868, a BKV-specific therapy, may be successful in treating clinically 
significant BKV infection in those at risk and, thus, has the potential to greatly simplify post-
transplantation care and eliminate a threat to the survival of the renal allograft. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 31 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
1.9 
Blood Sample Volumes 
The timing of blood sample collections during the study is outlined in Appendix A (Schedule of 
Events). 
A summary blood log is provided in the Laboratory Manual. Instructions for all sample collection, 
processing, storage and shipment information are made available in the central laboratory manual. 
All lab samples will be shipped to a Central Laboratory for dispatch, and as appropriate, to 
specialty laboratories. 
See Section 8.6.1 regarding the potential use of residual samples. 
2 
STUDY OBJECTIVES AND ENDPOINTS 
2.1 
Study Objectives 
The primary objective of this study is: 
• To assess the safety and tolerability of MAU868 
Secondary objectives of this study are: 
• To assess the impact of MAU868 on BKV related outcomes including viremia, BKV 
nephropathy, graft function and rejection among renal transplant recipients with BK viremia 
• To assess the pharmacokinetics of MAU868 
2.2 
Safety Endpoints 
Safety endpoints include physical examinations, vital signs, clinical safety laboratory parameters, 
12-lead ECGs, and adverse events. 
2.3 
Efficacy Endpoints 
• Time (weeks) to decrease of BKV plasma viral load by 1 log 
• Time (weeks) to first decrease of BKV plasma viral load to <LLOQ 
• Proportion of subjects with >1 log decrease of BKV plasma viral load by 1 week, 2 weeks, 
4 weeks, 8 weeks, 12 weeks, and 36 weeks. 
• Proportion of subjects with decrease BKV plasma viral load to <LLOQ by 1 week, 2 weeks, 
4 weeks, 8 weeks, 12 weeks, and 36 weeks  
• Rate of decrease in BKV plasma viral load over time by 1 week, 2 weeks, 4 weeks, 8 weeks, 
12 weeks, and 36 weeks  
• Change in eGFR from baseline to week 12 and from baseline to week 36 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 32 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
• Proportion of subjects with BKV nephropathy 
• Proportion of subjects with graft failure during the study 
• Proportion of subjects with acute rejection during the study 
• Mortality rate during the study 
2.4 
Exploratory 
• Presence of anti-drug antibodies (ADA) 
• Presence of genotypic resistance  
• Viral kinetics of BKV in plasma and urine 
2.5 
Pharmacokinetic Endpoints 
• MAU868 serum concentrations  
3 
STUDY DESCRIPTION 
3.1 
Summary of Study Design 
This is a randomized, placebo-controlled, blinded, proof-of-concept study in kidney transplant 
recipients. Up to 36 subjects with BK viremia will participate in 1 of 3 sequential cohorts.  Each 
cohort will randomize approximately 12 subjects (8 MAU868 and 4 placebo). The study will 
consist of a Screening period (pre-treatment) of up to 10 days, a treatment period of 12 weeks and 
a follow-up period of 24 weeks.  
Protocol specific procedures should not be performed until the subject has consented to 
participation in the study.  However, assessments and procedures performed as part of standard of 
care prior to informed consent, including determination of BK viral load in plasma may be used to 
qualify a subject for the study.  Once qualifying BK viremia has been confirmed, subjects should 
be randomized as soon as possible and no more than 10 days after the sample documenting the 
viremia was collected.   
MAU868 or placebo will be administered approximately every 28 days (every 4 weeks) for 
12 weeks (4 doses total).  Urine and blood will be monitored for BKV DNA by PCR weekly for 
the first 6 weeks after initiation of treatment. For the remainder of the treatment period, urine and 
blood must be collected for BKV DNA by PCR at least every other week. PK, viral resistance and 
anti-drug antibodies will also be monitored.  However, the Investigator may also request testing 
more frequently (i.e., weekly) than mandated by the protocol after the first 4 weeks of treatment 
when clinically indicated.  During the study, BKV DNA by PCR will be tested at the central 
laboratory.  Subjects should continue study drug until the last scheduled dose, regardless of 
changes in plasma BK viral load, use of rescue therapy and/or need for change in 
immunosuppressive regimen for any reason.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 33 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
During the 24-week follow up period, 3 follow up visits will be scheduled at 4, 8 and 24-weeks 
post-treatment.   At each visit, urine and blood samples for BKV DNA and samples for PK will be 
collected.  Investigators may collect samples for BKV DNA more often as clinically indicated. 
During the follow-up period, BKV DNA by PCR will be tested at the central laboratory.   
Routine post-transplantation care is to be guided by the Investigator discretion and site standard of 
care. This includes decisions to change the immunosuppressive regimen for a subject for any 
reason except for changes in immunosuppression in response to BK viremia. In order to treat BK 
viremia, prior to randomization, (ie, prior to screening, during the screening period and at the 
Baseline Visit) Investigators are permitted to decrease or alter immunosuppressive therapy per 
their discretion and/or per standard of care at their site.   However, in the first 4 weeks after 
randomization, Investigators should refrain from additional changes in immunosuppressive 
regimen in response to BKV unless the viral load has increased by >1 log and the Investigator 
determines that a change is in the best interest of the subject. Use of other antiviral agents including 
cidofovir and leflunomide as well as IVIG are not permitted during the first 4 weeks of therapy 
and are strongly discouraged thereafter.  Use of fluoroquinolones for reasons other than treatment 
of BKV is permitted.  
Between screening and the last visit, subjects will attend a total of 14 visits.  
A schematic representing the study’s design is included below: 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 34 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Progression from Cohort 1 to Cohort 2  
Approximately 12 weeks after the 9th subject in Cohort 1 has been randomized, blinded safety data 
will be reviewed by the SSRC. Members of this committee will include a Sponsor medical 
representative, the Medical Monitor and the study’s Principal Investigator.  Cohort 2 will be 
opened for screening once the following criteria have been met: 
1. All 12 subjects from Cohort 1 have been randomized, 
2. No significant safety issues related to the administration of MAU868 have been identified by 
the SSRC based the blinded safety review described above as well as an assessment of any 
new SAEs reported after the SSRC review and before randomization of the 12th subject in 
Cohort 1.  
3. No significant safety issues related to the administration of MAU868 have been identified by 
the independent DSMB.  
The Chair of the DSMB will be notified of the SSRC’s decision to open Cohort 2. 
Accordingly, some subjects enrolled in Cohort 1 will continue participation in the study through 
the 24-week follow-up period while new subjects are screened and enrolled into Cohort 2.  
Progression from Cohort 2 to Cohort 3 
Cohort 3 will not be opened for screening and enrollment until an evaluation of unblinded safety, 
efficacy and pharmacokinetics findings from both Cohorts 1 and 2 through the 12-week treatment 
period has been completed by the Sponsor Study Review Committee SSRC. 
3.2 
Selection and Withdrawal of Subjects 
This study will enroll male and female subjects, aged 18 years and above, who meet study entry 
criteria for BK viremia AND have received a kidney transplant within the prior year.   
Subjects with BK viremia will be randomized to receive either MAU868 or placebo administered 
approximately every 28 days (every 4 weeks) for 12 weeks (4 doses total).   
3.2.1 
Inclusion Criteria 
Subjects must meet all of the following criteria to be eligible for study entry: 
1. Be a male or female 18 years of age or older.  
2. Recipient of a kidney (or kidney-pancreas) transplant within the year prior to enrollment.  
3. Documented BK viremia based on local or central laboratory testing within 10 days prior to 
randomization of either 
a) 
104 copies/mL OR 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 35 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
b) 
a detectable BK viral load in 2 consecutive plasma samples (collected between 1 and 
3 weeks apart) where the most recent sample demonstrates a BK viral load of 103 / mL. 
(Note: only the second, most recent sample must be collected within 10 days prior to 
randomization) 
4. Have a functioning graft that is producing urine. 
5. Females of childbearing potential (i.e., not postmenopausal or surgically sterilized) with male 
partners, and males with female partner(s) of childbearing potential, must agree to use 2 forms 
of highly effective contraception, 1 of which must be a barrier method, throughout the duration 
of the study and for 90 days following the last study drug administration. Acceptable barrier 
forms of contraception are condom and diaphragm. Acceptable non-barrier forms of 
contraception for this study are oral birth control pill, depot, patch, implants or injectable, 
abstinence, intrauterine device, and/or spermicide. 
6. Females of childbearing potential must have a negative urine or serum pregnancy test result 
within 96 hours prior to Baseline (i.e. predose on Study Day 1).  
7. Be willing to participate in the study, to give written informed consent and to comply with the 
study restrictions. 
3.2.2 
Exclusion Criteria 
Subjects who meet any of the following criteria will not be eligible for entry into the study: 
1. A BK plasma viral load which has exceeded 103 copies/mL for >4 months. 
2. A BK plasma viral load of >107 copies/mL. 
3. Are receiving, at the time of informed consent, mTOR inhibitors. 
4. Kidney transplant recipients who are anticipated to require Intravenous Immune Globulin 
(IVIG) treatment during the study period or who have received IVIG in the previous 9 months. 
5. Kidney transplant recipients who, in the opinion of the Investigator, are likely to require 
antibody-depletion. Antibody-depleting therapies include but are not necessarily limited to 
hemodialysis, plasmapheresis and immunoadsorption. 
6. Treatment within the previous month with the following medications: cidofovir, leflunomide.  
7. History of hypersensitivity or intolerance to intravenous or subcutaneous administration of 
biologic medications or to any of the excipients included in the formulation of MAU868. 
8. Platelet count <50,000/mm3 at the time of informed consent, as determined by local laboratory.  
9. History of splenectomy or asplenia.  
10. Are lactating and/or pregnant. 
11. Use of other investigational drugs at the time of enrollment, or within 5 half-lives of 
enrollment, or until the expected PD effect has returned to baseline, whichever is longer; or 
longer than 5 half-lives if required by local regulations. 
12. Prior exposure to MAU868. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 36 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
13. Any other condition or laboratory abnormality that, in the opinion of the Investigator or the 
Sponsor, would put the patient at unacceptable risk for participation in the study or would 
interfere with the assessments included in the study. 
3.3 
Discontinuation Rules 
3.3.1 
Study Stopping Rules 
The study may be discontinued or paused for reasons that may include (but are not limited to): 
reasons of safety, lack of study drug availability, inability to enroll the study, or decision by a 
regulatory authority or the Sponsor (see Appendix D). 
In the event that a dosing cohort shows efficacy and it is not anticipated that additional dosing 
would show added efficacy, the Sponsor may choose to stop and not complete the study.  
Further, in the instance of 2 or more treatment-related SAEs, 2 or more treatment-related AEs 
Grade 3 or higher or 2 or more clinically significant treatment-related Grade 3 or higher laboratory 
abnormalities, the study will be paused pending an SSRC review of the safety events. The Sponsor 
will inform the applicable regulatory authorities of any safety-related pause in the study.    
In the case that the study is discontinued, the Sponsor will promptly inform the Investigators and 
applicable regulatory authority(ies) of the termination of the study and the reason(s) for the 
termination. The Investigators are responsible for promptly informing subjects that they must 
discontinue study drug. The Institutional Review Board (IRB)/Independent Ethics Committee 
(IEC) will also be informed promptly and provided the reason(s) for the termination, as specified 
by the applicable regulatory requirement(s). 
3.3.2 
Discontinuation from Study Drug 
Study drug dosing for an individual subject must be discontinued for any of the following reasons: 
 
The subject withdraws consent or requests discontinuation for any reason. 
 
Occurrence of any medical condition or circumstance that exposes the subject to substantial 
risk and/or does not allow the subject to adhere to the requirements of the protocol. 
 
Any SAE, clinically significant adverse event, severe laboratory abnormality, intercurrent 
illness, or other medical condition which indicates to the Investigator or Sponsor that 
continued participation is not in the best interest of the subject. Specifically, study drug must 
be discontinued in subjects with development of a treatment-related SAE, a treatment-related 
AE Grade 3 or higher, or a clinically significant treatment-related laboratory abnormality 
Grade 3 or higher.  
 
Pregnancy during the study. 
 
Subject failure to comply with protocol requirements or study-related procedures. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 37 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
 
Subject experiences study drug related symptoms that the Investigator determines are 
consistent with any of the following: 
o Anaphylaxis or severe allergic reaction.  
o An infusion reaction determined to be Grade 3 or higher based on Common 
Terminology Criteria for Adverse Events (CTCAE) version 5. 
o Cytokine release syndrome determined to be CTCAE version 5 Grade 2 or higher. 
o Serum sickness determined to be CTCAE version 5 Grade 2 or higher. 
Changes in plasma BK viral load, use of rescue therapy, and/or need for change in 
immune-suppressive regimen for any reason should not prompt early discontinuation of therapy. 
As long as the subject is tolerating, study drug should be continued regardless of viremia (i.e., even 
if not responding). 
If a subject must be discontinued from study drug administration, the subject will still be 
encouraged to complete all follow-up visits and assessments necessary for appropriate safety 
follow-up. Subjects who are found to be pregnant should continue to be monitored for safety 
following study treatment discontinuation and the outcome of the pregnancy should be reported. 
In the case of discontinuation from study drug, subjects should be considered to have completed 
the treatment period and should complete the assessments required in the follow-up period 
(see Appendix A).  Although the actual study days will vary between subjects and will not align 
with protocol-defined visit study days, time from last study dose remains the same (i.e., subjects 
will be seen approximately every 28 days for 2 follow up visits and then once again approximately 
24 weeks after the last study dose).  If the subject cannot be seen on the precise protocol-defined 
study day, the acceptable visit window is ±10 days. 
3.3.3 
Discontinuation from Study Participation 
Study participation by an individual subject must be prematurely discontinued for any of the 
following reasons: 
 
The subject withdraws consent or requests discontinuation for any reason. 
 
Occurrence of any medical condition or circumstance that exposes the subject to substantial 
risk and/or does not allow the subject to adhere to the requirements of the protocol. 
 
Any SAE, clinically significant adverse event, severe laboratory abnormality, intercurrent 
illness, or other medical condition which indicates to the Investigator or Sponsor that 
continued participation is not in the best interest of the subject. 
 
