PERL: A Multicenter Clinical Trial of Allopurinol to Prevent GFR Loss in T1D
Phase: PHASE3
Conditions: Diabetic Nephropathies, Coronary Artery Disease
Sponsor: Alessandro Doria

 
 
 
Page 1 of 54 
 
 
 
 
 
 
 
 
 
 
STUDY PROTOCOL 
 
‘A multicenter clinical trial of allopurinol to prevent GFR loss in type 1 diabetes’ 
 
 
 
 
 
 
 
 
 
 
 
 
Version 10.0 
Approved by the DSMB  
March 6, 2018 
 
 
 
 

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Table of Contents 
GENERAL INFORMATION ........................................................................................................................ 5 
Funding Agencies ......................................................................................................................... 5 
Program Officers .......................................................................................................................... 5 
Grant Numbers ............................................................................................................................ 5 
Sponsor for IND #115313 ............................................................................................................. 5 
Principal Investigators .................................................................................................................. 5 
Directors of Clinical Sites ............................................................................................................... 6 
Global Clinical Coordinator ............................................................................................................ 8 
Data Coordinating Center .............................................................................................................. 8 
Central Laboratory ....................................................................................................................... 9 
PROTOCOL SUMMARY ........................................................................................................................... 10 
ABBREVIATIONS ................................................................................................................................... 13 
1. INTRODUCTION ................................................................................................................................ 15 
2. STUDY OBJECTIVE ............................................................................................................................ 16 
3. STUDY DESIGN .................................................................................................................................. 16 
4. PARTICIPATING CENTERS ................................................................................................................ 16 
4.1 Location of study visits .......................................................................................................... 17 
5. SUBJECT SELECTION ......................................................................................................................... 18 
5.1. Inclusion Criteria ................................................................................................................. 18 
5.2. Exclusion Criteria ................................................................................................................. 19 
5.3. Prohibited Medications and Restrictions ................................................................................. 20 
5.4. Randomization Procedures ................................................................................................... 20 
5.5. Discontinuation of study drug ............................................................................................... 21 
5.5.1. Reasons for discontinuation ............................................................................................ 21 
5.5.2. Handling of study drug discontinuation ............................................................................ 21 
5.5.3. Replacements  .............................................................................................................. 22 
5.5.4. Termination of Study ..................................................................................................... 22 
6. STUDY TREATMENTS ......................................................................................................................... 22 
6.1. Study Drug Description, Dosage, Administration, and Accountability ........................................ 22 
6.1.1. Description.................................................................................................................... 22 
6.1.2. Dosage ......................................................................................................................... 23 
6.1.3. Compliance and accountability ........................................................................................ 23 
6.2. Blinding Procedures ............................................................................................................. 24 
7. STUDY OUTCOMES ............................................................................................................................ 24 

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7.1. Primary outcome ................................................................................................................. 24 
7.1.1. iGFR quality assurance. .................................................................................................. 24 
7.1.2. iGFR quality control ....................................................................................................... 25 
7.1.3. Technically unacceptable iGFR measures. ........................................................................ 25 
7.2. Secondary outcomes ............................................................................................................ 25 
8. STUDY PROCEDURES ........................................................................................................................ 26 
8.1. Schedule of Events .............................................................................................................. 26 
 Figure 1.  Schedule of Events .................................................................................................. 27 
8.2. Screening and Enrollment in the Run-in Period (Visit 1) .......................................................... 28 
8.3. Run-in Period (Visits 2, 3, and 4) .......................................................................................... 28 
8.4. Enrollment in the Study and Randomization (Visit 5) ............................................................... 30 
8.5. Treatment Period (Visits 6 to 15) .......................................................................................... 31 
8.6. End of Intervention (Visit 16)................................................................................................ 31 
8.7. End of Wash-out Period (Visit 17) ......................................................................................... 32 
8.8. RAS blocking and anti-hypertensive therapy after completion of the study ................................ 32 
8.9. Future biomarker studies ...................................................................................................... 32 
8.10. Early Withdrawal................................................................................................................ 33 
9. SAFETY ASSESSMENTS ...................................................................................................................... 33 
9.1. Demographic Data/Medical History ........................................................................................ 33 
9.2 Skin exam ............................................................................................................................ 33 
9.3. Vital Signs ........................................................................................................................... 33 
9.4. Clinical Laboratory Tests ...................................................................................................... 33 
9.5. Management of Uric Acid Levels ........................................................................................... 33 
10. ADVERSE EVENT REPORTING ......................................................................................................... 33 
10.1. Definitions ......................................................................................................................... 33 
10.2. Adverse Events Reporting ................................................................................................... 34 
10.3. Assessment of Causality and Severity .................................................................................. 34 
10.4. Serious Adverse Events Reporting ....................................................................................... 35 
11. STATISTICAL ANALYSIS.................................................................................................................. 35 
11.1. Analysis Population ............................................................................................................ 35 
11.2. Initial Data Analysis ........................................................................................................... 35 
11.3. Primary Efficacy Analysis .................................................................................................... 35 
11.4. Secondary Efficacy Analyses ............................................................................................... 36 
11.5. Incomplete Data ................................................................................................................ 37 

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11.6. Pilot participants ................................................................................................................ 37 
11.7. Model assumptions and alternative analyses ........................................................................ 37 
11.8. Safety Analyses ................................................................................................................. 38 
11.9. Interim Analysis ................................................................................................................. 38 
11.10. Sample Size ..................................................................................................................... 38 
12. DATA COLLECTION AND QUALITY ASSURANCE .............................................................................. 39 
12.1. Case Report Forms ............................................................................................................ 40 
12.2. Quality Control and Quality Assurance ................................................................................. 40 
12.2.1. Clinical monitoring ....................................................................................................... 40 
12.2.2. Statistical monitoring.................................................................................................... 40 
12.2.3. Laboratory quality monitoring ....................................................................................... 41 
12.3. Study Record Retention ...................................................................................................... 41 
12.4. Data and Biosample Archiving in the NIDDK Central Repository ............................................. 41 
13.  PROTECTION OF HUMAN SUBJECTS .............................................................................................. 41 
13.1. Characteristics of the study population ................................................................................ 41 
13.2. Sources of research material ............................................................................................... 42 
13.3. Plans for recruitment of subjects and consent procedures. .................................................... 42 
13.4. Potential Risks ................................................................................................................... 42 
13.4.1. Risks associated with screening procedures and blood tests ............................................ 42 
13.4.2. Risks associated with allopurinol treatment .................................................................... 43 
13.4.3. Risks associated with RAS blocker treatment .................................................................. 43 
13.5. Procedures for protecting against and minimizing potential risks ............................................ 44 
13.6. Incentives/remuneration .................................................................................................... 46 
13.7. Institutional Review Board .................................................................................................. 46 
14. DATA AND SAFETY MONITORING PLAN ......................................................................................... 47 
15. STUDY ADMINISTRATION .............................................................................................................. 48 
15.1. Organization ...................................................................................................................... 48 
15.2. Protocol Deviations, Violations, and Amendments ................................................................. 49 
15.3. Financial Disclosure ............................................................................................................ 50 
15.4. Publications ....................................................................................................................... 50 
16. REFERENCES ................................................................................................................................... 50 
 
 
 

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GENERAL INFORMATION 
Funding Agencies 
 
National Institute of Diabetes and Digestive and Kidney Diseases 
 
Juvenile Diabetes Research Foundation (JDRF) 
Program Officers  
Teresa Jones, MD 
Division of Diabetes, Endocrinology, & Metabolic Diseases 
NIDDK, National Institutes of Health 
6707 Democracy Blvd. Room 609 
Bethesda, MD 20892-5460 
Phone: (301) 435-2996 
Fax: (301) 480-3503 
jonester@mail.nih.gov 
 
Afshin Parsa, MD, MPH 
Program Director, Clinical Kidney Genomics, PKD and CKD NIDDK/NIH 
6707 Democracy Blvd. Room 6139 
Bethesda, MD 20892-5460 
Tel: (301) 827-1375 
afshin.parsa@nih.gov 
Marlon Pragnell, PhD 
Senior Scientist, Translational Development 
Juvenile Diabetes Research Foundation 
26 Broadway 
New York, NY 10004 
Phone: (212) 479-7690 
Fax: (212) 785-9609 
mpragnell@jdrf.org  
 
Grant Numbers 
NIH UC4 DK101108-01 
JDRF 17-2012-377 
ClinicalTrials.gov NCT02017171 
 
Sponsor for IND #115313 
Alessandro Doria, MD PhD MPH  
Joslin Diabetes Center and Harvard Medical School 
One Joslin Place 
Boston, MA 02215 
Phone: (617) 309-2406 
Fax: (617) 309-2667 
alessandro.doria@joslin.harvard.edu  
 
Principal Investigators 
Alessandro Doria, MD PhD MPH  
Joslin Diabetes Center and Harvard Medical School 
One Joslin Place 
Boston, MA 02215 
Phone: (617) 309-2406 
Fax: (617) 309-2667 
alessandro.doria@joslin.harvard.edu  
 

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S. Michael Mauer, MD 
University of Minnesota 
2450 Riverside Ave.  
East Building, MB681 
Minneapolis, MN  55454 
Phone: (612) 626-2720 
Mobile:  (612) 703-5884 
Fax: (612) 626-2791 
mauer002@umn.edu 
 
Directors of Clinical Sites 
Maria Luiza Caramori, MD PhD 
University of Minnesota 
420 Delaware Street SE, MMC 101 
Minneapolis, MN,  55455 
Phone: (612) 625-7189 
Fax: (612) 626-3133 
caram001@umn.edu 
 
Sylvia Rosas, MD 
Joslin Diabetes Center and Harvard Medical School 
One Joslin Place 
Boston, MA 02215 
Phone: (617) 309-2477 
Fax: (617) 309-3403 
Sylvia.Rosas@joslin.harvard.edu 
 
Sarit Polsky, MD, MPH 
Barbara Davis Center for Diabetes  
University of Colorado at Denver - Anschutz Medical Campus  
1775 Aurora Court, Mail Stop A140  
Aurora, CO 80045 P 
Phone: (303) 724-8575 
Fax: (303) 724-6784 
sarit.polsky@ucdenver.edu  
 
Bruce Perkins, MD MPH 
Mount Sinai Hospital 
University of Toronto 
Room L5-210, Mail Box 16 
60 Murray St. 
Toronto, ON 
Canada, M5G 1X5 
Phone: (416) 586-8763 
Fax: (647) 826-1528 
bruce.perkins@mtsinai.ca 
 
Ronnie Aronson, MD 
LMC Diabetes and Endocrinology 
1929 Bayview Avenue, Suite 107 
Toronto, ON Canada M4G 3E8 
Ph: (416) 646-2929 
Fax: (416) 645-2930 
Email: Ronnie.Aronson@LMC.CA 
 
Rodica Pop-Busui, MD PhD 

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University of Michigan 
Division of Metabolism, Endocrinology and Diabetes 
5329 Brehm Tower 
1000 Wall Street 
Ann Arbor MI 48105 
Phone: (734) 763-3056 
rpbusui@umich.edu 
 
Peter Rossing, MD 
Steno Diabetes Center 
Niels Steensens Vej 1 
DK-2820 Gentofte 
Denmark 
Phone: +45 4443-7310 
pro@steno.dk 
 
Mark Molitch, MD 
Division of Endocrinology, Metabolism and Molecular Medicine 
Northwestern University Feinberg School of Medicine 
645 N. Michigan Avenue, Suite 530 
Chicago, IL 60611 
Phone: (312) 503-4130 
Fax: (312) 926-8693 
molitch@northwestern.edu 
 
Jill Crandall, MD 
Albert Einstein College of Medicine  
Jack and Pearl Resnick Campus  
1300 Morris Park Avenue  
Belfer Building, Room 702  
Bronx, NY 10461 
Phone: (718) 430-3765  
Fax: (718) 430-8557  
jill.crandall@einstein.yu.edu 
 
Janet McGill, MD 
Washington University School of Medicine 
660 S. Euclid, Campus Box 8127 
St. Louis, MO  63110 
Phone: (314) 362-8681 
Fax: (314) 362-4833 
hmcgill@dom.wustl.edu 
 
Ronald J. Sigal, MD, MPH 
Cumming School of Medicine, University of Calgary 
1820 Richmond Road SW 
Calgary, Alberta, Canada T2T 5C7 
Phone: (403) 955-8327 
Fax: (403) 955-8249 
rsigal@ucalgary.ca 
 
 
Peter Senior, MD 
Alberta Diabetes Institute 
2-004 Li Ka Shing Center for Health Research Innovation 
Edmonton, Alberta, Canada T6G2E1 
Phone: (780) 407-1480 

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Fax: (780) 492-9555 
petersenior@ualberta.ca 
 
Guillermo E. Umpierrez, MD 
Emory University School of Medicine 
101 Wodruff Circle, 1st Floor, RM 1311 
Atlanta, GA 30322 
Phone: (404) 778-1663 
geumpie@emory.edu 
 
Ian de Boer, MD, MS 
University of Washington Medical Center 
Box 359606 
325 9th Avenue, Room 3NJ357 
Seattle, WA 98104 
Phone: (206) 616-5403 
Fax: (206) 685-9399IDeBoer@Nephrology.washington.edu 
 
Ildiko Lingvay, MD, MPH, MSCS 
University of Texas Southwestern Medical Center  
5323 Harry Hines Blvd., U9.134E  
Dallas, TX 75390-9302  
Phone: (214) 648-2779 
Fax: (214) 648-2885 
ildiko.lingvay@utsouthwestern.edu 
 
Katherine R. Tuttle, MD 
Providence Medical Research Center  
104 W. 5th Avenue, Suite 350E  
Spokane, WA 99204  
Phone: (509) 474-4345 
Fax: (509) 474-4325 
katherine.tuttle@providence.org 
 
Tom Elliott MBBS, FRCPC 
BC Diabetes  
4102-2775 Laurel Street  
Vancouver, BC V5Z 1M9  
Phone: (604) 683-3734 ext. 1001  
Fax: (604) 628-3821 
telliott@bcdiabetes.ca 
 
Global Clinical Coordinator 
Debbie Conboy, RN CDE  
Joslin Diabetes Center 
One Joslin Place, Room 445 
Section on Genetics & Epidemiology 
Boston, MA  02215 
Phone:    (617) 309-4343 
Fax:  (617) 309-4170 
debbie.conboy@joslin.harvard.edu 
 
Data Coordinating Center  
Co-Director: Andrzej Galecki, MD PhD 
Division of Geriatrics, Medical School 
Department of Biostatistics, School of Public Health 

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University of Michigan 
300 North Ingalls  
Ann Arbor, MI 48109-2009  
Phone: (734) 936-2138 
Fax: (734) 936-2116  
agalecki@umich.edu 
 
Co-Director: Cathie Spino, ScD 
Statistical Analysis of Biomedical and Educational Research (SABER) unit 
University of Michigan 
M4507 SPH II 
1415 Washington Heights  
Ann Arbor, Michigan 48109-2029 
Phone: (734) 615-5469 
Fax: (734) 647-3711    
spino@umich.edu 
Central Laboratory 
Advanced Research and Diagnostics Laboratory 
Director:  Amy Karger, MD, PhD  
University of Minnesota  
Mayo Mail Code 609, Room Mayo D211  
420 Delaware Street, SE  
Minneapolis, MN 55455  
Ph: (612) 624-2150 
Fax: (612) 625-1121 
karge026@umn.edu 
 

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PROTOCOL SUMMARY 
 
Study Title 
A multicenter clinical trial of allopurinol to prevent GFR loss in type 1 diabetes 
Study Phase 
Phase 3 
Objectives 
To determine whether lowering serum uric acid by means of allopurinol early in 
the course of kidney disease may be effective in preventing or slowing the 
decline of renal function in T1D patients. 
Study Design 
Multicenter, double-blind, placebo-controlled, parallel-group randomized clinical 
trial. 
Participating Centers 
Joslin Diabetes Center (Boston), University of Minnesota (Minneapolis), University 
of Colorado (Denver), University of Michigan (Ann Arbor), University of Toronto 
(Toronto), Northwestern University (Chicago), Albert Einstein College of Medicine 
(New York), Steno Diabetes Center (Copenhagen, Denmark), University of 
Washington (Seattle), University of Calgary (Calgary), University of Alberta 
(Edmonton), Emory University (Atlanta), Washington University (St. Louis), 
University of Texas Southwestern (Dallas), Providence Medical Research Center 
(Spokane), BC Diabetes (Vancouver).   
Subject Population 
480 T1D subjects.  
 
Inclusion criteria:  
1. Male or female T1D patients. 
 
2. T1D continuously treated with insulin within one year from diagnosis.        
If the onset was after age 35, the presence of one or more of the following 
will also be required:  
 
documentation of the presence of circulating T1D-associated 
autoantibodies at diagnosis or at any other time 
 
history of hospitalization for DKA 
 
plasma C-peptide below the limit of detection with standard assay (with 
concurrent blood glucose >100 mg/dl) 
 
3. Duration of T1D ≥ 8 years.  
 
4. Age 18-70 years. 
 
5. History or presence of microalbuminuria or moderate macroalbuminuria, or 
evidence of declining kidney function regardless of history or presence of 
albuminuria and/or RAS Blocker treatment. Micro- or moderate 
macroalbuminuria will be defined as at least two out of three consecutive 
urinary albumin excretion rates [AERs] or albumin creatinine ratios [ACRs] 
taken at any time during the two years before screening or at screening in 
the 30-5000 mg/24 hr (20-3333 µg/min) or 30-5000 mg/g range, 
respectively, if not on RASB agents, or in the 18-5000 mg/24 hr (12-3333 
µg/min) or 18-5000 mg/g range, respectively, if on RASB agents); Evidence 
of declining kidney function will be defined as an eGFR (CKD-EPI) decline 
≥3.0 ml/min/1.73 m2/year, estimated from the slope derived from all the 
available serum creatinine measurements (including the one at screening 
assessment) from the previous 3 years. If at least 3 serum creatinine 
measures are not available in the previous 3 years, then the slope can be 
derived from creatinine values from the previous 5 years. 
 
6. Estimated GFR (eGFR) based on serum creatinine between 40 and 99.9 
ml/min/1.73 m2 at screening. The upper and the lower limits should be 

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decreased by 1 ml/min/1.73 m2 for each year over age 60 (with a lower limit 
of 35 ml/min/1.73m2) and by 10 ml/min/1.73 m2 for strict vegans.  
 
7. Serum UA (UA) ≥ 4.5 mg/dl at screening. 
 
8. Valid baseline (Visit 4) iGFR measurement.  
 
OR  
 
9. Being an active participant in the PERL Pilot Study. 
 
Exclusion criteria:  
1. History of gout or xanthinuria or other indications for uric acid lowering 
therapy such as cancer chemotherapy.  
 
2. Recurrent renal calculi.  
 
3. Use of urate-lowering agents within 2 months before screening.  
 
4. Current use of azathioprine, 6-mercaptopurine, didanosine, warfarin, 
tamoxifen, amoxicillin/ampicillin, or other drugs interacting with allopurinol.  
 
5. Known allergy to xanthine-oxidase inhibitors or iodine containing substances.   
 
6. HLA B*58:01 positivity (tested before randomization).  
 
7. Renal transplant.  
 
8. Non-diabetic kidney disease.  
 
9. SBP>160 or DBP >100 mmHg at screening or SBP>150 or DBP>95 mmHg at 
the end of the run-in period.  
 
10. Cancer treatment (excluding non-melanoma skin cancer treated by excision) 
within two years before screening.  
 
11. History of clinically significant hepatic disease including hepatitis B or C 
and/or persistently elevated serum liver enzymes at screening and/or history 
of HBV/HCV positivity.  
 
12. History of acquired immune deficiency syndrome or human 
immunodeficiency virus (HIV) infection.  
 
13. Hemoglobin concentration <11 g/dL (males), <10 g/dL (females) at 
screening.  
 
14. Platelet count <100,000/mm3 at screening.  
 
15. History of alcohol or drug abuse in the past 6 months.  
 
16. Blood donation in the 3 months before screening.  
 
17. Breastfeeding or pregnancy or unwillingness to be on contraception 
throughout the trial.  
 
18. Poor mental function or any other reason to expect patient difficulty in 

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complying with the requirements of the study.  
 
19. Serious pre-existing medical problems other than diabetes, e.g. congestive 
heart failure, pulmonary insufficiency.  
  
Study Duration 
9-week run-in period, during which RAS inhibition will be introduced and/or 
standardized, if indicated, and BP normalized, if elevated above 140/90 mmHg, 
followed by a 3-year treatment period and then by a 2-month wash-out period. 
Study Treatment, Dosage, 
and Route of Administration 
After the run-in period, eligible subjects will be randomized in a 1 to 1 ratio to 
receive placebo or oral allopurinol at a dose of 100 mg per day for 4 weeks and 
then at a dose ranging from 200 to 400 mg per day depending on kidney 
function.  
Efficacy Assessments 
Primary outcome measure: GFR at the end of the 2-month wash-out period 
following the 3-year treatment period, measured by the plasma clearance of non-
radioactive iohexol (iGFR) and adjusted for the iGFR at baseline.  
 
Secondary outcome measures: 1. iGFR the end of the 3-yr treatment period 
(before the washout period) adjusted for the iGFR at baseline. 2. iGFR time 
trajectory estimated from periodical iGFR measurements. 3. eGFR at 4 months 
estimated from serum creatinine and cystatin C and adjusted for the eGFR at 
baseline. 4. eGFR time trajectory estimated from quarterly serum creatinine and 
cystatin C measurements (eGFR). 5. Time to serum creatinine doubling or end 
stage renal disease (ESRD). 6. AER at the end of the 2-month wash-out following 
the 3-yr treatment period, adjusted for the AER at baseline. 7. AER at the end of 
the 3-yr treatment period, adjusted for the AER at baseline. 8. Time to fatal or 
non-fatal cardiovascular events. 
 
Safety Assessment 
Examination for skin rash, measurements of liver enzymes, serum creatinine, and 
CBC, carried out 1 month after randomization and every 3-4 months thereafter. 
Statistical Methods 
The majority of data analyses, including the primary analysis, will be performed 
according to an intention-to-treat approach.  Differences between treatment 
arms in the primary outcome will be tested for significance by means of a linear 
model with correlated errors. Intervention effects on other secondary outcomes 
will be tested by mixed-effect models (GFR time trajectory), ANCOVA (AER), and 
survival analysis (time to serum creatinine doubling/ESRD and CVD events).  
 