Subject failure to comply with protocol requirements or study-related procedures. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 38 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
If a subject withdraws prematurely from the study, study staff should make every effort to contact 
the Sponsor prior to discontinuation, if possible, and to complete the full panel of assessments 
scheduled for the Early Termination Visit. The reason for subject withdrawal must be documented 
in the electronic Case Report Form (CRF).  
In the case of subjects lost to follow-up, attempts to contact the subject must be made and 
documented in the subject’s medical records.  
The SSRC may recommend enrolling more than 12 subjects into a cohort (Cohort 1, 2, and/or 3) 
to allow adequate data collection for assessment of cohort progression and/or study objectives. 
Expansion of a given cohort, if needed, will not affect the size of subsequent cohort(s). 
3.4 
Early Termination Visit and Withdrawal Procedures 
For subjects who are withdrawn from the study prior to completion of the study, the subject should 
return for an Early Termination Visit. The reason for subject withdrawal from the study must be 
documented in the eCRF. 
4 
TREATMENTS ARMS 
The following treatment arms and dosing regimens are planned.  
4.1 
Treatment Groups 
Subjects entering Cohort 1will be randomized to 1 of 2 treatment arms in a ratio of 2:1 
(MAU868:placebo): 
• 
MAU868 1350 mg every 28 days for a total of 4 doses 
• 
Placebo every 28 days for a total of 4 doses.   
Subjects entering Cohort 2 will be randomized to 1 of 2 treatment arms in a ratio of 2:1 
(MAU868:placebo): 
• 
MAU868 6750 once and 1350 mg every 28 days for a total of 4 doses 
• 
Placebo every 28 days for a total of 4 doses.   
Subjects entering Cohort 3 will be randomized to 1 of 2 treatment arms in a ratio of 2:1 
(MAU868:placebo): 
• 
MAU868 6750 mg every 28 days for a total of 4 doses 
• 
Placebo every 28 days for a total of 4 doses.   
Minimum duration of the infusion for 6750 mg is at least 180 minutes and for 1350 mg is at least 
60 minutes. All infusions will be followed by at least a 25 mL D5W flush to run at the same 
infusion rate as the dose of study drug. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 39 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
A Pharmacy Manual will provide instructions for preparation of the infusion. The study drug is 
prepared as a dilution of the 450 mg/3mL stock solution in a total volume of 250 mL D5W. 
The investigational product is to be stored at 2° to 8° Celsius, protected from light and not shaken.  
4.2 
Randomization 
Study participants will be randomly assigned to their treatments. Two participants will be assigned 
to receive treatment with MAU868 for each participant assigned to receive treatment with placebo 
(2:1 randomization). Randomization will occur via an Interactive Web Response System (IWRS). 
The Investigator or delegate will contact the IWRS after confirming that a potential study 
participant is eligible. The IWRS will assign a randomization number that will be used to link the 
subject to a treatment arm.  
The randomization number is only used to identify which treatment study participants have been 
assigned to receive. The number assigned to a subject at screening remains the unique identifier 
for the subject throughout the study. For information on subject numbering, please see “Subject 
numbering” section in the IWRS manual.  The randomization numbers will be generated using 
procedures that ensure that treatment assignment is unbiased and concealed from the Sponsor, 
subjects, and Investigator staff. A subject randomization list will be produced by a CRO. 
The randomization scheme for subjects will be reviewed and approved by the Sponsor. 
Follow the details outlined in the IWRS Manual regarding the process and timing of treatment 
assignment and randomization of subjects. 
4.3 
Treatment Arm Blinding 
This is a subject, Investigator, and Sponsor-blinded study. Subjects and Investigators will remain 
blinded to study treatment arm (MAU868 or placebo) throughout the study. 
Drug product will be supplied in bulk, so an unblinded pharmacist, or appropriately designated 
study site staff who is independent of the study team, will be required in order to maintain the 
blind. This unblinded associate at the site will be notified by the IWRS that a subject is randomized 
and to which treatment arm, which will then enable and instruct them to prepare the study drug. 
4.3.1 
Breaking the Treatment Blind 
Blinding is critical to the integrity of this clinical study. However, in the event of a medical 
emergency or pregnancy in an individual subject, in which knowledge of the investigational 
product is critical to the subject’s management, the Investigator should contact the Medical 
Monitor to review the situation prior to breaking the blind. 
Before breaking the blind of an individual subject’s treatment, the Investigator should have 
determined that the information is necessary (i.e., that it will alter the subject’s immediate 
management). In many cases, particularly when the emergency is clearly not investigational 
product related, the problem may be properly managed by assuming that the subject is receiving 
active product without the need for unblinding. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 40 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
When the Investigator contacts the system to break a treatment code for a subject, he/she must 
provide the requested subject identifying information and confirm the necessity to break the 
treatment code for the subject. The Investigator will then receive details of the investigational drug 
treatment for the specified subject via the IWRS. The system will automatically inform the study 
monitor for the site and the Study Team that the code has been broken. 
It is the Investigator’s responsibility to ensure that there is a dependable procedure in place to 
allow access to the IWRS /code break at any time in case of emergency.  
An assessment will be done by the appropriate site personnel and Sponsor after an emergency 
unblinding to assess whether or not study drug should be discontinued for a given subject. 
In cases of accidental unblinding, contact the Medical Monitor and ensure every attempt to 
preserve the blind is made. 
5 
DRUG SUPPLIES 
5.1 
Formulation and Packaging 
There is no administration kit. A disposable syringe will be used to withdraw the contents of the 
vial. 
MAU868 
MAU868 450 mg/3 mL (150 mg/mL) solution for infusion and injection is a slightly opalescent 
and colorless to slightly colored aqueous solution packaged in a 6 mL clear glass vial with a grey 
rubber stopper, which is sealed with an aluminum cap with plastic flip-off disk. The vial is 
overfilled by 10% (containing a total volume of 3.3 mL) to allow for the complete removal of the 
dose (450 mg).  
MAU868 450 mg/3 mL solution for infusion and injection contains, in addition to MAU868 drug 
substance, L-histidine, L-histidine-hydrochloride monohydrate, sucrose and polysorbate 20. 
The excipients utilized are standard pharmacopeial grade excipients that are commonly used in 
antibody parenteral products. The formulation does not contain any preservative; it is to be used 
for single-dose administration only. 
Placebo 
Placebo solution D5W will be supplied by the clinical site.  
5.2 
Study Drug Preparation and Dispensing 
MAU868 will be administered via IV infusion. Refer to the Pharmacy Manual for dose preparation 
and administration instructions. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 41 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
5.3 
Study Drug Administration 
Study drug should be administered only at clinical sites.  All clinical sites must have the 
appropriate equipment and trained personnel needed to effectively manage hypersensitivity 
reactions including anaphylaxis and infusion reactions. 
Cohort 1 MAU868 Arm:  
• 
MAU868 1350 mg IV over at least 60 minutes approximately every 28 days for a total of 
4 doses.  
Cohort 2 MAU868 Arm:  
• 
MAU868 6750 mg IV over at least 180 minutes on Study Day 1, then 1350 mg IV over at 
least 60 minutes for subsequent doses approximately every 28 days for a total of 4 doses.  
Cohort 3 MAU868 Arm:  
• 
MAU868 6750 mg IV over at least 180 minutes approximately every 28 days for a total of 
4 doses.  
Placebo  
• 
Cohort 1: Placebo (D5W) will be administered as an IV infusion over at least 60 minutes 
approximately every 28 days for a total of 4 doses.  
• 
Cohort 2: Placebo (D5W) will be administered as an IV infusion over at least 180 minutes on 
Day 1 and then over 60 minutes approximately every 28 days for a total of 4 infusions. 
• 
Cohort 3: Placebo (D5W) will be administered as an IV infusion over at least 180 minutes 
approximately every 28 days for a total of 4 infusions. 
• 
Placebo is prepared as a standard 250 mL volume of intravenous fluid. 
All infusions will be followed by at least a 25 mL D5W flush to run at the same infusion rate as 
the dose of study drug. 
Refer to the Pharmacy Manual for additional dose preparation and administration instructions. 
5.3.1 
Dose Adjustments and Interruption of Study Drug 
Dose adjustments and interruptions of study drug are not permitted. Interruptions of individual 
infusions, however, are permitted in the event venous access becomes compromised or a subject 
is not tolerating the infusion (Section 7.3.1). The details of any interruption of an infusion, 
including the reason(s), the timing, and the resumption and completion of the infusion if 
applicable, must be recorded in the source documents and the eCRF. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 42 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
For subjects who may require a hemodialysis, plasmapheresis, or immunoadsorption treatment, 
it shall be assumed that the study drug has been removed. A blood sample for PK analysis should 
be collected prior to and following these treatments. In the event that a subject requires 
hemodialysis, plasmapheresis, or immunoadsorption treatments; if <15 days since last 
MAU868/placebo treatment another dose will be given as soon as possible, and the next scheduled 
monthly dose skipped. Regular dosing will occur the following month. If the last dose was 15 days 
or greater no interim dose will be administered, and the regular monthly schedule will be followed. 
No subject will receive more than 4 doses. Subjects anticipated to require hemodialysis, 
plasmapheresis or immunoadsorption treatment at the time of randomization should not be 
randomized (Exclusion Criterion 5). 
5.3.2 
Study Drug Compliance 
All study drug will be administered at the clinical center, by qualified site staff, under the 
supervision of the Investigator or qualified designee. Any interruption to the IV infusion or 
changes to the infusion rate and duration must be recorded in the source documents and in the 
eCRF. 
All study drug must be recorded in the Drug Accountability Log. 
5.4 
Storage and Accountability 
The recommended storage condition of the drug product is 2-8°C, protected from light. The drug 
product should not be shaken or frozen. Details on the requirements for storage and management 
of study drug, and instructions to be followed for subject numbering, prescribing/dispensing and 
administering the study drug are outlined in the Pharmacy Manual. 
6 
PRIOR AND CONCOMITANT MEDICATIONS AND/OR PROCEDURES 
6.1 
Excluded Medications and/or Procedures 
The following medications are excluded from use during this study and patients anticipated to 
require these interventions should not be included: 
• 
Systemic mTOR inhibitors (e.g., rapamycin, sirolimus, everolimus, temsirolimus, etc.) 
• 
IVIG 
• 
antibody-depleting therapies (e.g., hemodialysis, plasmapheresis, immunoadsorption, etc.)  
• 
any other investigational drug  
If, after randomization, it is determined that these therapies are essential for the subject’s health 
and well-being and cannot be delayed until study completion, the subject should not be 
discontinued from study medication or the study due to receipt of these medications.  
See Section 5.3.1 and the Schedule of Events (Appendix A) for more information regarding dosing 
and PK collection in the event a subject requires hemodialysis, plasmapheresis, or 
immunoadsorption treatments.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 43 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
6.2 
Rescue Medication 
In order to treat BK viremia, prior to randomization, (ie, prior to screening, during the screening 
period and at the Baseline Visit), Investigators are permitted to decrease or alter 
immunosuppressive therapy per their discretion and/or per standard of care at their site.   However, 
in the first 4 weeks after randomization, Investigators should refrain from additional changes in 
immunosuppressive regimen in response to BKV unless the viral load has increased by >1 log and 
the Investigator determines that a change is in the best interest of the patient.   
Additional rescue medication including cidofovir, leflunomide and IVIG is strongly discouraged.  
However, if 4 weeks after randomization, the Investigator feels the subject is failing study drug 
and the subject is at significant risk of graft damage, and that additional medications are required 
for the subject’s care, the Investigator may add additional therapies at their discretion.   
Regardless of the use of rescue medication (changes in immunosuppressive regiment or addition 
of anti-viral medication), all subjects should complete study infusion(s) as long as they are 
tolerating the study drug.    
6.3 
Documentation of Prior and Concomitant Medication Use 
The Investigator must instruct the subject to notify the study site about any new medications he/she 
takes after the subject was enrolled into the study. 
All prescription medications; including over-the-counter drugs and significant non-drug therapies 
(including blood transfusions) received by the subject within 10  days prior to the initial dose of 
study drug administration and any concomitant medications used through the Follow-Up Visit will 
be recorded in the source documents and on the appropriate eCRF. In addition, all 
immunosuppressive therapy received since kidney transplantation (including the induction 
regimen) will be recorded.  
6.4 
Infusion Reactions  
Although not previously reported following administration of MAU868, infusion reactions and 
infusion associated symptoms may occur following infusion of a monoclonal antibody due to 
sensitization due to the antibody or to the excipients in the infusion materials. 
Symptoms indicative of anaphylaxis, or (based on CTCAE version 5 classification) Grade 3 or 
higher infusion reaction, Grade 2 or higher cytokine release syndrome, or Grade 2 or higher serum 
sickness should result in immediate halting of the infusion and prompt initiation of appropriate 
therapy.  Subjects should not be re-challenged with study drug.  Study drug should be permanently 
discontinued, but the patient should remain in the study for continued follow-up. Milder symptoms 
that do not meet criteria for immediate discontinuation from study drug may be managed by drug 
interruption and symptom management. The infusion should be temporarily stopped and the 
subject assessed.  Diphenhydramine 50 mg and acetaminophen 650 mg should be administered. 
Ifsymptoms improve after 30-60 minutes, the subject may be re-challenged with a reduced infusion 
rate of approximately 50% the initial rate.   Medication(s) to treat gastrointestinal symptoms may 
also be given if needed.  If the subject tolerates a re-challenge, they should receive pre-medication 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 44 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
with diphenhydramine 50 mg and acetaminophen 650 mg administered approximately 
30-60 minutes prior to start of the next scheduled infusion.  Subsequent infusions should be 
administered at a slower rate.  For subsequent infusions of 1350 mg, study drug should be 
administered over approximately 120 minutes (2 hours).  For subsequent infusions of 6750 mg, 
study drug should be administered over approximately 240 minutes (4 hours).   
It is expected that the clinical site will have adequate facilities at the location of the study drug 
infusions to effectively manage and treat infusion reactions promptly. 
7 
STUDY PROCEDURES 
7.1 
Informed Consent 
Eligible subjects may only be included in the study after providing written (witnessed, where 
required by law or regulation), IRB/IEC-approved informed consent.  
Informed consent must be obtained before conducting any study-specific procedures (i.e., all of 
the procedures described in the protocol). However, assessments or procedures performed as 
standard of care may be used for the purposes of screening. The process of obtaining informed 
consent must be documented in the subject source documents. 
Information about common side effects already known about the investigational drug can be found 
in the Investigator's Brochure (IB). This information will be included in the subject informed 
consent and should be discussed with the subject during the study as needed. Any new information 
regarding the safety profile of the investigational drug that is identified between IB updates will 
be communicated as appropriate. New information might require an update to the informed 
consent and then must be discussed with the subject. 
Once the subject has signed the informed consent, the subject may enter the Screening Period of 
the study. 
7.2 
Screening Period 
Subjects who have had their renal transplant within the previous year may be considered for 
participation and entrance into the Screening Period following signing of the consent. Subjects 
may, enter the Screening Period (pre-treatment period) of up to 10 days following signing of the 
consent. If a subject does not meet all criteria within the 10-day window they will be considered a 
screen failure. 
No study-specific procedures or activities may be performed until the informed consent process 
has been completed and the subject has signed the Informed Consent Form. However, assessments 
or procedures performed as standard of care may be used for the purposes of screening. Once a 
subject has signed the Informed Consent Form for study participation, the subject enters the 
Screening Period. 
See Section 8, Study Procedures and Assessments. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 45 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
During the Screening Period, the following activities will be performed: 
• 
Review of Inclusion Criteria (Section 3.2.1) and Exclusion Criteria (Section 3.2.2). 
• 
Review and record medical and surgical history and current medical conditions. 
• 
Review and record concomitant medications (see Section 6.1 Excluded Medications and/or 
Procedures, for a list of prohibited medications). 
• 
Review and record subject demography. 
• 
Review and record Kidney Donor Profile Index (KDPI). 
• 
Perform urine or serum pregnancy test on women of childbearing potential only. Note: either 
serum or urine must be documented as negative within 96 hours prior to Baseline.    
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, oxygen 
saturation and height and weight. 
• 
Perform physical examination. 
• 
Review of local and/or central plasma BKV PCR results 
• 
Review of Adverse Events after informed consent is signed. 
If the subject meets all inclusion and has no exclusion criteria during the Screening Period, 
the subject may enter the randomization portion of the study.  
7.3 
Treatment Period (Day 1 to Day 84) 
If the subject meets all inclusion and exclusion criteria, the subject may then be randomized to 
receive either MAU868 or placebo. Randomization should occur as soon as possible, but not 
longer than 10 calendar days, after the local qualifying sample was collected.  
Subjects will be randomized to study drug in the ratio of 2:1 (MAU868: placebo). 
During the treatment period, subjects will receive MAU868 or placebo approximately every 
28 days (every 4 weeks) for 12 weeks (4 doses total).  Urine and blood will be monitored for BKV 
DNA weekly by PCR for the first 6 weeks of treatment and then every other week until completion 
of treatment and at each follow up visit.  During this time, BKV DNA by PCR will be tested at the 
central laboratory.  
During the treatment period, subjects should be seen approximately every 7 days (+/- 3 days) 
during the first 6 weeks and approximately every 14 days (+/-5 days) for the duration of treatment. 
Subjects may be seen more often at the Investigator’s discretion.  Visit dates are determined from 
the Baseline Visit. 
NOTE: 
• 
After the first 4 weeks of treatment, the Investigator may request BK viral load (urine and 
blood) testing more frequently (e.g., weekly) than mandated by the protocol, if clinically 
indicated.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 46 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
• 
Subjects should continue with the study drug (i.e., MAU868 or placebo) until the last 
scheduled dose, regardless of documented viremia, need for rescue therapy and/or changes in 
the subject’s immunosuppressive regimen. 
7.3.1 
Day 1 (Baseline; Study Drug Infusion 1) 
The day on which the subject receives their first study drug infusion will be designated Day 1 
(Baseline).   
The following procedures will be performed prior to initiation of the study drug infusion; 
see Schedule of Events (Appendix A): 
• 
Review and record medical conditions. 
• 
Review and record concomitant medications. 
• 
Obtain subject weight 
• 
Collect blood (serum and plasma) and urine samples for BKV testing, pharmacokinetics, 
immunogenicity, hematology, clinical chemistry, and urinalysis for analysis at central 
laboratories.  
• 
Females of childbearing potential must have a negative urine or serum pregnancy test result 
within 96 hours prior to Baseline. If applicable, perform urine or serum pregnancy test. 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, and 
oxygen saturation within 30 minutes prior to the initiation of the infusion. 
• 
Perform electrocardiogram (12-lead). 
The following procedures will be performed after the initiation of the study drug infusion; 
see Schedule of Events (Appendix A): 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, and 
oxygen saturation approximately every 30 minutes (+/- 10 minutes) after the start of the 
infusion until at least 2 hours after completing the infusion. Vital signs may also be collected 
at any time during or after the infusion at the Investigator’s discretion.  
• 
Collect blood (serum) for pharmacokinetics within 30 minutes following the completion of 
the infusion and again within 3 to 6 hours after the end of the infusion. 
• 
Review and record adverse events. 
• 
Review and record any new concomitant medications. 
It is expected that the clinical site will have adequate facilities at the location of the study drug 
infusions to effectively manage and treat infusion reactions. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 47 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
If a subject has experienced an infusion reaction following an infusion of study drug, the 
Investigator should discontinue the infusion.  If symptoms resolve promptly the infusion may be 
resumed at a slower rate. In this case, the Investigator is encouraged to continue the subject’s 
participation in the study.  If the subject continues in the study, future infusions should be 
administered at a slower rate and preceded by use of premedication.  
Cohort 1: Study Drug Administration Day 1 
The subject will receive their study drug infusion (MAU868 1350 mg or Placebo). The respective 
infusions will be delivered over at least 60 minutes. Following completion of the infusion (infusion 
bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the same infusion 
rate as the dose of IP. Start and stop times will be recorded on the eCRF. 
Cohort 2: Study Drug Administration Day 1 
The subject will receive their study drug infusion (MAU868 6750 mg or Placebo). The respective 
infusions will be delivered over at least 180 minutes. Start and stop times will be recorded on the 
eCRF. For subsequent doses the subject will receive their study drug infusion (MAU868 1350 mg 
or Placebo). The respective infusions will be delivered over at least 60 minutes. Following 
completion of the infusion (infusion bag completely emptied into the drip chamber) a 25 mL D5W 
flush is to infuse at the same infusion rate as the dose of IP. Start and stop times will be recorded 
on the eCRF. 
Cohort 3: Study Drug Administration Day 1 
The subject will receive their study drug infusion (MAU868 6750 mg or Placebo). The respective 
infusions will be delivered over at least 180 minutes. Following completion of the infusion 
(infusion bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the 
same infusion rate as the dose of IP. Start and stop times will be recorded on the eCRF. 
7.3.2 
Day 7 
The following procedures will be performed at this visit; see Schedule of Events (Appendix A): 
• 
Record vital signs (if visit performed in person), including temperature, blood pressure, heart 
rate, respiratory rate, and oxygen saturation. 
• 
Review and record adverse events. 
• 
Review and record concomitant medications. 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing, viral resistance, 
and pharmacokinetics for analysis at central laboratories. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 48 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
7.3.3 
Day 14 
The following procedures will be performed at this visit; see Schedule of Events (Appendix A): 
• 
Record vital signs (if visit performed in person), including temperature, blood pressure, heart 
rate, respiratory rate, and oxygen saturation. 
• 
Review and record adverse events. 
• 
Review and record concomitant medications. 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing, viral resistance, 
pharmacokinetics, hematology, clinical chemistry, and urinalysis for analysis at central 
laboratories 
7.3.4 
Day 21 
The following procedures will be performed at this visit; see Schedule of Events (Appendix A): 
• 
Record vital signs (if visit performed in person), including temperature, blood pressure, heart 
rate, respiratory rate, and oxygen saturation. 
• 
Review and record adverse events. 
• 
Review and record concomitant medications. 
• 
Collect blood (serum and plasma) and urine samples for BKV testing, viral resistance, and 
pharmacokinetics for analysis at central laboratories. 
7.3.5 
Day 28 (Study Drug Infusion 2) 
The following procedures will be performed prior to initiation of the study drug infusion; 
see Schedule of Events (Appendix A): 
• 
Review and record adverse events. 
• 
Review and record concomitant medications. 
• 
Obtain subject weight 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing, viral resistance, 
immunogenicity, pharmacokinetics, hematology, clinical chemistry, and urinalysis for 
analysis at central laboratories. 
• 
Perform urine or serum pregnancy test for women of childbearing potential. 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, and 
oxygen saturation within approximately 30 minutes prior to the initiation of the infusion. 
If the subject experienced an infusion reaction during their prior administration of study drug, 
future infusions should be preceded by use of premedication and decreasing the infusion rate 
(see Section 6.4). 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 49 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
The following procedures will be performed after the initiation of the study drug infusion; 
see Schedule of Events (Appendix A): 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, and 
oxygen saturation approximately every 30 minutes (+/- 10 minutes) after the start of the 
infusion until at least 2 hours after completing the infusion. Vital signs may also be collected 
at any time during or after the infusion at the Investigator’s discretion.   
• 
Collect blood (serum) for pharmacokinetics within approximately 30 minutes following the 
completion of the infusion. 
• 
Review and record adverse events. 
• 
Review and record any new concomitant medications. 
Study Drug Administration 
Cohort 1: Study Drug Administration Day 28 
The subject will receive their study drug infusion (MAU868 1350 mg or Placebo). The respective 
infusions will be delivered over at least 60 minutes. Following completion of the infusion (infusion 
bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the same infusion 
rate as the dose of IP. Start and stop times will be recorded on the eCRF. 
Cohort 2: Study Drug Administration Day 28 
The subject will receive their study drug infusion (MAU868 1350 mg or Placebo). The respective 
infusions will be delivered over at least 60 minutes. Following completion of the infusion (infusion 
bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the same infusion 
rate as the dose of IP. Start and stop times will be recorded on the eCRF. 
Cohort 3: Study Drug Administration Day 28 
The subject will receive their study drug infusion (MAU868 6750 mg or Placebo). The respective 
infusions will be delivered over at least 180 minutes. Following completion of the infusion 
(infusion bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the 
same infusion rate as the dose of IP. Start and stop times will be recorded on the eCRF.  
7.3.6 
Day 35 
The following procedures will be performed at this visit; see Schedule of Events (Appendix A): 
• 
Record vital signs (if visit performed in person), including temperature, blood pressure, heart 
rate, respiratory rate, and oxygen saturation 
• 
Review and record adverse events 
• 
Review and record concomitant medications 
• 
Collect blood (serum and plasma) and urine samples for BKV testing and viral resistance for 
analysis at central laboratories 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 50 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
7.3.7 
Day 42 
The following procedures will be performed at this visit; see Schedule of Events (Appendix A): 
• 
Record vital signs (if visit performed in person), including temperature, blood pressure, heart 
rate, respiratory rate, and oxygen saturation 
• 
Review and record adverse events 
• 
Review and record concomitant medications 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing and viral 
resistance for analysis at central laboratories 
7.3.8 
Day 56 (Study Drug Infusion 3) 
The following procedures will be performed prior to initiation of the study drug infusion; 
see Schedule of Events (Appendix A): 
• 
Review and record adverse events 
• 
Review and record concomitant medications 
• 
Obtain subject weight 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing, viral resistance, 
immunogenicity, pharmacokinetics, hematology, clinical chemistry, and urinalysis for 
analysis at central laboratories 
• 
Perform urine or serum pregnancy test for women of childbearing potential 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, and 
oxygen saturation within approximately 30 minutes prior to the initiation of the infusion 
If the subject experienced an infusion reaction during their prior administration of study drug, 
future infusions should be preceded by use of premedication and decreasing the infusion rate 
(refer to Section 6.4). 
The following procedures will be performed after the initiation of the study drug infusion; 
see Schedule of Events (Appendix A). 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, and 
oxygen saturation approximately every 30 minutes (+/- 10 minutes) after the start of the 
infusion until at least 2 hours after completing the infusion. Vital signs may also be collected 
at any time during or after the infusion at the Investigator’s discretion. 
• 
Collect blood (serum) for pharmacokinetics within approximately 30 minutes following the 
completion of the infusion  
• 
Review and record adverse events  
• 
Review and record any new concomitant medications 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 51 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Study Drug Administration 
Cohort 1: Study Drug Administration Day 56 
The subject will receive their study drug infusion (MAU868 1350 mg or Placebo). The respective 
infusions will be delivered over at least 60 minutes. Following completion of the infusion (infusion 
bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the same infusion 
rate as the dose of IP. Start and stop times will be recorded on the eCRF. 
Cohort 2: Study Drug Administration Day 56 
The subject will receive their study drug infusion (MAU868 1350 mg or Placebo). The respective 
infusions will be delivered over at least 60 minutes. Following completion of the infusion (infusion 
bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the same infusion 
rate as the dose of IP. Start and stop times will be recorded on the eCRF. 
Cohort 3: Study Drug Administration Day 56 
The subject will receive their study drug infusion (MAU868 6750 mg or Placebo). The respective 
infusions will be delivered over at least 180 minutes. Following completion of the infusion 
(infusion bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the 
same infusion rate as the dose of IP. Start and stop times will be recorded on the eCRF. 
7.3.9 
Day 70 
The following procedures will be performed at this visit; see Schedule of Events (Appendix A): 
• 
Record vital signs (if visit performed in person), including temperature, blood pressure, heart 
rate, respiratory rate, and oxygen saturation 
• 
Review and record adverse events 
• 
Review and record concomitant medications 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing and viral 
resistance for analysis at central laboratories 
7.3.10 
Day 84 (Study Drug Infusion 4) 
The following procedures will be performed prior to initiation of the study drug infusion; 
see Schedule of Events (Appendix A): 
• 
Review and record adverse events 
• 
Review and record concomitant medications 
• 
Obtain subject weight 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing, viral resistance, 
immunogenicity, pharmacokinetics, hematology, clinical chemistry, and urinalysis for 
analysis at central laboratories 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 52 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
• 
Perform urine or serum pregnancy test for women of childbearing potential 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, 
and oxygen saturation within approximately 30 minutes prior to the initiation of the infusion 
• 
Perform physical examination 
If the subject experienced an infusion reaction during their prior administration of study drug, 
future infusions should be preceded by use of premedication and decreasing the infusion rate. 
The following procedures will be performed after the initiation of the study drug infusion; 
see Schedule of Events (Appendix A): 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, and 
oxygen saturation approximately every 30 minutes (+/- 10 minutes) after the start of the 
infusion until at least 2 hours after completing the infusion. Vital signs may also be collected 
at any time during or after the infusion at the Investigator’s discretion.   
• 
Collect blood (serum) for pharmacokinetics within approximately 30 minutes following the 
completion of the infusion and again within approximately 3 to 6 hours after the end of the 
infusion 
• 
Perform electrocardiogram (12-lead) 
• 
Review and record adverse events 
• 
Review and record any new concomitant medications 
Study Drug Administration 
Cohort 1: Study Drug Administration Day 84 
The subject will receive their study drug infusion (MAU868 1350 mg or Placebo). The respective 
infusions will be delivered over at least 60 minutes. Following completion of the infusion (infusion 
bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the same infusion 
rate as the dose of IP. Start and stop times will be recorded on the eCRF. 
Cohort 2: Study Drug Administration Day 84 
The subject will receive their study drug infusion (MAU868 1350 mg or Placebo). The respective 
infusions will be delivered over at least 60 minutes. Following completion of the infusion (infusion 
bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the same infusion 
rate as the dose of IP. Start and stop times will be recorded on the eCRF. 
Cohort 3: Study Drug Administration Day 84 
The subject will receive their study drug infusion (MAU868 6750 mg or Placebo). The respective 
infusions will be delivered over at least 180 minutes. Following completion of the infusion 
(infusion bag completely emptied into the drip chamber) a 25 mL D5W flush is to infuse at the 
same infusion rate as the dose of IP. Start and stop times will be recorded on the eCRF.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 53 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
7.4 
Follow-up Period (Day 112 to Day 252) 
Subjects will be seen approximately every 28 days for 2 follow up visits and then once again 
approximately 24 weeks after the last study dose.  If the subject cannot be seen on the precise 
protocol-defined study day, the acceptable visit window is ±10 days. 
7.4.1 
Day 112 (Follow Up 1) 
The following procedures will be performed; see Schedule of Events (Appendix A): 
• 
Review and record adverse events 
• 
Review and record concomitant medications 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing, viral resistance, 
immunogenicity, pharmacokinetics, hematology, clinical chemistry, and urinalysis for 
analysis at central laboratories 
• 
Record vital signs (if visit performed in person), including temperature, blood pressure, heart 
rate, respiratory rate, and oxygen saturation  
7.4.2 
Day 140 (Follow Up 2) 
The following procedures will be performed; see Schedule of Events (Appendix A): 
• 
Review and record adverse events 
• 
Review and record concomitant medications 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing, viral resistance, 
immunogenicity, pharmacokinetics, hematology, clinical chemistry, and urinalysis for 
analysis at central laboratories 
• 
Record vital signs (if visit performed in person), including temperature, blood pressure, heart 
rate, respiratory rate, and oxygen saturation 
7.4.3 
Day 252 (Last Follow Up) 
The following procedures will be performed at this visit; see Schedule of Events (Appendix A): 
• 
Review and record adverse events 
• 
Review and record concomitant medications 
• 
Obtain subject weight 
• 
Collect blood (serum and plasma) and urine samples for BK viral load testing, viral resistance, 
immunogenicity, pharmacokinetics, hematology, clinical chemistry, and urinalysis for 
analysis at central laboratories 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, 
and oxygen saturation 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 54 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
• 
Perform physical examination 
• 
Perform electrocardiogram (12-lead) 
7.4.4 
Early Termination Visits 
For subjects who are withdrawn from the study prior to completion, the following procedures will 
be performed at the Early Termination Visit: 
• 
Review and record adverse events 
• 
Review and record concomitant medications 
• 
Obtain subject weight 
• 
Collect blood (serum and plasma) and urine samples for BKV testing, viral resistance, 
immunogenicity, pharmacokinetics, hematology, clinical chemistry, and urinalysis for 
analysis at central laboratories 
• 
Record vital signs, including temperature, blood pressure, heart rate, respiratory rate, 
and oxygen saturation 
• 
Perform physical examination 
• 
Perform electrocardiogram (12-lead) 
8 
STUDY PROCEDURES AND ASSESSMENTS 
8.1 
Schedule of Events 
Subjects should be seen for all visits/assessments as outlined in the assessment schedule or as close 
to the designated day/time as possible. 
Missed, late, or rescheduled visits should not lead to automatic discontinuation from the study.  
Subjects who prematurely discontinue study drug should remain in the study.  In the case of 
premature discontinuation from study drug, subjects should be considered to have completed the 
treatment period and should complete the assessments required in the follow-up period 
(see Appendix A).  Although the actual study days will vary between subjects and will not align 
with protocol-defined visit study days, time from last study dose remains the same (i.e., subjects 
will be seen approximately every 28 days for 2 follow up visits and then once again approximately 
24 weeks after the last of study dose received).  If the subject cannot be seen on the precise 
protocol-defined study day, the acceptable visit window is ±10 days. 
Subjects who prematurely discontinue the study for any reason should be scheduled for a final study 
visit as soon as possible, at which time all of the assessments listed for the Early Termination Visit will 
be performed. At this final visit, all investigational product should be reconciled, and the adverse event 
and concomitant medications recorded on the eCRF and the reason for discontinuation of study 
documented.  (See Appendix A, Schedule of Events). 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 55 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
8.2 
Subject Demographics/Other Baseline Characteristics 
Demographic and other baseline characteristics will be collected for all subjects. Relevant medical 
and surgical history, including the primary cause of end-stage renal disease and other past or 
ongoing conditions, shall be recorded. Investigators have the discretion to determine the relevance 
of the medical and surgical history for individual subjects.  
The Kidney Donor Profile Index (KDPI) will be recorded for all subjects who receive a kidney 
from a deceased donor. The information necessary for determining the KDPI includes donor age, 
height, weight, ethnicity, history of hypertension, history of diabetes mellitus, cause of death, 
serum creatinine, hepatitis C serostatus, and whether donation occurred after circulatory death.  
More specific instructions and details regarding the baseline characteristics of subjects are outlined 
in the eCRF completion guidelines. 
8.3 
Efficacy / Pharmacodynamics 
The efficacy of MAU868 in treating BK viremia will be measured primarily by measuring the 
viral load in the plasma over time. 
Samples (plasma or urine) will be collected for viral load assessment at the time points defined in 
the Assessment schedule. (See Appendix A, Schedule of Events.) 
Follow instructions outlined in the Laboratory Manual regarding sample collection, numbering, 
processing and shipment. A centralized, validated quantitative PCR (qPCR) assay, targeting 
multiple conserved regions of the viral genome, will be utilized for quantification of BKV viral 
load. These results of each subject’s testing will be reported to the Investigator. It is recommended 
that these results be used by the Investigator in the management of the subject during their 
participation in the study. The presence of MAU868 is not expected to affect the results of the 
qPCR BKV viral load assay because viral nucleic acid will first be isolated from the sample for 
quantitation, removing all antibodies and virus/host proteins. A detailed Virology Analysis Plan 
will be prepared separately. 
8.4 
Clinical Outcome Assessments (COAs) 
Several clinical outcome assessments will be evaluated. These include:  
• 
Graft function as measured by eGFR using the CK-EPI equation, 
• 
Graft survival as determined by presence of a functioning graft that has not required a 
re-transplant or permanent renal replacement therapy, 
• 
Subject survival,   
• 
Graft rejection based on kidney biopsy results and 2017 Banff Kidney Meeting Report, 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 56 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
• 
BKV nephropathy: based on kidney biopsy results and the Banff Working Group on 
Polyomavirus Nephropathy classification system 
NOTE: Renal biopsies are not mandated, but if they are performed during the study period, 
results will be recorded in the eCRF. The assessments are incorporated into endpoints 
analyzed for efficacy. See Section 10.5, Efficacy Analysis. 
8.5 
Safety 
Safety assessments are specified below. 
8.5.1 
Pregnancy 
Pregnancy tests (urine or serum) of β-hCG are required of all female study participants of 
childbearing potential within 96 hours prior to Study Day 1. In addition, urine or serum pregnancy 
testing for all females of childbearing potential will be performed before infusions #2 on Day 28, 
#3 on Day 56 and #4 on Day 84.  
8.5.2 
Physical Examination 
Information from physical examinations will be kept at the clinical site as source data and will not 
be transferred to the Sponsor as part of the study analysis (i.e., recorded in the eCRF) unless 
findings are related to an adverse event or are otherwise significant (and so are reported as an 
adverse event or medical history). 
The eCRF manual provides more details. 
8.5.3 
Vital Signs 
Vital signs will include temperature, blood pressure, heart rate, respiratory rate, and oxygen 
saturation. 
8.5.4 
Laboratory Evaluations 
Clinically relevant deviations of laboratory test results occurring during or at completion of the 
study should be evaluated for criteria defining an adverse event and reported as such if the criteria 
are met. See Section 9, Safety Assessments. 
Screening laboratory assessments to determine eligibility should be performed at the local 
laboratory and may be collected as standard of care within 10 days prior to Study Day 1 (Baseline). 
Laboratory assessments collected after Screening will be sent to the central laboratory for analysis.  
Clinical laboratory assessments (serum chemistry, hematology [including CBC with differential], 
and urinalysis) will occur at Screening, and on Days 1 (Baseline), 14, 28, 56, 84, 112, 140 and 
252. These assessments will also occur at the Early Termination Visit (if applicable).  
A urine or serum pregnancy test will be performed locally at Screening.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 57 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
If clinically indicated and at the discretion of the Investigator, or if a suspected adverse event is 
identified, clinical laboratory assessments may be conducted at any time during the study and 
compared to Baseline. See Appendix B for a complete list of clinical laboratory analytes. 
8.5.5 
Electrocardiogram 
Standard 12-lead electrocardiograms (ECGs) will be performed in a supine position. Interpretation 
of the tracing must be made by a qualified physician and documented on the ECG / in the ECG 
section of the eCRF. Original ECG tracings, appropriately signed, will be archived at the study 
site. 
8.5.6 
Pharmacokinetics 
PK samples will be collected at the timepoints defined in the Schedule of Events (Appendix A). 
Follow instructions outlined in the Laboratory Manual. regarding sample collection, numbering, 
processing and shipment. See Section 8.3, Use of Residual Biological Samples. 
MAU868 levels in serum will be determined by a validated ELISA-based method. A detailed 
description of the method used will be included in the PK bioanalytical data report.  
Actual time of dosing and actual times of blood collection will be recorded on the PK blood 
collection eCRF page. For a detailed description of blood sampling, handling, labeling and 
shipment instructions please refer to the Laboratory Manual.  
PK samples obtained after study drug infusion should be collected from a vein opposite the arm 
into which the study drug was infused.  
Results of PK samples will not be reported to the site. These samples will be analyzed, and the 
results reported by centralized third-party specialty labs.  
8.5.7 
BKV by PCR Sample Collection 
Plasma and urine for BKV by PCR samples will be collected at the timepoints defined in the 
Schedule of Events (Appendix A). Follow the instructions outlined in the Laboratory Manual, 
regarding sample collection, numbering, processing and shipment.  
8.5.8 
Other Assessments: Viral Resistance and Immunogenicity 
To monitor for the possible development of resistance-associated variants (RAVs) to MAU868, 
the BKV VP1 coding region will be sequenced and translated to the corresponding amino acid 
sequence. The VP1 amino acid sequences from subjects will be aligned to their corresponding 
baseline sequences (derived from BKV detected in the urine at Baseline) and reference isolate 
sequences to determine if any change from-baseline or change-from-reference RAVs are present. 
The susceptibility of RAVs to MAU868 will be determined by cloning the subject derived VP1 
gene into a BKV reference isolate vector, generating a chimeric virus for MAU868 phenotypic 
assessment. The EC50 and EC90 values and fold change from baseline and reference values will 
be reported. If the resulting chimeric virus does not replicate, the individual RAV(s) may be 
engineered directly into the BKV reference isolate vector through site-directed mutagenesis and 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 58 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
assessed for susceptibility to neutralization by MAU868. The emergence of RAV(s) conferring 
reduced susceptibility will be correlated to the MAU868 exposure. For subjects with confirmed 
RAV(s) displaying reduced MAU868 susceptibility, the persistence of the RAV(s) will be 
monitored for at least 6 months following the end of MAU868 therapy by periodic BKV 
sequencing provided the virus remains detectable in either the blood or the urine. To date, no 
epitope-mutant BK viruses with both a significant loss of susceptibility to MAU868 and a 
preservation of replicative fitness have been identified. 
Details of viral resistance monitoring and detection will be described in the Virology Analysis 
Plan. 
Immunogenicity will be evaluated using a validated ligand binding assay (ELISA or MSD) for the 
detection of potential anti-MAU868 antibodies.  
The detailed methods for immunogenicity assessment will be described in the Bioanalytical Data 
Report. 
Results of the viral resistance and immunogenicity samples will not be reported to the site. These 
samples will be analyzed, and the results reported by centralized third-party specialty labs.  
8.6 
Other Samples 
8.6.1 
Use of Residual Biological Samples 
Any residual blood or urine samples remaining at the central laboratories after the protocol-defined 
analyses have been performed may be used for additional exploratory analyses and will be 
completed within 5 years after the protocol defined analyses are reported.  These exploratory 
analyses may include, but are not necessarily limited to, investigations of other biomarkers related 
to kidney disease or kidney function, other immunologic markers, other viral RNA or DNA, 
protein binding, metabolite profiling, biomarkers of transporters or metabolic enzyme activity 
(such as 4-beta-hydroxycholesterol levels) or other bioanalytical purposes (e.g., investigations 
related to individual infusion reactions or other adverse events). Given the exploratory nature of 
the work, the analytical methods used for these investigations may not be validated. The results 
from these exploratory analyses, if pursued, will not be included in the clinical study report. 
9 
SAFETY ASSESSMENTS 
9.1 
Adverse Events 
An adverse event is defined as any untoward medical occurrence in a patient or clinical 
investigation subject administered a pharmaceutical product, which does not necessarily have a 
causal relationship with this treatment. An adverse event can therefore be any unfavorable and/or 
unintended sign (including an abnormal laboratory finding), symptom, or disease temporally 
associated with the use of study drug, whether or not related to the study drug. All adverse events, 
including observed or volunteered problems, complaints, or symptoms, are to be recorded on the 
appropriate eCRF. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 59 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Adverse events, which include clinical laboratory test variables, will be monitored and 
documented from the time the subject signs consent through the Follow Up Visit. Subjects should 
be instructed to report any adverse event that they experience to the Investigator, whether or not 
they think the event is due to study drug. Beginning at Screening (following completion of an 
Informed Consent Form by the subject), Investigators should make an assessment for adverse 
events at each visit and record the event on the appropriate adverse event eCRF. 
Wherever possible, a specific disease or syndrome rather than individual associated signs and 
symptoms should be identified by the Investigator and recorded on the eCRF. However, if an 
observed or reported sign or symptom is not considered a component of a specific disease or 
syndrome by the Investigator, it should be recorded as a separate adverse event on the eCRF. 
Additionally, the condition that led to a medical or surgical procedure (e.g., surgery, endoscopy, 
tooth extraction, or transfusion) should be recorded as an adverse event, not the procedure itself.  
Any medical condition already present at consent should be recorded as medical history and not 
be reported as an adverse event unless the medical condition or signs or symptoms present at 
Baseline changes in severity, frequency, or seriousness at any time during the study. In this case, 
it should be reported as an adverse event. 
Subjects who develop treatment-related SAEs, treatment-related Grade 3 or higher AEs, or 
clinically significant treatment-related Grade 3 or higher laboratory abnormalities should be 
followed until resolution of the AE or laboratory abnormality, or, if the AE or laboratory 
abnormality was present at baseline, until the value returns to baseline level. 
Clinically significant abnormal laboratory or other examination (e.g., ECG) findings that are 
detected during the study or are present at initial dosing and significantly worsen during the study 
should be reported as adverse events, as described below. The Investigator will exercise his or her 
medical and scientific judgment in deciding whether an abnormal laboratory finding or other 
abnormal assessment is clinically significant. Clinically significant abnormal laboratory values 
occurring during the clinical study will be followed until repeat tests return to normal, stabilize, or 
are no longer clinically significant. Abnormal test results that are determined to be an error should 
not be reported as an adverse event. Laboratory abnormalities or other abnormal clinical findings 
(e.g., ECG abnormalities) should be reported as an adverse event if any of the following are 
applicable: 
• 
If an intervention is required as a result of the abnormality 
• 
If action taken with the study drug is required as a result of the abnormality 
• 
Based on the clinical judgment of the Investigator  
9.1.1 
Adverse (Drug) Reaction 
All noxious and unintended responses to a study drug related to any dose should be considered an 
adverse drug reaction. “Responses” to a study drug means that a causal relationship between a 
study drug and an adverse event is at least a reasonable possibility, i.e., the relationship cannot be 
ruled out. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 60 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
9.1.2 
Unexpected Adverse Drug Reaction 
An Unexpected Adverse Drug Reaction is defined as an adverse reaction, the nature or severity of 
which is not consistent with the applicable product information. For MAU868 the reference safety 
information is included in the IB currently in force. The reference safety information will be 
reviewed yearly, and the periodicity of the review will be harmonized with the reporting period of 
the Development Safety Update Report. 
9.1.3 
Assessment of Adverse Events by the Investigator 
The Investigator will assess the severity (intensity) of each adverse event and will also categorize 
each adverse event as to its potential relationship to study drug using the categories of “yes” or 
“no.” 
Assessment of Severity 
The severity of all adverse events should be graded according to the CTCAE v5.0. For those 
adverse event terms not listed in the CTCAE, the following grading system should be used: 
• 
CTCAE Grade 1: Mild; asymptomatic or mild symptoms; clinical or diagnostic observations 
only; intervention not indicated 
• 
CTCAE Grade 2: Moderate; minimal local or noninvasive intervention indicated; limiting 
age-appropriate instrumental activities of daily living 
• 
CTCAE Grade 3: Severe or medically significant but not immediately life-threatening; 
hospitalization or prolongation of hospitalization indicated; disabling; limiting self-care 
activities of daily living 
• 
CTCAE Grade 4: Life threatening consequences; urgent intervention indicated 
CTCAE Grade 5: Death related to the adverse event 
Causality Assessment 
The relationship of an adverse event to the administration of the study drug is to be assessed 
according to the following definitions: 
No (not related, unlikely to be related) – The time course between the administration of study drug 
and the occurrence or worsening of the adverse event rules out a causal relationship and another 
cause (concomitant drugs, therapies, complications, etc) is suspected. 
Yes (possibly, probably, or definitely related) – The time course between the administration of 
study drug and the occurrence or worsening of the adverse event is consistent with a causal 
relationship and no other cause (concomitant drugs, therapies, complications, etc) can be 
identified. 
The definition implies a reasonable possibility of a causal relationship between the event and the 
study drug. This means that there are facts (evidence) or arguments to suggest a causal relationship. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 61 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
The following factors should also be considered: 
 
The temporal sequence from study drug administration 
The event should occur after the study drug is given. The length of time from study drug 
exposure to event should be evaluated in the clinical context of the event. 
 
Underlying, concomitant, intercurrent diseases 
Each report should be evaluated in the context of the natural history and course of the disease 
being treated and any other disease the subject may have. 
 
Concomitant drug 
The other drugs the subject is taking or the treatment the subject receives should be examined 
to determine whether any of them might be recognized to cause the event in question. 
 
Known response pattern for this class of study drug.  
Clinical and/or preclinical data may indicate whether a particular response is likely to be a 
class effect. 
 
Exposure to physical and/or mental stresses 
The exposure to stress might induce adverse changes in the recipient and provide a logical 
and better explanation for the event. 
 
The pharmacology and PK of the study drug.  
The known pharmacologic properties (absorption, distribution, metabolism, and excretion) of 
the study drug should be considered. 
9.1.4 
 AEs of Special Interest 
For subjects experiencing infusion-associated AEs, the Investigator, or designee, is responsible for 
determining if immediate discontinuation of study therapy is required (see Section 3.3.2).  
In addition, for all cases of AEs associated with study infusion that occur during or within 2 hours 
after the completion of infusion require enhanced reporting using the specified Infusion-associated 
AE Report eCRF, regardless of whether drug discontinuation criteria are met. 
Note:  All treatment-related AEs of grade 3 or higher and treatment-related AEs of cytokine 
release syndrome and serum sickness of grate 2 or higher require discontinuation from study 
drug (see Section 3.3.2). 
9.2 
Serious Adverse Events 
An adverse event or adverse reaction is considered serious if, in the view of either the Investigator 
or Sponsor, it results in any of the following outcomes: 
 