 
Date of protocol 
February 22, 2018 

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ABBREVIATIONS 
AE: Adverse Event 
ACE: Angiotensin Converting Enzyme 
ACR: Albumin Creatinine Ratio 
AER: Albumin Excretion Rate 
ALT: Alanine Transaminase 
ARB: Angiotensin Receptor Blocker 
CBC: Complete Blood Count 
CKD: Chronic Kidney Disease 
CRF: Case Report From 
CVD: Cardiovascular Disease 
DBP: Diastolic Blood Pressure 
DCC: Data Coordinating Center 
DMC: Drug Monitoring Committee 
DN: Diabetic Nephropathy 
DSMB: Data and Safety Monitoring Board 
ESRD: End Stage Renal Disease 
GFR: Glomerular Filtration Rate 
ITT: Intention to Treat 
HbA1c:  Glycated Hemoglobin A1C 
HBV: Hepatitis B Virus 
HCV: Hepatitis C Virus 
HIV: Human Immunodeficiency Virus 
IRB: Institutional Review Board 
MAP: Mean Arterial Pressure 
NO: Nitric Oxide 
PERL:  Preventing Early Renal Function Loss in Diabetes Consortium 
RAS: Renin Angiotensin System 
RASB: Renin Angiotensing System Blocker 

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SAE: Severe Adverse Event 
SBP: Systolic Blood Pressure 
SC: Steering Committee 
SOP: Standard Operating Procedure 
T1D: Type 1 Diabetes 
UA: Uric Acid 
 

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1. INTRODUCTION 
Diabetic nephropathy (DN) is the long-term complication of T1D that imposes the highest social 
and economic burden.  After 40 years of diabetes, about one in three patients with T1D has developed 
kidney abnormalities, which frequently progress to end stage renal disease (ESRD).1  Despite 
improvements during the past 20 years in glycemic and blood pressure control, and the introduction of 
‘renoprotective’ drugs such as renin–angiotensin system (RAS) blockers, the overall incidence of DN is 
not declining.2-4 Thus, DN remains one of the most important causes of excess morbidity and mortality in 
patients with diabetes mellitus, and novel therapies to complement and increase the therapeutic effects 
of glycemic control and RAS inhibition are urgently needed.   
DN has been traditionally viewed as a multi-stage process, in which an initial clinical phase 
characterized by increased urinary excretion of small amounts of albumin (microalbuminuria) is followed 
by excretion of larger amounts of proteins (overt proteinuria), which then ushers in progressive decline 
in renal function ultimately leading to end-stage renal disease (ESRD).1 This paradigm, however, is 
changing with the demonstration in prospective studies that, in a substantial proportion of T1D patients, 
renal function starts to decline before the onset of overt proteinuria.5-7 These findings indicate that T1D 
patients should be screened for GFR loss when albumin excretion rate (AER) is still in the 
microalbuminuria range, and that interventions aimed at preventing ESRD should be started at these 
earlier stages. The earlier the rate of GFR loss is reduced through appropriate interventions, the longer 
will be the delay of ESRD.    
Mounting evidence from epidemiological studies indicates that serum UA levels are strong risk 
factors for the development of chronic kidney disease and loss of kidney function among persons with 
T1D.  Prospective data from the Second Joslin Kidney Study (JKS) identified elevated baseline serum UA 
as one of the strongest independent predictors of early GFR loss among T1D persons with 
microalbuminuria and normal renal function at baseline.8  The unadjusted odds ratio of developing 
increased GFR loss was 1.5 (95% CI 1.3-1.9, p=0.0002) for each mg/dl increase in serum UA. This 
translates into a ~2.4-fold increase in the risk of early GFR loss for UA levels ≥ 4.5 mg/dl as compared to 
UA levels <4.5 mg/dl. The magnitude of this effect did not significantly change after adjustment for 
urinary AER, gender, HbA1c, or, importantly, baseline GFR. The U. of Colorado group also found that 
serum UA predicted the transition from normoalbuminuria to micro- or macro-albuminuria as well as the 
progression of subclinical atherosclerosis in the CACTI study.9,10  As in the JKS, the effect of UA was not 
influenced by adjustment for other baseline variables. An association between UA and development of 
persistent macroalbuminuria has also been reported by the Steno group.  It is very important to note 
that, in that study, the UA levels shortly after the onset of T1D was a significant independent predictor of 
macroalbuminuria 18 years later (hazard ratio 1.90 per mg/dl increase in UA level; p=0.04)11, this being 
suggestive of a pathogenetic role. 
The prospective nature of these findings and their robustness after adjustment for potential 
confounders strongly support the concept that moderately elevated serum UA has a pathogenetic role in 
DN development and in the deterioration of kidney function observed in T1D. Consistent with this 
hypothesis, hyperuricemia has predicted chronic renal failure in population-based studies12-14 and mild 
UA elevation has been shown to cause renal disease in animal models.15,16  Alterations of nitric oxide 
(NO) pathways and induction of pro-inflammatory cytokines17,18, and increased oxidative stress resulting 
from the generation of UA by xanthine oxidase19,20 have been proposed as being responsible for these 
effects. Two small clinical trials have recently provided proof of concept data for translating these 
findings into a novel intervention by showing that the urate-lowering agent allopurinol was effective in 
slowing the progression of non-diabetic renal disease among hyperuricemic as well as normouricemic 
individuals with moderately reduced GFR.21,22  A beneficial effect of urate-lowering drugs on the 
progression of kidney disease has also been observed in animal models.23  These findings, along with the 
observational data discussed above, strongly suggest that lowering serum UA levels may prevent 
or slow the loss of kidney function among diabetic subjects. 

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To test this hypothesis, we have established a consortium of investigators from academic centers 
where large rosters of T1D patients are available along with long-standing expertise in the study of 
diabetic complications, especially DN, and in DN clinical trials. Included in this initiative are the Joslin 
Diabetes Center, the Universities of Minnesota, Colorado, Toronto, Michigan, Washington (Seattle), 
Texas Southwestern, Calgary, and Alberta Northwestern University, Washington University (St. Louis), 
Emory University, Albert Einstein College of Medicine, BC Diabetes, Providence Medical Research Center, 
and Steno Diabetes Center in Copenhagen, Denmark. The Consortium, led by Dr. Alessandro Doria from 
the Joslin Kidney Study, and by Dr. Michael Mauer, who recently led the Renin Angiotensin System Study 
(RASS) clinical trial, has been named PERL (Preventing Early Renal Function Loss in Diabetes) to 
emphasize the Consortium’s focus on intervening early in the course of kidney disease, when renal 
damage is most likely to be able to be arrested or reversed and interventions are more likely to be 
effective.   
PERL has designed the present 3-year clinical trial to test whether the uric acid lowering drug 
allopurinol can preserve kidney function among type 1 diabetic patients. In preparation for this trial, the 
Consortium has been conducting a pilot study to determine the study feasibility and establish study 
procedures.  Funded by JDRF (JDRF file # 17-2012-377), the pilot study has a comparable design as the 
pivotal trial, but a smaller size and shorter duration. As of February 1, 2014 a total of 31 pilot study 
subjects have been randomized to allopurinol or placebo.  Upon activation of the present trial, pilot 
participants will be re-consented and rolled-over to the present study at a time point corresponding to 
their next scheduled visit.  The first 7 visits have identical timing in the two protocols. Visit schedules 
slightly differ after that, but given the current follow-up status, it will be possible to transfer all pilot 
participants to the pivotal trial before the timing diverges. 
 
2. STUDY OBJECTIVE 
To determine whether lowering serum UA by means of oral allopurinol is effective in preventing 
or slowing decline of renal function in T1D patients with microalbuminuria or moderate 
macroalbuminuria who still have only mildly or moderately impaired kidney function. 
 
3. STUDY DESIGN 
The study will be a multi-center, double-blind, placebo-controlled, parallel-group randomized 
clinical trial including a total of 480 patients with type 1 diabetes (T1D) who are at high risk for GFR loss 
because of increased albuminuria and a relatively high serum UA (≥ 4.5 mg/dl), but have only mildly or 
moderately decreased renal function.   
 
4. PARTICIPATING CENTERS  
The study will involve 16 centers that are part of the PERL Consortium: 
• 
Joslin Diabetes Center (Boston) 
• 
University of Minnesota (Minneapolis) 
• 
University of Colorado (Barbara Davis Center for Childhood Diabetes, Denver) 
• 
University of Michigan (Ann Arbor) 
• 
University of Toronto (Toronto) 
• 
Northwestern University (Chicago) 
• 
Albert Einstein College of Medicine (New York) 

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• 
Steno Diabetes Center (Copenhagen, Denmark) 
• 
Washington University (St. Louis, MO)  
• 
University of Calgary (Calgary, Alberta, Canada) 
• 
University of Alberta (Edmonton, Alberta, Canada) 
• 
Emory University (Atlanta) 
• 
University of Washington (Seattle) 
• 
University of Texas Soutwestern (Dallas) 
• 
Providence Medical Research Center (Spokane) 
• 
BC Diabetes (Vancouver) 
 
4.1 Location of study visits 
Study visits will be generally conducted at the Study Sites or their Satellites (hereby referred to 
as “In-Person Visits”).  However, if a participant lives far from a study site or satellite, or travel 
impediments are present, visits V1, V3, V5-10, and V12-15 may be conducted remotely (Visit 2 and all 
the visits including an iohexol-GFR measurement, i.e., V4, V11, V16, V17, will always be done “In-
person”). In the case of remote visits, study procedures that do not require physical interactions (e.g., 
collection of medical history, compliance issues) will be carried out over the phone or other media such 
as Skype (hereby referred to as “Phone Visits”).  Blood draws and urine collections scheduled at the time 
of Phone Visits will be performed at local facilities close to where participants live (hereby referred to as 
“Remote Biospecimen Collections”).  For any given study visit to be conducted remotely, a Phone Visit 
and a Remote Biospecimen Collection will be both required. Phone Visits and Remote Biospecimen 
Collections will be conducted according to the following protocol: 
Phone Visits 
• 
Phone Visits will be scheduled based on the same calendar and time windows used for In-Person 
Visits (see paragraph 8.1 and Fig 1). 
• 
All Phone Visits will be carried out by the same trained study personnel performing the In-Person 
Visits according to the same standards as those in place for In-Person Visits. 
• 
If Visit 1 is a Phone Visit, a copy of the informed consent form (ICF) will be mailed, faxed, or 
sent electronically to the study subject before the visit.  After reviewing the ICF content with the 
study personnel over the phone/Skype, subjects who agree to participate in the study will be 
invited to mail, fax, or send electronically a signed copy of the ICF back to the study site.  Phone 
Visit 1 and any other study activity will take place only after the signed ICF has been received by 
the study site.  
• 
Study procedures that may be carried out during Phone Visits include:  
o Collection of demographic data. 
o Collection of medical history. 
o Collection of family history. 
o Review of concomitant medications. 
o Evaluation of eligibility. 
o Randomization. 
o Review of RASB medication and BP control. 

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o Study drug prescription and instructions. 
o Review of study drug compliance. 
o Review of adverse events. 
o Any other study procedure that can be carried out by talking on the phone.  
• 
Study procedures will be carried out according to the same protocol as the corresponding In-
Person Visits and as described in the Manual of Operations. 
• 
All study material that would be provided to participants at In-Person Visits (e.g., urine collection 
instructions, urine containers, study drug instruction, BP monitoring logs) will be mailed, faxed, 
or sent electronically to participants right after the Phone Visit. In addition, specific instructions 
will be provided for presentation to the local lab for specimen collection, handling and tube 
labeling for specimens requiring shipment to the Study Site or Central lab. Pre-addressed 
shipping containers will also be provided.  
• 
Following a Phone Visit, participants may be invited to an In-Person Visit at the Study Site, at 
their PCP’s office, or at other local healthcare facilities if procedures that require physical 
interactions are deemed to be necessary (e.g., BP measurement to confirm the self-report of 
elevated BP values, physical exam to confirm the self report of skin rash). Sites for remote in-
person visits will be chosen by the Study Site based on the participant’s preference, logistic and 
financial considerations, and site’s qualifications. Study personnel will discuss study requirements 
with the remote site health providers and operators and will provided with written instructions on 
how to carry out the procedures that will be conducted at their locations and report the results to 
the Study Site.   
 
Remote Biospecimen Collections 
• 
Local sites for Remote Biospecimen Collections will be chosen by the Study Site based on the 
participant’s preference, logistic and financial considerations, and site’s qualifications. 
• 
Specific instructions will be provided for presentation to the local sites for collection, handling 
and tube labeling for specimens requiring shipment to the Study Site or Central Laboratory.  Pre-
addressed shipping containers will also be provided along with an inventory sheet for faxing to 
the Study Site or Central Laboratory and inclusion with the shipment. 
• 
Blood samples for local lab tests (serum creatinine, K, and ALT, CBC, pregnancy tests) will be 
processed and analyzed at the facilities where samples are collected or shipped to commercial 
laboratories or to the Central Laboratory for testing. Results will be transmitted to the Study Site 
by fax or other secure methods. 
• 
Blood and urine samples for central lab tests (serum creatinine, Cystatin C, uric acid, HbA1c, 
urinary ACR and AER) will be mailed to the Central Lab or to the Study Site where they will be 
processed, aliquoted, and forwarded to the Central Lab.  Blood tubes and urine containers will be 
provided by the Study Site. 
 
5. SUBJECT SELECTION 
5.1. Inclusion Criteria 
1. Male or female T1D patients between 18 and 70 years of age, inclusive. 
2. T1D continuously treated with insulin within one year from diagnosis. If the onset was after age 
35, documentation of the presence of one or more of the following will also be required:  
 

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a. documentation of the presence of circulating T1D-associated autoantibodies at diagnosis 
or at any other time 
b. history of hospitalization for DKA  
c. plasma C-peptide below the limit of detection with standard assay (with concurrent blood 
glucose >100 mg/dl)  
3. Duration of T1D ≥ 8 years; 
4. History or presence of microalbuminuria or moderate macroalbuminuria, or evidence of declining 
kidney function regardless of history or presence of albuminuria and/or RAS Blockage.  Micro- or 
moderate macroalbuminuria will be defined as at least two out of three consecutive urinary 
albumin excretion rates [AERs] or albumin creatinine ratios [ACRs] taken during the two years 
before screening or at screening in the 30-5000 mg/24 hr (20-3333 g/min) or 30-5000 mg/g 
range, respectively, if not on RASB agents, or in the 18-5000 mg/24 hr (12-3333 g/min) or 18-
5000 mg/g range, respectively, if on RASB. Evidence of declining kidney function will be defined 
as an eGFR (CKD-EPI) decline ≥3.0 ml/min/1.73 m2/year, estimated from all the available 
creatinine measurements (including the one at screening assessment) from the previous 3 years. 
If at least 3 serum creatinine measures are not available in the previous 3 years, then the slope 
can be derived from creatinine values from the previous 5 years.  
5. Estimated GFR (eGFR) based on serum creatinine between 40 and 99.9 ml/min/1.73 m2 at 
screening. The upper and the lower limits should be decreased by 1 ml/min/1.73 m2 for each 
year over age 60 (with a lower limit of 35 ml/min/1.73m2) and by 10 ml/min/1.73 m2 for strict 
vegans.  
6. Serum UA ≥ 4.5 mg/dl at the screening visit. 
7. Willing to comply with schedule of events and protocol requirements, including written informed 
consent. 
8. Valid baseline (Visit 4) iohexol GFR measurement prior to randomization. 
OR 
9. Being an active participant in the PERL Pilot Study.  
 
5.2. Exclusion Criteria 
1. History of gout requiring allopurinol therapy or xanthinuria or other indications for uric acid 
lowering therapy such as cancer chemotherapy or extremely high serum uric acid values (>12 
mg/dl). 
2. Recurrent renal calculi (history of more than one episode). 
3. Use of urate-lowering agents within 2 months before screening. 
4. Current use of azathioprine, 6-mercaptopurine, didanosine, warfarin, tamoxifen, 
amoxicillin/ampicillin, or other drugs interacting with allopurinol. 
5. Known allergy to xanthine-oxidase inhibitors or iodine containing substances.  
6. HLA B*58:01 genotype (determined prior to randomization) indicating increased risk of Stevens-
Johnson syndrome in response to allopurinol. 
7. Renal transplant.  
8. Non-diabetic kidney disease as indicated by medical history and/or laboratory findings. 
9. SBP>160 or DBP >100 mmHg at screening or SBP>150 or DBP>95 mmHg at the end of the run-
in period. 

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10. Cancer treatment (excluding non-melanoma skin cancer treated by excision) within two years 
before screening. 
11. History of clinically significant hepatic disease including hepatitis B or C and/or ALT (SGPT) >2.50 
x ULN at screening and/or history of HBV/HCV antibody positivity. 
12. History of acquired immune deficiency syndrome or human immunodeficiency virus (HIV) 
infection. 
13. Hemoglobin concentration <11 g/dL (males), <10 g/dL (females) at screening. 
14. Platelet count <100,000/mm3 at screening.  
15. Ongoing alcohol or drug abuse or history of treatment for these conditions in the past 6 months.  
16. Blood donation in the 3 months before screening (subjects become eligible once 3 months have 
elapsed since the last donation). 
17. Breastfeeding or pregnancy or unwillingness to be on contraception if still fertile. 
18. Poor mental function or any other reason to expect patient difficulty in complying with the 
requirements of the study. 
19. Serious pre-existing medical problems other than diabetes, e.g. congestive heart failure, 
pulmonary insufficiency. 
5.3. Prohibited Medications and Restrictions 
 
Allopurinol and other urate lowering agents (e.g., probenecid, rasburicase rys) for the treatment 
of gout. Patients treated with uric acid lowering agents for elevated uric acid levels with no 
history of gout can, with the agreement of their treating physician, undergo a 2 month washout 
of uric acid lowering medication and then be tested to determine if uric acid entry criteria are 
met. 
 
Herbal supplements that may have urate lowering actions (e.g., Devil’s Claw or Harpagophytum 
procumbens, Indigenous cinnamon or Cinnamomum osmophloeum, Skunkvine or Paederia 
scandens or Paederia foetida)  
 
Azathioprine 
 
6-Mercaptopurine 
 
Didanosine 
 
Warfarin 
 
Tamoxifen 
 
Amoxicillin/ampicillin 
 
Any other drug for which there is evidence of interaction with allopurinol 
 
Dual RASB therapy (i.e., another RASB medication in addition to that already in use) 
 
Non-RASB antihypertensives that are not listed in the PERL approved menu of antihypertensive 
drugs, unless these were in use before joining the study. 
5.4. Randomization Procedures 
After the run-in period (described in Section 8.3) and with a valid baseline iohexol GFR 
measurement prior to randomization, participants will be randomized in a 1 to 1 ratio to receive either 
oral allopurinol or placebo. Randomization will be stratified by center, uric acid (≤6.0 vs. >6.0 mg/dl), 
and HbA1c (≤7.8 vs. >7.8%). Randomization will be performed using permuted blocks, with a block size 
that is known only to the DCC. After a participant has been randomized, the clinical site will send a study 
medication request to the research pharmacy, including the participant’s address, so that the study 
medication can be directly mailed to the participant. Clinical sites will not have access to the treatment 

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assignment (see 6.2., Blinding Procedures). This will be directly communicated or made electronically 
available to the pharmacy by the DCC.   
5.5. Discontinuation of study drug 
5.5.1. Reasons for discontinuation 
The study drug will be temporarily discontinued if a participant: 
 
Has clinically significant persistent changes from baseline based on laboratory safety assessment 
results (the response to discontinuation will be monitored to assess whether the drug can be re-
instituted, see next paragraph on permanent discontinuations).  
 
Requires treatment with allopurinol or medications that make allopurinol contraindicated (see 
5.5.2 and 9.5). 
 
Becomes pregnant or breastfeeding (see 5.5.2)   
Whenever the reason for temporary discontinuation of the study drug ceases to exist, the study 
medication will be resumed with the consensus of the drug monitoring committee, according to the 
following procedures: 
 
If the study medication was discontinued because of a suspected drug reaction or the 
participant was off-medication for 3 months or longer, the study drug will be re-started at a 
dosage of 100 mg for 4 weeks, which will then be increased to the full dosage appropriate for 
the eGFR. (see 6.1.2)  
 
If the study medication was not discontinued because of a drug reaction and the participant 
was off-medication for less than 3 months, the study medication will be re-started, at the full 
dosage appropriate for the eGFR.  
The study drug will be permanently discontinued if a participant: 
 
Experiences an SAE related to the study drug or an intolerable AE such as a persistent allergy or 
rash. 
 
Has clinically significant persistent changes from baseline based on laboratory safety assessment 
results which do not respond to temporary 2-week discontinuation of study drug and re-
institution of drug at ½ of the initial dose. 
 
Develops end-stage renal disease (confirmed eGFR ≤15 ml/min/1.73 m2 in the absence of acute 
kidney injury [AKI], institution of chronic dialysis treatment or kidney transplantation) or iGFR 
decreases by 50% from one measurement to the next or serum creatinine levels double over any 
12 month interval in the post-randomization period.  If any of these renal function changes prove 
to be temporary, the study medication could be resumed as described above with the consensus 
of the drug monitoring committee. 
5.5.2. Handling of study drug discontinuation 
 
Date and reason for drug discontinuation will be recorded on the relevant Case Report Form. 
 
All study discontinuations decided by a clinical site will have to be reviewed and approved by the 
Drug Monitoring Committee within 10 days from their start. 
 
If the study drug is discontinued due to treatment with medications that make allopurinol 
contraindicated (e.g. amoxicillin/ampicillin) or due to pregnancy/breastfeeding, the possibility of 
resuming the study drug will be evaluated by the Drug Monitoring Committee once those 
medications have been discontinued or pregnancy/breastfeeding has ended.  

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 
If the study drug is temporarily discontinued and then re-instated, the end-date of the 
intervention will remain the same as if the study drug had not been discontinued. All visits will be 
carried out as scheduled while the study drug is temporarily discontinued.   
 
Unless a participant withdraws consent all participants that are permanently discontinued from 
study drug or who discontinue study medication on their own will be followed for the full study 
period (i.e., 164 weeks, including the washout period) and all data will be collected as scheduled. 
 