Death. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 62 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
• 
A life-threatening adverse event. 
Note: An adverse event or adverse reaction is considered “life-threatening” if, in view of 
either the Investigator or Sponsor, its occurrence places the subject at immediate risk of death. 
It does not include an event that, had it occurred in a more severe form, might have caused 
death. 
• 
Requires hospitalization or prolongation of existing hospitalizations. 
Note: Any hospital admission with at least one overnight stay will be considered an inpatient 
hospitalization. An emergency room or urgent care visit without hospital admission will not 
be recorded as a SAE under this criterion, nor will hospitalization for a procedure scheduled 
or planned before signing of informed consent, or elective treatment of a pre-existing 
condition that did not worsen from Baseline. However, unexpected complications and/or 
prolongation of hospitalization that occur during elective surgery should be recorded as 
adverse events and assessed for seriousness. Admission to the hospital for social or situational 
reasons (i.e., no place to stay, live too far away to come for hospital visits, respite care) will 
not be considered inpatient hospitalizations.  
• 
A persistent or significant disability/incapacity or substantial disruption of the ability to 
conduct normal life functions. 
• 
A congenital anomaly/birth defect. 
• 
An important medical event. 
Note: Important medical events that do not meet any of the above criteria may be considered 
an SAE when, based upon appropriate medical judgment, they may jeopardize the subject and 
may require medical or surgical intervention to prevent one of the outcomes listed 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 
inpatient hospitalizations, or the development of drug dependency. 
Note:  All treatment related SAEs require discontinuation from study drug (see Section 3.3.2) 
9.3 
Serious Adverse Event Reporting − Procedures for Investigators 
9.3.1 
Initial Reports 
All SAEs occurring from the time of initial dosing until the Follow Up Visit must be reported to 
Medpace Clinical Safety within 24 hours of the knowledge of the occurrence (After the Follow 
Up Visit, any SAE that the Investigator considers related to study drug must be reported to the 
Medpace Clinical Safety or the Sponsor/designee). 
To report the SAE, complete the SAE form electronically in the electronic data capture (EDC) 
system for the study. When the form is completed, Medpace Safety personnel will be notified 
electronically by the EDC system and will retrieve the form. If the event meets serious criteria and 
it is not possible to access the EDC system, send an email to Medpace Safety at Medpace 
safetynotification@medpace.com  or call the Medpace SAE reporting line (phone number listed 
below), and fax/email the completed paper SAE form to Medpace (contact information listed in 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 63 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Section 13.2 Address List) within 24 hours of awareness. When the EDC system becomes 
available, the SAE information must be entered within 24 hours of the system becoming available. 
Safety Contact Information: 
Medpace Clinical Safety 
Medpace SAE reporting line – USA: 
Telephone: +1-800-730-5779, dial 3 or +1-513-579-9911, dial 3 
Fax: +1-866-336-5320 or +1-513-570-5196 
Email: Medpace-safetynotification@medpace.com  
9.3.2 
Follow-up Reports 
The Investigator must continue to follow the subject until the SAE has subsided or until the 
condition becomes chronic in nature, stabilizes (in the case of persistent impairment), or the subject 
dies. 
Within 24 hours of receipt of follow-up information, the Investigator must update the SAE form 
electronically in the EDC system for the study and submit any supporting documentation 
(eg, patient discharge summary or autopsy reports) to Medpace Clinical Safety via fax or email. 
If it is not possible to access the EDC system, refer to the procedures outlined above for initial 
reporting of SAEs.  
9.4 
Pregnancy Reporting 
If a subject becomes pregnant during the treatment period, the Investigator is to stop dosing with 
study drug immediately.  
A pregnancy is not considered to be an adverse event or SAE; however, it must be reported to 
Medpace Clinical Safety within 24 hours of knowledge of the event. Medpace Clinical Safety will 
then provide the Investigator/site the Exposure In Utero (EIU) form for completion. 
The Investigator/site must complete the EIU form and fax/email it back to Medpace Clinical 
Safety.  
If the female partner of a male subject becomes pregnant while the subject is receiving study drug 
or within the safety follow-up period defined in the protocol, the Investigator should notify 
Medpace Clinical Safety as described above.  
The pregnancy should be followed until the outcome of the pregnancy, whenever possible. Once 
the outcome of the pregnancy is known, the EIU form should be completed and faxed/emailed to 
Medpace Clinical Safety. If the outcome of the pregnancy meets the criteria for immediate 
classification as an SAE (i.e., postpartum complication, spontaneous abortion, stillbirth, neonatal 
death, or congenital anomaly), the Investigator should follow the procedures for reporting an SAE. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 64 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
9.5 
Expedited Reporting 
The Sponsor/designee will report all relevant information about Suspected Unexpected Serious 
Adverse Reactions (SUSAR) that are fatal or life-threatening as soon as possible to the Food and 
Drug Administration (FDA), Health Canada, and to the Central Ethics Committee, and in any case 
no later than 7 days after knowledge by the Sponsor/designee of such a case. Relevant follow-up 
information will subsequently be communicated within an additional 8 days.  
All other SUSARs will be reported to the FDA, applicable competent authorities concerned, and 
to the Central Ethics Committee concerned as soon as possible but within a maximum of 15 days 
of first knowledge by the Sponsor/designee.  
The Sponsor/designee will also report any additional expedited safety reports required in 
accordance with the timelines outlined in country-specific legislation.  
The Sponsor/designee will also inform all Investigators as required per local regulation. 
The requirements above refer to the requirements relating to Study MAU868-201. 
9.6 
Special Situation Reports 
Special situation reports include reports of overdose, misuse, abuse, medication error, and reports 
of adverse reactions associated with product complaints. 
• 
Overdose: Refers to the administration of a quantity of a study drug given per administration 
or cumulatively (accidentally or intentionally), which is above the maximum recommended 
dose according to the protocol. Clinical judgment should always be applied. In cases of a 
discrepancy in the drug accountability, overdose will be established only when it is clear that 
the subject has taken additional dose(s) or the Investigator has reason to suspect that the 
subject has taken additional dose(s).  
• 
Misuse: Refers to situations where the study drug is intentionally and inappropriately used 
not in a way that is not in accordance with the protocol instructions or local prescribing 
information and may be accompanied by harmful physical and/or psychological effects.  
• 
Abuse: Is defined as persistent or sporadic, intentional excessive use of a study drug, which 
is accompanied by harmful physical or psychological effects. 
• 
Medication error: Is any unintentional error in the prescribing, dispensing, or administration 
of a study drug by a healthcare professional, patient, or consumer, respectively. 
The administration or consumption of the unassigned treatment and administration of an 
expired product are always reportable as medication errors, cases of subjects missing doses 
of study drug are not considered reportable as medication error. 
• 
Product complaint: Is defined as any written, electronic, or oral communication that alleges 
deficiencies related to the identity, quality, durability, reliability, safety, effectiveness, 
or performance of a drug or device after it is released for distribution. A special situations 
form will only be completed if a complaint is associated with an adverse drug reaction.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 65 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
All special situation events as described above must be reported on the Special Situations Report 
form and faxed/emailed to Medpace Clinical Safety (contact information listed below) within 
24 hours of knowledge of the event. All adverse events associated with these Special Situation 
reports should be reported as adverse events or SAEs as well as recorded on the adverse event 
eCRF and/or the SAE report form. Details of the symptoms and signs, clinical management, 
and outcome should be provided, when available. 
Safety Contact Information:  
Medpace Clinical Safety 
Medpace SAE reporting line – USA: 
Telephone: +1-800-730-5779, dial 3 or +1-513-579-9911, dial 3 
Fax: +1-866-336-5320 or +1-513-570-5196 
Email: Medpace-safetynotification@medpace.com  
9.7 
Data Safety Monitoring Board 
An independent data safety monitoring board (DSMB) will review cumulative unblinded safety 
data as outlined in the DSMB charter.   
9.8 
Evaluations for Safety 
See Section 7, Study Procedures for a description of various tests performed during this study. 
See Appendix A for a complete list of clinical laboratory analytes and Appendix A, Schedule of 
Events, for timing of various determinations. 
10 
STATISTICS 
A detailed analysis plan will be described in a separate Statistical Analysis Plan (SAP). The SAP 
will supersede the protocol in the event of any differences between the 2 documents in the plans 
for data analysis, and the protocol will be amended if appropriate. The SAP will be included as an 
appendix in the clinical study report for this protocol. 
10.1 
General Design and Analysis 
This is a randomized, double-blind, placebo-controlled Phase 2 study to assess the safety, 
tolerability, and efficacy of MAU868 for the treatment of BK viremia in kidney transplant 
recipients. The study will be conducted at approximately 20 clinical trial sites in the United States 
and Canada. 
The Study includes a Screening Period (up to 10 days), a double-blind, placebo-controlled, 
randomized Treatment Period (12 weeks) and a Follow-up Period of 24 weeks.  
Approximately 36 subjects will be randomized. Cohorts 1, 2 and 3 will randomize subjects to 1 of 
2 treatment arms in a ratio of 2:1 (MAU868: placebo).  Treatment groups within each cohort are: 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 66 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Cohort 1 
• 
MAU868 1350 mg IV q28 days for 4 doses 
• 
Placebo (D5W) q28 days for 4 doses 
Cohort 2 
• 
MAU868 6750 mg Study Day 1 then 1350 mg IV q28 days for 3 doses (4 doses total) 
• 
Placebo (D5W) q28 days for 4 doses 
Cohort 3 
• 
MAU868 6750 mg IV q28 days for 4 doses 
• 
Placebo (D5W) q28 days for 4 doses 
10.2 
Determination of Sample Size 
This study will randomize approximately 36 subjects (12 per cohort) to MAU868 and placebo in 
a 2:1 ratio (24 MAU868 and 12 placebo; 8 MAU868 and 4 placebo per cohort).  This study is not 
powered to an efficacy endpoint.  The number of subjects chosen will provide data useful in 
determining proof of concept. 
10.3 
Analysis Populations 
The primary efficacy analysis will be performed in the modified ITT (MITT) analysis population. 
The MITT includes subjects who meet all of the following criteria: 
• 
Received at least 1 dose of study drug.  
• 
Has at least 1 post baseline plasma BKV PCR result available. 
Additional analyses will be performed in the intent-to-treat (ITT) analysis population (all subjects 
randomized). The safety population will include all subjects who received at least 1 dose of study 
drug. The PK population will include all subjects with at least 1 post baseline PK sample available.   
10.4 
Safety Analysis 
The primary objective of this study is to assess the safety and tolerability of MAU868 as measured 
by adverse events, vital signs (blood pressure, pulse rate, body temperature, oxygen saturation), 
ECG, and laboratory measurements. 
10.5 
Efficacy Analysis 
Efficacy objectives of this study are secondary and include: 
• 
To assess the impact of MAU868 on BKV related outcomes including viremia, 
BKV nephropathy, graft function and rejection among renal transplant patients with 
BK viremia 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 67 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
• 
To assess the pharmacokinetics of MAU868 
Exploratory: 
• 
To investigate the potential immunogenicity of MAU868 
• 
To investigate genotypic resistance 
10.5.1 
Efficacy Endpoints 
The efficacy endpoints for this study are: 
• 
Time (weeks) to decrease of BKV plasma viral load by 1 log 
• 
Time (weeks) to decrease of BKV plasma viral load to < lower limit of detection 
• 
Proportion of subjects with > 1 log decrease of BKV plasma viral load at 1 week, 2 weeks, 
4 weeks, 8 weeks, 12 weeks, and 36 weeks  
• 
Proportion of subjects with BKV plasma viral load to < lower limit of detection at 1 week, 
2 weeks, 4 weeks, 8 weeks, 12 weeks, and 36 weeks  
• 
Rate of decrease in BKV plasma viral load over time.  
• 
Change in eGFR from baseline to Week 12 and from baseline to Week 36 calculated using 
CK-EPI 
• 
Proportion of subjects with BKV nephropathy 
• 
Proportion of subjects with graft failure 
• 
Proportion of subjects with acute rejection 
• 
Survival 
Exploratory: 
• 
Presence of anti-drug antibodies (ADA) 
• 
Presence of genotypic resistance 
Statistical Methods 
Efficacy Analyses 
In all efficacy analyses, the placebo subjects from the cohorts will be combined.   Thus, the analysis 
models will include treatment group (four levels: placebo, low dose, medium dose, high dose) as 
a factor. Time-to-event endpoints will be analyzed using Cox proportional hazards regression 
models.  Proportion endpoints will be analyzed using logistic regression models. Quantitative 
endpoints will be analyzed using one-way analysis of variance (ANOVA) models.  In all analyses, 
pairwise contrasts comparing each of the three active groups to the combined placebo group will 
be tested.  All efficacy analyses will be conducted using two-sided tests at the alpha=0.05 level of 
significance, with no adjustment for multiplicity. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 68 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Additional efficacy analyses will be conducted using the data from each cohort. Quantitative 
endpoints will be analysed using the two-sample t test and proportion endpoints will be analysed 
using Fisher’s exact test. Due to the small sample sizes, time-to-event variables will be 
summarized descriptively. Details of the data and process for the interim analyses will be described 
in the Statistical Analysis Plan and SSRC Charter. 
Safety Analyses 
All safety analyses will be performed on data from the Safety Analysis Population. Adverse events 
(AEs), vital signs, ECGs and clinical laboratory evaluations will be summarized by appropriate 
descriptive statistics.  
Pharmacokinetic Analysis 
MAU868 levels in serum will be determined by a validated ELISA-based method. A detailed 
description of the method used will be included in the PK bioanalytical data report. The anticipated 
LLOQ is 50.0 ng/mL. Concentrations will be expressed in mass per volume units (e.g., ng/mL). 
Missing values or those concentrations below the LLOQ will be labeled as such in the data listings 
and reported as “zero” in data presentations and calculations. 
MAU868 serum concentration data will be listed by subject and visit/sampling time point. 
Descriptive summary statistics of trough levels will be provided by visit/sampling time point, 
including the frequency (n, %) of concentrations below the LLOQ and reported as zero. Summary 
statistics will include mean (arithmetic and geometric), SD, CV (arithmetic and geometric), 
median, minimum and maximum. Concentrations below LLOQ will be treated as zero in summary 
statistics.  
10.6 
Disposition, Demographics and Baseline Characteristics 
Enrollment and randomization, protocol deviations, disposition and demographic data will be 
summarized and listed by treatment group Continuous variables will be summarized by treatment 
group and combined using traditional statistics such as number of subjects, mean, median, standard 
deviation, minimum and maximum. Categorical variables will be summarized using frequency 
counts and percentages.  
No inferential testing will be performed. 
10.7 
Concomitant Medications 
Prior and concomitant medications will be identified using the most current version of the 
WHO Drug dictionary. The incidence of prior and concomitant medications will be summarized. 
10.8 
Safety 
Adverse events, vital signs (blood pressure, pulse rate, body temperature), ECG intervals, 
laboratory results, and ADA results will be summarized and listed by treatment group.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 69 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
10.8.1 
Vital Signs 
All vital signs data will be listed by treatment, subject, and visit/time and if normal ranges are 
available, abnormalities (and relevant orthostatic changes) will be flagged. Summary statistics will 
be provided by treatment and visit/time. 
10.8.2 
ECG Evaluations 
All ECG data will be listed by treatment, subject and visit/time, abnormalities will be flagged. 
Summary statistics will be provided by treatment and visit/time. 
10.8.3 
Clinical Laboratory Evaluations 
All laboratory data will be listed by treatment, subject, and visit/time and abnormalities will be 
flagged. Summary statistics will be provided by treatment and visit/time. 
10.8.4 
Adverse Events 
All information obtained on adverse events will be displayed by treatment and subject. 
The number and percentage of subjects with adverse events overall, treatment emergent AEs 
(TEAEs), related TEAEs, TEAEs leading to discontinuation of study drug or study and serious 
TEAEs will be tabulated by System Organ Class and preferred term with a breakdown by 
treatment. A subject with multiple adverse events within a body system is only counted once 
towards the total of this body system. 
10.8.5 
Pharmacokinetics 
Population PK will be performed on all subjects. The PK analysis of MAU868 plasma 
concentration data will be performed using validated software in order to derive the population 
mean (and variance) values of specific PK parameters. Plasma concentrations will be summarized 
descriptively by time point of collection. 
The PK endpoints for MAU868 are: area under the concentration-time curve to the end of the 
dosing period (AUC0-24), area under the concentration-time curve up to the last measurable 
concentration (AUC0-last), concentration at the end of infusion (Ceoi) and minimum concentration 
observed (Ctrough). Plasma samples for pharmacokinetic (PK) evaluations will be collected at the 
time points described in the Schedule of Events (Appendix A). 
Results of the PK analysis will be reported separately. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 70 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
10.8.6 
Interim Analysis 
Interim Analyses 
Following completion of the 12-week treatment period of Cohort 1, unblinded safety and 
tolerability data (adverse events, clinical laboratories, vitals/physical exams and ECGs), efficacy 
data (BKV viral load in the plasma) and PK (MAU868 plasma levels) will be reviewed by the 
Sponsor Study Review Committee (SSRC). The treatment assignment in Cohort 1 will be 
unblinded; however, these data will not include associated subject or site identifiers. The objectives 
of this interim analysis are to evaluate whether four doses MAU868 1350 mg IV administered 
every 28 days for a total of 4 doses demonstrate: 
• 
safety and tolerability signals compared to placebo 
• 
a decrease in BK plasma viral load compared to placebo 
• 
predicted MAU868 plasma levels 
The conclusions from this first analysis will be used by the Sponsor to evaluate the safety and 
efficacy of MAU868 early-on in this first-in-patient study. Unless a significant safety issue related 
to administration of MAU868 has been identified, the conclusions will have no impact on Cohort 2 
or the study’s design. 
Following completion of the 12-week treatment periods for Cohorts 1 and 2, cumulative unblinded 
data from both cohorts will be reviewed for safety and tolerability (adverse events, clinical 
laboratories, vitals/physical exams and ECGs), efficacy (BKV viral load in the plasma) and PK 
(MAU868 plasma levels). The treatment assignments will be unblinded; however, these data will 
not include associated subject or site identifiers. The objectives of this second interim analysis are 
to evaluate whether four doses MAU868 1350 mg IV administered every 28 days for a total of 
4 doses or MAU868 6750 mg IV administered as a first dose followed by 3 more doses of 
MAU868 1350 mg IV administered every 28 days demonstrate: 
• 
safety and tolerability signals compared to placebo 
• 
a decrease in viral load compared to placebo 
• 
predicted MAU868 plasma levels 
Based on the SSRC’s safety, efficacy and PK conclusions for Cohorts 1 and 2, the dosing regimen 
for Cohort 3 may be adjusted in dosage and/or duration; however, the dosage and duration for 
Cohort 3 will not exceed the dose already specified in the protocol. Cohort 3 will not be opened 
for screening and enrollment this evaluation has been completed 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 71 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
11 
DATA MANAGEMENT AND RECORD KEEPING 
11.1 
Data Management 
11.1.1 
Data Handling 
Data will be recorded at the site on eCRFs and reviewed by the CRA during monitoring visits. 
The CRAs will verify data recorded in the EDC system with source documents. All corrections or 
changes made to any study data must be appropriately tracked in an audit trail in the EDC system. 
An eCRF will be considered complete when all missing, incorrect, and/or inconsistent data has 
been accounted for. 
11.1.2 
Computer Systems 
Data will be processed using a validated computer system conforming to regulatory requirements. 
11.1.3 
Data Entry 
Data must be recorded using the EDC system as the study is in progress. All site personnel must 
log into the system using their secure username and password in order to enter, review, or correct 
study data. These procedures must comply with Title 21 of the Code of Federal Regulations 
(21 CFR Part 11) and other appropriate international regulations. All passwords will be strictly 
confidential. 
11.1.4 
Medical Information Coding 
For medical information, the following thesauri will be used: 
• 
Medical Dictionary for Regulatory Activities (latest) for medical history and adverse events 
• 
World Health Organization Drug Dictionary for prior and concomitant medications 
11.1.5 
Data Validation 
Validation checks programmed within the EDC system, as well as supplemental validation 
performed via review of the downloaded data, will be applied to the data in order to ensure 
accurate, consistent, and reliable data. Data identified as erroneous, or data that are missing, will 
be referred to the investigative site for resolution through data queries. The eCRFs must be 
reviewed and electronically signed by the Investigator. 
11.2 
Record Keeping 
Records of subjects, source documents, monitoring visit logs, eCRFs, inventory of study drug, 
regulatory documents, and other Sponsor correspondence pertaining to the study must be kept in 
the appropriate study files at the site. Source data is defined as all information in original records 
and certified copies of original records of clinical findings, observations, or other activities in a 
clinical study necessary for the evaluation and reconstruction of the clinical study. Source data are 
contained in source documents (original records or certified copies). These records will be retained 
in a secure file for the period as set forth in the Clinical Study Agreement. Prior to transfer or 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 72 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
destruction of these records, the Sponsor must be notified in writing and be given the opportunity 
to further store such records.  
12 
INVESTIGATOR REQUIREMENTS AND QUALITY CONTROL 
12.1 
Ethical Conduct of the Study 
Good Clinical Practice is an international ethical and scientific quality standard for designing, 
conducting, recording, and reporting studies that involve human subjects. Compliance with this 
standard provides public assurance that the rights, safety, and wellbeing of study subjects are 
protected, consistent with the principles that have their origin in the Declaration of Helsinki, 
and that the clinical study data are credible. 
12.2 
Institutional Review Board/Independent Ethics Committee 
The IRB/IEC will review all appropriate study documentation in order to safeguard the rights, 
safety, and well-being of subjects. The study will only be conducted at sites where IRB/IEC 
approval has been obtained. The protocol, IB, informed consent form (ICF), advertisements 
(if applicable), written information given to the subjects, safety updates, annual progress reports, 
and any revisions to these documents will be provided to the IRB/IEC by the Investigator. 
Federal regulations and International Council for Harmonization (ICH) Guidelines require that 
approval be obtained from an IRB/IEC prior to participation of subjects in research studies. Prior to 
study onset, the protocol, any protocol amendments, ICFs, advertisements to be used for subject 
recruitment, and any other written information regarding this study to be provided to a subject 
must be approved by the IRB/IEC. 
No drug will be released to the site for dosing until written IRB/IEC authorization has been 
received by the Sponsor. 
12.3 
Informed Consent 
The ICF and any changes to the ICF made during the course of the study must be agreed to by the 
Sponsor or designee and the IRB prior to its use and must be in compliance with all ICH GCP, 
local regulatory requirements, and legal requirements.   
The Investigator must ensure that each study subject is fully informed about the nature and 
objectives of the study and possible risks associated with participation and must ensure that the 
subject has been informed of his/her rights to privacy. The Investigator will obtain written 
informed consent from each subject before any study-specific activity is performed and should 
document in the source documentation that consent was obtained prior to enrollment in the study. 
The original signed copy of the ICF must be maintained by the Investigator and is subject to 
inspection by a representative of the Sponsor, their representatives, auditors, the IRB and/or 
regulatory agencies. A copy of the signed ICF will be given to the subject. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 73 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
12.4 
Subject Card 
On enrollment in the study, the subject will receive a subject card to be carried at all times. 
The subject card will state that the subject is participating in a clinical research study, type of 
treatment, and contact details in case of an SAE. 
12.5 
Study Monitoring Requirements 
It is the responsibility of the Investigator to ensure that the study is conducted in accordance with 
the protocol, ICH GCP, Directive 2001/20/EC, applicable regulatory requirements, and the 
Declaration of Helsinki and that valid data are entered into the eCRFs. 
To achieve this objective, the monitor’s duties are to aid the Investigator and, at the same time, 
the Sponsor in the maintenance of complete, legible, well organized and easily retrievable data. 
Before the enrollment of any subject in this study, the Sponsor or their designee will review with 
the Investigator and site personnel the following documents: protocol, IB, eCRFs and procedures 
for their completion, informed consent process, and the procedure for reporting SAEs. 
The Investigator will permit the Sponsor or their designee to monitor the study as frequently as 
deemed necessary to determine that data recording and protocol adherence are satisfactory. During 
the monitoring visits, information recorded on the eCRFs will be verified against source 
documents and requests for clarification or correction may be made. After the eCRF data is entered 
by the site, the CRA will review the data for safety information, completeness, accuracy, 
and logical consistency. Computer programs that identify data inconsistencies may be used to help 
monitor the clinical study. If necessary, requests for clarification or correction will be sent to 
Investigators. The Investigator and his/her staff will be expected to cooperate with the monitor and 
provide any missing information, whenever possible. 
All monitoring activities will be reported and archived. In addition, monitoring visits will be 
documented at the investigational site by signature and date on the study-specific monitoring log. 
12.6 
Disclosure of Data 
Data generated by this study must be available for inspection by the FDA, the Sponsor or their 
designee, applicable foreign health authorities, and the IRB as appropriate. Subjects may request 
their medical information be given to their personal physician or other appropriate medical 
personnel responsible for their welfare. 
Patient medical information obtained during the study is confidential and disclosure to third parties 
other than those noted above is prohibited. 
12.7 
Retention of Records 
To enable evaluations and/or audits from regulatory authorities or the Sponsor, the Investigator 
will keep records, including the identity of all participating subjects (sufficient information to link 
records, e.g., eCRFs and hospital records), all original signed ICFs, copies of all eCRFs, 
SAE forms, source documents, and detailed records of treatment disposition. The records should 
be retained by the Investigator according to specifications in the ICH guidelines, local regulations, 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 74 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
or as specified in the Clinical Study Agreement, whichever is longer. The Investigator must obtain 
written permission from the Sponsor before disposing of any records, even if retention 
requirements have been met. 
If the Investigator relocates, retires, or for any reason withdraws from the study, the Sponsor should 
be prospectively notified. The study records must be transferred to an acceptable designee, such 
as another Investigator, another institution, or to the Sponsor.   
12.8 
Publication Policy 
Following completion of the study, the data may be considered for publication in a scientific 
journal or for reporting at a scientific meeting. Each Investigator is obligated to keep data 
pertaining to the study confidential. The Investigator must consult with the Sponsor before any 
study data are submitted for publication. The Sponsor reserves the right to deny publication rights 
until mutual agreement on the content, format, interpretation of data in the manuscript, and journal 
selected for publication are achieved. 
12.9 
Financial Disclosure 
Investigators are required to provide financial disclosure information to the Sponsor to permit the 
Sponsor to fulfill its obligations under 21 CFR Part 54. In addition, Investigators must commit to 
promptly updating this information if any relevant changes occur during the study and for a period 
of 1 year after the completion of the study. 
12.10 
Insurance and Indemnity 
In accordance with the relevant national regulations, the Sponsor has taken out subject liability 
insurance for all subjects who have given their consent to the clinical study. This cover is designed 
for the event that a fatality, physical injury, or damage to health occurs during the clinical study’s 
execution. 
12.11 
Legal Aspects 
The clinical study is submitted to the relevant national competent authorities in all participating 
countries to achieve a clinical trial authorization (CTA). 
The study will commence (i.e., initiation of study centers) when the CTA and favorable Ethics 
opinion have been received.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 75 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
13 
STUDY ADMINISTRATIVE INFORMATION 
13.1 
Protocol Amendments 
Any amendments to the study protocol will be communicated to the Investigators by Medpace or 
the Sponsor. All protocol amendments will undergo the same review and approval process as the 
original protocol. A protocol amendment may be implemented after it has been approved by the 
IRB/IEC, unless immediate implementation of the change is necessary for subject safety. In this 
case, the situation must be documented and reported to the IRB/IEC within 5 working days. 
13.2 
Address List 
13.2.1 
Sponsor 
Amplyx Pharmaceuticals, Inc. 
12730 High Bluff Drive, Suite 160 
San Diego, CA 92130 
Telephone: +1-858-345-1755 
Fax: +1-858-345-1346 
13.2.2 
Contract Research Organization 
Medpace, Inc. 
5375 Medpace Way 
Cincinnati, OH 45227 
Telephone: +1-513-579-9911 
Fax: +1-513-579-0444 
13.2.3 
Clinical Safety 
Medpace, Inc. 
5375 Medpace Way 
Cincinnati, OH 45227 
Telephone: +1-513-579-9911, dial 3 
Fax: +1-513-579-0444 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 76 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
14 
REFERENCES 
Ambalathingal GR, Francis RS, Smyth MJ, et al. BK Polyomavirus: Clinical Aspects, Immune 
Regulation, and Emerging Therapies. Clin Microbiol Rev 2017; 30:503-528. 
Antonsson A, Green AC, Mallitt KA, et al. Prevalence and stability of antibodies to the BK and 
JC polyomaviruses: a long-term longitudinal study of Australians. J Gen Virol 2010; 
91:1849-1853. 
Babel N, Fendt J, Karaivanov S, et al. Sustained BK viruria as an early marker for the development 
of BKV-associated nephropathy: analysis of 4128 urine and serum samples. Transplantation. 
2009;88:89-95. 
Bohl DL, Brennan DC. BK virus nephropathy after kidney transplantation. J Am Soc Nephrol. 
2007;2 Suppl 1:S36-46. 
Boothpur R, Brennan DC. Human polyoma viruses and disease with emphasis on clinical BK and 
JC. J Clin Virol. 2010;47:306-12. 
Brennan DC, Agha I, Bohl DL, et al. Incidence of BK with tacrolimus versus cyclosporine and 
impact of preemptive immunosuppression reduction. Am J Transplant. 2005;5:582-94. 
Dharnidharka VR, Abdulnour HA, Araya CE. The BK virus in renal transplant recipients—review 
of pathogenesis, diagnosis, and treatment. Pediatr Nephrol. 2011;26:1763-74. 
Egli A, Infanti L, Dumoulin A, et al. Prevalence of polyomavirus BK and JC infection and 
replication in 400 healthy blood donors. J Infect Dis. 2009;199:837-46. 
Hirsch HH, Steiger J. Polyomavirus BK. Lancet Infect Dis. 2003;3:611-23. 
Hirsch HH, Vincenti F, Friman S, et al. Polyomavirus BK replication in de novo kidney transplant 
patients receiving tacrolimus or cyclosporine: A prospective, randomized, multicenter study.  
Am J Transplantation. 2013;13:136-45. 
KDIGO Clinical Practice Guideline.  Kidney Disease: Improving Global Outcomes (KDIGO) 
Transplant Work Group, KDIGO clinical practice guideline for the care of kidney transplant 
recipients. Am J Transplant. 2009;9(Suppl 3):S1-S157. 
Kean JM, Rao S, Wang M, Garcea RL. Seroepidemiology of human polyomaviruses. PLoS Pathog 
2009;5:e1000363. 
Moura EB, Petzhold SV, Amaral AR, et al. Evaluation of the predisposition and clinical impact of 
BK virus replication in kidney transplant patients. An Acad Bras Cienc. 2017;89:675-684. 
Sawinski D and Goral S. BK virus infection: an update on diagnosis and treatment. Nephrol Dial 
Transplant. 2015;30:209-17.  


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 77 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Shah A, Betts M. Antibody biodistribution coefficients: Inferring tissue concentrations of 
monoclonal antibodies based on the plasma concentrations in several preclinical species and 
human. mAbs. 2013;5:297-305. 
Sood P, Senanayake S, Sujeet K, et al. Management and outcome of BK viremia in renal transplant 
recipients: A prospective single-center study. Transplant. 2012;94:814-821. 
Tsai B and Qian M. Cellular entry of polyomaviruses. Curr Top Microbiol Immunol. 
2010;343:177-94. 
Zheng H-Y, Nishimoto Y, Chen Q, et al. Relationships between BK virus lineages and human 
populations. Microbes Infect; 9:204-13; 2007. 
Zhong S, Randhawa PS, Ikegaya H, et al. Distribution patterns of BK polyomavirus (BKV) 
subtypes and subgroups in American, European, and Asian populations suggest comigration of 
BKV and the human race. J Gen Virol; 90:144-52.D. K; 2009. 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 78 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
Appendix A: Schedule of Events 
Subjects should be seen for all visits/assessments as outlined in the assessment schedule or as close to the designated day/time as possible. 
 
Pre-treatment1,7 
Treatment Period2 
(12 weeks) 
Follow-up Period3 
(24 weeks) 
Visit Name 
Screening 
Baseline Tx1 
Tx2 
Tx3 
Tx4 
Tx5 
Tx6 
Tx7 
Tx8 
Tx9 
FU1 
FU2 
FU3/ET 
Study Weeks 
 
0 
1 
2 
3 
4 
5 
6 
8 
10 
12 
16 
20 
36 
Study Days 
-10 to -1 
14 
7 
14 
21 
28 
35 
42 
56 
70 
84 
112 
140 
252 
Informed consent  
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
I/E criteria 
X 
X 
 
 
 
 
 
 
 
 
 
 
 
 
Medical history 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
KDPI5 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
Prior and concomitant 
medications6 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Demography 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
Randomization7 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
Dose administration4,8 
 
X 
 
 
 
X 
 
 
X 
 
X 
 
 
 
Urine for BKV PCR 
and resistance testing9 
 
X10 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Plasma for BKV PCR 
and resistance 
testing11 
X 
X10 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
PK sample12,  
 
X13 
X 
X 
X 
X14 
 
 
X14 
 
X13 
X 
X 
X 
Anti-drug antibodies10 
 
X10 
 
 
 
X 
 
 
X 
 
X 
X 
X 
X 
Anti-donor 
antibodies15 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Pregnancy test16 
X 
 
 
 
 
X 
 
 
X 
 
X 
 
 
X 
Vital signs17 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Body height 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
Body weight 
X 
X 
 
 
 
X 
 
 
X 
 
X 
 
 
X 
Physical examination 
X 
 
 
 
 
 
 
 
 
 
X 
 
 
X 
ECG (12-lead)18 
 
X 
 
 
 
 
 
 
 
 
X 
 
 
X 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 79 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
 
Pre-treatment1,7 
Treatment Period2 
(12 weeks) 
Follow-up Period3 
(24 weeks) 
Visit Name 
Screening 
Baseline Tx1 
Tx2 
Tx3 
Tx4 
Tx5 
Tx6 
Tx7 
Tx8 
Tx9 
FU1 
FU2 
FU3/ET 
Study Weeks 
 
0 
1 
2 
3 
4 
5 
6 
8 
10 
12 
16 
20 
36 
Study Days 
-10 to -1 
14 
7 
14 
21 
28 
35 
42 
56 
70 
84 
112 
140 
252 
Blood and urine for 
safety19 
 
X10 
 
X 
 
X 
 
 
X 
 
X 
X 
X 
X 
Adverse events 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
BKV BK virus; PCR polymerase chain reaction; PK pharmacokinetic; ECG electrocardiogram 
1. Protocol specific procedures should not be performed until the subject has consented to participation in the study.  However, assessments and procedures 
performed as part of standard of care prior to informed consent, including determination of BK viral load in plasma may be used to qualify a subject for the 
study.   
2. During the treatment period, subjects should be seen approximately every 7 days (+/-3 days) during the first 6 weeks and approximately every 14 days  
(+/-5 days) for the duration of treatment. Subjects may be seen more often at the Investigator’s discretion.  Visit dates are determined from the Baseline Visit.  
3. During the follow-up period, if the subject cannot be seen on the precise protocol-defined study day, the acceptable visit window is +/10 days. 
4. Study Day 1 is the calendar day on which the first dose of study drug is administered.  Subsequent study days are based on calendar days.  
5. The information necessary for determining the KDPI includes donor age, height, weight, ethnicity, history of hypertension, history of diabetes mellitus, cause 
of death, serum creatinine, hepatitis C serostatus, and whether donation occurred after circulatory death.  
6. Record any and all immunosuppressive medication from induction to randomization as well as any other medications taken during the 10 days prior to 
randomization.  
7. Randomization should occur as soon as possible after confirmation of qualifying viremia but not more than 10 days after the qualifying sample was collected. 
Dosing of study drug should occur as soon as possible after randomization.  
8. In the event that a subject requires hemodialysis, plasmapheresis, or immunoadsorption treatments; if <15 days since last MAU868/placebo treatment another 
dose will be given as soon as possible, and the next scheduled monthly dose skipped. Regular dosing will occur the following month. If the last dose was 15 days 
or greater no interim dose will be administered and the regular monthly scheduled will be followed. No subject will receive more than 4 doses. 
9. A sufficient amount of urine should be collected at each assessment to accommodate three tests; one for BKV DNA PCR, one for possible genotypic resistance 
testing and a back up sample. Refer to the study’s Laboratory Manual for volume requirements. 
10. On Study Day 1 collect samples for BKV PCR, antidrug antibodies, and safety labs prior to administration of first dose of MAU868.  Refer to the study’s 
Laboratory Manual for collection requirements. 
11. After screening, plasma samples should be collected and sent to the central laboratory at each assessment for BKV DNA PCR, possible genotypic resistance 
testing and a backup sample. During screening, only BKV PCR is required and may be performed by the laboratory used by the site for usual clinical care, or 
sent to the central lab for testing. Refer to the study’s Laboratory Manual for volume requirements. 
12. In the event subject undergoes hemodialysis, plasmapheresis, or immunoadsorption treatment, a PK sample should be collected prior to and following the 
respective treatment. 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 80 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
13. Three PK samples should be collected on Study Day 1 (first dose administration) and Study Day 84 (last dose administration) :  within approximately 30 minutes 
prior to the start of the infusion, within approximately 30 minutes following the end of the infusion and between approximately 3-6 hours after the end of 
infusion.   
14. On Study days 28 and 56 (2nd and 3rd dose administrations), two PK samples should be collected: within 30 minutes prior to the start of infusion and within 
30 minutes following the end of infusion.  
15. Any anti-donor antibodies collected by the site should be recorded in the eCRF, but collection is not mandatory.  
16. Only for females of child-bearing potential. A negative urine or serum pregnancy test performed locally within 96 hours prior to Study Day 1 (Baseline). 
Local urine dipstick or serum pregnancy testing should be performed before infusions #2 on Day 28, #3 on Day 56 and #4 on Day 84.  
17. Vital signs (temperature, blood pressure, heart rate, respiratory rate and oxygen saturation) should be obtained at each visit if the visit is in person. If the visit 
is not in person vital signs are not required.  On drug infusion days, vitals should be taken within 30 minutes before starting the infusion, and then approximately 
every 30 minutes (+/- 10 minutes) after the start of the infusion until at least 2 hours after completing the infusion.  
18. ECGs should be performed prior to dose administration on Study Day 1 and after dose administration on Study Day 84 and on Day 252 (or at the 
Early Termination Visit) 
19. Blood and urine for safety should be collected and sent to the central laboratory.  Laboratory tests used in for the management and monitoring of the subject 
per standard practice may be performed at the local laboratory at the Investigator’s discretion.   


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 81 of 91 
Confidential & Proprietary 
Version 2.0, 15Apr2020 
Appendix B: Clinical Safety Laboratory Analytes 
Standard Safety Chemistry Panel 
Alanine aminotransferase 
Albumin 
Alkaline phosphatase 
Amylase 
Aspartate aminotransferase 
Bicarbonate 
Blood urea nitrogen 
Calcium 
Chloride 
Creatine kinase 
Creatinine 
Estimated glomerular filtration rate 
Gamma-glutamyl transferase 
Glucose 
Inorganic phosphorus 
Lactate dehydrogenase 
Lipase 
Potassium 
Sodium 
Bilirubin (total, direct, and indirect) 
Total protein 
Uric acid 
Hematology 
Hematocrit 
Hemoglobin 
Platelets 
Red blood cell count 
White blood cell count and differential [1] 
 
1. 
Manual microscopic review is performed only if white blood cell count and/or differential values are out of 
reference range.  
Coagulation 
Prothrombin time 
International normalized ratio (INR) 
Activated Partial Thromboplastin Time (aPTT) 
 
Urinalysis 
Bilirubin 
Blood 
Glucose 
Ketones 
Leukocyte esterase 
Microscopy [1] 
Nitrite 
pH 
Protein 
Specific gravity 
Urobilinogen  
 
2. 
Microscopy is performed only as needed based on positive dipstick test results. 
Other Tests 
Urine or serum pregnancy test [1] 
 
1. 
Women of childbearing potential only.  
 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 82 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
Appendix C: PK Sample Schedule 
PK Draws 
Within ~30min 
Prior to Infusion 
Within ~30min 
following Infusion 
End 
3-6 hours Post Dose 
Infusion 
Non-Dose Visit PK 
Draw 
Day 1 
X 
X 
X 
  
Day 7 
  
  
  
X 
Day 14 
  
  
  
X 
Day 21 
  
  
  
X 
Day 28 
X 
X 
  
  
Day 35 
  
  
  
  
Day 42 
  
  
  
  
Day 56 
X 
X 
  
  
Day 70 
  
  
  
  
Day 84 
X 
X 
X 
  
Day 112 
  
  
  
X 
Day 140 
  
  
  
X 
Day 252 
  
  
  
X 
Samples collected prior to and during infusion should be collected within approximately 30 minutes of specified 
timepoints. 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 83 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
Appendix D: CTCAE 5 
Section 3.3.2 of the protocol outlines criteria for discontinuation from study drug.  All treatment-
related SAEs and certain treatment-related AEs and treatment-related laboratory abnormalities 
should result in immediate discontinuation from study drug.  Re-challenge is not permitted. 
Determination of whether an individual treatment related non-serious AE and/or treatment related 
laboratory abnormality should prompt discontinuation of study drug depends on the severity of the 
AE and laboratory abnormality based on Common Terminology Criteria for Adverse Events 
(CTCAE) version 5 grade.   
Note that the following requires immediate discontinuation of study drug: 
• Treatment-related AEs of Grade 3 or higher (including infusion reactions) except for 
cytokine release syndrome and serum sickness where a severity grade of 2 or higher should 
prompt discontinuation. CTCAE criteria for infusion related reactions, cytokine release 
syndrome, and serum sickness are below.  The complete CTCAE criteria for other 
treatment 
related 
AEs 
may 
be 
accessed 
at 
the 
following 
website: 
(https://ctep.cancer.gov/protocoldevelopment/electronic_applications/docs/CTCAE_v5_
Quick_Reference_5x7.pdf ). 
• Clinically significant treatment-related laboratory abnormality Grade 3 or higher.  
CTCAE criteria for laboratory abnormalities (i.e., investigations) are also displayed below.   
INFUSION RELATED REACTION: 
Injury, poisoning and procedural complications 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Infusion related 
reaction 
Mild transient 
reaction; 
interruption not 
indicated; 
intervention not 
indicated 
Therapy or 
infusion 
interruption 
indicated but 
responds 
promptly to 
symptomatic 
treatment 
(e.g., antihistam
ines, NSAIDS, 
narcotics, 
IV fluids); 
prophylactic 
medications 
indicated for 
<=24 hrs 
Prolonged 
(e.g.  not rapidly 
responsive to 
symptomatic 
medication 
and/or brief 
interruption f 
infusion); 
recurrence of 
symptoms 
following initial 
improvement; 
hospitalization 
indicated for 
clinical sequelae 
Life-threatening 
consequences; 
urgent 
intervention 
indicated 
Death 
Definition: A disorder characterized by adverse reaction to the infusion of pharmacological or biological substances. 
 
 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 84 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
CYTOKINE RELEASE SYNDROME: 
Injury, poisoning and procedural complications 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Cytokine release 
syndrome 
 
Fever with or 
without 
constitutional 
symptoms 
Hypotension 
responding to 
fluids; hypoxia 
responding to 
<40% O2 
Hypotension 
managed with 
one pressor; 
hypoxia 
requiring >40% 
O2 
Life-threatening 
consequences: 
urgent 
intervention 
indicated 
Death 
Definition: disorder characterized by fever, tachypnea, headache, tachycardia, hypotension, rash, and/or hypoxia 
caused by the release of cytokines. 
Navigational Note: Also consider reporting other organ dysfunctions including neurological toxicities such as: 
Psychiatric disorders: Hallucinations or Confusion; Nervous system disorders: Seizure, Dysphasia, Tremor, or 
Headache. 
 
SERUM SICKNESS: 
Injury, poisoning and procedural complications 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Serum sickness 
 
Asymptomatic; 
clinical or 
diagnostic 
observations 
only; 
intervention not 
indicated 
Moderate 
arthralgia: fever, 
rash, urticaria, 
antihistamines 
indicated 
Sever arthralgia 
or arthritis; 
extensive rash; 
steroids or IV 
fluids indicated 
Live-threatening 
consequences; 
pressor or 
ventilatory 
support 
indicated 
Death 
Definition: A disorder characterized by a delayed-type hypersensitivity reaction to foreign proteins derived from an 
animal serum. It occurs approximately six to twenty-one days following the administration of the foreign antigen. 
Symptoms include fever, arthralgias, myalgias, skin eruptions, lymphadenopathy, chest marked discomfort and 
dyspnea. 
Navigational Note: - 
 
 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 85 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
INVESTIGATIONS: 
Injury, poisoning and procedural complications 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Activated partial 
thromboplastin 
time prolonged 
>ULN – 1.5 x 
ULN 
>1.5 – 2.5 x 
ULN 
>2.5 x ULN; 
bleeding 
- 
- 
Definition: A finding based on laboratory test results in which the partial thromboplastin time is found to be greater 
than the control value. As a possible indicator of coagulopathy, a prolonged partial thromboplastin time (PTT) may 
occur in a variety of diseases and disorders, both primary and related to treatment. 
Navigational Note: -  
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Alanine 
aminotransferase 
increased 
>ULN – 3.0 x 
ULN if baseline 
was normal;  
1.5 – 3.0 x 
baseline if 
baseline was 
abnormal 
>3.0 – 5.0 x 
ULN if baseline 
was normal; 
>3.0-5.0 
baseline if 
baseline was 
abnormal 
>5.0 – 20.0 x 
ULN if baseline 
was normal; 
>5.0 – 20.0 x 
baseline if 
baseline was 
abnormal 
>20.0 x ULN if 
baseline was 
normal; >20.0 x 
baseline if 
baseline was 
abnormal 
 
Definition: A finding based on laboratory results that indicate an increase in the level of alanine aminotransferase 
(ALT or SGPT) in the blood specimen. 
Navigational Note: Also consider Hepatobiliary disorders: Hepatic failure 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Alkaline 
phosphatase 
increased 
>ULN – 2.5 x 
ULN if baseline 
was normal;  
2.0 – 2.5 x 
baseline if 
baseline was 
abnormal 
>2.5 – 5.0 x 
ULN if baseline 
was normal; 
>2.5-5.0 
baseline if 
baseline was 
abnormal 
>5.0 – 20.0 x 
ULN if baseline 
was normal; 
>5.0 – 20.0 x 
baseline if 
baseline was 
abnormal 
>20.0 x ULN if 
baseline was 
normal; >20.0 x 
baseline if 
baseline was 
abnormal 
- 
Definition: A finding based on laboratory test results that indicate an increase in the level of alkaline phosphatase in 
blood specimen.  
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Aspartate 
aminotransferase 
increased 
>ULN – 3.0 x 
ULN if baseline 
was normal; 1.5-
3.0 x baseline if 
baseline was 
abnormal 
>3.0 – 5.0 x 
ULN if baseline 
was normal; 
>3.0-5.0 
baseline if 
baseline was 
abnormal 
>5.0 – 20.0 x 
ULN if baseline 
was normal; 
>5.0 – 20.0 x 
baseline if 
baseline was 
abnormal 
>20.0 x ULN if 
baseline was 
normal; >20.0 x 
baseline if 
baseline was 
abnormal 
- 
Definition: A finding based on laboratory test results that indicate an increase in the level of aminotransferase 
(ALT or SGPT) in blood specimen.  
Navigational Note: - 
 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 86 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Blood antidiuretic 
hormone 
abnormal 
Asymptomatic; 
clinical or 
diagnostic 
observations 
only; intervention 
not indicated 
Symptomatic; 
medical 
intervention 
indicated 
Hospitalization 
indicate 
 
- 
Definition: A finding based on laboratory test results that indicate abnormal levels of antidiuretic hormone in the 
blood specimen.  
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Blood bicarbonate 
decrease 
<LLN and no 
intervention 
initiated 
- 
- 
- 
- 
Definition: A finding based on laboratory test results that indicate a decrease in levels of bicarbonate in a venous 
blood specimen.  
Navigational Note: Also consider Metabolism and nutrition disorder: Acidosis or Alkalosis 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Blood bilirubin 
increased  
>ULN – 1.5 x 
ULN if baseline 
was normal;  
> 1.0 – 1.5 x 
baseline if 
baseline was 
abnormal 
>ULN – 1.5 -3.0 
x ULN if 
baseline was 
normal;  
> 1.5 – 3.0 x 
baseline if 
baseline was 
abnormal 
>ULN – 3.0 – 
10.0 x ULN if 
baseline was 
normal;  
> 3.0 – 10.0 x 
baseline if 
baseline was 
abnormal 
> 10.0 ULN if 
baseline was 
normal;  
> 10.0 x 
baseline if 
baseline was 
abnormal 
 
Definition: A finding based on laboratory test results that indicate an abnormally high level of bilirubin in the blood. 
Excess bilirubin ins associated with Jaundice. 
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Blood 
corticotrophin 
decreased 
Asymptomatic; 
clinical or 
diagnostic 
observations 
only; intervention 
not indicated 
Symptomatic; 
medical 
intervention 
indicated 
Hospitalization 
indicated 
- 
- 
Definition: a finding based on laboratory test results that indicate a decrease in levels of corticotrophin in a blood 
sample. 
 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 87 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Blood 
gonadotrophin 
abnormal 
Asymptomatic; 
clinical or 
diagnostic 
observations 
only; intervention 
not indicated 
Symptomatic; 
medical 
intervention 
indicated; 
limiting 
instrumental 
ADL 
Severe 
symptoms; 
limiting 
self-care ADL 
 
 
Definition: A finding based on laboratory test results that indicate abnormal levels of gonadotrophin hormone in a 
blood specimen. 
Navigational Note: -  
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Blood lactate 
dehydrogenase 
increased 
>ULN 
- 
- 
- 
- 
Definition: A finding based on laboratory test results that indicate increased levels of lactate dehydrogenase in a 
blood specimen. 
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Blood prolactin 
abnormal 
Asymptomatic; 
clinical or 
diagnostic 
observations 
only; intervention 
not indicated 
Moderate 
symptoms; 
limiting 
instrumental 
ADLs 
- 
- 
- 
Definition: A finding based on laboratory test results that indicate abnormal levels of prolactin hormone in a blood 
specimen. 
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Carbon monoxide 
diffusing capacity 
decrease 
3-5 units below 
LLN; for 
follow-up, a 
decrease of  
3-5 units 
(ml/min/mm Hg) 
below the 
baseline value; 
asymptomatic and 
intervention not 
indicated 
6-8 units below 
LLN; for 
follow--up, an 
asymptomatic 
decrease of  
>5 – 8 units 
(ml/min/mm 
Hg) below the 
baseline value; 
symptomatic 
and intervention 
no indicated 
Asymptomatic 
decrease of  
>8 units drip;  
>5 units drop 
along with the 
presence of 
pulmonary 
symptoms  
(e.g., >Grade 2 
hypoxia or 
>Grade 2 
dyspnea); 
intervention 
indicated 
- 
- 
Definition: A finding based on lung function test results that indicate a decrease in the lung capacity to absorb carbon 
monoxide. 
Navigational Note: Also consider Respiratory, thoracic and mediastinal disorders: Respiratory failure or Dyspnea 
 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 88 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Ejection fraction 
decreased 
- 
Resting ejection 
fraction (EF) 
50-40%;  
10 -19% drop 
from baseline 
Resting ejection 
(EF) 39 – 20%; 
>=20% drop 
from baseline 
Resting ejection 
fraction (EF)  
< 20% 
- 
Definition: The percentage computed when the amount of blood effected during a ventricular contraction of the heart 
is compared to the amount that was present prior to the contraction. 
Navigational Note: -  
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Electrocardiogram 
QT corrected 
interval prolonged 
Average QTc  
450 – 480 ms 
Average QTc 
481 – 500 ms 
Average QTc 
>=501ms; >60 
ms change from 
baseline 
Torsade dep 
pointes; 
polymorphic 
ventricular 
tachycardia; 
signs/symptoms 
of serious 
arrhythmia 
- 
Definition: A finding of a cardiac dysrhythmia characterized by an abnormally long corrected QT interval 
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Electrocardiogram 
T wave abnormal 
T wave flattening 
Nonspecific ST 
segment change 
- 
- 
- 
Definition: A disorder characterized by Electrocardiogram T wave amplitude changes.  
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Fibrinogen 
decreased 
<1.0 – 0.5 x LLN; 
if abnormal, 
<25% decrease 
from baseline 
<0.75 – 0.5 x 
LLN; if 
abnormal  
25 – 50% 
decrease from 
baseline 
<0.5 – 0.25 x 
LLN; if 
abnormal,  
50-75% 
decrease from 
baseline 
,0.25 x LLN 5% 
decrease from 
baseline; 
absolute value 
<50mg/dl 
- 
Definition: A finding based on laboratory test results that indicate a decrease in levels of fibrinogen in a blood 
specimen.   
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Forced expiratory 
volume decreased 
FEV1% 
(percentages of 
observed FEV1 
and FVC related 
to their respective 
predicted values) 
99-70% predicted 
FEV1 60-69% 
50-59% 
<=49% 
- 
Definition: A finding based on test results that indicate a relative decrease in the fraction of the forced vital capacity 
that is exhaled in a specific number of seconds.  
Navigational Note: Also consider Respiratory, thoracic and mediastinal disorder: Respiratory failure or Dyspnea 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 89 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
GGT increased 
>ULN – 2.5 x 
ULN if baseline 
was normal;  
2.0-2.5 x baseline 
if baseline was 
abnormal 
>ULN – 2.5 – 
5.0 x ULN if 
baseline was 
normal;  
2.5-5.0 x 
baseline if 
baseline was 
abnormal 
>ULN – 5.0 – 
20.0 x ULN if 
baseline was 
normal;  
> 5.0 – 20.0 x 
baseline if 
baseline was 
abnormal 
>20.0 x ULN if 
baseline was 
normal; >20.0 x 
baseline if 
baseline was 
abnormal 
- 
Definition: A finding based on laboratory test results that indicate higher than normal levels of the enzyme gamma-
glutamyltransferase in the blood specimen. GGT (gamma-glutamyltransferase) catalyzes the transfer of gamma 
glutamyl group from a gamma glutamyl peptide to another peptide, amino acids or water. 
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Growth hormone 
abnormal 
Asymptomatic; 
clinical or 
diagnostic 
observations 
only; intervention 
not indicated 
Symptomatic; 
medical 
intervention 
indicated; 
limiting 
instrumental 
ADL 
- 
- 
- 
Definition: A finding based on laboratory test results that indicate abnormal levels of growth hormone in a biological 
specimen. 
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Haptoglobin 
decreased 
<LLN 
- 
- 
- 
- 
Definition: A finding based on laboratory test results that indicate a decrease in levels of haptoglobin in a blood 
specimen. 
Navigational Note:  - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Hemoglobin 
increased 
Increase in  
>0 - 2 g/dL 
Increase in  
>2 - 4 g/dL 
Increase in  
>4 g/dL 
- 
- 
Definition: A finding based on laboratory test results that indicate increased levels of hemoglobin above normal. 
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
INR increased 
>1.2 - 1.5;  
>1 - 1.5 x 
baseline if on 
anticoagulation; 
monitoring only 
indicated 
>1.5 - 2.5;  
>1.5 - 2.5 x 
baseline if on 
anticoagulation; 
dose adjustment 
indicated 
>2.5; >2.5 x 
baseline if on 
anticoagulation; 
bleeding 
- 
- 
Definition: A finding based on laboratory test results that indicate an increase in the ratio of the patient's prothrombin 
time to a control sample in the blood. 
Navigational Note: - 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 90 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Lipase increased 
>ULN - 1.5 x 
ULN 
>1.5 - 2.0 x 
ULN; >2.0 - 5.0 
x ULN and 
asymptomatic 
>2.0 - 5.0 x 
ULN with signs 
or symptoms; 
>5.0 x ULN and 
asymptomatic 
>5.0 x ULN and 
with signs or 
symptoms 
- 
Definition: A finding based on laboratory test results that indicate an increase in the level of lipase in a biological 
specimen.  
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Lymphocyte 
count decreased 
<LLN -800/mm3; 
<LLN- 0.8x 
10e9/L 
<800 - 500/ 
mm3;  
<LLN- 0.8 -0.5 
x 10e9/L 
<500 - 200/ 
mm3; <0.5 - 0.2 
x 10e9/L 
<200/mm3; 
<0.2 x 10e9/L 
- 
Definition: A finding based on laboratory test results that indicate a decrease in number of lymphocytes in a blood 
specimen.  
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Lymphocyte 
count increased 
- 
>4000/mm3 - 
20,000/mm3 
>20,000/mm3 
- 
- 
Definition: A finding based on laboratory test results that indicate an abnormal increase in the number of 
lymphocytes in the blood, effusions or bone marrow.  
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Neutrophil count 
decreased 
<LLN - 1500/ 
mm3;  
<LLN - 1.5 x 
0e9/L 
<1500 - 1000/ 
mm3;  
<1.5 - 1.0 x 
10e9/L 
<1000 - 500/ 
mm3;  
<1.0 - 0.5 x 
10e9/L 
<500/mm3; 
<0.5 x 10e9/L 
- 
Definition: A finding based on laboratory test results that indicate a decrease in number of neutrophils in a blood 
specimen.  
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Pancreatic 
enzymes 
decreased 
<LLN and 
asymptomatic 
Increase in stool 
frequency, bulk, 
or odor; 
steatorrhea 
Sequelae of 
absorption 
deficiency 
- 
- 
Definition: A finding based on laboratory test results that indicate a decrease in levels of pancreatic enzymes in a 
biological specimen.  
Navigational Note: - 
 
 


 
 
Amplyx Pharmaceuticals, Inc. 
 