If a participant reaches ESRD as defined above under 5.5.1,, he/she will be permanently 
discontinued from the study and invited to participate in a study close-out call or visit to be held 
within three months from the occurrence of ESRD.  Data collection at this call or visit will be 
limited to standard adverse event reporting. In addition, sites should continue to contact 
participants who have reached end-stage renal disease to determine their final status until 3 
years and 2 months after randomization. Major attempts will be made to schedule an end-of-
study assessment for all participants who are lost to follow-up during the course of the study.  
5.5.3. Replacements 
Participants that withdraw consent from the study during the Run-in period (i.e., before 
randomization) or do not qualify for study continuation at the end of the Run-in period will be replaced 
until the target number of randomized study participants is reached. Participants that withdraw consent 
from the study or discontinue the study drug after randomization will not be replaced.   
 
5.5.4. Termination of Study 
Premature termination of this clinical trial may occur because of a regulatory authority decision, 
drug safety problems as determined by the Data Safety Monitoring Board (DSMB), or at the discretion of 
the funding agency (NIDDK). 
 
6. STUDY TREATMENTS 
6.1. Study Drug Description, Dosage, Administration, and Accountability 
6.1.1. Description  
Eligible study subjects who agree to participate in the study will all be randomized to receive 
placebo or allopurinol – a serum UA lowering medication that has been on the market since 1964 as the 
main drug for the therapy of symptomatic hyperuricemia and for the prophylaxis of gout in cancer 
patients receiving chemotherapy.  Allopurinol is an inhibitor of xanthine oxidase, which is responsible for 
the conversion of hypoxanthine to xanthine and of xanthine to UA.  It is metabolized to the 
corresponding xanthine analogue, oxypurinol (alloxanthine), which is also an inhibitor of xanthine 
oxidase. At the average dosage (300 mg/day), allopurinol causes a 30-40% reduction in serum UA24-26, 
but up to a 60% reduction can be obtained using the maximum dosage of 600 mg.27  While allopurinol is 
mostly used in individuals with gout and very high UA levels, several studies have shown that it is also 
effective at lower UA levels27-29. 
Because of its rapid oxidation to its active metabolite oxypurinol, allopurinol has a short plasma half-life 
(~1-2 hrs).  However, since oxypurinol has a longer half-life (~15 hrs), effective xanthine oxidase 
inhibition can be maintained over 24 hrs with a single daily dose of allopurinol. Since both allopurinol and 
oxypurinol are eliminated through the kidneys, patients with impaired renal function require lower doses 
than those with normal renal function. A common rule of thumb is to use 75% of the dosage in 
individuals with eGFR in the 50-90 ml/min range, and 50% of the dosage in individuals in the 10-50 
ml/min range.  

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6.1.2. Dosage 
After an initial four weeks where all participants randomized to allopurinol will take 100 mg per 
day, the allopurinol dosage will vary from 200 to 400 mg per day based on eGFR levels. Participants will 
take 400 mg per day if their eGFR is ≥50 ml/min/1.73 m2, 300 mg per day if their eGFR is in the 25 to 
<50 ml/min/1.73 m2 range, and 200 mg per day if the eGFR is in the 15 to <25 ml/min/1.73 m2 range. 
Allopurinol will be continued at this dosage throughout the study unless the eGFR changes, in which case 
the dosage will be modified to that appropriate for the new eGFR class. 
All participants, whether they are randomized to allopurinol or placebo, will be given four tablets 
per day to be taken orally following breakfast.  Tablets will be provided in four vials (A, B, C, and D) or 
in blister packs, in which each blister contains the four tablets for a given day. If the medication is 
provided in bottles, participants randomized to allopurinol will receive a dosage of 100 mg as a 100 mg 
tablet (from vial A) plus three placebo tablets (from vials B, C, D), 200 mg as two 100 mg (from vials A 
and C) and two placebo tablets (from vials B and D), 300 mg as three 100 mg (from vials A, B, C) and 
one placebo tablet (from vial D), 400 mg as four 100 mg tablets (from vials A, B, C, D). Subjects 
randomized to placebo will be given four placebo tablets (from vials A, B, C, D). If the medication is 
provided in blister packs, each blister will contain the four tablets for a given day, with the same 
proportion of active and placebo tablets described above for each allopurinol dosage and for placebo. 
The dose adjustment will be carried out as follows: 
1. At each follow-up visit, a study drug requisition will be sent by the clinical site to the research 
pharmacy indicating the study ID, name, and address of the participant, the most recent eGFR 
value (CKD-EPI), calculated using a recent local lab creatinine value, and the number of days to 
be covered by the drug supply.  
2. At the pharmacy, a clinical pharmacist will determine the allopurinol dose (ranging from 0 to 400 
mg) that should be given at that time according to the study protocol given the participant’s 
treatment assignment and the most recent eGFR value (CKD-EPI) calculated using a recent local 
lab serum creatinine value. 
3. The research pharmacy will mail the new batch of study medication directly to the study 
participant.  
4. At some sites the study medication may be dispensed directly to the study participant at a 
relevant in person study visit or by mail from the site following a relevant in-person or phone 
study visit. 
5. Participants will be instructed to immediately inform the clinical site upon receipt of the new 
tablets and mail the pill bottles or blister packs with the tablets remaining from the previous 
prescription in a provided pre-addressed mailer, to the clinical site for drug accounting and 
compliance assessment. 
6.1.3. Compliance and accountability 
Skills will be taught and reinforced at each visit with regard to scheduling and administration of 
pills at home and while traveling.  Methods (e.g. record-keeping) will be taught to help participants 
monitor tablet usage and enhance compliance. To complement the regular compliance interventions at 
the scheduled visits, study information and motivational materials (postcards, newsletters, etc.) will be 
mailed. In addition, at midpoint between clinic visits, participants will be phoned by the clinic staff to 
review pill-taking. Patients will be provided with random but known numbers of excess medications, 
providing extras in case of pill loss. Adherence will be monitored by instructing participants to expect 
extra pills and to mail the pill bottles or the blister packs with the tablets remaining from the previous 
prescription to the study center upon receipt of a new batch of tablets. The number of extra pills 
included in each supply of medications will be decided by the pharmacist, who will keep a record of it 
and will transmit this information to the Study Site.  Personnel at the Study Site will enter this 

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information in the appropriate electronic Case Report Form along with the expected number of pills used 
during the period covered by the supply and the number of unused pills returned by the participant.  
These data will be used to analyze compliance. If poor adherence is noticed, measures will be taken to 
increase compliance, such as explaining the purpose of the study again, providing pill reminders, and 
more frequently contacting the study subject by phone. Participants at each visit will be asked about 
their perceived compliance and about any difficulties with taking the study medications, but the 
individualized strategies to improve compliance will not be openly linked to the pill counts, i.e. 
participants will not be informed of the results of pill counting. Participants showing poor compliance will 
not be withdrawn from the study. 
6.2. Blinding Procedures 
Study participants, the investigators and research staff at the Clinical Sites, and the PERL co-PIs 
(Drs. Doria and Mauer) will be blinded to treatment assignment whereas the Data Coordinating Center 
Co-Directors and staff and the pharmacy personnel will have access to this information. Serum uric acid 
values, from which the treatment assignment might be inferred, will not be transmitted to the Clinical 
Sites by the central or local laboratory and will not be available for viewing in the study database. Should 
unblinding of a study participant be necessary because of an emergency, the site personnel will login to 
the password-protected electronic database application that will provide the treatment assignment.  
Audit procedures will ensure that the name of the individual associated with the login will be 
communicated to the Data Coordinating Center project manager and Co-Directors.  As an additional 
safety measure, the personnel at the Clinical Sites will be provided with telephone numbers to contact 
the Data Coordinating Center and/or Pharmacy personnel having access to the treatment assignment on 
a 24-7 basis. If unblinding occurs, the circumstances that led to it will be reviewed and reported. 
 
7. STUDY OUTCOMES 
7.1. Primary outcome 
The primary outcome will be the iGFR at the end of the 2-month wash-out period following the 3-
year treatment period, measured by the plasma clearance of non-radioactive iohexol (iGFR) and 
adjusted for the iGFR at baseline. The rationale of measuring the primary outcome at the end of the 
wash-out period is to test allopurinol for permanent effects of on the natural history of kidney disease, 
independent from any transient, hemodynamic effect that the medication may have on GFR.  Plasma 
iohexol clearance has been shown to provide accurate and reproducible GFR measurements.30,31  It is 
highly correlated with inulin clearance (the gold standard to measuring GFR)32 and is a safe, cost-
effective method to test hundreds of patients enrolled in multicenter clinical trials.33 The method consists 
of injecting a 5 mL bolus of Iohexol (Omnipaque, 300 mg iodine/mL) and drawing blood samples at 
baseline and 120, 150, 180, 210, and 240 minutes after the injection. Plasma concentrations of iohexol 
at different time points are measured by HPLC and used to calculate the plasma clearance of iohexol 
(Cl=Dose/AUC, where AUC is the area under the plasma concentration time curve), which is taken after 
appropriate body surface area corrections as a measure of GFR. 30,31   
7.1.1. iGFR quality assurance 
It is of the foremost importance that reliable iGFR measurements are obtained. To maximize 
accuracy and precision, the following procedure will be in place.  
1. Personnel performing the iohexol clearance test will undergo a standardized training program 
administered under the Site Directors’ supervision through in-person meetings or on-line 
modules. All clinical site staff will complete the online knowledge testing in order to perform 
the tests.   
2. Participants will be instructed to discontinue non-steroidal anti-inflammatory drugs (NSAIDs) 
for at least 3 days and avoid large protein meals for one day prior to the test, since these 

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could influence GFR.  They will also be instructed to aim for a fasting glycemia between 90 
and 160 mg/dl on the day of the test.  Before the test, participants will have a light breakfast 
at the clinic along with their morning insulin. The insulin dose will be adjusted to keep their 
blood glucose in the 90-160 mg/dl range.  If blood glucose is outside this range right before 
or during the test, small amounts of intravenous insulin (if blood glucose is too high) or 
orange juice/milk (if glucose is too low) may be administered to bring blood glucose levels 
within the desired interval.  
3. In the case of extreme deviations from the target blood glucose values, the test may be 
rescheduled to another day (within 2 weeks).  The test will also be postponed in the case of 
recent febrile illness, diarrhea or vomiting, dehydration, poor fluid intake, recent intake of 
nephrotoxic drugs such as NSAIDS, urinary tract infection, or a positive pregnancy test. 
7.1.2. iGFR quality control 
The quality of iGFR results will be monitored by: 
1. Systematically checking for deviations from the study protocol, such as deviations from the 
target blood draws time points during the test or the presence of medical conditions that 
should have prompted a postponement of the test.  
2. Calculating the R-square (R2) of the regression between log-iohexol values and time. iGFR 
tests will be defined as technically acceptable if the R2 is >0.90. R2 calculations will be 
performed by the DCC using all 5 time points of the iGFR test. 
7.1.3. Technically unacceptable iGFR measures 
If an iGFR test is deemed to be technically unacceptable according to the above QC criterion 
(R2≤0.90), or a study protocol deviation is suspected, the following procedures will be followed: 
1. Source documents related to the test in question will be reviewed to verify whether there was 
a protocol deviation or a technical error in the iGFR procedure (e.g., presence of 
contraindications to iGFR, swapping of tubes, wrong collection times, typos, etc.).  In the 
case of an R2≤0.90, the iohexol measurements will be repeated by the central laboratory. 
2. If a technical error is found and the error can be rectified, or the new laboratory measures 
yield an R2>0.90, the iGFR value will be recalculated after the appropriate corrections are 
made. The study site or the central laboratory, as applicable, will be alerted about the error 
and measures aimed at improving iGFR quality will be implemented.  
3. If the error is confirmed and cannot be fixed, or no error can be found, the iGFR will be 
dropped and will be repeated within 4 weeks from when the iGFR results become available.   
4. If the repeated test is technically unacceptable, or the test cannot be repeated within 4 
weeks for logistical reasons, the iGFR value at that time point will be considered as missing 
for the analysis of the primary outcome. It is therefore critical that every effort be made to 
obtain this repeat iGFR measure. 
7.2. Secondary outcomes 
1. Iohexol-clearance GFR at the end of the 3-year treatment period (before the washout). 
2. Iohexol-clearance GFR time trajectory estimated from periodical iohexol-GFR measurements. 
3. Estimated (eGFR) at 4 months estimated from serum creatinine and cystatin C and adjusted 
for the eGFR at baseline. 
4. Estimated GFR (eGFR) time trajectory estimated from quarterly serum creatinine and cystatin 
C measurements using the CKD-EPI SCr and the CKD-EPI SCr-SCysC equations.34,35  
5. Time to doubling of baseline serum creatinine value or ESRD (eGFR ≤ 15 ml/min/1.73 m2, 
institution of dialysis, kidney transplantation).   
6. Geometric mean of two AER measurements at the end of the 2-month wash-out period 
following the 3-year treatment period, adjusted for the mean urinary AER at baseline. Urinary 

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AER will be determined in timed overnight urine collections brought by study participants to 
 
7. Geometric mean of urinary AER during the last three months of the treatment period (Visits 
15 and 16), adjusted for the mean urinary AER at baseline.  
8. Time to fatal or non-fatal cardiovascular events, defined as the composite of CVD death (ICD-
10 code I10 to I74.9), myocardial infarction, stroke (ischemic or hemorrhagic), coronary 
artery bypass grafting, or percutaneous coronary intervention. 
 
8. STUDY PROCEDURES 
8.1. Schedule of Events 
The schedule of events that will take place in the proposed study is outlined in Figure 1.  Visits 
will be frequent during the Run-In period and during the first 30 days after randomization in order to 
escalate the allopurinol dosage and closely monitor the occurrence of AEs. After that, participants will be 
seen every 3-4 months to monitor their UA levels, renal function, occurrence of AEs, and medication 
compliance and, if necessary, to perform interventions to improve compliance.  Visit 1 will be considered 
as Time 0 for scheduling Visits 2-5, Visit 5 will be considered as Time 0 for scheduling Visit 6-16, Visit 16 
as Time 0 for scheduling Visit 17.  The study windows that define when study visits may occur are noted 
in Figure 1 and differ by type of visit.  Visits 2, 3, and 6 will be carried out within 6 business days (before 
or after) from their scheduled dates; visits 11, 16, and 17 within 2 weeks before and 4 weeks after their 
scheduled dates; visit 4A (if necessary) within 1 week before and 3 weeks after its scheduled date, and 
all other visits within 2 weeks (before or after) from their schedule dates. Additional blood or urine 
samples may be required in between visits if clinically significant changes are observed in blood or urine 
measurements that need to be confirmed or otherwise monitored. iGFR measurements may be repeated 
for medical reasons or technical problems (see 7.1).  Safety laboratory tests (CBC, serum creatinine, K+, 
ALT, and pregnancy tests in women) will be performed by local laboratories.  Outcome variables (plasma 
iohexol, serum creatinine and cystatin C, urinary AER), HbA1c, and serum uric acid will be measured by 
the Central Laboratory at the University of Minnesota, directed by Dr.  Amy Karger. 

 
 
 
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 Figure 1.  Schedule of Events 
 
*If normal blood pressure control is not achieved at Visit 4, the run-in period may be extended for two more weeks after which participants will be examined as in Visit 4 (Visit 4A).  In this event, 
the GFR measurement scheduled for Visit 4 will be conducted at Visit 4A. 
^ Study visits will be generally conducted at the Study Sites or their Satellites.  "In-Person Visits" (V) are required for Visit 2 and all visits requiring iohexol-GFR measurements.  If a participant 
lives far from a study site or satellite, or travel impediments are present, other (O) visits may be conducted remotely or in-person. For any given study visit to be conducted remotely, a Phone 
Visit and a Remote Biospecimen Collection will be both required; a Phone Visit is performed by the study coordinator using the telephone or other media such as Skype to collect results of study 
procedures that do not require physical interactions (e.g., collection of medical history), and a Remote Biospecimen Collection is performed at a clinical laboratory close to where participants live.  
Note:  (x) indicates an optional assessment  For BP and Measurements, (x) indicates an optional assessment only if the patient is NOT seen in-person. 

 
 
 
Page 28 of 54 
8.2. Screening and Enrollment in the Run-in Period (Visit 1) 
Subjects who have a confirmed history of micro- or macroalbuminuria (at least two out of three 
consecutive urinary AER or ACR in micro- or macroalbuminuria range as defined in Section 5.1) will not 
need to bring a sample of urine to Visit 1. Subjects who have incomplete or no previous evidence of 
micro- or macroalbuminuria  or have unknown albuminuria status, will be mailed two containers before 
Visit 1 along with instructions for collecting two samples of urine from their first morning void and 
bringing it to the visit to confirm the presence of micro- or macro-albuminuria. During Visit 1, subjects 
will undergo the following procedures: 
 
Obtain written informed consent. 
 
Collect prior and concomitant medications, and demographic information. 
 
Measure weight and height. 
 
Measure vital signs. 
 
Perform pregnancy test in women of childbearing potential. 
 
Review the fetal risks of RAS blockade.  
 
Collect samples for clinical laboratory assessment.   
 
Provide a container and instructions for an overnight urine collection to be made immediately 
before Visit 3 if subject qualifies for the study. 
 
Upon receipt of laboratory measurements, confirm that inclusion/exclusion criteria are met. 
The Screening Visit can be repeated after 4 weeks if the circumstances that led to the exclusion 
of a participant are deemed to have possibly changed.  
Patients on losartan with uric acid levels between 4.2-4.4mg/dl at initial screening may, with the 
agreement of the patient and their PCP, be switched to another angiotensin receptor blocker (ARB) and 
have their uric acid level rechecked in one month. 
8.3. Run-in Period (Visits 2, 3, and 4) 
Starting at Visit 2, eligible subjects who agree to participate in the study will enter a run-in 
period of 9 weeks (see note at the end of this section for exceptions to this duration).  During this visit, 
subjects will undergo the following procedures: 
 
Obtain written informed consent to enter run-in period (if the consent at V1 was only for 
screening). 
 
Review the fetal risks of RAS blockade.  
 
Collect medical history. 
 
Perform ECG. 
 
Collect concomitant medications. 
 
Measure weight and height. 
 
Measure vital signs. 
 
Physical Examination 
 
Obtain a urine pregnancy test 
RAS antagonist treatment will be standardized, and BP, if elevated (>140/90 mm Hg), 
normalized.  Letters will be written to the participants’ physicians informing them about the study and 
notifying them of the study's protocol RAS blocker requirements and blood pressure goals. The letter will 
propose active participation of the participants’ physicians in blood pressure management with the 

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availability of advice from the PERL site physicians and, if needed, the PERL Drug monitoring Committee 
for out of range blood pressure values during the course of the study. The run-in period will start at 
Visit 2.  If a participant is already on a RAS Blocker, its dose will be increased, if necessary, to make it 
at least equivalent to ramipril 10 mg (if on ACE inhibitor [ACEI]) or irbesartan 300 mg (if on an 
angiotensin receptor blocker [ARB]), if acceptable to the patient’s primary physician, if tolerated and if 
not contraindicated (see below).  Participants who were not taking a RAS Blocker will be prescribed and 
instructed to start taking 10 mg of ramipril daily or 300 mg of irbesartan daily (if ramipril is 
contraindicated or has side effects) or another ACE inhibitor or ARB at equivalent doses if there are 
impediments to the use of ramipril or irbesartan. Participants who have contraindications to RAS blockers 
(e.g., SBP<100 mmHg, K+>5.5 mEq) or do not have evidence or history of micro- or macroalbuminuria 
(as defined in 5.1.4), are normotensive, and are not being treated with RASB or other anti-hypertensive 
agents will not be treated with these drugs, as this represents the standard of care.   
Participants who are placed for the first time on RAS blockers as part of this study will start with 
half a dose; if there are no side effects, this will be increased to a full dose at Visit 3 and their serum K+ 
and creatinine measured at a local laboratory after 2 weeks.  RAS blockers will be immediately 
discontinued in the case of allergic reactions or angioedema or the suspicion of pregnancy. If pregnancy 
is confirmed, the patient will remain off RAS blockade until the pregnancy and breast-feeding are 
completed. Their dose will be decreased to half if symptomatic hypotension (SBP<100%) or intractable 
cough develops, followed by their discontinuation.  For persistent cough with ramipril or other ACEI, 
irbesartan or another ARB will be prescribed in substitution of the ACEI. 
In the case of hyperkalemia (K+ >6.0 mEq) or serum creatinine elevation (>30% increase over 
baseline values), the participant will be asked to immediately obtain a confirmatory lab value at their 
local lab or clinical site and then discontinue the RAS blocker while awaiting this confirmatory result. If 
confirmed, the participant will resume RAS blockade at half dose 72 hours later and will have repeat labs 
one week later. If the problem persists, RAS blockade will be discontinued for the remainder of the trial 
and BP managed by alternate drugs (see below). If not confirmed, the participant will resume RAS 
blockade at their usual dose and have a repeat lab check one week later. These same steps will be taken 
if hyperkalemia develops during the trial.  
Participants will continue to take any other antihypertensive drug that they may have been taking 
before study entry.  Participants will be provided with a blood pressure monitoring device (if they do not 
already have access to one), will be trained on its use, and will be instructed to periodically monitor their 
blood pressure at home and to record the results into a BP diary, and to communicate them to study 
personnel if values are abnormal.   
If hypotension develops (SBP<100 or significant lightheadedness), the dosage of non-RAS 
antagonist antihypertensive drugs will be progressively reduced until discontinuation, followed by a 
reduction of RAS blockers to half the dose and their discontinuation if the problem persists.  If BP is 
found to be elevated (>140/90 mm Hg) on three consecutive occasions, the dosage of existing non-RAS 
antagonists antihypertensive drugs will be maximized, followed, if necessary, by the introduction of 
antihypertensive drugs of a different class. These will be chosen in collaboration with the other health 
care providers that are involved in managing the participant’s anti-hypertensive therapy33.  If the goal of 
BP ≤140/90 is not achieved with these drugs, a Drug Monitoring Committee conference call will be 
convened to consider the possibility of causes of hypertension other than diabetic nephropathy and 
discuss alternative therapeutic approaches.  BP will continue to be monitored and the anti-hypertensive 
therapy to be adjusted in a similar way throughout the study. 
After 2 weeks of run-in, participants will come in for Visit 3 during which they will undergo the 
following procedures: 
 
Obtain interval medical history (with special emphasis on CVD events). 
 