 
Clinical Study Protocol MAU868-201 
Page 91 of 91 
Confidential & Proprietary 
Version 2.0, 15APR2020 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
White Blood cell 
decreased  
<LLN – 3000/ 
mm3; <LLN – 3.0 
x 10e9/L 
<3000 – 2000/ 
mm3; <3.0 – 2.0 
x 10e9 
<2000 -1000/ 
mm3; <2.0 – 1.0 
x 10e9/L 
<1000/mm3; 
<1.0 x 10e9/L 
- 
Definition: a finding based on laboratory test results that indicate a decrease in number of white blood cells in a 
blood specimen. 
Navigational Note: - 
CTCAE Term 
Grade 1 
Grade 2 
Grade 3 
Grade 4 
Grade 5 
Investigations – 
Other, specify 
Asymptomatic or 
mild symptoms; 
clinical or 
diagnostic 
observations 
only; intervention 
not indicated 
Moderate; 
minimal. Local 
or noninvasive 
intervention 
indicated; 
limiting age-
appropriate 
instrumental 
ADL 
Sever or 
medically 
significant but 
not immediately 
life-threatening; 
hospitalization 
or prolongation 
of existing 
hospitalization 
indicate; 
limiting 
self-care ADL 
Life-threatening 
consequences; 
urgent 
intervention 
indicated 
Death 
 

SAP_001.pdf: 
 
 
 
 
1 
 
STATISTICAL ANALYSIS PLAN 
 
 
 
Protocol Title: 
A Randomized, Double-blind, Placebo-controlled Study to 
Assess the Safety, Pharmacokinetics and Efficacy of 
MAU868 for the Treatment of BK Viremia in Kidney 
Transplant Recipients 
 
Protocol Number: 
MAU868-201 
Protocol Version/Date: 
Version 2.0, 15 April 2020 
Investigational Product: 
MAU868 
Phase: 
2 
Sponsor: 
Amplyx Pharmaceuticals, Inc. 
12730 High Bluff Drive, Suite 160 
San Diego, CA 92130 
United States
 
 
SAP Version/Date: 
Version 1.0, 27 May 2021 
 
 
 
 
 
CONFIDENTIAL 
The information in this document is confidential and is not to be disclosed without the written 
consent of Amplyx Pharmaceuticals, Inc. except to the extent that disclosure would be required 
by law and for the purpose of evaluating and/or conducting a clinical study for Amplyx 
Pharmaceuticals, Inc. You are allowed to disclose the contents of this document only to your 
Institutional Review Board or Independent Ethics Committee and study personnel directly 
involved with conducting this protocol. Persons to whom the information is disclosed must be 
informed that the information is confidential and proprietary to Amplyx Pharmaceuticals, Inc. 
and that it may not be further disclosed to third parties. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
 
Version 1.0, 27 May 2021 
2 
 
SIGNATURE PAGE 
Protocol Title: 
A Randomized, Double-blind, Placebo-controlled Study to 
Assess the Safety, Pharmacokinetics and Efficacy of MAU868 
for the Treatment of BK Viremia in Kidney Transplant 
Recipients 
 
Protocol Number: 
MAU868-201 
SAP Version/Date: 
Version 1.0, 27 May 2021 
 This Statistical Analysis Plan is prepared by: 
 
 
 
 
Sixiu Xiao 
Project Statistician 
Medpace, Inc. 
 
 We, the undersigned, have reviewed and approved this Statistical Analysis Plan: 
 
  
Signature 
 Date 
 
 
 
 
 
Mei Chen, PhD 
Vice-President, Biostatistics 
Medpace, Inc. 
 
 
 
 
 
 
 
 
Herve Mommeja-Marin, MD 
Vice President, Medical Department 
Medpace, Inc. 
 
 
 
 
 
 
 
 
Michael R. Hodges, MD 
Chief Medical Officer 
Amplyx Pharmaceutical, Inc. 
 
 
 
 
 
 
 
 
Sixiu Xiao
Electronically signed by: Sixiu Xiao
Reason: Approved
Date: May 27, 2021 17:53 EDT
27-May-2021
Mei Chen
Electronically signed by: Mei Chen
Reason: Approved
Date: May 27, 2021 18:13 EDT
27-May-2021
Electronically signed by: Herve Mommeja-Marin
Reason: Approved
Date: May 27, 2021 18:15 EDT
27-May-2021
Electronically signed by: michael hodges
Reason: Approved
Date: May 27, 2021 15:49 PDT
27-May-2021


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
 
Version 1.0, 27 May 2021 
3 
 
TABLE OF CONTENTS 
1 
INTRODUCTION ................................................................................................................ 6 
2 
STUDY OVERVIEW ........................................................................................................... 6 
2.1 
Study Objectives ............................................................................................................ 6 
2.1.1 
Primary Objective ................................................................................................... 6 
2.1.2 
Secondary Objectives .............................................................................................. 6 
2.2 
Study Design ................................................................................................................. 6 
2.2.1 
Overview ............................................................................................................... 6 
2.2.2 
Randomization and Blinding ..................................................................................... 8 
2.2.3 
Breaking the Blind .................................................................................................. 8 
2.2.4 
Study Drug ............................................................................................................. 9 
2.2.5 
Study Assessments .................................................................................................10 
3 
Sample Size Determination ................................................................................................14 
4 
DATA SAFETY MONITORING BOARD (DSMB) ...............................................................14 
5 
SPONSOR STUDY REVIEW COMMITTEE (SSRC) ..........................................................14 
6 
Study Endpoints .................................................................................................................14 
6.1.1 
Safety Endpoints ....................................................................................................14 
6.1.2 
Efficacy Endpoints .................................................................................................14 
6.1.3 
Exploratory Endpoints ............................................................................................15 
6.1.4 
Pharmacokinetic Endpoints .....................................................................................15 
7 
STATISTICAL METHODOLOGY .......................................................................................15 
7.1 
General Considerations ..................................................................................................15 
7.1.1 
Analysis Day .........................................................................................................15 
7.1.2 
Analysis Visits .......................................................................................................16 
7.1.3 
Definition of Baseline .............................................................................................16 
7.1.4 
Summary of Statistics .............................................................................................16 
7.1.5 
Handling of Dropouts and Missing Data ....................................................................16 
7.2 
Analysis Populations .....................................................................................................17 
7.2.1 
Intent-to-Treat (ITT) Population ...............................................................................17 
7.2.2 
Modified Intent-to-Treat (MITT) Population..............................................................17 
7.2.3 
Safety Population ...................................................................................................17 
7.2.4 
Pharmacokinetic (PK) Population .............................................................................17 
7.3 
Subject Data and Study Conduct .....................................................................................17 
7.3.1 
Subject Disposition .................................................................................................17 
7.3.2 
Protocol Deviations ................................................................................................18 
7.3.3 
Demographic and Baseline Characteristics ................................................................18 
7.3.4 
Medical History .....................................................................................................19 
7.3.5 
Concomitant Medications ........................................................................................19 
7.3.6 
Study Drug Exposure ..............................................................................................19 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
 
Version 1.0, 27 May 2021 
4 
 
7.4 
Safety Assessment .........................................................................................................20 
7.4.1 
Adverse Events (AEs) .............................................................................................20 
7.4.2 
Clinical Laboratory Tests ........................................................................................21 
7.4.3 
Vital Signs.............................................................................................................22 
7.4.4 
Electrocardiograms .................................................................................................22 
7.4.5 
Physical Examinations ............................................................................................22 
7.4.6 
Other Safety Assessments .......................................................................................22 
7.5 
Efficacy Assessment ......................................................................................................22 
7.5.1 
Efficacy Endpoints .................................................................................................23 
7.5.2 
Exploratory Endpoints ............................................................................................27 
7.5.3 
Other Efficacy Data ................................................................................................27 
7.6 
Pharmacokinetic Assessment ..........................................................................................28 
8 
INTERIM ANALYSIS ..........................................................................................................28 
8.1 
First Interim Analysis ....................................................................................................28 
8.2 
Second Interim Analysis ................................................................................................28 
8.2.1 
Cohorts 1 & 2: Safety and Tolerability ......................................................................29 
8.2.2 
Cohorts 1 & 2: Response to Study Treatment .............................................................29 
8.2.3 
Pharmacokinetics Cohort 1 and 2 .............................................................................30 
9 
CHANGES FROM PROTOCOL-SPECIFIED STATISTICAL ANALYSES ..........................30 
10 PROGRAMMING SPECIFICATIONS ................................................................................31 
 
 
 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
 
Version 1.0, 27 May 2021 
5 
 
LIST OF ABBREVIATIONS 
Abbreviation 
Definition 
ADA
Antidrug antibody
AE
Adverse event
ALP
Alkaline phosphatase
ALT
Alanine transaminase
ANOVA
Analysis of variance
AST
Aspartate aminotransferase
ATC
Anatomical therapeutic chemical
BKV
BK virus
CI
Confidence interval
CSR
Clinical study report
DNA
Deoxyribonucleic acid
DSMB
Data and safety monitoring board
ECG
Electrocardiogram
eCRF
Electronic Case Report Form
eGFR
Estimated glomerular filtration rate
I/E
Inclusion and exclusion
INR
International normalized ratio
ITT
Intent-to-Treat
IV
Intravenous
IWRS
Interactive Web Response System
KDPI
Kidney donor profile index
LLN
Lower limit of normal
LLOQ
Lower limit of quantification
LOCF
Last observation carried forward
LOD
Limit of detection
LS
Least squares
MedDRA
Medical dictionary for regulatory activities
MITT
Modified Intent-to-Treat
PCR
Polymerase chain reaction
PK
Pharmacokinetic(s)
SAE
Serious adverse event
SAP
Statistical analysis plan
SE
Standard error
SSRC
Sponsor study review committee
TEAE
Treatment-emergent adverse event
ULN
Upper limit of normal
WHO
World Health Organization
 
 
 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
 
Version 1.0, 27 May 2021 
6 
 
1 
INTRODUCTION 
The purpose of this Statistical Analysis Plan (SAP) is to provide a description of the statistical 
methods to be implemented for the analysis of data from the study with protocol number MAU868-
201.  The SAP will be finalized prior to database lock.  Any deviations from the SAP after database 
lock will be documented in the final Clinical Study Report (CSR). 
2 
STUDY OVERVIEW 
2.1 
Study Objectives 
2.1.1 Primary Objective 
The primary objective of this study is to assess the safety and tolerability of MAU868. 
2.1.2 Secondary Objectives 
The secondary objectives of this study are to: 
 Assess the impact of MAU868 on BK viremia and BK viremia related outcomes i.e., BK 
virus nephropathy, graft function and acute rejection among renal transplant recipients with 
BK viremia; and 
 Assess the pharmacokinetics of MAU868. 
2.2 
Study Design 
2.2.1 Overview 
This is a randomized, placebo-controlled, double-blinded, proof-of-concept study in kidney 
transplant recipients. Up to 36 subjects with BK viremia will participate in 1 of 3 sequential 
cohorts.  Each cohort will randomize approximately 12 subjects (8 MAU868 and 4 placebo).  
The study will consist of a screening period, a 12-week treatment period and a 24-week follow up 
period.  
Protocol-specific procedures should not be performed until the patient has consented to 
participation in the study.  However, assessments and procedures performed as part of standard of 
care prior to informed consent, including determination of BK viral load in plasma may be used to 
qualify a patient for the study.  Once qualifying BK viremia has been confirmed, subjects should 
be randomized as soon as possible and no more than 10 days after the sample documenting the 
viremia was collected.   
During the treatment period, subjects will receive MAU868 or placebo approximately every 28 
days (every 4 weeks) for 12 weeks (4 doses total). Urine and blood will be monitored for BKV 
DNA by polymerase chain reaction (PCR) weekly for the first 6 weeks after initiation of treatment. 
For the remainder of the treatment period, urine and blood must be collected for BKV DNA by 
PCR at least every other week. However, the Investigator may also request testing more frequently 
(i.e., weekly) than mandated by the protocol after the first 6 weeks of treatment and when clinically 
indicated. During the study, BKV DNA by PCR will be tested at the central laboratory.  
Pharmacokinetics (PK), viral resistance, and anti-drug antibodies (ADA) will also be monitored. 
Subjects should continue study drug until the last scheduled dose, regardless of changes in plasma 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
 
Version 1.0, 27 May 2021 
7 
 
BK viral load, use of rescue therapy, and/or need for change in immunosuppressive regimen for 
any reason.  
During the 24-week follow-up period, 3 follow-up visits will be scheduled. At each visit, urine 
and blood samples for BKV DNA and samples for PK will be collected. Investigators may collect 
samples for BKV DNA more often as clinically indicated. During the follow-up period, BKV DNA 
by PCR will be tested at the central laboratory. 
Routine post-transplantation care is to be guided by the Investigator’s discretion and site standard 
of care.  This includes decisions to change the immunosuppressive regimen for a subject for any 
reason except for changes in immunosuppression in response to BK viremia. In order to treat BK 
viremia, prior to randomization, (i.e., prior to screening, during the screening period and at the 
Baseline Visit) Investigators are permitted to decrease or alter immunosuppressive therapy at their 
discretion and/or per standard of care at their site.   However, in the first 4 weeks after 
randomization, Investigators should refrain from additional changes in immunosuppressive 
regimen in response to BKV unless the viral load has increased by >1 log and the Investigator 
determines that a change is in the best interest of the subject. Use of other antiviral agents including 
cidofovir and leflunomide as well as IVIG are not permitted during the first 4 weeks of therapy 
and are strongly discouraged thereafter.   
Use of fluoroquinolones for reasons other than treatment of BKV is permitted.  
Between screening and the last visit, subjects will attend a total of 14 planned visits. Unscheduled 
visits are permitted at the Investigator’s discretion. 
A schematic representing the study’s design is included below.  
 
 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
 
Version 1.0, 27 May 2021 
8 
 
2.2.2 Randomization and Blinding 
Study participants will be randomly assigned to their treatments. Two participants will be assigned 
to receive treatment with MAU868 for each participant assigned to receive treatment with placebo 
(2:1 randomization). Randomization will occur via an Interactive Web Response System (IWRS). 
The Investigator or delegate will contact the IWRS after confirming that a potential study 
participant is eligible. The IWRS will assign a randomization number that will be used to link the 
subject to a treatment arm. 
The randomization number is only used to identify which treatment study participants have been 
assigned to receive. The number assigned to a subject at screening remains the unique identifier 
for the subject throughout the study. The randomization numbers will be generated using 
procedures that ensure that treatment assignment is unbiased and concealed from the Sponsor, 
subjects, and Investigator staff. 
This is a subject, Investigator, and Sponsor-blinded study. Subjects and Investigators will remain 
blinded to study treatment arm (MAU868 or placebo) throughout the study. 
Drug product will be supplied in bulk, so an unblinded pharmacist, or appropriately designated 
study site staff who is independent of the study team, will be required in order to maintain the 
blind. This unblinded associate at the site will be notified by the IWRS that a subject is randomized 
and to which treatment arm, which will then enable and instruct them to prepare the study drug. 
2.2.3 Breaking the Blind 
Blinding is critical to the integrity of this clinical study. However, in the event of a medical 
emergency or pregnancy in an individual subject, in which knowledge of the investigational 
product is critical to the subject’s management, the Investigator should contact the Medical 
Monitor to review the situation prior to breaking the blind. 
Before breaking the blind of an individual subject’s treatment, the Investigator should have 
determined that the information is necessary (i.e., that it will alter the subject’s immediate 
management). In many cases, particularly when the emergency is clearly not investigational 
product related, the problem may be properly managed by assuming that the subject is receiving 
active product without the need for unblinding. 
When the Investigator contacts the system to break a treatment code for a subject, he/she must 
provide the requested subject identifying information and confirm the necessity to break the 
treatment code for the subject. The Investigator will then receive details of the investigational drug 
treatment for the specified subject via the IWRS. The system will automatically inform the study 
monitor for the site and the Study Team that the code has been broken. 
It is the Investigator’s responsibility to ensure that there is a dependable procedure in place to 
allow access to the IWRS /code break at any time in case of emergency.  
An assessment will be done by the appropriate site personnel and Sponsor after an emergency 
unblinding to assess whether or not study drug should be discontinued for a given subject. 
In cases of accidental unblinding, contact the Medical Monitor and ensure every attempt to 
preserve the blind is made. 
 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
 
Version 1.0, 27 May 2021 
9 
 
2.2.4 Study Drug 
Study drug is administered only at clinical sites.  All clinical sites must have the appropriate 
equipment and trained personnel needed to effectively manage hypersensitivity reactions including 
anaphylaxis and infusion reactions. 
A brief description of study drug administration is listed below. 
Cohort 1 MAU868 Arm: 
 MAU868 1350 mg IV over at least 60 minutes approximately every 28 days for a total of 
4 doses. 
Cohort 2 MAU868 Arm: 
 MAU868 6750 mg IV over at least 180 minutes on Study Day 1, then 1350 mg IV over at 
least 60 minutes for subsequent doses approximately every 28 days for a total of 4 doses. 
Cohort 3 MAU868 Arm: 
 MAU868 6750 mg IV over at least 180 minutes approximately every 28 days for a total of 
4 doses. 
Placebo 
 Cohort 1: Placebo (D5W) will be administered as an IV infusion over at least 60 minutes 
approximately every 28 days for a total of 4 doses.  
 Cohort 2: Placebo (D5W) will be administered as an IV infusion over at least 180 minutes 
on Day 1 and then over 60 minutes approximately every 28 days for a total of 4 infusions. 
 Cohort 3: Placebo (D5W) will be administered as an IV infusion over at least 180 minutes 
approximately every 28 days for a total of 4 infusions. 
 Placebo is prepared as a standard 250 mL volume of intravenous fluid. 
All infusions will be followed by at least a 25 mL D5W flush to run at the same infusion rate as 
the dose of study drug. 
Dose adjustments and interruptions of study drug are not permitted. Interruptions of individual 
infusions, however, are permitted in the event venous access becomes compromised or a subject 
is not tolerating the infusion. The details of any interruption of an infusion, including the reason(s), 
the timing, and the resumption and completion of the infusion if applicable, must be recorded in 
the source documents and the eCRF. 
For subjects who may require a hemodialysis, plasmapheresis, or immunoadsorption treatment, it 
shall be assumed that the study drug has been removed. A blood sample for PK analysis should be 
collected prior to and following these treatments. In the event that a subject requires hemodialysis, 
plasmapheresis, or immunoadsorption treatments; if <15 days since last MAU868/placebo 
treatment another dose will be given as soon as possible, and the next scheduled monthly dose 
skipped. Regular dosing will occur the following month. If the last dose was 15 days or greater no 
interim dose will be administered, and the regular monthly schedule will be followed. No subject 
will receive more than 4 doses. Subjects anticipated to require hemodialysis, plasmapheresis or 
immunoadsorption treatment at the time of randomization should not be randomized. 
 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
 
Version 1.0, 27 May 2021 
10 
 
2.2.5 Study Assessments 
Table 1 illustrates the visit schedule and procedures of the study to be conducted at each visit. 
 