Review concomitant medications and AEs 

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 
Review RASB and BP therapy. 
 
Collect samples for clinical laboratory assessments as outlined in Figure 1. 
 
Perform pregnancy test in women of childbearing potential. 
 
Be provided with a container and instructions for an overnight urine collection to be made 
immediately before Visit 4. 
After 6 weeks of run-in, participants will come in for Visit 4 during which they will undergo the 
following procedures: 
 
Obtain interval medical history (with special emphasis on CVD events). 
 
Conduct a physical exam (if deemed to be required by the study physician) 
 
Review concomitant medications and AEs 
 
Review BP therapy. 
 
Review the fetal risks of RAS blockade.  
 
Measure height, weight and vital signs. 
 
Perform ECG. 
 
Collect samples for clinical laboratory assessments (including HLA B*58:01) as outlined in 
Figure 1. 
 
Perform pregnancy test in women of childbearing potential. 
 
Measure iohexol GFR.  
If normal blood pressure control is not achieved at Visit 4, the run-in period may be extended for 
two more weeks after which participants will be examined as in Visit 4 (Visit 4A).  In this event, the GFR 
measurement scheduled for Visit 4 will be conducted at Visit 4A.  Participants whose SBP is >150 or 
whose DBP is >95 mmHg at the end of the run-in period will be discontinued from the study (prior to 
randomization). 
IMPORTANT: Visit 2 and Visit 3 can be skipped, i.e., a participant can move directly from Visit 1 to Visit 
4, if the following criteria are met at Visit 1: 
1. The participant is eligible based on the results of Visit 1 assessments, including laboratory values; 
2. Blood pressure is <140/90 mmHg; 
AND 
3. The participant meets one of the following criteria: 
o Has been treated with a RASB for at least two months at a dose at least equivalent to 
Ramipril 10 mg or Irbesartan 300 mg;  
o Has contraindications to RASB; 
o Does not have evidence or history of micro- or macroalbuminuria (as defined in 5.1.4) 
and is not being treated with RASB or other anti-hypertensive agents. 
If the above criteria are met and Visits 2 and 3 are skipped, Visit 4 will be scheduled 3 weeks after Visit 
1 with a window of 2 weeks before and 3 weeks after the target date. The collection of medical history 
and the physical exam scheduled at Visit 2 will be conducted at Visit 4. 
8.4. Enrollment in the Study and Randomization (Visit 5) 
 
At the end of the run-in period, eligibility will be re-assessed based on the BP measures 
obtained at Visits 4 or 4A (if applicable), HLA-based genetic susceptibility to allopurinol skin 
reactions36,37 (tested at Visit 4)and a valid baseline iGFR measurement.  Participants who are 
eligible for randomization based on those measures (SBP ≤ 150 and DBP ≤95 mmHg) and a 
negative HLA B*58:01 test will be telephoned by the study coordinator to discuss how the 

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study medication should be taken and its potential side effects. 
 
Immediately after the phone call, the participants will be randomized. 
 
Immediately after randomization the first batch of study medication will be mailed to the 
participant by the research pharmacy along with written instructions on how to take it. 
Participants will be instructed to notify the study personnel by phone and start taking the 
study medication as soon as they receive it.  
 
If the participant is positive for HLA-based genetic susceptibility to allopurinol skin reactions, 
or acceptable BP measurements, or a valid iGFR measurement cannot be obtained, he/she 
will be discontinued from the study prior to randomization. 
8.5. Treatment Period (Visits 6 to 15) 
During the treatment period, the following procedures will be completed at each visit for each 
participant: 
 
Obtain interval medical history (with special emphasis on BP control and CVD events). 
 
Review of concomitant medications and AEs.   
 
Review RASB and BP therapy. 
 
Measure height, weight, and vital signs according to the schedule outlined in Figure 1 
 
Inspect for skin rash. 
 
Conduct a physical exam (Visit 11). 
 
Perform ECG according to the schedule outlined in Figure 1 (Visit 11). 
 
Collect samples for clinical laboratory assessments and for storage of serum, plasma and 
urine for later biomarker research according to the schedule outlined in Figure 1. 
 
Perform pregnancy test in women of childbearing potential. 
 
Measure GFR by means of plasma disappearance of non-radioactive iohexol, iGFR at Visit 11.  
 
Provide a container and instructions for an overnight urine collection whenever an AER 
measurement is scheduled at the following visit. 
In the days immediately after each visit, upon completion of serum creatinine measurements, 
participants will receive a new batch of study medication by mail from the research pharmacy.  Upon 
receipt of the new tablets, participants will be instructed to immediately mail the pill bottles or the blister 
packs with the tablets remaining from the previous prescription to the study center for drug accounting 
and compliance assessment (see 6.1.2). A pre-stamped and addressed envelope will be provided to 
participants for this purpose. 
At some sites the study medication may be dispensed directly to the study participant at a 
relevant in person study visit or by mail from the site following a relevant in-person or phone study visit. 
8.6. End of Intervention (Visit 16) 
At the end of the treatment period (Visit 16), the following procedures will be completed for each 
participant: 
 
Obtain interval medical history (with special emphasis on CVD events). 
 
Review of concomitant medications and AEs. 
 
Review RASB and BP therapy. 
 
Collect unused study medication and document compliance. 

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 
Measure height, weight and vital signs. 
 
Inspect for skin rash. 
 
Conduct a physical exam. 
 
Perform ECG. 
 
Collect samples for clinical laboratory assessments as outlined in Figure 1 and for storage for 
later biomarker research. 
 
Perform pregnancy test in women of childbearing potential. 
 
Measure iGFR. 
 
Provide containers and instructions for 2 overnight urine collections to be made immediately 
before Visit 17. 
Participants will be instructed to stop taking the study medication and to mail the pill bottles or 
the blister packs with the tablets remaining from the last prescription to the study center if they did not 
already bring the unused study medication at the visit.  The RAS and BP therapy will be continued as 
before until the closing visit (Visit 17). The importance of coming back in 8 weeks for the closing visit 
(Visit 17) will be emphasized. 
8.7. End of Wash-out Period (Visit 17) 
After the end of the treatment period, participants will enter an 8-week wash-out period at the 
end of which the following procedures will be completed: 
 
Obtain medical history. 
 
Review of concomitant medications and AEs. 
 
Measure height and weight and vital signs. 
 
Inspect for skin rash. 
 
Collect samples for clinical laboratory assessments as outlined in Figure 1 and for storage for 
later biomarker research. 
 
Perform pregnancy test in women of childbearing potential. 
 
Measure iGFR. 
8.8. RAS blocking and anti-hypertensive therapy after completion of the study 
When the participant completes the study, control of the RAS-blocking and anti-hypertensive 
therapy will be relinquished to the participants’ physicians, who will decide whether or not to continue 
the therapy established during the study. Participants will continue the anti-hypertensive therapy 
established during the study until they see their physicians. 
8.9. Future biomarker studies 
Plasma, serum, and urine specimens and DNA will be stored the Advanced Research and 
Diagnostics Laboratory at the University of Minnesota and the NIDDK Central Repository for possible 
future studies of biomarkers of kidney disease in diabetes or other diabetic complications.  Twelve ml of 
plasma, 12 mL of serum, and 24 ml of urine will be collected at Visit 4, 11, 16, and 17, with one quarter 
of the aliquots of each stored at the University of Minnesota and three quarters of the aliquots sent to 
the NIDDK Central Repository for storage.  Ten ml of whole blood will be obtained at Visit 3.  This will be 
used for white blood cell DNA extraction and subsequent storage. Altogether, the stored plasma and 
serum aliquots will correspond to about 210 ml of blood collected for this purpose over the entire 
duration of the study.  Participants will be allowed to elect to participate in the study while not having 
any or one or more of these samples stored, if they so choose. 

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8.10. Early Withdrawal  
Unless the participant withdraws consent, all randomized participants will be followed for the full 
study period (through week 164) and all data will be collected as scheduled.   
 
9. SAFETY ASSESSMENTS 
9.1. Demographic Data/Medical History 
After collecting a detailed medical history at Visit 1, this information will be updated at each visit 
through a structured interview, with a special emphasis on skin symptoms and signs such as rash, 
itching and exfoliation and on pregnancy in females. Participants will be instructed to communicate any 
change in their health status and intervening hospitalizations to the study coordinator in-between visits.  
In particular, they will be instructed to discontinue study medication and immediately contact the study 
coordinator if they develop a suspicious skin rash, swelling of the lips or mouth, arthralgias, and/or 
jaundice, which may indicate a hypersensitivity reaction to allopurinol.  Fever and chills should also be 
reported but would not require cessation of medication prior to discussion with study personnel.  
9.2 Skin exam 
The skin of study participants will be examined for the presence of any kind of rash at each in-
person visit.  Participants will be instructed to carry-out periodical skin self-exams. If skin abnormalities 
are reported to the study personnel during the phone visits or on any other occasion, participants will be 
asked to immediately report to the study site, their PCP’s office, or other local healthcare facilities for an 
in-person skin exam. Suspicion of drug allergy or Stevens-Johnson Syndrome SJS would require 
immediate discontinuation of study medication and dermatologic consultation. 
9.3. Vital Signs 
Blood pressure and heart rate will be recorded at each in-person visit.  BP readings at home will 
be reviewed during each phone visits; if abnormal values are reported, participants will be asked to visit 
the study site, their PCP’s office, or other local healthcare facilities to have their BP measured. 
9.4. Clinical Laboratory Tests    
Serum ALT, creatinine and K+, and CBC will be monitored and a pregnancy test, if a female of 
child bearing potential, performed at each visit.  Participants who are started for the first time on RAS 
blockers as part of this study will have their serum K+ and creatinine measured at a local laboratory after 
2 weeks of full dose RASB treatment (i.e., after Visit 3).  HbA1c will be measured at Visits 1, 4, and 7-
17. An ECG will be performed at Visits 2, 4, 11, and 16.  
9.5. Management of Uric Acid Levels 
Study participants and study personnel, other than the DCC and the study pharmacists, will be 
masked as to the uric acid levels obtained during the study.  The patients' physicians will receive written 
requests to refrain from measuring uric acid levels during the time of the patients' participation in the 
study, except as is mandatory for the patient's wellbeing, e.g., in the treatment of malignancy or 
diagnosis of a clinical syndrome highly likely to represent gout.  If gout is diagnosed, open-label 
treatment with allopurinol will become indicated.  In such case, the study drug will be discontinued but 
the patient will remain in the study and will continue to be followed as if he/she was taking the study 
medication.  If uric acid lowering for malignancy treatment is required, the patient will receive open-
label treatment until such time as return to study drug is deemed clinically reasonable by their physician. 
 
10. ADVERSE EVENT REPORTING 
10.1. Definitions 

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An Adverse Event (AE) is any untoward medical occurrence in a study participant regardless of its 
relationship to study treatment.  A treatment-emergent AE is an adverse event occurring during the 
period between the first dose and 30 days after the final dose of the study medication. A Serious 
Adverse Event (SAE) is any untoward medical occurrence that results in death, is life-threatening, 
requires hospitalization or prolongation of an existing hospitalization, results in persistent or significant 
disability, or is a congenital anomaly/birth defect.  Important medical events that do not fall into the 
above categories may also be considered an SAE when, based on medical judgment, such events may 
jeopardize the patient’s safety and require medical/surgical intervention to prevent one of the outcomes 
listed in the SAE definition.  The term SAE is not intended as a measure of severity or intensity. All 
AE’s/SAE’s that occur after the time of informed consent will be reported. 
A Suspected Adverse Reaction is any adverse event for which there is a reasonable possibility 
that the drug caused the adverse event. For the purposes of IND safety reporting, "reasonable 
possibility" means there is evidence to suggest a causal relationship between the drug and the adverse 
event. Suspected adverse reaction implies a lesser degree of certainty about causality than adverse 
reaction, which means any adverse event caused by a drug.  An Unexpected Adverse Event or 
Unexpected Suspected Adverse Reaction is an adverse event or suspected adverse reaction that is not 
listed in the investigator brochure or is not listed at the specificity or severity that has been observed; or, 
if an investigator brochure is not required or available, is not consistent with the risk information 
described in the general investigational plan or elsewhere in the current application, as amended. For 
example, under this definition, hepatic necrosis would be unexpected (by virtue of greater severity) if 
the investigator brochure referred only to elevated hepatic enzymes or hepatitis. Similarly, cerebral 
thromboembolism and cerebral vasculitis would be unexpected (by virtue of greater specificity) if the 
investigator brochure listed only cerebral vascular accidents. “Unexpected”, as used in this definition, 
also refers to adverse events or suspected adverse reactions that are mentioned in the investigator 
brochure as occurring with a class of drugs or as anticipated from the pharmacological properties of the 
drug, but are not specifically mentioned as occurring with the particular drug under investigation.  An 
Expected Adverse Event or Expected Adverse Reaction is any adverse experience that has been 
identified in nature or severity in the current investigator brochure and/or protocol. 
10.2. Adverse Events Reporting 
All AEs will be reported on the Adverse Events form that will be completed by the study staff, 
who are masked as to study treatment assignment, at each regular follow-up visits.  This will insure that 
AEs are ascertained in an unbiased manner using the same standardized methodology for participants in 
both treatment arms.  Forms will include standardized questions relating to specific events of import in 
diabetic patients on either of the study treatment arms as well as any significantly abnormal physical 
finding identified on examination and any significantly abnormal laboratory results obtained on the 
patient between visits or at the time of the visit.  AEs reported or ascertained between clinic visits will be 
captured and reported at the time of the next schedule visit.  Pre-existing conditions (that is, any 
condition that was known to be present prior to the signing of informed consent or was identified during 
the screening procedures at Visit 1) will not be considered or recorded as AEs unless the condition 
worsens in intensity or frequency after Visit 1.  Likewise, continuing AEs will not be reported as AEs at 
subsequent visits unless they increase in severity or frequency between visits, they results in criteria for 
a SAEs, and/or they resolve between visits.  Each site will be responsible for reporting all AE's to their 
IRB according to its AE reporting policy and procedures.   
10.3. Assessment of Causality and Severity 
The seriousness of adverse events will be ascertained by the study staff according to the criteria 
listed in 10.1 and the need for further evaluation, follow-up, or referral.  The relationship between study 
participation and AEs will be determined according to the following criteria:  
A. Not related – temporal relationship of the onset of the event, relative to study participation, 
is not reasonable or another cause can by itself explain the occurrence of the event. 

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B. Possibly related – temporal relationship of the onset of the event, relative to study 
participation, is reasonable but the event could have been due to another, equally likely cause. 
C. Probably related – temporal relationship of the onset of the event, relative to study 
participation, is reasonable and the event is more likely explained by the study treatment than by 
another cause. 
D. Definitely related – temporal relationship of the onset of the event, relative to study 
participation, is reasonable and there is no other cause to explain the event. 
10.4. Serious Adverse Events Reporting 
See Section 15 – Data and Safety Monitoring Plan. 
 
11. STATISTICAL ANALYSIS 
This section presents a summary of the planned statistical analyses. A statistical analysis plan 
(SAP) will be written for the study that contains detailed descriptions of the analyses to be performed. 
The SAP will be written prior to database lock. 
 
11.1. Analysis Population 
For most of the analyses, including the primary efficacy analysis described in section 11.3, an 
intention to treat (ITT) analytical approach will be employed.  Accordingly, the population for statistical 
analysis will consist of all randomized study participants considered in their original randomization group, 
regardless of treatment discontinuation or loss to follow-up. 
Selected secondary efficacy analyses will be performed using a per-protocol analytical approach. 
In this case, the analysis population will consist of the ITT population excluding data points which 1. had 
cumulative exposure to the study medication from randomization that was less than 80% of the 
theoretical full exposure; or 2. during major protocol deviations (e.g., treatment with prohibited 
medications), which could affect primary outcome. 
 
11.2. Initial Data Analysis 
The initial data analysis will be performed to detect any differences in distributions of 
characteristics measured at baseline, 4, 20, 36, and 38 months (0, 16, 80, 156, and 164 weeks, 
respectively) between study groups. The number of patients screened, enrolled, and completing the 
study will be summarized within and across study centers. Measures of central tendency (means, 
medians) and variability (standard deviations, ranges) will be estimated from the data for continuous 
variables. Frequency distributions will be provided for categorical data. This preliminary analysis step will 
provide us with insight into data, distributions of the variables considered, and will allow us to find 
additional invalid values not detected earlier during data validation.  
11.3. Primary Efficacy Analysis  
For the primary endpoint (iGFR at the end of the 2-month wash-out period following the 3-year 
intervention), we will follow the recommendations by Carpenter et al38,39 and perform the analysis by 
means of a linear model for correlated errors with general/unstructured covariance matrix using all 
available iGFR measures (including those at baseline, 80, 156, and 164 weeks, respectively) as the 
dependent variable. By conditioning on the baseline iGFR measure we will also effectively use this 
variable as a covariate. Treatment group, study center, stratifying variables, albuminuria status (subjects 
who qualified by ACR or AER or were albuminuric at baseline vs. subjects who did qualified by eGFR 
slope and were normoalbuminuric at baseline), baseline AER, time, and time by treatment interaction 
will also be included as covariates in the model. Three features make this analytical approach especially 
attractive:  

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1. If there is no dropout (a very unlikely case), the estimate of the treatment effect at the end 
of the 2-month wash-out period following the 3-year intervention and its precision obtained 
using this approach will be exactly the same as those based on a classical approach 
employing an analysis of covariance (ANCOVA) model with treatment group, study center, 
iGFR and AER/ACR measured at baseline included as covariates.  
2. If the iGFR measure at the end of the wash-out period is missing, we will be able to 
efficiently use the information contained in the intermediate iGFR measurements obtained at 
80 and 156 weeks, by virtue of them being correlated with the GFR measurement at 
washout. Estimate of the treatment effect obtained this way is valid under the missing at 
random (MAR) assumption. This is in contrast to the ANCOVA approach, which would lead to 
the loss of this information and would require a more stringent assumption about the 
mechanism of data missingness, i.e. a missing completely at random (MCAR) mechanism.  
3. The underlying analytical framework allows the use of all post-randomization data and is well 
suited to investigate the reason for withdrawal, for example to study whether participants 
having low iGFR values are more likely to withdraw. 
Calculations will be performed using SAS PROC/MIXED. Results of the analysis will be expressed 
in terms of point estimate and its corresponding 95% confidence interval for the treatment effect at the 
end of the 2-month wash-out period following the 3-year treatment and will be accompanied by the 
corresponding p value.  
11.4. Secondary Efficacy Analyses 
1. The effect of treatment on the iGFR at the end of the 3-year treatment period (before the 
washout) will be evaluated using the same analytical approach employed for the primary 
outcome. 
2. The effect of treatment on the eGFR at 4 months after randomization will be evaluated using 
the same analytical approach employed for the primary outcome. 
3. The iGFR and eGFR time trajectories, estimated from periodical iGFR measures and quarterly 
serum creatinine and cystatin C measurements using the CKD-EPI SCr and the CKD-EPI SCr-
SCysC equations34,35, respectively, will be analyzed using linear mixed-effects models.40-42 The 
main objective of the analysis will be to construct confidence interval for the effect of the 
intervention over three years of observation (treatment main effect) and investigate whether 
the effect of the intervention changes with time (time by treatment interaction).  
4. Time to serum creatinine doubling or ESRD in the two treatment groups is subject to 
censoring due to dropouts or reaching the end of study before the participant experiences the 
event.  Survival time will be defined as the time from randomization to the event (the first of 
serum creatinine doubling from baseline or occurrence of ESRD, defined as eGFR < 15 
ml/min/1.73 m2, hemodialysis, or kidney transplant) or, for participants who did not 
experienced an event, to the last study visit.  Data will be summarized by means of Kaplan-
Meier survival curves and by providing the proportions of participants surviving without 
events at 1, 2, 3 years, and at the end of the wash-out period along with their 95% CIs. 
Given the potentially small number of events, differences between study groups will be tested 
by means of the log rang test or by means of simple Cox regression models including a 
limited number of predictors in addition to treatment group.  
5. The effect of treatment on the AER at the end of the wash-out period, based on the 
geometric mean of two AER measured at this time point and adjusted for the geometric mean 
of AER at baseline (Visit 3 and 4), will be investigated in a linear regression model framework 
as in the case of the primary outcome. 