 


Amplyx Pharmaceuticals, Inc.                                                              CONFIDENTIAL                                                        Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
                                                                                                    Version 1.0, 27 May 2021 
11 
 
TABLE 1: SCHEDULE OF EVENTS 
 
Pre-treatment1,7
Treatment Period2 
(12 weeks) 
Follow-up Period3 
(24 weeks) 
Visit Name 
Screening 
Baseline
Tx1 
Tx2 
Tx3 
Tx4 
Tx5 
Tx6 
Tx7 
Tx8 
Tx9 
FU1 
FU2 
FU3/ET 
Study Weeks 
 
0 
1 
2 
3 
4 
5 
6 
8 
10 
12 
16 
20 
36 
Study Days 
-10 to -1 
14 
7 
14 
21 
28 
35 
42 
56 
70 
84 
112 
140 
252 
Informed consent  
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
I/E criteria 
X 
X 
 
 
 
 
 
 
 
 
 
 
 
 
Medical history 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
KDPI5 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
Prior and concomitant 
medications6 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Demography 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
Randomization7 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
Dose administration4,8
 
X 
 
 
 
X 
 
 
X 
 
X 
 
 
 
Urine for BKV PCR 
and resistance testing9
 
X10 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Plasma for BKV PCR 
and resistance 
testing11 
X 
X10 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
PK sample12,  
 
X13 
X 
X 
X 
X14 
 
 
X14 
 
X13 
X 
X 
X 
Anti-drug antibodies10
 
X10 
 
 
 
X 
 
 
X 
 
X 
X 
X 
X 
Anti-donor 
antibodies15 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Pregnancy test16 
X 
 
 
 
 
X 
 
 
X 
 
X 
 
 
X 
Vital signs17 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Body height 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
Body weight 
X 
X 
 
 
 
X 
 
 
X 
 
X 
 
 
X 
Physical examination 
X 
 
 
 
 
 
 
 
 
 
X 
 
 
X 
ECG (12-lead)18 
 
X 
 
 
 
 
 
 
 
 
X 
 
 
X 


Amplyx Pharmaceuticals, Inc.                                                              CONFIDENTIAL                                                        Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
                                                                                                    Version 1.0, 27 May 2021 
12 
 
 
Pre-treatment1,7
Treatment Period2 
(12 weeks) 
Follow-up Period3 
(24 weeks) 
Visit Name 
Screening 
Baseline
Tx1 
Tx2 
Tx3 
Tx4 
Tx5 
Tx6 
Tx7 
Tx8 
Tx9 
FU1 
FU2 
FU3/ET 
Study Weeks 
 
0 
1 
2 
3 
4 
5 
6 
8 
10 
12 
16 
20 
36 
Study Days 
-10 to -1 
14 
7 
14 
21 
28 
35 
42 
56 
70 
84 
112 
140 
252 
Blood and urine for 
safety19 
 
X10 
 
X 
 
X 
 
 
X 
 
X 
X 
X 
X 
Adverse events 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
BKV BK virus; PCR polymerase chain reaction; PK pharmacokinetic; ECG electrocardiogram 
1. Protocol specific procedures should not be performed until the subject has consented to participation in the study.  However, assessments and procedures 
performed as part of standard of care prior to informed consent, including determination of BK viral load in plasma may be used to qualify a subject for the 
study.   
2. During the treatment period, subjects should be seen approximately every 7 days (+/-3 days) during the first 6 weeks and approximately every 14 days  
(+/-5 days) for the duration of treatment. Subjects may be seen more often at the Investigator’s discretion.  Visit dates are determined from the Baseline Visit.  
3. During the follow-up period, if the subject cannot be seen on the precise protocol-defined study day, the acceptable visit window is +/10 days. 
4. Study Day 1 is the calendar day on which the first dose of study drug is administered.  Subsequent study days are based on calendar days.  
5. The information necessary for determining the KDPI includes donor age, height, weight, ethnicity, history of hypertension, history of diabetes mellitus, cause 
of death, serum creatinine, hepatitis C serostatus, and whether donation occurred after circulatory death.  
6. Record any and all immunosuppressive medication from induction to randomization as well as any other medications taken during the 10 days prior to 
randomization.  
7. Randomization should occur as soon as possible after confirmation of qualifying viremia but not more than 10 days after the qualifying sample was collected. 
Dosing of study drug should occur as soon as possible after randomization.  
8. In the event that a subject requires hemodialysis, plasmapheresis, or immunoadsorption treatments; if <15 days since last MAU868/placebo treatment another 
dose will be given as soon as possible, and the next scheduled monthly dose skipped. Regular dosing will occur the following month. If the last dose was 15 days 
or greater no interim dose will be administered and the regular monthly scheduled will be followed. No subject will receive more than 4 doses. 
9. A sufficient amount of urine should be collected at each assessment to accommodate three tests; one for BKV DNA PCR, one for possible genotypic resistance 
testing and a back up sample. Refer to the study’s Laboratory Manual for volume requirements. 
10. On Study Day 1 collect samples for BKV PCR, antidrug antibodies, and safety labs prior to administration of first dose of MAU868.  Refer to the study’s 
Laboratory Manual for collection requirements. 
11. After screening, plasma samples should be collected and sent to the central laboratory at each assessment for BKV DNA PCR, possible genotypic resistance 
testing and a backup sample. During screening, only BKV PCR is required and may be performed by the laboratory used by the site for usual clinical care, or 
sent to the central lab for testing. Refer to the study’s Laboratory Manual for volume requirements. 
12. In the event subject undergoes hemodialysis, plasmapheresis, or immunoadsorption treatment, a PK sample should be collected prior to and following the 
respective treatment. 


Amplyx Pharmaceuticals, Inc.                                                              CONFIDENTIAL                                                        Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
                                                                                                    Version 1.0, 27 May 2021 
13 
 
13. Three PK samples should be collected on Study Day 1 (first dose administration) and Study Day 84 (last dose administration) :  within approximately 30 minutes 
prior to the start of the infusion, within approximately 30 minutes following the end of the infusion and between approximately 3-6 hours after the end of 
infusion.   
14. On Study days 28 and 56 (2nd and 3rd dose administrations), two PK samples should be collected: within 30 minutes prior to the start of infusion and within 
30 minutes following the end of infusion.  
15. Any anti-donor antibodies collected by the site should be recorded in the eCRF, but collection is not mandatory.  
16. Only for females of child-bearing potential. A negative urine or serum pregnancy test performed locally within 96 hours prior to Study Day 1 (Baseline). 
Local urine dipstick or serum pregnancy testing should be performed before infusions #2 on Day 28, #3 on Day 56 and #4 on Day 84.  
17. Vital signs (temperature, blood pressure, heart rate, respiratory rate and oxygen saturation) should be obtained at each visit if the visit is in person. If the visit 
is not in person vital signs are not required.  On drug infusion days, vitals should be taken within 30 minutes before starting the infusion, and then approximately 
every 30 minutes (+/- 10 minutes) after the start of the infusion until at least 2 hours after completing the infusion.  
18. ECGs should be performed prior to dose administration on Study Day 1 and after dose administration on Study Day 84 and on Day 252 (or at the 
Early Termination Visit) 
19. Blood and urine for safety should be collected and sent to the central laboratory.  Laboratory tests used in for the management and monitoring of the subject 
per standard practice may be performed at the local laboratory at the Investigator’s discretion.   
 
 
 
 
 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
14 
 
3 
SAMPLE SIZE DETERMINATION 
This study will randomize approximately 36 subjects (12 per cohort) to MAU868 and placebo in 
a 2:1 ratio (24 MAU868 and 12 placebo; 8 MAU868 and 4 placebo per cohort). This study is not 
powered to an efficacy endpoint. The number of subjects chosen will provide data useful in 
determining proof of concept. 
4 
DATA SAFETY MONITORING BOARD (DSMB) 
An independent DSMB will review cumulative unblinded safety data as outlined in the DSMB 
charter. The DSMB will advise the Sponsor on the continuing safety of the study patients and those 
yet to be recruited to the study, as well as the continuing validity and scientific merit of the study. 
At any time, the DSMB may temporarily suspend enrollment until any significant safety concerns 
are resolved or terminate the study to ensure patient safety, if in the opinion of the DSMB, further 
dosing would pose an inappropriate safety risk.  
5 
SPONSOR STUDY REVIEW COMMITTEE (SSRC) 
The SSRC includes a Sponsor medical representative, the Medical Monitor and a selected site 
Principal Investigator acting as the SSRC Chair. Approximately 12 weeks after the 9th subject in 
Cohort 1 has been randomized, blinded safety data will be reviewed by the SSRC to determine 
progression from Cohort 1 to Cohort 2. Cohort 3 will not be opened for screening and enrollment 
until an evaluation of unblinded safety, efficacy and pharmacokinetics findings from both Cohorts 
1 and 2 through the 12-week treatment period has been completed by the SSRC.  
The SSRC may recommend enrolling more than 12 subjects into a cohort (Cohort 1, 2, and/or 3) 
to allow adequate data collection for assessment of cohort progression and/or study objectives. 
Expansion of a given cohort, if needed, will not affect the size of subsequent cohort(s). 
In addition, a first interim analysis on unblinded safety and tolerability data, efficacy data will be 
reviewed by the SSRC once all 12 subjects in Cohort 1 have completed the treatment period. 
Unless a significant safety issue related to administration of MAU868 has been identified, the 
conclusions will have no impact on Cohort 2 or the study’s design. 
Following completion of the 12-week treatment periods for Cohorts 1 and 2, a second interim 
analysis on cumulative unblinded data from both cohorts will be reviewed for safety and 
tolerability, efficacy and PK. Based on the SSRC’s safety, efficacy and PK conclusions for Cohorts 
1 and 2, the dosing regimen for Cohort 3 may be adjusted in dosage and/or duration; however, the 
dosage and duration for Cohort 3 will not exceed the dose already specified in the protocol. 
6 
STUDY ENDPOINTS 
6.1.1 Safety Endpoints 
Safety endpoints include physical examinations, vital signs, clinical safety laboratory parameters, 
12-lead ECGs, and adverse events. 
6.1.2 Efficacy Endpoints 
The efficacy endpoints are the following:   


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
15 
 
 Time (weeks) to decrease of BKV plasma viral load by 1 log; 
 Time (weeks) to first decrease of BKV plasma viral load to <LLOQ; 
 Time (weeks) to first decrease of BKV plasma viral load to <LOD; 
 Proportion of subjects with ≥1 log decrease of BKV plasma viral load by 1 week, 2 
weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks  and 36 weeks; 
 Proportion of subjects with decrease BKV plasma viral load to <LLOQ by 1 week, 2 
weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 weeks; 
 Proportion of subjects with decrease BKV plasma viral load to <LOD by 1 week, 2 
weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 weeks; 
 Rate of decrease in BKV plasma viral load over time by 1 week, 2 weeks, 4 weeks, 8 
weeks, 12 weeks, 16 weeks and 36 weeks; 
 Change in eGFR from baseline to week 12, baseline to week 16 and from baseline to 
week 36; 
 Proportion of subjects with BKV nephropathy at week 12, week 16 and 36;  
 Proportion of subjects with graft failure at week 12, week 16 and 36; 
 Proportion of subjects with acute rejection at week 12, week 16 and 36 ; and 
 Proportion of subjects who have died at week 12, week 16 and 36. 
6.1.3 Exploratory Endpoints 
The exploratory endpoints include the following: 
 Presence of anti-drug antibodies (ADA); 
 Presence of genotypic resistance. Genotype resistance data will be described in a separate 
report; 
 Association between BKV genotype and outcome; and 
 Viral kinetics of BKV in plasma and urine including rate of decrease in BKV urine viral 
load over time by 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 weeks. 
6.1.4 Pharmacokinetic Endpoints 
The pharmacokinetic endpoints include the following: 
 MAU868 serum concentrations and the pharmacokinetic parameters estimated from them. 
7 
STATISTICAL METHODOLOGY 
7.1 
General Considerations 
7.1.1 Analysis Day 
Analysis day will be calculated from the date of first dose of study drug.  The day of the first dose 
of study drug will be Day 1, and the day immediately before Day 1 will be Day -1.  There will be 
no Day 0. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
16 
 
7.1.2 Analysis Visits 
Scheduled visits will be assigned to analysis visits as recorded on the CRF.  
7.1.3 Definition of Baseline 
Baseline is defined as the last measurement prior to the first dose of study drug. 
7.1.4 Summary of Statistics 
Summary statistics will be presented by treatment group. The placebo subjects from the cohorts 
will be combined. For continuous variables, the number of observations (n), mean, standard 
deviation, median, minimum, and maximum will be provided. For categorical variables, the 
frequency and percentage in each category will be displayed. 
For summary statistics, the mean and median will be displayed to one decimal place greater than 
the original value and the measure of variability (e.g. standard deviation) will be displayed to two 
decimal places greater than the original value. 
All efficacy analyses will be conducted using two-sided tests at the alpha=0.05 level of 
significance, with no adjustment for multiplicity. 
7.1.5 Handling of Dropouts and Missing Data 
For Viracor/Eurofins BK viral load test results in both plasma and urine, the non-numerical results 
will be imputed as below in the analysis: 
 ‘Detected:<39 copies/mL’ will be imputed as ‘38 copies/mL’ for plasma;  
 ‘Detected:<61 copies/mL’ will be imputed as ‘60 copies/mL’ for urine;  
 ‘Not Detected’ will be imputed as ‘25 copies/ mL’; and  
 ‘>1.00E+10 copies/ mL’ will be imputed as ‘10^10 +1 copies/ mL’.  
If there are multiple BK viral load test results for a single timepoint from both initial and back-up 
samples, the result from the back-up sample will be used in the analysis. If there are exceptions 
that require a different rule, it will be documented separately for the scenarios.   
For Viracor/Eurofins BK viral load test results in both plasma and urine, missing data at each 
scheduled post-baseline visit will be imputed using the last post-baseline observation carried 
forward (LOCF) in the analysis. 
Subjects who dropped out or had missing data will be included in the denominator for safety and 
efficacy analyses as described in Section 7.2.  
In cases of missing or incomplete dates (e.g. Adverse event [AE] and concomitant medications), 
the missing component(s) will be assumed as the most conservative value possible. For example, 
AEs with missing start dates, but with stop dates either overlapping into the treatment period or 
missing, will be counted as treatment-emergent, taking the worst-case approach. When partial 
dates are present in the data, both a partial start date and/or a partial stop date will be evaluated to 
determine whether it can be conclusively established that the AE started prior to the start of study 
drug or ended prior to the start of study drug. If the above cannot be conclusively established based 
on the partial and/or present dates, then the AE will be considered as treatment-emergent. Actual 
data values as they appear in the original eCRF will be presented in the data listings.  


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
17 
 
Missing values for other variables will not be imputed and only observed values will be used in 
data analyses and summaries. 
7.2 
Analysis Populations 
7.2.1 Intent-to-Treat (ITT) Population 
The ITT Population includes all randomized subjects in the study. 
7.2.2 Modified Intent-to-Treat (MITT) Population 
The MITT Population includes subjects who had the disease under study (had renal transplant 
within the year with a graft that is currently functioning and have met the BK viremia protocol 
entry criteria [baseline BK PCR plasma viral load test result ≥103 based on central laboratory 
data]), received at least 1 dose of study drug and have at least 1 post-baseline plasma BK viral load 
result available. 
7.2.3 Safety Population 
The Safety Population includes all subjects who received at least 1 dose of study drug. 
7.2.4 Pharmacokinetic (PK) Population 
The PK Population includes all subjects with at least 1 post-baseline PK sample available. A 
separate PK analysis plan will outline PK analyses.  
7.3 
Subject Data and Study Conduct 
7.3.1 Subject Disposition 
Subject disposition will be summarized by treatment group and in total for the ITT and MITT 
Populations. The following subject disposition categories will be included in the summary: 
 Subjects who received study drug; 
 Subjects who did not receive study drug; 
 Subjects who completed the study drug; 
 Subjects who did not complete the study drug (and reason); 
 Subjects who did not complete the study drug due to the impacts of the COVID-19 
pandemic; 
 Subjects who completed the study; 
 Subjects who did not complete the study (and reason); and 
 Subjects who did not complete the study due to the impacts of the Covid-19 pandemic. 
For subjects who did not complete study drug and subjects who did not complete study, a summary 
will be provided by reason of discontinuation. In addition, the total number of subjects for each 
defined analysis population will be tabulated. 
Subject disposition will also be listed by treatment and subject. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
18 
 
7.3.2 Protocol Deviations 
The number of subjects with at least one reportable protocol deviation, and the number of patients 
with at least one reportable deviation in each deviation category defined in the study protocol 
deviation plan will be presented by treatment group and in total based on the ITT and MITT 
Populations. In addition, the protocol deviations related to COVID-19 pandemic will be 
categorized and summarized separately. 
Protocol deviations will also be listed by treatment and subject.  
7.3.3 Demographic and Baseline Characteristics 
The following demographic and baseline characteristics will be summarized: 
 Age (years) and age categories (<65 years vs. ≥65 years); 
 Sex; 
 Race; 
 Ethnicity 
 Height (cm); 
 Weight (kg); 
 Body mass index (BMI) (kg/m2) ; 
 eGFR based on the CK-EPI equation (mL/min/1.73m²) and eGFR categories (<15, 15-<30, 
30-<60, 60-<90, and >=90); 
 Living donor (Yes vs. No); 
 Pre-existing BKV nephropathy (Yes); 
Note: Pre-existing BKV nephropathy can be identified based on the following CRF data: 
o Medical history using the preferred term ‘Polyomavirus-associated nephropathy’; 
and 
o Clinical outcome assessments indicating subjects developed or possibly developed 
BKV associated nephropathy at Baseline visit. 
 Time from kidney transplant (days); 
Time from kidney transplant (days) is calculated as the first dose date of study drug - date 
of kidney transplant; 
 Baseline plasma viral load (copies/mL); 
 Duration of BK viremia  
Duration of BK viremia (days) is calculated as the first dose date of study drug - date of 
first reported BK plasma positive PCR 
Note: the first reported BK plasma positive PCR is based on CRF data of Historical BKV 
Blood Sample Results and the quantitative result in copies/mL ≥103. 
 BKV genotype 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
19 
 
Demographic and Baseline characteristics will be summarized with descriptive statistics or counts 
and percentages of subjects as appropriate for the ITT, MITT, and Safety Populations. Other 
parameters of Kidney donor profile index (KDPI) will be listed.  
7.3.4 Medical History 
Medical history will be coded to system organ class and preferred term using the Medical 
Dictionary for Regulatory Activities (MedDRA, Version 22.1). Counts and percentages of subjects 
with medical history by system organ class and preferred term will be summarized by treatment 
based on the ITT, MITT and Safety Populations.  
All medical history will be listed by treatment and subject. 
7.3.5 Concomitant Medications 
Prior and Concomitant medications will be coded to anatomical therapeutic chemical (ATC) class 
and preferred term using the World Health Organization (WHO) Drug Dictionary (September 
2019G B3).  
Prior medications are medications used before the first dose of study drug. Concomitant 
medications are medications that were taken on or after first dose of study drug. Any medications 
used before first dose of study drug and continued will be counted as both prior and concomitant 
medications. 
The number and percentages of patients who receive the following prior and concomitant 
medications will be summarized by ATC class and preferred term based on ITT, MITT, and Safety 
Populations: 
 Prior medications;  
 Concomitant medications;  
 Prior immunosuppressive agents with dose decreased or discontinued due to BKV; 
 Concomitant immunosuppressive agents with dose decreased or discontinued due to BKV; 
 Prior immunosuppressive agents with clinically significant decrease in dose or 
discontinuation; 
 Concomitant immunosuppressive agents with clinically significant decrease in dose or 
discontinuation. 
All prior and concomitant medications will be listed by treatment and subjects. 
Any clinically significant (based on blinded review of medical monitor) decrease in dose or 
discontinuation of prior or concomitant immunosuppressive medication will be described 
regardless of whether the reason was due to BKV or not. 
7.3.6 Study Drug Exposure 
All study drug will be administered by IV infusion. Days of exposure to study drug will be 
calculated as the last dose date of study drug – first dose date of study drug + 1. The days of 
exposure to study drug will be summarized based on the Safety and MITT Populations with 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
20 
 
descriptive statistics and with counts and percentages of subjects with exposure in the following 
categories: 
 ≤28 days 
 >28 to ≤56 days 
 >56 to ≤84 days 
 >84 days 
Total number of doses received will be summarized based on the Safety and MITT Populations 
with counts and percentages of subjects in the following categories: 1, 2, 3, and 4 doses. 
7.4 
Safety Assessment 
Safety data will be summarized based on the Safety Population. 
7.4.1 Adverse Events (AEs) 
AEs will be captured from the date of informed consent through study completion.  All AEs will 
be coded to system organ class and preferred term using the MedDRA, Version 22.1. 
Treatment-emergent adverse events (TEAEs) are defined as AEs that start on or after the 
administration of study drug.   
An overview of AEs will be provided including counts and percentages of subjects (and event 
counts) with the following: 
 Any AEs; 
 Any infusion reactions; 
 Any TEAEs (overall and by maximum severity); 
 Any study drug-related TEAEs (overall and by maximum severity); 
 Any TEAEs leading to discontinuation of study drug; 
 Any TEAEs leading to discontinuation of the study; 
 Any serious AEs (SAEs) (overall and by maximum severity); 
 Any treatment-emergent SAEs (TESAEs); 
 Any study drug-related treatment-emergent SAEs (TESAEs); 
 Any death. 
The number and percentage of subjects who experienced at least one TEAE will be presented by 
system organ class and preferred term. Drug-related TEAEs, study drug withdrawals due to 
TEAEs, study discontinuation due to TEAEs, and all SAEs will be summarized in the same 
manner.  
Summaries will be provided by worst grade for the number and percentage of subjects with TEAEs 
and for subjects with drug-related TEAEs by system organ class and preferred term. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
21 
 
Although a subject may have two or more TEAEs, the subject is counted only once within a system 
organ class and preferred term category. The same subject may contribute to two or more preferred 
terms in the same system organ class category. 
A list of patients who have SAEs, a list of patients who discontinue from study drug due to TEAEs, 
and a list of death due to AEs will be provided. All adverse events will be listed.  
7.4.2 Clinical Laboratory Tests 
Central laboratory test results (chemistry, hematology, coagulation, and urinalysis) at each 
scheduled visit and change from baseline will be summarized with descriptive statistics. See 
Appendix A for a complete list of clinical laboratory analytes. 
Shift tables from baseline to each scheduled post-baseline visit will be provided for selected 
chemistry parameters (ALT, AST, ALP, Total Bilirubin, Creatinine, Creatinine Kinase, Sodium, 
Potassium, Bicarbonate, Calcium, and Phosphorus) and hematology parameters (Hematocrit, 
Hemoglobin, Platelets, White blood cell count and differential). For chemistry parameters, the 
following categories will be used: < the lower limit of normal (LLN), normal, >ULN to ≤2×ULN, 
>2×ULN to ≤3×ULN, >3×ULN to ≤5×ULN, >5×ULN, and missing. For hematology parameters, 
the following categories will be used: low, normal, high, and missing. 
The number and percentage of patients with the following potentially clinically significant 
abnormal liver function tests at any post-baseline visit will be summarized: 
 ALT ≥3×ULN 
 ALT ≥5×ULN 
 ALT ≥10×ULN 
 AST ≥3×ULN 
 AST ≥5×ULN 
 AST ≥10×ULN 
 ALT or AST ≥3×ULN 
 Total Bilirubin >1.5×ULN 
 Total Bilirubin >2×ULN 
 ALT or AST ≥3×ULN and Total Bilirubin >1.5×ULN 
 ALT or AST ≥3×ULN and Total Bilirubin >2×ULN 
 Potential Hy’s Law cases: ALT or AST ≥3×ULN and Total Bilirubin >2×ULN, and ALP 
≤ 2×ULN 
A listing of subjects with any post-baseline clinically significant abnormal liver function tests will 
be presented. 
All clinical laboratory data will be listed. Values outside the normal ranges will be flagged. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
22 
 