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6. The effect of treatment on the AER at the end of the treatment period, based on the 
geometric mean of the AER measures at visit 15 and 16 adjusted for the geometric mean of 
AER at baseline (Visit 3 and 4) will be investigated as in #5. 
7. Time to fatal or non-fatal cardiovascular events will be analyzed as proposed for time to 
serum creatinine doubling or ESRD. 
8. We will perform a per-protocol analysis (as defined in 11.1) for the primary efficacy endpoint 
(iGFR at the end of the 2-month wash-out period following the 3-year intervention).  
11.5. Incomplete Data 
Missing values represent a potential source of bias. Efforts will be made to keep all participants in 
the study. If this is not feasible, at least some information regarding the status at the end of the trial will 
be obtained. For randomized patients, the number of completing and dropouts will be summarized. This 
procedure will help to compare characteristics of the participants’ groups who drop out from the study 
with those who completed the study by treatment group, within and across study centers. The models 
considered in the proposal allow for a missing at random (MAR) mechanism. MAR means that the 
missing values mechanism can be explained by observed data and does not depend on the unobserved 
values of outcome measures. The differences in distributions between characteristics of the groups may 
indicate potential sources of bias due to missing values. For instance, some patients may dropout from 
the study due to unobserved factors related to the intervention itself. If we suspect such bias is present, 
the methods discussed in this section, assuming (MAR), are not applicable. We will incorporate plausible 
missing values mechanism into the model as discussed in Little43 and investigate how such mechanism 
may affect the estimates of treatment effect.  To this end, sensitivity analyses will be conducted 
involving selection and/or pattern-mixture models44 with an appropriate submodel used to describe 
dropout. 
11.6. Pilot participants 
All pilot participants who were already randomized to allopurinol or placebo during the pilot will 
be included in the final analysis of the pivotal trial.  Those who do not consent to the pivotal trial will be 
treated as having dropped from the study at a time corresponding to their last pilot visit.  Sensitivity 
analyses will be performed to investigate whether results may be potentially affected by the roll-over of 
pilot subjects in the pivotal trial.  
11.7. Model assumptions and alternative analyses 
Model assumptions will be thoroughly checked for individual and systematic departures, using 
informal, e.g. inspection of residuals, and formal methods such as score test for extra parameter or 
methods based on likelihood displacement. If individual outliers are detected, their influence will be 
evaluated using influence diagnostics methods based on comparing estimates from models fitted to data 
with and without outlying values. Whenever we are not successful in fitting the parametric model (linear 
or non-linear), then non-parametric analyses and/or transformation of the variables involved in the 
analysis will be considered. To investigate the potential hemodynamic influence of allopurinol on 
treatment effect, in addition to the aforementioned analyses, we will consider models including the post-
randomization measure of GFR at 4 months as an additional covariate.  To investigate the possible 
presence of heterogeneity in the response to allopurinol, subgroup analyses (based on the primary 
efficacy analysis described in section 11.3, with the inclusion of an interaction term of the treatment 
group by the subgroup variable) will be performed by age groups (≤40 and >40 yrs), gender, 
racial/ethnic group, HbA1c (≤7.8 and >7.8%), serum uric acid (≤6.0 and > 6.0 mg/dl), baseline iGFR 
(≤70 ml/min and >70 ml/min/1.73m2), AER at baseline (≤300 and >300 mg/24 hr), and albuminuria 
status (subjects who qualified by ACR or AER or were albuminuric at baseline vs. subjects who did 
qualify by eGFR slope and were normoalbuminuric at baseline). To investigate possible influence of using 
selected covariates on the treatment effect estimate in the models considered in Section 11, we will 

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perform appropriate sensitivity analyses. These additional analyses will be considered as strictly 
exploratory. 
11.8. Safety Analyses 
Adverse events will be independently reviewed by an independent data safety monitoring board 
(DSMB, see Sections 15 and 16). All safety data will be available in data listing in the clinical protocol 
report. Data will be described in terms of descriptive statistics and presented by treatment group. 
Presentation will include graphs (scatterplots, boxplots, histograms), measures of central tendency 
(mean, median) and variability (confidence intervals) for continuous variables and frequency tables for 
categorical variables. 
11.9. Interim Analysis  
No formal interim analyses of efficacy to stop for benefit or futility are planned, given the timing 
of the primary endpoint. 
11.10. Sample Size 
Since a variance-covariance matrix for the iGFR measures is not available and this matrix is 
essential in order to perform formal power calculations for a model with correlated errors, we performed 
alternative power calculations based on an intent-to-treat analysis within an ANCOVA framework. 
Specifically, we assumed that the primary hypothesis is tested in the following model: 
 
 
M1: iGFR at washout = iGFR at baseline + treatment group  
Compared to the model that will be used in the primary analysis, model M1 is simplified in two 
aspects. First, it does not use information from iGFR values measured at intermediate time points. 
Second, it does not include covariates such as the stratifying variables (HbA1c and UA) or other GFR 
predictors such as baseline AER.  Both of these aspects may lead to loss of precision of the treatment 
effect estimate. Consequently, our sample size calculations should be considered as conservative.   
The hypothesis being tested, i.e. the effect of treatment on iGFR at washout, corresponds to 
testing whether the treatment group factor in Model M1 is significant.  The choice of the ANCOVA model 
for the purpose of power calculations is sensible, as residuals from a univariate model involving baseline 
iGFR as covariate fitted to data from RASS study conform to normal distribution. Sample size calculations 
were performed based on Cohen45 and making the following assumptions: 
1. Post
 = 3 ml/min/1.73 m2.  We deem this effect to be 
clinically meaningful and attainable. It is clinically meaningful because it would translate on 
average into a 10-year delay in the progression to ESRD. It is attainable because it is smaller 
than the difference in 3-year GFR that we observed in the JKS between subjects with serum 
UA ≥ 4.5 mg/dl compared to those with levels below this value. The postulated effect was 
based on the following changes in GFR levels in the two treatment groups: 
a. Untreated group = 3 ml/min/1.73 m2 per year.  This estimate is based on data from the 
Joslin Kidney Study (JKS), in which the median GFR loss among 43 subjects meeting the 
above criteria was 3.1 ml/min/1.73 m2 per year, with 70% of subjects having a GFR loss 
>1.5 ml/min/1.73 m2 per year.  Also, among 116 subjects from Steno who met the 
albuminuria and GFR criteria, but for whom serum uric acid values were not available, the 
median GFR loss was 3.3 ml/min/1.73 m2 per year, with 71% of subjects having a GFR 
loss >1.5 ml/min/1.73 m2 per year. 
b. Treated group = 2 ml/min/1.73 m2 per year. The average GFR loss in the JKS subjects 
with serum UA <4.5 mg/dl was 1.5 ml/min per year.  On this basis, we conservatively 
assumed that the allopurinol treatment, if effective, would decrease the GFR loss to 2 
ml/min per year (a 33% decrease compared to the untreated group).  

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2. Standard deviation (SD) of residual error = 10.1 ml/min/1.73 m2.  This was estimated based 
on the root-mean-squared error from a regression model with eGFR at 3 yrs as the 
dependent variable and baseline eGFR as the independent variable fitted to data concerning 
T1D patients from the Joslin Kidney Study meeting the PERL inclusion criteria.  
 Assuming a two-sided alpha error equal to 0.05, the effective sample size needed to detect the pre-
2) at washout adjusted for baseline iGFR with 80% 
power is equal to n=180 per group. To take into account the anticipated overall dropout rate (up to 
5%/yr or 15% over the entire duration of the study) and drug discontinuation or non-compliance in the 
treatment group (up to 2%/yr or 6% over the entire duration of the study), and to maintain the desired 
 power of at least 80%, it will be necessary to recruit n=240 
subjects per group. In Table 1, we show the power of the 
proposed sample size for Model M1 under different dropout 
and non-compliance scenarios.  We also provide the 
corresponding power for a model (Model M2) including the two 
stratifying variables (Hb1Ac and UA) and baseline AER as 
covariates to illustrate the effect of adding these variables to 
Model M1. In this analysis, we assumed that adding these 
covariates reduces the residual variance by 10%, which 
corresponds to these covariates explaining merely 4% of the 
total iGFR variation over and above the variability explained by 
iGFR at baseline. As shown in Table 1, once these covariates 
are accounted for, power is expected to exceed the 
conservative estimates provided by Model M1 and reach almost 
90% for 15% dropout and 6% non-compliance rates.  
 
12. DATA COLLECTION AND QUALITY ASSURANCE 
Comprehensive data coordinating center (DCC) functions for this clinical trial, including clinical 
monitoring, database development, web-based data entry and management, as well as the creation and 
export of study reports for the DSMB will be provided by the University of Michigan Statistical Analysis of 
Biomedical and Education Research (SABER) group.  Housed in the top nationally ranked Department of 
Biostatistics, SABER, in its 13-year existence, has served as the DCC for over 50 studies, including 
multiple NIH-sponsored networks.   
The DCC will use OpenClinica® (OpenClinica Clinical Trial Software; OpenClinica, LLC, Waltham, 
MA), a clinical trial software platform for electronic remote (i.e., site-based entry) data capture and 
clinical data management, as the basis for our custom-designed data entry and management system. 
We expect that the majority of data will be collected via Case Report Forms (CRFs); however, other data 
sources, such as laboratory data from the central laboratory, may be used. In these circumstances, the 
DCC will also utilize electronic data transfer. Protocols for the transfer of data, with careful attention to 
data integrity, will be written by experienced programmers and stored in the OpenClinica database or 
data mart.   
The DCC has established a set of standard operating procedures (SOPs) governing the processes 
used to ensure patient privacy and data confidentiality, including the use of anonymous participant IDs 
on CRFs and in reports. In addition to clinical study databases, the UM DCC has also incorporated 
MEDdra® [www.meddramsso.com/] and database into our systems to have the capacity to code 
adverse events and illnesses by body organ system, respectively.  OpenClinica® enables compliance 
with Good Clinical Practice (GCP) and regulatory requirements by providing differentiated user roles and 
privileges, password and user authentication security, electronic signatures, SSL encryption, and 
comprehensive auditing to record and monitor access and data changes. 
Table 1. Power to detect treatment effect for 
two ANCOVA models under different drop-out 
and non-compliance scenarios. 
Overall 
Dropout 
(%) 
Non-
compliance 
(%) 
Model 
M1 
M2 
9 
0 
.87 
.92 
12 
0 
.86 
.91 
15 
0 
.85 
.90 
 
 
 
 
9 
6 
.83 
.89 
12 
6 
.82 
.88 
15 
6 
.80 
.87 

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12.1. Case Report Forms 
Study information will be collected for each participant by study staff using standardized 
electronic Case Report Forms (CRFs).  CRFs will be developed by the DCC, modeling their formats on the 
CRFs developed for the RASS clinical trial33, to which the study group has access through Dr. Mauer.  
CRFs will not report information about treatment assignment, in order to maintain blinding of study site.  
Forms will be stored at a secure location at the clinical sites.   
 
12.2. Quality Control and Quality Assurance 
DCC staff will prepare data management and clinical monitoring plans. The clinical monitoring 
plan will detail procedures to assess accuracy of the database relative to source documents, as well as 
site adherence to regulatory and study procedures. Emphasis will be placed on the process of consenting 
subjects, compliance with regulatory requirements and study protocol, values of key endpoints, and 
identification of SAEs that may not have been reported. The data management plan will describe the 
front-and back-end edit checks, as well as forms tracking procedures, that will be implemented to ensure 
timely and high-quality data collection.  It will also define the periodic reports that will be shared with 
site coordinators and PIs that summarize site performance.  The clinical monitoring and data 
management procedures will be consistent with the International Conference on Harmonisation (ICH E6) 
standards for Good Clinical Practice (GCPs).46  
12.2.1. Clinical monitoring 
During trial conduct, the DCC will conduct periodic monitoring visits to ensure that the protocol 
and GCPs are being followed.  The monitors may review source documents to confirm that the data 
recorded on CRFs is accurate.  The investigator and institution will allow DCC monitors direct access to 
source documents to perform this verification.  It is important that the investigator(s) and their relevant 
personnel are available during the monitoring visits and that sufficient time is devoted to the process. 
Clinical monitoring will be conducted through approximately yearly on-site visits by qualified 
personnel. In the first year, site initiation visits will be conducted to review the protocol, verify that the 
Site Director and his/her collaborators receive all necessary trial documents for a proper trial conduct, 
and review the procedures related to CRFs completion and query resolution. Investigators will be 
instructed about the importance of recording accurate and clean data, avoiding protocol violations, and 
retaining participants in the study. Follow-up monitoring visits will involve the verification of source 
documents and reporting of adverse events. Monitors will also verify that an informed consent form is on 
file for each subject screened, with appropriately dated signatures and all pages present, that all of the 
inclusion and exclusion criteria were met for each subject enrolled into the study, and that all the 
withdrawals and dropouts of enrolled participants from the trial are reported and explained in the 
appropriate CRFs. Accrual and retention rates will also be monitored and if these fall appreciably below 
the projected levels, attempts will be made to identify the reasons. At the end of each monitoring visit, a 
clinical monitoring report will be prepared by the DCC Clinical Monitor and sent to the site PI and to a 
NIDDK representative with recommendations to correct problems and/or improve the trial quality.  
 
 
12.2.2. Statistical monitoring 
Clinical monitoring will be complemented by statistical central monitoring, as described by Venet 
et al.47. Such a statistical approach to central monitoring relies on assessing the clinical data for 
departures from expected patterns (e.g., baseline variables in our randomized trial should be comparable 
between treatment arms for each site; visit days should be randomly distributed over the week), and 
assessment of a greater number of data values than those associated with site performance metrics.  

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The statistical monitoring plan will be incorporated into the larger data management plan, and will 
identify the specific descriptive statistics, graphical presentations, and formal hypothesis tests to be 
performed and at what frequency.  Pattern recognition may require a sufficient number of participants 
followed for a sufficient amount of time in order to be valid.   
12.2.3. Laboratory quality monitoring 
The Central Laboratory at the U. of Minnesota uses internal quality control methods to assess 
assay precision and drift as well external quality control (e.g., proficiency testing) to assess accuracy.  
The laboratory is well versed in both aspects and adheres to rigid performance standards.  For all 
analytes, enough commercial lyophilized control material is typically purchased prior to beginning the 
study, so that a single control pool lot can be used throughout.  Control pool mean and between-day 
SD’s for each analyte are routinely established at a minimum of two different analyte concentrations on 
a minimum of one hundred different analytical batches.  In the unlikely event that a new control pool lot 
becomes necessary during the study, both the new and old control pool lots will be run for a minimum of 
20 days to establish a target mean for the new pool.  The target SD’s are not changed if the new and 
old lots of control material are the same “matrix” (e.g., lyophilized human serum).  An in-house control 
pool is also typically prepared from the exact same specimen type (e.g., 0.5-mL aliquots of pooled serum 
or EDTA-plasma from several individual donors), kept at -70°C, and incorporated as an internal control 
in all analytical batches throughout the study.  This sort of control is very useful since occasionally the 
commercial pools of lyophilized serum have matrix effects that make assessment of the true accuracy of 
the given assay difficult to assess. Accuracy is assessed by comparison of external quality control 
proficiency testing results.  For most of the assays, the laboratory participates in either the College of 
American Pathologists’ Surveys Program (uric acid, creatinine, ALT, glycosylated hemoglobin, urine 
albumin, urine creatinine) or by sample exchange in a survey program with another laboratory (iohexol). 
The laboratory is CLIA certified.  
12.3. Study Record Retention 
The source documents will be stored for at least 10 years after the study ends.  
12.4. Data and Biosample Archiving in the NIDDK Central Repository 
In agreement with NIDDK’s policy on the sharing of data from large, NIDDK-sponsored, multi-site 
studies, the data and biosamples collected in the course of the trial will be archived in anonymized form 
in the NIDDK Central Repository for future distribution to the scientific community.  All samples and data 
transferred to the Repository will be under the custodianship of the NIDDK, although the study’s 
Steering Committee will have proprietary control of and exclusive access to the sample and data for an 
agreed-upon period of time before these are made available to the wider scientific community.    
 
13.  PROTECTION OF HUMAN SUBJECTS 
13.1. Characteristics of the study population  
Participants will be patients who have had T1D for 8 years or more and who will be 18-70 years 
old at entry into the study.  We anticipate that there will be approximately an equal number of males 
and females.  There will be no selection criterion based on race, although most patients will be of 
Western background and European extraction, given the demographics of the cities in which the centers 
are located and the fact that T1D is 30-40% less common among Blacks and Hispanics than among 
Whites.  Inclusion and exclusion criteria are as noted above.  Female patients of child-bearing potential 
will be included in the study but only if pregnancy is not planned during the time frame of the study.  
Women who become pregnant during the study will be discontinued from the study medication, if they 
had already been randomized, and from RAS blockers until pregnancy and breast feeding are complete; 
iGFR will not be obtained during or for 6 months after pregnancy is completed. Individuals younger than 

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18 will not be included since kidney complications are rare before this age.  Patients will be tested for 
HLA-based genetic susceptibility to Stevens-Johnson Syndrome and excluded if this is found. 
13.2. Sources of research material 
1. Specimens on patients obtained specifically for research purposes. 
a. Renal function studies requiring multiple blood specimens drawn from an indwelling IV 
over 4-6 hours for measurement of glomerular filtration rate at yearly intervals. 
b. Collection of urine for measurement of urinary albumin and creatinine at 3-4 month 
intervals. 
c. Blood for measurement of serum UA, creatinine, and liver enzymes, and WBC at quarterly 
intervals. 
2. Specimens or measures obtained quarterly as component of routine patient care 
a. HbA1c 
b. Blood pressure 
c. Height and weight 
3. Patient and family medical information. 
All study participants will be assigned a unique study identifier and in no publications or public 
presentations will information be available which could identify individual study participants or their 
families. 
13.3. Plans for recruitment of subjects and consent procedures. 
Potential participants will be sought (1) from among the patients attending the study centers 
(including the satellite centers) involved in the study, (2) by placing advertisements at other health care 
facilities and in newspapers or other media, and (3) by soliciting referrals from other health care 
providers.  At each clinical site, potential candidates will be identified and contacted according to the 
procedures established by the local IRBs in compliance with local laws protecting patient confidentiality. 
Invitation letters to patients attending the study centers will clearly offer the possibility to opt out of any 
further contacts with the study.  Patients who agree to participate will be screened by means of a 
telephone or in-person interview to determine whether exclusion criteria apply. Subjects who respond to 
advertisements will undergo the same screening interview. Subjects who pass this initial screening will 
be given or mailed an informed consent form and will be invited to come to the clinic for a screening visit 
(Visit 1) during which a final eligibility determination will be made on the basis of a detailed medical 
history and laboratory tests. Written consent will be obtained on that occasion from all subjects 
undergoing the screening visit after explaining again the purpose and procedures of the study. In the 
initial contact and again at the time of the screening visit, study subjects will be encouraged to ask 
questions and they will be reassured that they may withdraw from the study at any time. Written 
consent will be obtained again at V2 if the consent at V1 was only for the screening procedures.  
13.4. Potential Risks 
13.4.1. Risks associated with screening procedures and blood tests 
After participating in the screening tests and procedures, or after the run-in period, subjects may 
find out that they are not eligible to participate in the study. In that case, they will be told the reasons 
for their ineligibility and will be given the results of clinically approved tests such as serum UA, serum 
creatinine, urinary albumin/creatinine ratio, and ALT.  The results of the test for genetically increased 
risk of allopurinol-induced SJS will also be given to their physician, if the subject agrees with this.  Thus, 
they may learn about as yet unknown health problems such as anemia or liver disease, more advanced 
kidney disease, or the need for allopurinol avoidance. This and/or the exclusion from the study may 

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cause psychological distress. The drawing of blood samples may cause some pain and discomfort and 
hematoma formation at the site of venipuncture. The total amount of blood taken for the entire study 
will be about 520 mL (16 ml at Visits 1, 3, 6-10, and 12-15; 67 ml at Visits 4, 11, 16, and 17).  At the 
dose used in the study, there are no known risks to the infusion of the substance used for the 
measurement of renal function other than the very small risk of allergic reactions (<0.5%), diminished 
by the exclusion of patients with a history of iodine allergy and by having appropriate treatment drugs 
for allergic reactions on hand.  
13.4.2. Risks associated with allopurinol treatment 
Allopurinol has been used for several decades for the long-term therapy of symptomatic gout. 
The risks associated with its use are low and include: 
a. Skin rashes, usually pruritic maculopapular skin eruptions, sometimes scaly or exfoliative, are 
the most commonly reported adverse effect of allopurinol. Skin reactions were observed in 
the past in up to 3% of treated patients, but more recent data suggest that their frequency is 
now less than 1% (www.drugs.com/pro/allopurinol.html) perhaps more likely due to changes 
in the filler compounds rather than the actual drug. Rashes may be followed by more severe 
hypersensitivity reactions such as exfoliative lesions and the Stevens-Johnson syndrome 
(erythema multiforme major), which can be fatal.  Although such occurrence is very rare, in 
the order of 1 in 10,00048, treatment with allopurinol will be immediately discontinued if a 
rash develops and will not be reinstated. As noted, those with HLA-based genetic 
susceptibility to allopurinol-related SJS will be screened out. About 0.7% of Whites and 2-3% 
of African Americans and Asians are carriers of such genetic susceptibility. 
b. An increased frequency of acute gout attacks has been reported during the early stages of 
allopurinol administration, possibly resulting from the mobilization of urates from tissue 
deposits causing fluctuations in serum UA levels. Early studies estimated the risk of such 
events to be about 6%, but an analysis of current usage suggests that the risk has now 
decreased to less than 1% (www.drugs.com/pro/ allopurinol.html).  The risk is expected to 
be even lower in this study population since individuals with a previous history of gout will be 
excluded and UA levels will be on average lower than in patients usually taking allopurinol for 
elevated UA levels. 
c. Reversible liver damage as well as asymptomatic rises in liver enzymes has been observed in 
1-2% of patients taking allopurinol. Some very rare cases of irreversible liver damage have 
been observed in the context of the Stevens-Johnson syndrome.  
d. Bone marrow depression has been reported in patients receiving allopurinol, most of whom 
received concomitant drugs with the potential for causing this reaction. Bone marrow 
depression has been rarely observed in patients receiving allopurinol alone.  
e. Experience with allopurinol during human pregnancy is limited because women of 
reproductive age rarely require this treatment.  Given this paucity of data, the study will 
consider it unsafe for the fetus or the mother to receive this drug.  Allopurinol has been 
found in the milk of a mother on this drug and, therefore, will not be taken by nursing 
mothers. 
13.4.3. Risks associated with RAS blocker treatment 
Treatment with RAS blockers (either ACE inhibitors such as ramipril or angiotensin receptor 
blockers such as irbesartan) is currently the standard of care for diabetic individuals who have micro- or 
macroalbuminuria.  The risk associated with the use of these drugs during the trial will not be greater 
than the risks participants would face outside the trial by being treated with these agents. These risks 
include allergic reactions, hyperkalemia, hypotension, increased serum creatinine, persistent cough (with 
ramipril), liver damage, bone marrow depression, and fetal and neonatal morbidity and death when RAS 

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blockers are taken during pregnancy.  The occurrence of these adverse events will be monitored during 
the trial.  
13.5. Procedures for protecting against and minimizing potential risks 
a. General 
The patients are under constant medical supervision.  They are told that the data which are 
collected will be used for scientific report, but they will not be identified in such reports. 
b. Specific  
1. Regular pregnancy tests and education regarding fetal risk of the study drug will be provided to 
female patients of child bearing age.   
2. Quarterly measures of liver enzyme and white blood cell count will allow for early detection of 
liver injury or leucopenia potentially representing drug toxicity.  
3. Quarterly measures of serum creatinine will allow titration of allopurinol in relation to kidney 
function to avoid excessive dosage of the medication.  
4. IV's for kidney function studies will be placed by trained skilled clinical research nurses or 
technicians or by experienced physicians.   
5. Blood drawing for laboratory studies will be performed by trained skilled phlebotomy personnel at 
the respective institutions, thus limiting the risk of discomfort or local hematoma formation. 
6. Participants will be advised not to donate blood throughout the time they are in the study. 
7. Regarding possible drug toxicity: 
a. To avoid fetal risks from the study drug, patients planning pregnancies will not be included.  
Sexually active female patients will be instructed to immediately discontinue study drugs and 
RAS blockers if a menstrual period is missed by more than two weeks and, if found to be 
pregnant, the study medication and RAS blocker will be discontinued and not resumed until 
pregnancy and nursing are completed.  Pregnancy tests will be done on all women of child-
bearing potential at each visit.  
b. Subjects with known allergy to xanthine-oxidase inhibitors will be excluded from the study. 
Patients will be instructed to immediately report skin reactions and allergic symptoms and to 
immediately stop the study medication should these occur. Patients will be given 
antihistamines for symptom relief.  A small supply of antihistamines to be used in such an 
event will be supplied to each patient.  Should an allergic reaction or skin rash occur, the 
study drug will be permanently discontinued. 
c. To minimize the risk of gout attacks, subjects with a gout history will be excluded from the 
study and the allopurinol dosage in those enrolled in the study will be gradually increased 
over several weeks. Should a gout attack occur, this will be treated with colchicine or anti-
inflammatory agents according to current standards of care by study personnel. Study uric 
acid levels <2.0 mg/dl will be flagged by the DCC and reported to the appropriate study 
pharmacist who will initiate a 50% dose reduction in study drug at the next quarterly visit.  In 
order to avoid gout attacks, if uric acid levels exceed 12 mg/dl this will be flagged by the DCC 
and the center informed  and open-label allopurinol will be started and titrated with the goal 
of bringing and keeping serum uric acid below 7.0 mg/dl.  Participants will continue to be 
followed according to the study protocol and will be analyzed according to their blinded 
treatment groups.    
d. Primary care physicians will be notified (with the participants’ permission) of the patients’ 
participation in the trial, so that they avoid the prescription of drugs interacting with 
allopurinol or notify the study personnel that treatment with such drugs is necessary.  