7.4.3 Vital Signs 
Descriptive statistics will be provided for vital sign data (systolic and diastolic blood pressure, 
heart rate, respiratory rate, body temperature, and oxygen saturation) presented as both actual 
values and changes from baseline for each scheduled visit. 
The number and percentage of patients with the following potentially clinically significant 
abnormal vital signs at any post-baseline visit will be summarized: 
 SBP ≥180 mmHg and Increase ≥20 mmHg from Baseline 
 SBP ≤90 mmHg and Decrease ≥20 mmHg from Baseline or SBP decrease >40 mmHg from 
baseline 
 DBP ≥150 mmHg and Increase ≥15 mmHg from Baseline 
 DBP ≤50 mm Hg and Decrease ≥15 mm Hg from Baseline 
 HR ≥120 bpm and Increase ≥15 bpm from Baseline 
 HR ≤50 bpm and Decrease ≥15 bpm from Baseline 
A listing of all vital signs will be provided by treatment and subject. 
7.4.4 Electrocardiograms 
Descriptive statistics will be provided by treatment for 12-lead ECG interval data (Heart rate, PR 
interval, QRS duration, QT interval, and RR interval) and changes from baseline for each 
scheduled visit. The ECG overall interpretation categories (Normal, Abnormal not clinically 
significant, and Abnormal clinically significant) will be summarized by visit. 
All ECG measurements and the overall interpretation will be listed by treatment and subject. 
7.4.5 Physical Examinations 
Physical examination data will be listed by treatment and subject. 
7.4.6 Other Safety Assessments 
Other safety assessments not summarized in the sections above will be listed by treatment and 
subject. 
7.5 
Efficacy Assessment 
The efficacy analysis will be performed based on the MITT Population and will be repeated on the 
ITT Population. 
In efficacy analyses, pairwise contrasts comparing each of the three active groups to the combined 
placebo group will be tested. Efficacy analyses will be conducted using two sided tests at the 
alpha=0.05 level of significance, with no adjustment for multiplicity. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
23 
 
7.5.1 Efficacy Endpoints 
7.5.1.1 Time (weeks) to First Decrease of BKV Plasma Viral Load by 1 Log 
Time (weeks) to first decrease of BKV plasma viral load by >1 log is defined as the number of 
days from first dose date of study drug to the first decrease of BKV plasma viral load during the 
study by 1 log from baseline plus 1, then divided by 7. 
Subjects who did not have a decrease of BKV plasma viral load by >1 log at any post-baseline 
visits, discontinued from the study, or died will be considered censored. For the censored subjects, 
the last assessment date will be used as the date of censoring. 
The number and percentage of subjects with a decrease of BKV plasma viral load by 1 log during 
the study and subjects who are censored will be tabulated. Time to first decrease of BKV plasma 
viral load by 1 log will be summarized using descriptive statistics. 
The median time to first decrease of BKV plasma viral load by 1 log and associated 95% 
confidence interval (CI) will be estimated for each treatment group using the Kaplan-Meier 
method. The estimate of the hazard ratio for the treatment comparison between each treatment 
dose group and the combined placebo group along with the 95% CI will be calculated using a Cox 
proportional hazard model with treatment (four levels) as a factor. The log-rank p-value for the 
treatment comparison will be presented as well.  
Time (weeks) to first decrease of BKV plasma viral load by >1 log will also be summarized by 
baseline BKV genotype.  
7.5.1.2 Time (weeks) to First Decrease of BKV Plasma Viral Load to <LLOQ 
The lower limit of quantitation (LLOQ) of BKV plasma viral load is 39 copies/mL BK virus DNA 
detected <LLOQ will be reported as ‘Detected:<39 copies/mL’ in data. 
Time (weeks) to first decrease of BKV plasma viral load to <LLOQ is defined as the number of 
days from first dose date of study drug to the first decrease of BKV plasma viral load to <LLOQ 
during the study plus 1, then divided by 7. 
Subjects who did not have a decrease of BKV plasma viral load to <LLOQ at any post-baseline 
visits, discontinued from the study, or died will be considered censored. For the censored subjects, 
the last assessment date will be used as the date of censoring. 
The number and percentage of subjects with a decrease of BKV plasma viral load to <LLOQ 
during the study and subjects who are censored will be tabulated. Time to first decrease of BKV 
plasma viral load to <LLOQ will be summarized using descriptive statistics. 
The median time to first decrease of BKV plasma viral load to <LLOQ and associated 95% CI 
will be estimated for each treatment group using the Kaplan-Meier method. The estimate of the 
hazard ratio for the treatment comparison between each treatment dose group and the combined 
placebo group along with the 95% CI will be calculated using a Cox proportional hazard model 
with treatment (four levels) as a factor. The log-rank p-value for the treatment comparison will be 
presented as well. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
24 
 
Time (weeks) to first decrease of BKV plasma viral load to <LLOQ will also be summarized by 
baseline BKV genotype. 
7.5.1.3 Time (weeks) to First Decrease of BKV Plasma Viral Load to <LOD 
The limit of detection (LOD) of BKV plasma viral load is 26 copies/mL. BK virus DNA detected 
<LOD will be reported as ‘Not Detected’ in data. 
Time (weeks) to first decrease of BKV plasma viral load to <LOD is defined as the number of 
days from first dose date of study drug to the first decrease of BKV plasma viral load to <LOD 
during the study plus 1, then divided by 7. 
Time (weeks) to first decrease of BKV plasma viral load to <LOD will be analyzed in the same 
manner as Time (weeks) to first decrease of BKV plasma viral load to <LLOQ. 
7.5.1.4 Proportion of Subjects with ≥1 log Decrease of BKV Plasma Viral Load by Visit 
The number and percentage of subjects with ≥1 log decrease of BKV plasma viral load by 1 week, 
2 weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 weeks will be tabulated. The last 
observation by the specified timepoint will be used to identify ‘≥1 log decrease of BKV plasma 
viral load’. 
The proportion of subjects with ≥1 log decrease of BKV plasma viral load by the specified visit 
will be analyzed using a logistic regression model with treatment (four levels) as a factor. For the 
treatment comparison between each treatment dose group and combined placebo group, the 
estimated odds ratio, 95% CI, and p-value will be presented. 
In addition, the pairwise treatment comparisons in the proportion will be made using Fisher’s Exact 
Test. The treatment difference estimates, the exact 95% CI, and p-values from Fisher’s Exact Test 
will be presented. 
The proportion of subjects with ≥1 log decrease of BKV plasma viral load by the specified visit 
will also be summarized by baseline BKV genotype. 
7.5.1.5 Proportion of Subjects with Decrease of BKV Plasma Viral Load to <LLOQ by Visit 
The number and percentage of subjects with decrease of BKV plasma viral load to <LLOQ by 1 
week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 weeks will be tabulated. The last 
observation by the specified timepoint will be used to identify ‘decrease of BKV plasma viral load 
to <LLOQ’. 
The proportion of subjects with decrease of BKV plasma viral load to <LLOQ by the specified 
visit will be analyzed using a logistic regression model with treatment (four levels) as a factor. For 
the treatment comparison between each treatment dose group and combined placebo group, the 
estimated odds ratio, 95% CI, and p-value will be presented. 
In addition, the pairwise treatment comparisons in the proportion will be made using Fisher’s Exact 
Test. The treatment difference estimates, the exact 95% CI, and p-values from Fisher’s Exact Test 
will be presented. 
The proportion of subjects with decrease of BKV plasma viral load to <LLOQ by the specified 
visit will also be summarized by baseline BKV genotype. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
25 
 
7.5.1.6 Proportion of Subjects with Decrease of BKV Plasma Viral Load to <LOD by Visit 
The number and percentage of subjects with decrease of BKV plasma viral load to <LOD by 1 
week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 weeks will be tabulated. The last 
observation by the specified timepoint will be used to identify ‘decrease of BKV plasma viral load 
to <LOD’. 
The proportion of subjects with decrease of BKV plasma viral load to <LOD by visit will be 
analyzed in the same manner as the proportion of subjects with decrease of BKV plasma viral load 
to <LLOQ by visit.    
7.5.1.7 Rate of Decrease in BKV Plasma Viral Load by Visit 
Rate of decrease in BKV plasma viral load is calculated using the following formula: 
Rate of decrease = Change from baseline (copies/mL) / time (weeks) between baseline and post-
baseline.  
The BKV plasma viral load at 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 
weeks with LOCF, change from baseline and rate of decrease will be summarized with descriptive 
statistics. 
Treatment difference in the rate of decrease between each treatment dose group and combined 
placebo group will be assessed at the specified visit with LOCF using an ANOVA model with 
treatment (four levels) as a factor. The least squares (LS) mean, SE, 95% CI, and p-value will be 
obtained from the model estimates. The normality of the residuals from the ANOVA model will 
be assessed using the Shapiro-Wilk statistic and graphical examination. If data shows significant 
deviation from normality, the Wilcoxon rank sum test will be applied if necessary. 
In addition, the pairwise treatment differences will be analysed using the two-sample t test. The p-
value from each t test will be presented. 
7.5.1.8 Change in eGFR from Baseline to Week 12, Week 16 and Week 36 
eGFR is calculated using the CK-EPI equation. The eGFR at Week 12, Week 16 and Week 36 
with LOCF, change from baseline will be summarized with descriptive statistics. 
Treatment difference in the eGFR change from baseline between each treatment dose group and 
combined placebo group will be assessed at Week 12, Week 16 and Week 36 with LOCF using an 
ANOVA model with treatment (four levels) as a factor. The LS mean, SE, 95% CI, and p-value 
will be obtained from the model estimates. The normality of the residuals from the ANOVA model 
will be assessed using the Shapiro-Wilk statistic and graphical examination. If data shows 
significant deviation from normality, the Wilcoxon rank sum test will be applied if necessary. 
In addition, the pairwise treatment differences will be analysed using the two-sample t test. The p-
value from t test will be presented. 
7.5.1.9 Proportion of Subjects with BKV Nephropathy by Week 12, Week 16 and Week 36 
The number and percentage of subjects with BKV nephropathy by Week 12, Week 16 and Week 
36 based on renal biopsy, clinical diagnosis or other method of diagnosis as reported in the eCRF 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
26 
 
will be tabulated and summarized by whether BKV nephropathy was confirmed by biopsy or 
diagnosed clinically in the absence of biopsy results. All instances of biopsies demonstrating BKV 
nephropathy will be reported in the CSR, however cases of biopsy-proven BKV nephropathy in 
patients with no pre-study biopsy, stable or improvement serum creatinine and improving BKV 
plasma viral loads will be excluded from the summary to avoid counting patients who most likely 
had BKV nephropathy prior to study entry. Exclusion of these patients from the summary will be 
based on the opinion of the SSRC and documented.  
The method of diagnosis during the study reported in eCRF will be summarized at an overall post-
baseline visit. If the subjects have different methods of diagnosis reported at different post-baseline 
visits, the same subject will be counted in the different methods of diagnosis. 
The proportion of subjects with BKV nephropathy by Week 12, Week 16 and Week 36 will be 
analyzed using a logistic regression model with treatment (four levels) as a factor. For the treatment 
comparison between each treatment dose group and combined placebo group, the estimated odds 
ratio, 95% CI, and p-value will be presented. 
In addition, the pairwise treatment comparisons in the proportion will be made using Fisher’s Exact 
Test. The treatment difference estimates, the exact 95% CI, and p-values from Fisher’s Exact Test 
will be presented. 
7.5.1.10 Proportion of Subjects with Graft Failure by Week 12, Week 16 and Week 36 
The number and percentage of subjects with graft failure (i.e., permanent requirement for renal 
replacement therapy) by Week 12, Week 16 and Week 36 will be tabulated. 
The proportion of subjects with graft failure by Week 12, Week 16 and Week 36 will be analyzed 
using a logistic regression model with treatment (four levels) as a factor. For the treatment 
comparison between each treatment dose group and combined placebo group, the estimated odds 
ratio, 95% CI, and p-value will be presented. 
In addition, the pairwise treatment comparisons in the proportion will be made using Fisher’s Exact 
Test. The treatment difference estimates, the exact 95% CI, and p-values from Fisher’s Exact Test 
will be presented. 
7.5.1.11 Proportion of Subjects with Acute Rejection by Week 12, Week 16 and Week 36 
The number and percentage of subjects with acute rejection (based on kidney biopsy results and 
2017 Banff Kidney Meeting Report) by Week 12, Week 16 and Week 36 will be tabulated. 
The proportion of subjects with acute rejection by Week 12, Week 16 and Week 36 will be 
analyzed using a logistic regression model with treatment (four levels) as a factor. For the treatment 
comparison between each treatment dose group and combined placebo group, the estimated odds 
ratio, 95% CI, and p-value will be presented. 
In addition, the pairwise treatment comparisons in the proportion will be made using Fisher’s Exact 
Test. The treatment difference estimates, the exact 95% CI, and p-values from Fisher’s Exact Test 
will be presented. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
27 
 
7.5.1.12 Mortality Rate/Survival by Week 12, Week 16 and Week 36  
Time (weeks) to death is defined as the number of days from first dose date of study drug to the 
date of death during the study plus 1, then divided by 7. 
Subjects who are alive by Week 12, Week 16 and Week 36, not known to die, or lost to follow-up 
will be censored on the last date the subject is known to be alive. 
The number and percentage of subjects who died by Week 12, Week 16 and Week 36 and subjects 
who are censored will be tabulated. Time (weeks) to death will be summarized using descriptive 
statistics. 
The median time to death by Week 12, Week 16 and Week 36 and associated 95% CI will be 
estimated for each treatment group using the Kaplan-Meier method. The estimate of the hazard 
ratio for the treatment comparison between each treatment dose group and the combined placebo 
group along with the 95% CI will be calculated using a Cox proportional hazard model with 
treatment (four levels) as a factor. The log-rank p-value for the treatment comparison will be 
presented as well. 
7.5.2 Exploratory Endpoints 
7.5.2.1 Proportion of Subjects with Presence of Anti-Drug Antibodies (ADA) at Any Time 
during the Study 
The number and percentage of subjects with presence of anti-drug antibodies (ADA) at any post-
baseline visits during the study will be summarized descriptively.  
All ADA data will be listed by treatment and subject. 
7.5.2.2 Presence of genotypic resistance 
The presence of genotypic resistance and association between genotypic resistance and outcome 
will be an exploratory endpoint described in a separate report.  
7.5.2.3 Viral Kinetics of BKV in Plasma and Urine 
The BKV plasma and urine viral load, change from baseline and rate of decrease over  time by 1 
week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 weeks will be summarized with 
descriptive statistics. Missing data at each scheduled post-baseline visit will be imputed using the 
LOCF approach. The corresponding line plots of the plasma and urine BKV viral load over time 
will be presented by treatment group and study visit. 
All plasma and urine BKV viral load data will be listed by treatment and subject.  
7.5.3 Other Efficacy Data 
All other efficacy data will be listed by treatment and subject. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
28 
 
7.6 
Pharmacokinetic Assessment 
All pharmacokinetic analyses will be performed by another vendor and described in a standalone 
PK analysis plan. 
The PK of MAU868 will be assessed by fitting a compartmental model to each subject’s full set 
of data, i.e. data collected over the full course of treatment.  The specific model will be determined 
from the data and will be parameterized in terms of clearance(s) and volume(s) of distribution.  
Additional parameters such as area under the curve and distribution and/or elimination half-lives 
will also be estimated.  Relationships between PK parameters and subject covariates such as age, 
gender, weight, etc., will be examined as appropriate. 
8 
INTERIM ANALYSIS 
8.1 
First Interim Analysis 
Following completion of the 12-week treatment period of Cohort 1, unblinded safety and 
tolerability data (adverse events, clinical laboratories, vitals/physical exams and ECGs), efficacy 
data (BKV viral load in the plasma) and PK (MAU868 plasma levels) will be provided in the form 
of individual subject case data packages and reviewed by the SSRC. The treatment assignment in 
Cohort 1 will be unblinded; however, these data will not include associated subject or site 
identifiers. The objectives of this interim analysis/this data review are to evaluate whether four 
doses MAU868 1350 mg IV administered every 28 days for a total of 4 doses demonstrate: 
 safety and tolerability signals compared to placebo 
 a decrease in BK plasma viral load compared to placebo 
 predicted MAU868 plasma levels 
The conclusions from this first interim analysis will be used by the Sponsor to evaluate the safety 
and efficacy of MAU868 early-on in this first-in-patient study. Unless a significant safety issue 
related to administration of MAU868 has been identified, the conclusions will have no impact on 
Cohort 2 or the study’s design. 
For the first interim analysis, unblinded programmed patient profiles will be provided. 
8.2 
Second Interim Analysis 
Following completion of the 12-week treatment periods for Cohorts 1 and 2, cumulative unblinded 
programmed data from both cohorts will be reviewed for safety and tolerability (adverse events, 
clinical laboratories, vitals/physical exams and ECGs), efficacy (BKV viral load in the plasma) 
and PK (MAU868 plasma levels).  The objectives of this second interim analysis are to evaluate 
whether four doses MAU868 1350 mg IV administered every 28 days for a total of 4 doses or 
MAU868 6750 mg IV administered as a first dose followed by 3 more doses of MAU868 1350 
mg IV administered every 28 days demonstrate: 
 safety and tolerability signals compared to placebo 
 a decrease in viral load compared to placebo 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
29 
 
 predicted MAU868 plasma levels 
Based on the SSRC’s assessment of safety and tolerability and the sponsor assessment of the safety 
and tolerability, efficacy and PK conclusions for Cohorts 1 and 2, the dosing regimen for Cohort 
3 may be adjusted in dosage and/or duration; however, the dosage and duration for Cohort 3 will 
not exceed the dose already specified in the protocol. Cohort 3 will not be opened for screening 
and enrollment this evaluation has been completed. 
For the second interim analysis, cumulative unblinded programmed patient profiles will be 
provided. In addition, the programmed statistical tables and  listings for Cohorts 1 and 2 will be 
presented.  
8.2.1 Cohorts 1 & 2: Safety and Tolerability 
Physical examinations, vital signs, clinical safety laboratory parameters, concomitant procedures 
and medications, and adverse events will be assessed by the SSRC via programmed statistical 
tables and listings for both Cohorts 1 and 2.  
8.2.2 Cohorts 1 & 2: Response to Study Treatment 
The following efficacy endpoints are included in the second interim analysis and will be assessed 
by the SSRC for subjects in Cohorts 1 and 2. The analysis will be performed based on the MITT 
Population and will be repeated on the ITT Population. 
 Time (weeks) to decrease of BKV plasma viral load by 1 log; 
 Time (weeks) to first decrease of BKV plasma viral load to <LLOQ ; 
 Proportion of subjects with >1 log decrease of BKV plasma viral load by 1 week, 2 weeks, 
4 weeks, 8 weeks, and 12 weeks; 
 Proportion of subjects with decrease of BKV plasma viral load to <LLOQ by 1 week, 2 
weeks, 4 weeks, 8 weeks, and 12 weeks;  
 Rate of decrease in BKV plasma viral load by 1 week, 2 weeks, 4 weeks, 8 weeks, and 
12 weeks;  
 Change in eGFR from baseline to week 12;  
 Proportion of subjects with BKV nephropathy through week 12; 
 Proportion of subjects with graft failure through week 12;  
 Proportion of subjects with acute rejection through week 12; 
 Proportion of subjects who have died through week 12. 
In the efficacy analyses, pairwise contrasts comparing each of the two active groups to the 
combined placebo group will be tested. The treatment groups will be 3 levels (i.e. Cohort 1 active 
group, Cohort 2 active group and combined placebo group). The analyses will be conducted using 
two sided tests at the alpha=0.05 level of significance, with no adjustment for multiplicity. 
The efficacy endpoints above for the second interim analysis will be summarized and analyzed in 
the same manner as described in Section 7.5.1 with the exception that Cohort 3 subjects will not 
be included in the interim analysis. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
30 
 
8.2.3 Pharmacokinetics Cohort 1 and 2 
MAU868 serum concentrations through Week 16 will be evaluated by the SSRC for both Cohorts 
1 and 2. The pharmacokinetic analyses will be performed by another vendor and described in a 
standalone PK analysis plan. 
9 
CHANGES FROM PROTOCOL-SPECIFIED STATISTICAL ANALYSES 
The following changes are made in the SAP compared to the description in the protocol as 
clarification: 
 Changed the MITT Population definition ‘subjects who received at least 1 dose of study 
drug and has at least 1 post-baseline plasma BK viral load result available’ to be ‘subjects 
who had the disease under study (had renal transplant within the year with a graft that is 
currently functioning and have met the BK viremia protocol entry criteria [baseline BK 
PCR plasma viral load test result ≥103 based on central laboratory data]), received at least 
1 dose of study drug and have at least 1 post-baseline plasma BK viral load result 
available.’. 
 Added the following efficacy endpoints: 
o Time (weeks) to first decrease of BKV plasma viral load to <LOD;  
o Proportion of subjects with decrease BKV plasma viral load to <LOD by 1 week, 2 
weeks, 4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 weeks. 
 Added ‘Week 16’ in the following efficacy endpoints: 
o Proportion of subjects with ≥1 log decrease of BKV plasma viral load by 1 week, 2 
weeks, 4 weeks, 8 weeks, 12 weeks and 36 weeks; 
o Proportion of subjects with decrease BKV plasma viral load to <LLOQ by 1 week, 2 
weeks, 4 weeks, 8 weeks, 12 weeks and 36 weeks; 
o Proportion of subjects with decrease BKV plasma viral load to <LOD by 1 week, 2 
weeks, 4 weeks, 8 weeks, 12 weeks and 36 weeks; 
o Rate of decrease in BKV plasma viral load over time by 1 week, 2 weeks, 4 weeks, 8 
weeks, 12 weeks and 36 weeks; 
o Change in eGFR from baseline to week 12 and from baseline to week 36; 
 Added ‘Week 12, Week 16, and Week 36’ in the following efficacy endpoints: 
o Proportion of subjects with BKV nephropathy; 
o Proportion of subjects with graft failure during the study; 
o Proportion of subjects with acute rejection during the study; and 
o Mortality rate during the study. 
 Added ‘rate of decrease in BKV plasma and urine viral load over time by 1 week, 2 weeks, 
4 weeks, 8 weeks, 12 weeks, 16 weeks and 36 weeks’ in the exploratory endpoints. 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
31 
 
 Added presence of genotype and genotypic resistance and association with outcome in the 
exploratory endpoints, which will be described in a separate report. 
10 PROGRAMMING SPECIFICATIONS 
Analyses will be performed using SAS® version 9.3 or higher.  All available data will be presented 
in subject data listings which will be sorted by subject and visit date as applicable.  Detailed 
Programming Specifications will be provided in a separate document. 
 
 


Amplyx Pharmaceuticals, Inc. 
   CONFIDENTIAL 
Statistical Analysis Plan 
Clinical Study Protocol MAU868-201 
 
Version 1.0, 27 May 2021 
32 
 
Appendix A: Clinical Safety Laboratory Analytes 
Standard Safety Chemistry Panel 
Alanine aminotransferase 
Albumin 
Alkaline phosphatase 
Amylase 
Aspartate aminotransferase 
Bicarbonate 
Blood urea nitrogen 
Calcium 
Chloride 
Creatine kinase 
Creatinine 
Estimated glomerular filtration rate 
Gamma-glutamyl transferase 
Glucose 
Inorganic phosphorus 
Lactate dehydrogenase 
Lipase 
Potassium 
Sodium 
Bilirubin (total, direct, and indirect) 
Total protein 
Uric acid 
Hematology 
Hematocrit 
Hemoglobin 
Platelets 
Red blood cell count 
White blood cell count and differential [1] 
 
1. Manual microscopic review is performed only if white blood cell count and/or differential values are out of 
reference range.  
Coagulation 
Prothrombin time 
International normalized ratio (INR) 
Activated Partial Thromboplastin Time (aPTT) 
 
Urinalysis 
Bilirubin 
Blood 
Glucose 
Ketones 
Leukocyte esterase 
Microscopy [1] 
Nitrite 
pH 
Protein 
Specific gravity 
Urobilinogen  
 
2. Microscopy is performed only as needed based on positive dipstick test results. 
Other Tests 
Urine or serum pregnancy test [1] 
 
1. Women of childbearing potential only.