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e. Participants will be reminded at each visit to immediately to notify the study personnel if they 
start a new drug, so that possible interactions with allopurinol can be identified at once and 
appropriate precautions can be taken including discontinuation of the study drug.  
f. Subjects taking drugs known to interact with allopurinol in causing bone marrow depression 
will be excluded from the study.  White blood cell counts will be done before the study drugs 
are prescribed, and quarterly thereafter. The study drug should be temporarily discontinued 
should evidence of bone marrow depression (WBC<3500/mm3) be present and confirmed. 
WBC should be repeated two weeks after study drug discontinuation.  If WBC recovers, 
consider re-challenging and repeating WBC two weeks after drug re-introduction. In addition, 
if WBC is confirmed to be <2500/mm3 and/or ANC is <1000/mm3, the event also needs to be 
reported as an AE.   The Drug Monitoring Committee will review each case and decide 
whether a referral to a hematologist is warranted and whether study treatment can be 
reinstated after blood values have returned to normal. If drugs potentially causing bone 
marrow depression in combination with allopurinol are begun after entry into the trial, 
observations for this side effect will be intensified or, if recommended by the Drug Monitoring 
Committee, study drug may be interrupted. 
g. To minimize the risk of allergic reactions during the iGFR measurement, subjects with a 
history of iodine allergy will be excluded from the study. 
h. To minimize the risk of liver injury, subjects with clinically significant hepatic disease and/or 
elevated liver enzymes above 2.5 x the upper limit of normal at the screening visit will be 
excluded from the study. In those subjects that are enrolled in the study, liver enzyme levels 
will be monitored at each follow-up visit. If levels are abnormal, the measurement will be 
repeated and if values are confirmed to be elevated the study drug will be discontinued. The 
Drug Monitoring Committee will review each case and decide whether a referral to a 
hepatologist is warranted and whether study treatment can be reinstated after enzyme values 
have returned to normal on the recommendation of a hepatologist. 
i. 
To minimize the impact of blood draws, participants with low hemoglobin levels (<11 g/dL in 
males, <10 g/dl in females) will be excluded.  Subjects will be advised not to donate blood 
while participating in the study and for two months after their participation has ended. If they 
have just donated blood, their screening for the study will be delayed by 3 months. 
Hemoglobin levels will be monitored quarterly. 
j. Most of the participants will already be on RAS Blockers.  For those who were not previously 
taking these medications, risks will be minimized by not prescribing RAS Blockers to 
participants who have contraindications to these drugs and by prescribing an ARB whenever 
ACE inhibitors are contraindicated.  If adverse events develop that are deemed to be related 
to the use of RAS blockers, the dose of these drugs will be decreased, followed by their 
discontinuation if the problem persists (see 8.2. Run-in period), thus adhering to current 
standards of care.  If receiving discontinuation of RAS blockade becomes necessary, BP will 
be managed by alternate drugs as described above.  
k. Blood pressure will be measured quarterly with the goal of maintaining BP ≤140mmHg 
systolic and ≤90 mmHg diastolic. If elevated, a recheck will be performed within 2 weeks and 
if still elevated additional antihypertensive non-RAS blockers will be added in collaboration 
with the participants’ physicians. Failure to achieve satisfactory BP control within 2 months 
would lead to a case review by the Drug Monitoring Committee.  
l. 
Participants with a decrease in both iGFR (meeting the R2 criterion described in 7.1.2) and 
eGFR from one measurement to the following one corresponding to a GFR decline >20% per 
year will be referred to a nephrologist to investigate the causes of such rapid loss of kidney 
function.  If a decrease of such magnitude is observed for the iGFR but is less than a 20% 

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decline per year for the eGFR, the iGFR measurement will be repeated. If the >20% per year 
iGFR decrease is confirmed, the participant will be referred to a nephrologist for further 
evaluation. In this case, the first iGFR value will be used for the analysis of the primary 
outcome. If the >20% per year iGFR decrease is not confirmed, the participant will not be 
referred to a nephrologist.  The first iGFR test will be reviewed to verify whether medical 
conditions that should have prompted a test postponement, such as dehydration or recent 
use of NSAID (see 7.1.1.3), were present. In that case, the repeated iGFR value will be used 
for the primary outcome analysis. Otherwise, the first iGFR value will be used. 
m. Data monitoring will be performed on a regular basis.  Data entry computers will be 
programmed to flag any parameters outside clinically acceptable ranges.   
c. Protection of confidentiality 
All data, forms, and specimens will be labeled with each study participant’s unique study 
identifier.  All data transferred to the Data Coordinating Center for accumulation in the central database 
or to the NIDDK Central Repository will identify study participants only with their unique study identifier. 
Each study center will maintain a file on each study participant that includes personal identifiers, linking 
name and contact information to the unique study ID. These data will not be entered into the study data 
management system. Participants’ names and addresses will be shared with the Pharmacy along with 
selected laboratory results (serum creatinine and, if needed, uric acid) for the purpose of adjusting the 
dosage and mailing the study medication. Identifiers may also be shared with the local laboratories if 
required by the laboratory ordering procedures.  Study participants’ files will be kept in secure locations 
and the clinical center will be responsible for taking every other reasonable measure (those set by the 
state, the site, and the study) to ensure and maintain record confidentiality and patient privacy. 
Participants will be given the opportunity to decide whether or not the clinical information gained from 
the study should be shared with their health care providers.  Participants will be made aware that, 
despite these measures, confidentiality cannot be totally ensured. Each site will adhere as required by 
law to regulatory oversight by federal and state agencies that have authority over the conduct of clinical 
research such as the Department of Health and Human Services, the Food and Drug Administration, the 
National Institutes of Health, the Office of Human Research Protection, the Department of Social 
Services and the Data Safety Monitoring Board.  
d. Risk-benefit ratio 
If urate-lowering therapy is demonstrated to be effective in preventing or slowing early GFR decline, 
the reduction in morbidity and mortality resulting from the prevention or delay of ESRD would have a 
major impact on the lives of T1D patients as well as on society at large, significantly reducing the human 
suffering and financial costs associated with this condition.  Also, demonstrating a causal link between 
serum UA and kidney damage in T1D would prompt further research on the molecular mechanisms 
responsible for this link, which could lead to the development of further interventions to prevent renal 
disease in T1D.  Overall, the risks to study participants are deemed reasonable in relation to the anticipated 
benefit of identifying an effective therapy for early GFR loss in type 1 diabetes. 
13.6. Incentives/remuneration 
If allowed by local regulations, participants will be reimbursed for the time and effort associated 
with participating in this study. Reimbursement amounts will be decided locally. Payments will be made 
at each visit. Participants with financial hardships deriving, for example, from loss of income or child care 
costs, may be reimbursed for such costs on a case by case basis. Participants who do not complete the 
whole study will only be reimbursed for the visits they completed.  Transportation costs (e.g., parking or 
public transportation) may be reimbursed according to local policies.  Remote site participant costs 
associated with travel to a Main Site will be reimbursed according to Federal travel, hotel, and per diem 
rates (gsa.gov). 
13.7. Institutional Review Board 

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The protocol and informed consent forms and subsequent modifications will be reviewed and 
approved by the Human Subject Committees at all the centers involved in the study for compliance with 
applicable standards/regulations. 
 
14. DATA AND SAFETY MONITORING PLAN 
The Data and Safety Monitoring Plan for this study includes the following elements: 
1. A Data Safety Monitoring Board (DSMB), including outside experts in the design and conduct of 
clinical trials and in diabetic nephropathy, will be established by NIH.  The purpose of the DSMB 
is to assure independent review as to whether study patients are exposed to unreasonable risk 
because of study participation, and to monitor study progress and integrity The DSMB will receive 
detailed data from the Data Coordinating Center as frequently as deemed appropriate by the 
board, including summary tabulations and narratives of adverse events, and will meet periodically 
with the Study Investigators and the Data Coordinating Center personnel. They will have full 
access to all data, and their recommendations and input will be given high priority and will be 
incorporated into the study protocol.  To this end, the DSMB will meet separately, “in camera” 
(Closed Sessions), with the Co-Director of the Data Coordinating Center, Dr. Andrzej Galecki, to 
review all adverse event data in relation to the randomized treatment groups in order to detect 
any increased frequency of significant adverse events which could be study drug related, and 
decide whether continuation of the trial is warranted. 
2. IRB monitoring will be in place from: 
 
Joslin Diabetes Center 
 
University of Minnesota 
 
University of Colorado 
 
University of Michigan 
 
Northwestern University 
 
University of Toronto 
 
Albert Einstein University 
 
Washington University 
 
Steno Diabetes Center 
 
University of Calgary 
 
University of Alberta 
 
Emory University 
 
University of Washington 
 
University of Texas Southwestern 
 
Providence Medical Research 
 
BC Diabetes 
3. SAE reporting.  
All adverse events are reported to the DCC by completion of the Adverse Events Form.  All SAEs 
as defined previously will require expedited event notification within 72 hours of occurrence or 
identification to the DCC.  The DCC will promptly notify the study PIs, who may convene a Drug 

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Monitoring Committee (DMC) conference to acquire further information about the event and take 
appropriate actions concerning the study medication (see Section 15.1).     
An independent physician not involved in the study will serve as the Medical Safety Officer, 
reviewing all SAEs promptly after being reported in the database by the clinical sites.  Based on the 
clinical site report and any additional input from the DMC, the Medical Safety Officer will prepare a 
preliminary SAE narrative report (in cases where the SAE is not resolved) for each SAE which will be 
distributed to the PIs, NIDDK Program Director, DSMB Chair, clinical site director, and appropriate DCC 
staff.  Once the SAE is resolved, a final SAE narrative report is generated by the Medical Safety Officer. 
This report will be sent to the clinical site PI to review for accuracy and completeness. Following review 
by the clinical site PI, the Medical Safety Officer will send the final SAE narrative report to the PIs, 
NIDDK Program Director, DSMB Chair, clinical site director, and appropriate DCC staff. All SAE narrative 
reports, both preliminary and final, will be reviewed by the DSMB during their regularly scheduled 
meetings or on an expedited basis as determined by the NIDDK Program Director, who will solicit the 
input of the Chair of the DSMB as needed. The FDA definitions and requirements for expedited reporting 
will be used to determine if any individual SAE warrants notification to the FDA and to the IRBs of all 
participating PERL clinical sites. 
The clinical site at which the SAE occurred is responsible for expedited reporting of the SAE to 
their respective IRB. Each site is responsible to report all AE’s to their IRB according to its AE reporting 
policy and procedures. 
On behalf of the NIDDK, the Data Coordinating Center will submit an expedited safety report to 
the FDA for all serious unexpected suspected adverse reactions (SUSARs).  That is, when the SAE is 
unexpected and may be related to the study drug based on evidence of causality. This report will include 
information on frequency of similar events along with a narrative of similar events to provide context for 
the individual report.  Copies of the expedited safety report will be provided to the PIs, NIDDK, DSMB, 
and site investigators. 
4. When collecting data on participants, adequate safety levels will be set for flagging test results. 
When these levels are reached, the Data Coordinating Center will notify the appropriate clinic 
that an abnormal result has been received. Detailed follow-up procedures will be set in the 
Manual of Operations that will be followed by the clinic when any abnormal results are received. 
5. Monthly conference calls will be scheduled for the Steering Committee (SC) and the Trial 
Coordinators. Subject participation and compliance will be discussed in detail during these calls. A 
clinical psychology expert in the behavioral and compliance aspects of clinical trials, Dr. William 
Robiner from the University of Minnesota, will be included in the Trial Coordinator calls when 
discussing participant compliance issues. 
6. A Drug Monitoring Committee (DMC) consisting of the PERL Center Directors and PIs, a research 
pharmacist, and the Project Manager will discuss any serious medication related problem that a 
participant has.  Changes in study medication dose, medication discontinuation and medication 
re-institution will be included in these discussions.  
7. Twice a year, the Study Group will meet face-to-face with the Data Coordinating Center 
personnel for a 1½ day meeting to discuss the study in detail and any problems that may have 
occurred. The Trial Coordinators will hold a separate ½ day meeting with the Data Coordinating 
Center prior to the SC meeting and any issues needing discussion will be presented at that time 
and carried from and to the main Study Group meeting for discussion and resolution. 
 
15. STUDY ADMINISTRATION 
15.1. Organization 
The major organizational components of the study are: 

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 
The Study Group is composed of all investigators and study staff from the Clinical Sites, the 
Data Coordinating Center, and the Central Laboratory. The Study Group is responsible for the 
conduct of the study. 
 
The Steering Committee is responsible for the design of the study and provides guidance to 
its execution.  Members are the co-Chairs of the PERL Consortium (Drs. Mauer and Doria), 
the Directors of the Clinical Sites (Drs. Caramori, Rosas, Polsky, Perkins, Pop-Busui, Molitch, 
Crandall, Rossing, Sigal, Senior, Umpierrez, De Boer, Lingvay, Tuttle, Aronson and Elliott), the 
Directors of the Data Coordinating Center (Drs. Galecki and Spino), and the Director of the 
Central Laboratory (Dr. Karger), the NIH program officers (Drs. Jones and Parsa), and the 
JDRF program officer (Dr. Pragnell). 
 
The Executive Committee  will consist of the two PIs, Drs Doria and Mauer, the DCC leaders, 
Drs Galecki and Spino, the Project Manager, the Lead Clinical Coordinator, and the NIH 
officers. The EC will have at least monthly conference calls to discuss the overall conduct of 
the study and set the agendas for the Clinical Coordinators and Steering Committee 
conference calls. The EC will be responsible for the overall quality of the study, the setting of 
broad policy directions, and will address major budgetary issues, including, if necessary, 
reallocation of funds based on developed parameters of need and performance. 
 
The Drug Monitoring Committee is responsible for the oversight of the study drug 
administration as well as the RAS blocking and antihypertensive therapy during the trial. 
Members are Dr. Doria, Dr. Mauer, the PIs of the clinical sites, the Project Manager, the Lead 
Clinical Coordinator, and a research pharmacist. The participation of one of the PIs and 5 of 
the 16 Center Directors will be sufficient for making decisions. 
 
The Clinical Sites are located at the Joslin Diabetes Center, the University of Minnesota, the 
University of Colorado (Barbara Davis Center for Childhood Diabetes), the University of 
Michigan, Northwestern University, Albert Einstein College of Medicine, Washington University 
(St. Louis), the University of Toronto, the Steno Diabetes Center (Denmark), the University of 
Calgary (Calgary, Alberta, Canada), University of Alberta (Edmonton, Alberta, Canada), Emory 
University, the University of Washington (Seattle), University of Texas Southwestern, 
Providence Medical Research, and BC Diabetes are responsible for recruiting study 
participants and implementing the protocol. 
 
The Data Coordinating Center (DCC), based at the University of Michigan, is directed by Drs. 
Galecki and Spino and is responsible for managing the trial on a day-to-day basis, monitoring 
enrollment, retention, and protocol adherence and for collecting, monitoring, editing, and 
analyzing data from the Clinical Sites. 
 
The Central Laboratory, located at the University of Minnesota, is directed by Dr. Karger, and 
is responsible for all blood and urine tests. 
 
The Data Safety Monitoring Board (DSMB) will be composed of to-be-named outside experts 
in the design and conduct of clinical trials and in diabetic nephropathy.  The board will be 
responsible for reviewing the study documents, monitoring study progress and participant 
safety. 
Monthly conference calls will be scheduled for the Steering Committee and the trial coordinators 
to discuss subject participation and compliance. Twice a year, the Steering Committee, the Data 
Coordinating Center, and the trial coordinators will meet for two days to discuss the study progress. Dr. 
Robiner, the study psychologist, will attend this meeting annually.   
A study website will be maintained where all study meetings and phone call minutes will be 
maintained and where an updated version of the Manual of Operations will be available. 
15.2. Protocol Deviations, Violations, and Amendments 

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A Protocol Deviation is defined as any change, divergence, or departure from the approve study 
protocol that does not affect the participant’s safety, rights, welfare or the integrity of the study and its 
resultant data. A Protocol Violation is defined as a protocol deviation that may affect the participant's 
rights, safety, or wellbeing and/or the completeness, accuracy, and reliability of the study data.  
Deviation will be reported to the IRB at the time of continuing review whereas violations will be reported 
as soon as study personnel are aware of the event. The PI will keep an internal protocol deviation and 
violation log that will be forwarded to the IRB at the time of continuing review.  Adoption of protocol 
amendments will require three-fifths majority approval by members of the Steering Committee. The 
amended protocol is resubmitted to the IRB. 
15.3. Financial Disclosure 
On an annual basis or whenever there is a significant change in status, participating investigators 
will be required to disclose any financial or related interest that could present an actual conflict of 
interest or could be perceived as presenting a conflict of interest. The Steering Committee will determine 
(1) if the disclosed interest could directly and significantly affect the performance of study responsibility 
and, (2) the management, reduction, or elimination of the conflict.  
15.4. Publications 
It is anticipated that this research may lead to oral and written presentations including one or 
more jointly-authored publications. The contribution of investigators will be acknowledged in accordance 
with scientific custom in all published and oral communications concerning this study and its results. 
 
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2. U S Renal Data System. USRDS 2010 Annual Data Report: Atlas of Chronic Kidney Disease and 
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prevalence of diabetic kidney disease in the United States. JAMA 305, 2532-2539, 2011. 
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5. Caramori ML, Fioretto P, Mauer M. Low glomerular filtration rate in normoalbuminuric type 1 
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6. Perkins BA, Ficociello LH, Ostrander BE, Silva KH, Weinberg J, Warram JH, Krolewski AS. 
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Stanton RC, Galecki AT, Doria A, Warram JH, Krolewski AS. High-normal serum uric acid 
increases risk of early progressive renal function loss in type 1 diabetes: results of a 6-year 
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disease through its ability to lower serum uric acid level. Am J Kidney Dis 47, 51-59, 2006. 
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Effect of febuxostat on the progression of renal disease in 5/6 nephrectomy rats with and without 
hyperuricemia. Nephron Physiol 108, 69-78, 2008. 
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Joseph-Ridge N. Febuxostat compared with allopurinol in patients with hyperuricemia and gout. N 
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30. Gaspari F, Perico N, Matalone M, Signorini O, Azzollini N, Mister M, Remuzzi G. Precision of 
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35. Stevens LA, Coresh J, Schmid CH, Feldman HI, Froissart M, Kusek J, Rossert J, Van Lente F, 
Bruce RD, III, Zhang YL, Greene T, Levey AS. Estimating GFR using serum cystatin C alone and 
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Kang HR. HLA-B58 can help the clinical decision on starting allopurinol in patients with chronic 
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STUDY PROTOCOL 
 
‘A multicenter clinical trial of allopurinol to prevent GFR loss in type 1 diabetes’ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Version 6.0 
 December 17, 2013 

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GENERAL INFORMATION 
Funding Agencies 
 
National Institute of Diabetes and Digestive and Kidney Diseases 
 
Juvenile Diabetes Research Foundation (JDRF) 
Program Officers  
Michael Flessner, MD, PhD 
Division of Kidney, Urologic, & Hematologic Diseases 
NIDDK, National Institutes of Health 
Building 2DEM, Room 641 
6707 Democracy Blvd. 
Bethesda, MD 20817 
Tel: 301-451-4901 
flessnermf@mail.nih.gov 
 
Helen Nickerson, PhD 
Senior Scientific Program Manager: Complications 
Juvenile Diabetes Research Foundation 
26 Broadway 
New York, NY 10004 
Phone: (212) 479-7522 
Fax: (212) 480-2459 
hnickerson@jdrf.org  
 
Grant Numbers 
NIH UC4 DK101108-01 
JDRF 17-2012-377 
IND #115313 
ClinicalTrials.gov NCT02017171 
 
Principal investigators 
Alessandro Doria, MD PhD MPH  
Joslin Diabetes Center and Harvard Medical School 
One Joslin Place 
Boston, MA 02215 
Phone (617) 309-2406 
Fax (617) 309-2667 
alessandro.doria@joslin.harvard.edu  
 
S. Michael Mauer, MD 
University of Minnesota 
2450 Riverside Ave.  
East Building, MB681 
Minneapolis, MN  55454 
Phone: (612) 626-2720  
Fax: (612) 626-2791 
mauer002@umn.edu 
 
Directors of Clinical Sites 
Maria Luiza Caramori, MD PhD 
University of Minnesota 
420 Delaware Street SE, MMC 101 
Minneapolis, MN,  55455 
Phone (612) 625-7189 
Fax (612) 626-3133 
caram001@umn.edu 

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Allison Goldfine, MD 
Joslin Diabetes Center and Harvard Medical School 
One Joslin Place 
Boston, MA 02215 
Phone (617) 309-2643 
Fax (617) 309-3403 
allison.goldfine@joslin.harvard.edu 
 
David Maahs, MD PhD 
Barbara Davis Center 
University of Colorado Denver 
1775 Aurora Court 
PO Box 6511 
Aurora, CO 80045 
Phone (303) 724-2323 
Fax (303) 724-6779 
david.maahs@ucdenver.edu 
 
Bruce Perkins, MD MPH 
Toronto General Hospital 
University of Toronto 
Eaton North Wing 
12th  Floor Rm 12EN217 
200 Elizabeth St. 
Toronto, ON M5G 2C4 
Phone (416) 340-4800 x4333 
Fax (416) 340-3236 
bruce.perkins@uhn.ca 
 
Rodica Pop-Busui, MD PhD 
Brehm Center for Diabetes Research 
University of Michigan 
5329 Brehm Tower 
1000 Wall Street 
Ann Arbor, MI 48105 
Phone: (734) 763-3056 
rpbusui@med.michigan.edu 
 
Peter Rossing, MD 
Steno Diabetes Center 
Niels Steensens Vej 1 
DK-2820 Gentofte 
Denmark 
Phone +45 4443-7310 
pro@steno.dk 
 
Mark Molitch, MD 
Division of Endocrinology, Metabolism and Molecular Medicine 
Northwestern University Feinberg School of Medicine 
645 N. Michigan Avenue, Suite 530 
Chicago, IL 60611 
Phone (312) 503-4130 
Fax (312) 926-8693 
molitch@northwestern.edu 
 
 
 

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Jill Crandall, MD 
Albert Einstein College of Medicine  
Jack and Pearl Resnick Campus  
1300 Morris Park Avenue  
Belfer Building, Room 702  
Bronx, NY 10461 
Phone (718) 430-3765  
Fax: (718) 430-8557  
jill.crandall@einstein.yu.edu 
 
Data Coordinating Center  
Co-Director: Andrzej Galecki, MD PhD 
Division of Geriatrics, Medical School 
Department of Biostatistics, School of Public Health 
University of Michigan 
300 North Ingalls  
Ann Arbor, MI 48109-2009  
Phone (734) 936-2138 
Fax (734) 936-2116  
agalecki@umich.edu 
 
Co-Director: Cathie Spino, ScD 
Statistical Analysis of Biomedical and Educational Research (SABER) unit 
University of Michigan 
M4507 SPH II 
1415 Washington Heights  
Ann Arbor, Michigan 48109-2029 
Phone: (734) 615-5469 
Fax: (734) 647-3711 
spino@umich.edu 
 
Central laboratory 
Advanced Research and Diagnostics Laboratory 
Director: John Eckfeldt, MD PhD  
University of Minnesota 
Mayo Mail Code 8609 
420 Delaware Street 
Minneapolis, MN 55455 
Phone 612-626-3176 
Fax 612-626-2696 
eckfe001@umn.edu 

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PROTOCOL SUMMARY 
 
Study Title 
A multicenter clinical trial of allopurinol to prevent GFR loss in type 1 diabetes 
Study Phase 
Phase 3 
Objectives 
To determine whether lowering serum uric acid by means of allopurinol early in 
the course of kidney disease may be effective in preventing or slowing the 
decline of renal function in T1D patients. 
Study Design 
Multicenter, double-blind, placebo-controlled, parallel-group randomized clinical 
trial. 
Participating Centers 
Joslin Diabetes Center (Boston), University of Minnesota (Minneapolis), University 
of Colorado (Denver), University of Michigan (Ann Arbor), University of Toronto 
(Toronto), Northwestern University (Chicago), Albert Einstein College of Medicine 
(New York), Steno Diabetes Center (Copenhagen, Denmark).  
Subject Population 
480 T1D subjects.  
Inclusion criteria: 1.Male or female subjects with T1D diagnosed before age 35 
and continuously treated with insulin within one year from diagnosis; 2. Duration 
of T1D ≥ 8 years. 3. Age 18-65 years. 4. History or presence of microalbuminuria 
or moderate macroalbuminuria (at least two out of three consecutive urinary 
albumin excretion rates [AERs] or albumin creatinine ratios [ACRs] taken at any 
time before screening or at screening in the 30-2500 mg/24 hr (20-1667 g/min) 
or 30-2500 mg/g range, respectively, if not on RASB agents, or in the 18-2500 
mg/24 hr (12-1667 g/min) or 18-2500 mg/g range, respectively, if on RASB 
agents); if the evidence of micro-/macroalbuminuria dates back to more than 
two years before screening assessment, evidence of ongoing renal function 
decline (GFR loss ≥3 ml/min/1.73 m2/year) is required. 5. Estimated GFR (eGFR) 
based on serum creatinine between 45 and 99.9 ml/min/1.73 m2 at screening, 
with the upper limit being decreased by 1 ml/min/1.73 m2 for each year over age 
60. 6. Serum UA (UA) ≥ 4.5 mg/dl at screening. OR 7. Being an active 
participant in the PERL Pilot Study. Exclusion criteria: 1. History of gout or 
xanthinuria or other indications for uric acid lowering therapy such as cancer 
chemotherapy. 2. Recurrent renal calculi. 3. Use of urate-lowering agents within 
3 months before screening. 4. Current use of azathioprine, 6-mercaptopurine, 
didanosine, warfarin, tamoxifen, amoxicillin/ampicillin, or other drugs interacting 
with allopurinol. 5. Known allergy to xanthine-oxidase inhibitors or iodine 
containing substances.  6. HLA B*58:01 positivity (tested before randomization). 
7. Renal transplant. 8. Non-diabetic kidney disease. 9. SBP>160 or DBP >100 
mmHg at screening or SBP>140 or DBP>90 mmHg at the end of the run-in 
period. 10. Cancer treatment within two years before screening. 11. History of 
clinically significant hepatic disease including hepatitis B or C and/or persistently 
elevated serum liver enzymes and/or HBV/HCV positivity at screening. 12. 
History of acquired immune deficiency syndrome or human immunodeficiency 
virus (HIV) infection. 13. Hemoglobin concentration <11 g/dL (males), <10 g/dL 
(females) at screening. 14. Platelet count <100,000/mm3 at screening. 15. 
History of alcohol or drug abuse in the past 6 months. 16. Blood donation in the 
3 months before screening. 17. Breastfeeding or pregnancy or unwillingness to 
be on contraception throughout the trial. 18. Poor mental function or any other 
reason to expect patient difficulty in complying with the requirements of the 
study. 19. Serious pre-existing medical problems other than diabetes, e.g. 
congestive heart failure, pulmonary insufficiency. 
  
Study Duration 
9-week run-in period, during which RAS inhibition with ramipril 10 mg or 
acceptable alternative will be introduced and BP normalized, if elevated above 
130/80 mmHg, followed by a 3-year treatment period and then by a 2-month 
wash-out period. 

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Study Treatment, Dosage, 
and Route of Administration 
After the run-in period, eligible subjects will be randomized in a 1 to 1 ratio to 
receive placebo or oral allopurinol at a dose of 100 mg per day for 4 weeks and 
then at a dose ranging from 200 to 400 mg per day depending on kidney 
function.  
Efficacy Assessments 
Primary outcome measure: GFR at the end of the 2-month wash-out period 
following the 3-year treatment period, measured by the plasma clearance of non-
radioactive iohexol (iGFR) and adjusted for the iGFR at baseline. Secondary 
outcome measures: 1. iGFR at 4 months after randomization adjusted for the 
iGFR at baseline. 2. iGFR the end of the 3-yr treatment period (before the 
washout period) adjusted for the iGFR at baseline. 3. iGFR time trajectory 
estimated from periodical iGFR measurements. 4. eGFR time trajectory estimated 
from quarterly serum creatinine and cystatin C measurements (eGFR). 5. Time to 
serum creatinine doubling or end stage renal disease (ESRD). 6. AER at the end 
of the 2-month wash-out following the 3-yr treatment period, adjusted for the 
AER at baseline. 7. AER at the end of the 3-yr treatment period, adjusted for the 
AER at baseline. 8. Time to fatal or non-fatal cardiovascular events. 
Safety Assessment 
Examination for skin rash, measurements of liver enzymes, serum creatinine, and 
CBC, carried out 1 month after randomization and every 3 months thereafter. 
Statistical Methods 
Data will be analyzed according to an intention-to-treat approach.  Differences 
between treatment arms in the primary outcome will be tested for significance by 
means of a linear model with correlated errors. Intervention effects on other 
secondary outcomes will be tested by mixed-effect models (GFR time trajectory), 
ANCOVA (AER), and survival analysis (time to serum creatinine doubling/ESRD 
and CVD events). 
Date of protocol 
December 17, 2013 

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ABBREVIATIONS 
AE: Adverse Event 
ACE: Angiotensin Converting Enzyme 
ACR: Albumin Creatinine Ratio 
AER: Albumin Excretion Rate 
ALT: Alanine Transaminase 
ARB: Angiotensin Receptor Blocker 
CBC: Complete Blood Count 
CKD: Chronic Kidney Disease 
CRF: Case Report From 
CVD: Cardiovascular Disease 
DBP: Diastolic Blood Pressure 
DCC: Data Coordinating Center 
DMC: Drug Monitoring Committee 
DN: Diabetic Nephropathy 
DSMB: Data and Safety Monitoring Board 
ESRD: End Stage Renal Disease 
GFR: Glomerular Filtration Rate 
ITT: Intention to Treat 
HbA1c:  Glycated Hemoglobin A1C 
HBV: Hepatitis B Virus 
HCV: Hepatitis C Virus 
HIV: Human Immunodeficiency Virus 
IRB: Institutional Review Board 
MAP: Mean Arterial Pressure 
NO: Nitric Oxide 
PERL:  Preventing Early Renal Function Loss in Diabetes Consortium 
RAS: Renin Angiotensin System 
RASB: Renin Angiotensing System Blocker 

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SAE: Severe Adverse Event 
SBP: Systolic Blood Pressure 
SC: Steering Committee 
SOP: Standard Operating Procedure 
T1D: Type 1 Diabetes 
UA: Uric Acid 
 

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1. INTRODUCTION 
Diabetic nephropathy (DN) is the long-term complication of T1D that imposes the highest social and 
economic burden.  After 40 years of diabetes, about one in three patients with T1D has developed kidney 
abnormalities, which frequently progress to end stage renal disease (ESRD).1  Despite improvements during the 
past 20 years in glycemic and blood pressure control, and the introduction of ‘renoprotective’ drugs such as renin–
angiotensin system (RAS) blockers, the overall incidence of DN is not declining.2-4  Thus, DN remains one of the 
most important causes of excess morbidity and mortality in patients with diabetes mellitus, and novel therapies to 
complement and increase the therapeutic effects of glycemic control and RAS inhibition are urgently needed.   
DN has been traditionally viewed as a multi-stage process, in which an initial clinical phase characterized by 
increased urinary excretion of small amounts of albumin (microalbuminuria) is followed by excretion of larger 
amounts of proteins (overt proteinuria), which then ushers in progressive decline in renal function ultimately 
leading to end-stage renal disease (ESRD).1 This paradigm, however, is changing with the demonstration in 
prospective studies that, in a substantial proportion of T1D patients, renal function starts to decline before the 
onset of overt proteinuria.5-7  These findings indicate that T1D patients should be screened for GFR loss when 
albumin excretion rate (AER) is still in the microalbuminuria range, and that interventions aimed at preventing 
ESRD should be started at these earlier stages. The earlier the rate of GFR loss is reduced through appropriate 
interventions, the longer will be the delay of ESRD.    
Mounting evidence from epidemiological studies indicates that serum UA levels are strong risk factors for 
the development of chronic kidney disease and loss of kidney function among persons with T1D.  Prospective data 
from the Second Joslin Kidney Study (JKS) identified elevated baseline serum UA as one of the strongest 
independent predictors of early GFR loss among T1D persons with microalbuminuria and normal renal function at 
baseline.8  The unadjusted odds ratio of developing increased GFR loss was 1.5 (95% CI 1.3-1.9, p=0.0002) for 
each mg/dl increase in serum UA. This translates into a ~2.4-fold increase in the risk of early GFR loss for UA levels 
≥ 4.5 mg/dl as compared to UA levels <4.5 mg/dl. The magnitude of this effect did not significantly change after 
adjustment for urinary AER, gender, HbA1c, or, importantly, baseline GFR. The U. of Colorado group also found that 
serum UA predicted the transition from normoalbuminuria to micro- or macro-albuminuria as well as the progression 
of subclinical atherosclerosis in the CACTI study.9,10  As in the JKS, the effect of UA was not influenced by 
adjustment for other baseline variables. An association between UA and development of persistent 
macroalbuminuria has also been reported by the Steno group.  It is very important to note that, in that study, the 
UA levels shortly after the onset of T1D was a significant independent predictor of macroalbuminuria 18 years later 
(hazard ratio 1.90 per mg/dl increase in UA level; p=0.04)11, this suggestive of a pathogenetic role. 
The prospective nature of these findings and their robustness after adjustment for potential confounders 
strongly support the concept that moderately elevated serum UA has a pathogenetic role in DN development and in 
the deterioration of kidney function observed in T1D. Consistent with this hypothesis, hyperuricemia has predicted 
chronic renal failure in population-based studies12-14 and mild UA elevation has been shown to cause renal disease 
in animal models.15,16  Alterations of nitric oxide (NO) pathways and induction of pro-inflammatory cytokines17,18, 
and increased oxidative stress resulting from the generation of UA by xanthine oxidase19,20 have been proposed as 
being responsible for these effects. Two small clinical trials have recently provided proof of concept data for 
translating these findings into a novel intervention by showing that the urate-lowering agent allopurinol was 
effective in slowing the progression of non-diabetic renal disease among hyperuricemic as well as normouricemic 
individuals with moderately reduced GFR.21,22  A beneficial effect of urate-lowering drugs on the progression of 
kidney disease has also been observed in animal models.23  These findings, along with the observational data 
discussed above, strongly suggest that lowering serum UA levels may prevent or slow the loss of kidney 
function among diabetic subjects. 
To test this hypothesis, we have established a consortium of investigators from academic centers where 
large rosters of T1D patients are available along with long-standing expertise in the study of diabetic 
complications, especially DN, and in DN clinical trials. Included in this initiative are the Joslin Diabetes Center, the 
Universities of Minnesota, Colorado, Toronto, , and Michigan, Northwestern University, Albert Einstein College of 
Medicine, and the Steno Diabetes Center in Copenhagen, Denmark. The Consortium, led by Dr. Alessandro Doria 
from the Joslin Kidney Study, and by Dr. Michael Mauer, who recently led the Renin Angiotensin System Study 
(RASS) clinical trial, has been named PERL (Preventing Early Renal Function Loss in Diabetes) to emphasize the 
Consortium’s focus on intervening early in the course of kidney disease, when renal damage is most likely to be 
able to be arrested or reversed and interventions are more likely to be effective.   

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PERL has designed the present 3-year clinical trial to test whether the uric acid lowering drug allopurinol can 
preserve kidney function among type 1 diabetic patients. In preparation for this trial, the Consortium has been 
conducting a pilot study to determine the study feasibility and establish study procedures.  Funded by JDRF (JDRF 
file # 17-2012-377), the pilot study has a comparable design as the pivotal trial, but a smaller size and shorter 
duration. As of December 1, 2013, a total of 28 subjects have been randomized to allopurinol or placebo, with 
another 4 in the run-in period.  Upon activation of the present trial, pilot participants will be re-consented and 
rolled-over to the present study at a time point corresponding to their next scheduled visit.  The first 7 visits have 
identical timing in the two protocols. Visit schedules slightly differ after that, but given the current follow-up status, 
it will be possible to transfer all pilot participants to the pivotal trial before the timing diverges. 
   
2. STUDY OBJECTIVE 
To determine whether lowering serum UA by means of oral allopurinol is effective in preventing or slowing 
decline of renal function in T1D patients with microalbuminuria or moderate macroalbuminuria who still have only 
mildly or moderately impaired kidney function. 
 
3. STUDY DESIGN 
The study will be a multi-center, double-blind, placebo-controlled, parallel-group randomized clinical trial 
including a total of 480 patients with type 1 diabetes (T1D) who are at high risk for GFR loss because of increased 
albuminuria and a relatively high serum UA (≥ 4.5 mg/dl), but have only mildly or moderately decreased renal 
function.   
 
4. PARTICIPATING CENTERS  
The study will involve eight centers that are part of the PERL Consortium: 
 Joslin Diabetes Center (Boston) 
 University of Minnesota (Minneapolis) 
 University of Colorado (Barbara Davis Center for Childhood Diabetes, Denver) 
 University of Michigan (Ann Arbor) 
 University of Toronto (Toronto) 
 Northwestern University (Chicago) 
 Albert Einstein College of Medicine (New York) 
 Steno Diabetes Center (Copenhagen, Denmark)  
 
5. SUBJECT SELECTION 
5.1. Inclusion Criteria 
 
Male or female T1D patients between 18 and 65 years of age, inclusive. 
 
T1D diagnosed before age 35 and continuously treated with insulin within one year from diagnosis. If the 
onset was between ages 31 and 35, body mass index (BMI) will be required to be < 26 kg/m2 at the time 
of diagnosis; 
 
Duration of T1D ≥ 8 years; 
 
History or presence of microalbuminuria or moderate macroalbuminuria (at least two out of three 
consecutive urinary albumin excretion rates [AERs] or albumin creatinine ratios [ACRs] taken at any time 
before screening or at screening in the 30-2500 mg/24 hr (20-1667 g/min) or 30-2500 mg/g range, 
respectively, if not on RASB agents, or in the 18-2500 mg/24 hr (12-1667 g/min) or 18-2500 mg/g range, 
respectively, if on RASB. If the evidence of micro-/macroalbuminuria dates back to more than two years 
before the screening assessment and the participant is currently normoalbuminuric, evidence of ongoing 
renal function decline (GFR loss ≥3 ml/min/1.73 m2/year) is required. This evidence should be based on 
the eGFR (CKD-EPI) slope estimated from at least 3 serum creatinine measurements (including the one at 
screening assessment) spanning a period of 3 years or longer. 
 
Estimated GFR (eGFR, based on serum creatinine and the CKD-EPI equation) between 45 and 99.9 
ml/min/1.73 m2, inclusive, at the screening visit. The upper limit should be decreased by 1 ml/min/1.73 m2 
for each year over age 60. 
 
Serum UA ≥ 4.5 mg/dl at the screening visit.  
 
Willing to comply with schedule of events and protocol requirements, including written informed consent. 
OR 
 
Being an active participant in the PERL Pilot Study. 

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5.2. Exclusion Criteria 
 
History of gout requiring allopurinol therapy or xanthinuria or other indications for uric acid lowering 
therapy such as cancer chemotherapy or extremely high serum uric acid values (>12 mg/dl). 
 
Recurrent renal calculi (history of more than one episode). 
 
Use of urate-lowering agents within 3 months before screening. 
 
Current use of azathioprine, 6-mercaptopurine, didanosine, warfarin, tamoxifen, amoxicillin/ampicillin, or 
other drugs interacting with allopurinol. 
 
Known allergy to xanthine-oxidase inhibitors or iodine containing substances.  
 
HLA B*58:01 genotype (determined prior to randomization) indicating increased risk of Stevens-Johnson 
syndrome in response to allopurinol. 
 
Renal transplant.  
 
Non-diabetic kidney disease as indicated by medical history and/or laboratory findings. 
 
SBP>160 or DBP >100 mmHg at screening or SBP>140 or DBP>90 mmHg at the end of the run-in period. 
 
Cancer treatment within two years before screening. 
 
History of clinically significant hepatic disease including hepatitis B or C and/or ALT (SGPT) >2.50 x ULN at 
screening and/or HBV/HCV antibody positivity. 
 
History of acquired immune deficiency syndrome or human immunodeficiency virus (HIV) infection. 
 
Hemoglobin concentration <11 g/dL (males), <10 g/dL (females) at screening. 
 
Platelet count <100,000/mm3 at screening.  
 
Ongoing alcohol or drug abuse or history of treatment for these conditions in the past 6 months.  
 
Blood donation in the 3 months before screening (subjects become eligible once 3 months have elapsed 
since the last donation). 
 
Breastfeeding or pregnancy or unwillingness to be on contraception if still fertile. 
 
Poor mental function or any other reason to expect patient difficulty in complying with the requirements of 
the study. 
 
Serious pre-existing medical problems other than diabetes, e.g. congestive heart failure, pulmonary 
insufficiency. 
 
5.3. Prohibited Medications and Restrictions 
 
Allopurinol and other urate lowering agents (e.g., probenecid, rasburicase rys) 
 
Herbal supplements that may have urate lowering actions (e.g., Devil’s Claw or Harpagophytum 
procumbens, Indigenous cinnamon or Cinnamomum osmophloeum, Skunkvine or Paederia scandens or 
Paederia foetida)  
 
Azathioprine 
 
6-Mercaptopurine 
 
Didanosine 
 
Warfarin 
 
Tamoxifen 
 
Amoxicillin/ampicillin 
 
Any other drug for which there is evidence of interaction with allopurinol 
 
Dual RASB therapy (i.e., another RASB medication in addition to that already in use)  
 
Non-RASB antihypertensives that are not listed in the PERL approved menu of antihypertensive drugs, 
unless these were in use before joining the study. 
 
5.4. Randomization Procedures 
After the run-in period (described in Section 8.3), participants will be randomized in a 1 to 1 ratio to 
receive either oral allopurinol or placebo. Randomization will be stratified by center, uric acid (≤6.0 vs. >6.0 
mg/dl), and HbA1c (≤7.8 vs. >7.8%). Randomization will be performed using permuted blocks, with a block size 
that is known only to the DCC. After a participant has been randomized, the clinical site will send a study 
medication request to the research pharmacy, including the participant’s address, so that the study medication can 
be directly mailed to the participant. Clinical sites will not have access to the treatment assignment (see 6.2., 
Blinding Procedures). This will be directly communicated or made electronically available to the pharmacy by the 
DCC.   
 
 
 

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5.5. Discontinuation of study drug 
5.5.1. Reasons for discontinuation 
The study drug will be temporarily discontinued if a participant: 
 
Has clinically significant persistent changes from baseline based on laboratory safety assessment results 
(the response to discontinuation will be monitored to assess whether the drug can be re-instituted, see 
next paragraph on permanent discontinuations).  
 
Requires treatment with allopurinol or medications that make allopurinol contraindicated (see 5.5.2 and 
9.5). 
 
Becomes pregnant or breastfeeding (see 5.5.2)   
 
The study drug will be permanently discontinued if a participant: 
 
Experiences an SAE related to the study drug or an intolerable AE such as a persistent allergy or rash. 
 
Has clinically significant persistent changes from baseline based on laboratory safety assessment results 
which do not respond to temporary 2-week discontinuation of study drug and re-institution of drug at ½ of 
the initial dose. 
 
Develops end-stage renal disease (eGFR ≤15 ml/min/1.73 m2, institution of chronic dialysis treatment or 
kidney transplantation) or iGFR decreases by 50% from one measurement to the next or serum creatinine 
levels double over any 12 month interval in the post-randomization period.  
 
 
5.5.2. Handling of study drug discontinuation 
 
Date and reason for drug discontinuation will be recorded on the relevant Case Report Form. 
 
All study discontinuations decided by a clinical site will have to be reviewed and approved by the Drug 
Monitoring Committee within 10 days from their start. 
 
If the study drug is discontinued due to treatment with medications that make allopurinol contraindicated 
(e.g. amoxicillin/ampicillin) or due to pregnancy/breastfeeding, the possibility of resuming the study drug 
will be evaluated by the Drug Monitoring Committee once those medications have been discontinued or 
pregnancy/breastfeeding has ended.  
 
If the study drug is temporarily discontinued and then re-instated, the end-date of the intervention will 
remain the same as if the study drug had not been discontinued. All visits will be carried out as scheduled 
while the study drug is temporarily discontinued.   
 
Unless a participant withdraws consent, all participants that are permanently discontinued from study drug 
or who discontinue study medication on their own will be followed for the full study period (i.e., 164 
weeks, including the washout period) and all data will be collected as scheduled. Major attempts will be 
made to schedule an end-of-study assessment for all participants who are lost to follow-up during the 
course of the study. 
  
5.5.3. Replacements 
Participants that withdraw consent from the study during the Run-in period (i.e., before randomization) or 
do not qualify for study continuation at the end of the Run-in period will be replaced until the target number of 
randomized study participants is reached. Participants that withdraw consent from the study or discontinue the 
study drug after randomization will not be replaced.  
  
5.5.4. Termination of Study 
Premature termination of this clinical trial may occur because of a regulatory authority decision, drug safety 
problems as determined by the Data Safety Monitoring Board (DSMB), or at the discretion of the sponsor (NIDDK).   
6. STUDY TREATMENTS 
6.1. Study Drug Description, Dosage, Administration, and Accountability 
6.1.1. Description  
Eligible study subjects who agree to participate in the study will all be randomized to receive placebo or 
allopurinol – a serum UA lowering medication that has been on the market since 1964 as the main drug for the 
therapy of symptomatic hyperuricemia and for the prophylaxis of gout in cancer patients receiving chemotherapy.  
Allopurinol is an inhibitor of xanthine oxidase, which is responsible for the conversion of hypoxanthine to xanthine 
and of xanthine to UA.  It is metabolized to the corresponding xanthine analogue, oxypurinol (alloxanthine), which 

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is also an inhibitor of xanthine oxidase. At the average dosage (300 mg/day), allopurinol causes a 30-40% 
reduction in serum UA24-26, but up to a 60% reduction can be obtained using the maximum dosage of 600 mg.27  
While allopurinol is mostly used in individuals with gout and very high UA levels, several studies have shown that it 
is also effective at lower UA levels27-29.   
Because of its rapid oxidation to its active metabolite oxypurinol, allopurinol has a short plasma half-life 
(~1-2 hrs).  However, since oxypurinol has a longer half-life (~15 hrs), effective xanthine oxidase inhibition can be 
maintained over 24 hrs with a single daily dose of allopurinol. Since both allopurinol and oxypurinol are eliminated 
through the kidneys, patients with impaired renal function require lower doses than those with normal renal 
function. A common rule of thumb is to use 75% of the dosage in individuals with eGFR in the 50-90 ml/min range, 
and 50% of the dosage in individuals in the 10-50 ml/min range.  
 
6.1.2. Dosage 
After an initial four weeks where all participants randomized to allopurinol will take 100 mg per day, the 
allopurinol dosage will vary from 200 to 400 mg per day based on eGFR levels. Participants will take 400 mg per 
day if their eGFR is ≥50 ml/min/1.73 m2, 300 mg per day if their eGFR is in the 25 to <50 ml/min/1.73 m2 range, 
and 200 mg per day if the eGFR is in the 15 to <25 ml/min/1.73 m2 range. Allopurinol will be continued at this 
dosage throughout the study unless the eGFR changes, in which case the dosage will be modified to that 
appropriate for the new eGFR class. 
All participants, whether they are randomized to allopurinol or placebo, will be given four tablets per day to 
be taken orally following meals, two in the morning and two in the evening. Tablets will be provided in four vials 
(A, B, C, D). Participants randomized to allopurinol will receive a dosage of 100 mg as a 100 mg tablet (from vial A) 
plus three placebo tablets (from vials B, C, D), 200 mg as two 100 mg (from vials A and C) and two placebo tablets 
(from vials B and D), 300 mg as three 100 mg (from vials A, B, C) and one placebo tablet (from vial D), 400 mg as 
four 100 mg tablets (from vials A, B, C, D). Subjects randomized to placebo will be given four placebo tablets (from 
vials A, B, C, D).  
The dose adjustment will be carried out as follows: 
1. At each follow-up visit, a study drug requisition will be sent by the clinical site to the research pharmacy 
indicating the study ID, name, and address of the participant and the number of days to be covered by the 
drug supply.  
2. At the pharmacy, a clinical pharmacologist will determine the allopurinol dose (ranging from 0 to 400 mg) 
that should be given at that time according to the study protocol given the participant’s treatment 
assignment and the eGFR estimated from the most recent serum creatinine value (the pharmacy will retrieve 
this information from the online study database to which it will have access).   
3. The research pharmacy will mail the new batch of study medication directly to the study participant.  
4. Participants will be instructed to immediately inform the clinical site upon receipt of the new tablets and mail 
the pill bottles with the tablets remaining from the previous prescription in a provided pre-addressed mailer, 
to the clinical site for drug accounting and compliance assessment.   
 
6.1.3. Compliance and accountability. 
Skills will be taught and reinforced at each visit with regard to scheduling and administration of pills at 
home and while traveling.  Methods (e.g. record-keeping) will be taught to help participants monitor tablet usage 
and enhance compliance. To complement the regular compliance interventions at the scheduled visits, study 
information and motivational materials (postcards, newsletters, etc.) will be mailed. In addition, at midpoint 
between clinic visits, participants will be phoned by the clinic staff to review pill-taking. Patients will be provided 
with random but known numbers of excess medications, providing extras in case of pill loss. Adherence will be 
monitored by instructing participants to expect extra pills and to mail the pill bottles with the tablets remaining 
from the previous prescription to the study center upon receipt of a new batch of tablets. The number of extra pills 
included in each supply of medications will be decided by the pharmacist, who will keep a record of it and will 
transmit this information to the Study Site.  Personnel at the Study Site will enter this information in the 
appropriate electronic Case Report Form along with the expected number of pills used during the period covered by 
the supply and the number of unused pills returned by the participant.  These data will be used to analyze 
compliance. If poor adherence is noticed, measures will be taken to increase compliance, such as explaining the 
purpose of the study again, providing pill reminders, and more frequently contacting the study subject by phone. 
Participants at each visit will be asked about their perceived compliance and about any difficulties with taking the 
study medications, but the individualized strategies to improve compliance will not be openly linked to the pill 

PERL Protocol Version 6.0 
 
Page 14 of 38 
counts, i.e. participants will not be informed of the results of pill counting. Participants showing poor compliance 
will not be withdrawn from the study. 
 
6.2. Blinding Procedures 
 
Study participants, the investigators and research staff at the Clinical Sites, and the PERL co-PIs (Drs. Doria 
and Mauer) will be blinded to treatment assignment whereas the Data Coordinating Center Co-Directors and staff 
and the pharmacy personnel will have access to this information. Serum uric acid values, from which the treatment 
assignment might be inferred, will not be transmitted to the Clinical Sites by the central or local laboratory and will 
not be available for viewing in the study database. Should unblinding of a study participant be necessary because 
of an emergency, the site personnel will login to the password-protected electronic database application that will 
provide the treatment assignment.  Audit procedures will ensure that the name of the individual associated with 
the login will be communicated to the Data Coordinating Center project manager and Co-Directors.  As an 
additional safety measure, the personnel at the Clinical Sites will be provided with telephone numbers to contact 
the Data Coordinating Center and/or Pharmacy personnel having access to the treatment assignment on a 24-7 
basis. If unblinding occurs, the circumstances that led to it will be reviewed and reported. 
 
7. STUDY OUTCOMES 
7.1. Primary outcome 
The primary outcome will be the iGFR at the end of the 2-month wash-out period following the 3-year treatment 
period, measured by the plasma clearance of non-radioactive iohexol (iGFR) and adjusted for the iGFR at baseline. 
The rationale of measuring the primary outcome at the end of the wash-out period is to test allopurinol for 
permanent effects of on the natural history of kidney disease, independent from any transient, hemodynamic effect 
that the medication may have on GFR.  Plasma iohexol clearance has been shown to provide accurate and 
reproducible GFR measurements.30,31  It is highly correlated with insulin clearance (the gold standard to measuring 
GFR)32 and is a safe, cost-effective method to test hundreds of patients enrolled in multicenter clinical trials.33 The 
method consists of injecting a 5 mL bolus of Iohexol (Omnipaque, 300 mg iodine/mL) and drawing blood samples 
at baseline and 120, 150, 180, 210, and 240 minutes after the injection. Plasma concentrations of iohexol at 
different time points are measured by HPLC and used to calculate the plasma clearance of iohexol (Cl=Dose/AUC, 
where AUC is the area under the plasma concentration time curve), which is taken after appropriate body surface 
area corrections as a measure of GFR. 30,31   
 
7.1.1. iGFR quality assurance. 
It is of the foremost importance that reliable iGFR measurements are obtained. To maximize accuracy and 
precision, the following procedure will be in place.  
 
1. Personnel performing the iohexol clearance test will undergo a rigorous, standardized training program 
administered under the DCC supervision through in-person meetings or on-line modules. All staff will have 
to be study-certified as having undergone the training program in order to perform the tests.   
2. Participants will be instructed to discontinue non-steroidal anti-inflammatory drugs (NSAIDs) for at least 3 
days and avoid large protein meals for one day prior to the test, since these could influence GFR.  They will 
also be instructed to aim for a fasting glycemia between 90 and 160 mg/dl on the day of the test.  Before 
the test, participants will have a light breakfast at the clinic along with their morning insulin. The insulin 
dose will be adjusted to keep their blood glucose in the 90-160 mg/dl range.  If blood glucose is outside this 
range right before or during the test, small amounts of intravenous insulin (if blood glucose is too high) or 
orange juice/milk (if glucose is too low) may be administered to bring blood glucose levels within the 
desired interval.  
3. In the case of extreme deviations from the target blood glucose values, the test may be rescheduled to 
another day (within 2 weeks).  The test will also be postponed in the case of recent febrile illness, diarrhea 
or vomiting, dehydration, poor fluid intake, recent intake of nephrotoxic drugs such as NSAIDS, urinary tract 
infection, or a positive pregnancy test. 
 
7.1.2. iGFR quality control 
The quality of iGFR results will be monitored by: 
1. Systematically checking for deviations from the study protocol, such as deviations from the target blood 
draws time points during the test or the presence of medical conditions that should have prompted a 
postponement of the test.  

PERL Protocol Version 6.0 
 
Page 15 of 38 
2. Calculating the R-square (R2) of the regression between log-iohexol values and time. iGFR tests will be 
defined as technically acceptable if the R2 is >0.90. R2 calculations will be performed by the DCC using all 5 
time points of the iGFR test. 
7.1.3. Technically unacceptable iGFR measures. 
If an iGFR test is deemed to be technically unacceptable according to the above QC criterion (R2≤0.90), or a study 
protocol deviation is suspected, the following procedures will be followed: 
 
1. Source documents related to the test in question will be reviewed to verify whether there was a protocol 
deviation or a technical error in the iGFR procedure (e.g., presence of contraindications to iGFR, swapping 
of tubes, wrong collection times, typos, etc.).  In the case of an R2≤0.90, the iohexol measurements will be 
repeated by the central laboratory. 
2. If a technical error is found and the error can be rectified, or the new laboratory measures yield an 
R2>0.90, the iGFR value will be recalculated after the appropriate corrections are made. The study site or 
the central laboratory, as applicable, will be alerted about the error and measures aimed at improving iGFR 
quality will be implemented.  
3. If the error is confirmed and cannot be fixed, or no error can be found, the iGFR will be dropped and will 
be repeated within 4 weeks from when the iGFR results become available.  m 
4. If the repeated test is technically unacceptable, or the test cannot be repeated within 4 weeks for logistical 
reasons, the iGFR value at that time point will be considered as missing for the analysis of the primary 
outcome. It is therefore critical that every effort be made to obtain this repeat iGFR measure. 
 
7.2. Secondary outcomes 
1. Iohexol-clearance GFR at 4 months after randomization. 
2. Iohexol-clearance GFR at the end of the 3-year treatment period (before the washout). 
3. Iohexol-clearance GFR time trajectory estimated from periodical iohexol-GFR measurements. 
4. Estimated GFR (eGFR) time trajectory estimated from quarterly serum creatinine and cystatin C 
measurements using the CKD-EPI SCr and the CKD-EPI SCr-SCysC equations.34,35  
5. Time to doubling of baseline serum creatinine value or ESRD (eGFR ≤ 15 ml/min/1.73 m2, institution of 
dialysis, kidney transplantation).   
6. Geometric mean of two AER measurements at the end of the 2-month wash-out period following the 3-
year treatment period, adjusted for the mean urinary AER at baseline. Urinary AER will be determined in 
timed overnight urine collections brought by study participants to regular clinic visits, and expressed in 
g/minute and as urinary albumin/creatinine ratios. 
7. Geometric mean of urinary AER during the last three months of the treatment period (Visits 15 and 16), 
adjusted for the mean urinary AER at baseline.  
8. Time to fatal or non-fatal cardiovascular events, defined as the composite of CVD death (ICD-10 code I10 
to I74.9), myocardial infarction, stroke (ischemic or hemorrhagic), coronary artery bypass grafting, or 
percutaneous coronary intervention. 
 
8. STUDY PROCEDURES 
8.1. Schedule of Events 
 
The schedule of events that will take place in the proposed study is outlined in Figure 1.  Visits will be 
frequent during the Run-In period and during the first 30 days after randomization in order to escalate the 
allopurinol dosage and closely monitor the occurrence of AEs. After that, participants will be seen every 12 weeks 
to monitor their UA levels, renal function, occurrence of AEs, and medication compliance and, if necessary, to 
perform interventions to improve compliance.  Visit 1 will be considered as Time 0 for scheduling Visits 2-5, Visit 5 
will be considered as Time 0 for scheduling Visit 6-16, Visit 16 as Time 0 for scheduling Visit 17.   The study 
windows that define when study visits may occur are noted in Figure 1 and differ by type of visit.  Visits 2, 3, and 6 
will be carried out within 6 business days (before or after) from their scheduled dates; visits 7, 11, 16, and 17 
within 2 weeks before and 4 weeks after their scheduled dates; visit 4A (if necessary) within 1 week before and 3 
weeks after its scheduled date, and all other visits within 2 weeks (before or after) from their schedule dates. 
Additional blood or urine samples may be required in between visits if clinically significant changes are observed in 

PERL Protocol Version 6.0 
 
Page 16 of 38 
blood or urine measurements that need to be confirmed or otherwise monitored. iGFR measurements may be 
repeated for medical reasons or technical problems (see 7.1).  Safety laboratory tests (CBC, serum creatinine, K+, 
ALT, and pregnancy tests in women) will be performed by local laboratories.  Outcome variables (plasma iohexol, 
serum creatinine and cystatine C, urinary AER), HbA1c, and serum uric acid will be measured by the Central 
Laboratory at the University of Minnesota, directed by Dr. John Eckfeldt.  

PERL Protocol Version 6.0 
 
 
Page 17 of 38 
Year 
1
1
1
1
1
1
1
1
1
2
2
2
3
3
3
3
3
Week
-12
-9
-7
-3
0
4
16
32
48
64
80
96
112
128
142
156
164
VISIT
1
2
3
4
4a*
5
6
7
8
9
10
11
12
13
14
15
16
17
RANDO 
100 mg
 
EOS
Demographics
x
 
Medical Hx
x
Family History
Confidence Measure
x
 Concomitant Meds
x
x
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
Blood Pressure and Measurements 
x
x
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
ECG Report
x
x
(x)
x
x
x
 Physical Exam
x
(x)
(x)
x
x
x
Skin Assessment
x
x
x
x
x
x
x
x
x
x
x
x
x
Eligibility 
x
 Randomization
x
Family History
x
RAS and BP Med Log
x
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
IGFR Procedure
x
(x)
x
x
x
x
PERL Study Drug Prescription
x
x
x
x
x
x
x
x
x
x
x
Exemption Request 
ACR/AER 
X
x
x
(x)
x
x
x
x
x
x
x
Study Drug Compliance
X
X
X
X
X
X
X
X
X
X
Study Drug Exposure
X
X
X
X
X
X
X
X
X
X
Central Lab 
ARDL: serum uric acid, serum creat,     
x
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
ARDL: urine ACR/AER 
x
x
x
(x)
x
x
x
x
x
x
x
ARDL: HbA1c
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
ARDL: HLA B
 
x
(x)
ARDL: iGFR
x
(x)
x
x
x
x
ARDL: (HBV) HBsAg and anti-HBcAb; 
(HCV) anti-HCV; (HIV) anti HIV 1,2
x
ARDL: NIDDK Repository: serum, 
plasma, urine 
x
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
ARDL: Pregnancy test serum HCG
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
Local: Pregnancy test urine dipstick
x
x
x
x
x
Local: ALT, K, CBC, se creatinine, 
urine Multistix
x
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
Protocol Deviation
x
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
Serious Adverse Event 
x
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
Protocol Deviation
Wash-out
Allopurinol   or placebo 
200-400 mg
EVENT
Screen
Run-in
 
Figure 1.  Schedule of Events. 
 

PERL Protocol Version 6.0 
 
 
Page 18 of 38 
 
8.2. Screening and Enrollment in the Run-in Period (Visit 1) 
 
Subjects who have a confirmed history of micro- or macroalbuminuria (at least two out of three 
consecutive urinary AER or ACR in micro- or macroalbuminuria range as defined in Section 5.1) will not need to 
bring a sample of urine to Visit 1 (if the evidence of micro- or macroalbuminuria dates back to more than two years 
before screening, evidence of ongoing GFR decline should be gathered, see Section 5.1). Subjects who have 
incomplete evidence of micro- or macroalbuminuria (one of the last two urinary AER or ACR in the micro- or 
macroalbuminuria range), or have unknown albuminuria status will be mailed two containers before Visit 1 along 
with instructions for collecting two samples of urine from their first morning void and bringing it to the visit to 
confirm the presence of micro- or macro-albuminuria. During Visit 1, subjects will undergo the following 
procedures: 
 
Obtain written informed consent. 
 
Collect medical history, prior and concomitant medications, and demographic information. 
 
Complete Confidence Questionnaire 
 
Measure weight and height. 
 
Measure vital signs. 
 
Perform ECG. 
 
Perform pregnancy test in women of childbearing potential. 
 
Collect samples for clinical laboratory assessment.  
 
Provide a container and instructions for an overnight urine collection to be made immediately before Visit 3 
if subject qualifies for the study. 
 
Upon receipt of laboratory measurements, confirm that inclusion/exclusion criteria are met. 
 
The Screening Visit can be repeated after 8 weeks or longer if the circumstances that led to the exclusion of a 
participant are deemed to have possible changed.  
 
8.3. Run-in Period (Visits 2, 3, and 4) 
 
Starting at Visit 2, eligible subjects who agree to participate in the study will enter a run-in period of 9 
weeks.  During this visit, subjects will undergo the following procedures: 
 
Collect concomitant medications 
 
Measure weight and height. 
 
Measure vital signs. 
 
Physical Examination 
 
RAS antagonist treatment will be standardized, and BP, if elevated (>130/80 mm Hg), normalized. Letters 
will be written to the participants’ physicians informing them about the study and notifying them that study 
physicians will be assuming control of the participants’ antihypertensive therapy. The run-in period will start at 
Visit 2.  After discontinuing any existing RAS blockers, participants will be prescribed and instructed to start taking 
10 mg of ramipril daily or 300 mg of irbesartan daily, if ramipril is contraindicated or has side effects. Participants 
who are opposed to changing their RAS Blocker therapy will be offered the possibility to continue taking the RAS 
blocker that they are using after adjusting its dose to make it equivalent to ramipril 10 mg.  Participants who have 
contraindications to RAS blockers (e.g., SBP<100 mmHg, K+>5.5 mEq) will still qualify for the study but will not be 
treated with these drugs, as this would represent standard of care.  Participants who are started for the first time 
on RAS blockers as part of this study will have their serum K+ and creatinine measured at a local laboratory after 1 
week of treatment.  RAS blockers will be immediately discontinued in the case of allergic reactions or angioedema. 
Their dose will be decreased to half if symptomatic hypotension (SBP<100%) or intractable cough develops, 
followed by their discontinuation.  For persistent cough with ramipril or other ACEI, irbesartan will be prescribed in 
substitution of the ACEI.  In the case of hyperkalemia (K+ >6.0 mEq) or serum creatinine elevation (>30% 
increase over baseline values), the participant will be asked to immediately obtain a confirmatory lab value at their 
local lab or clinical site and then discontinue the RAS blocker while awaiting this confirmatory result. If confirmed, 
the participant will resume RAS blockade at half dose 72 hours later and will have repeat labs one week later. If 
the problem persists, RAS blockade will be discontinued for the remainder of the trial and BP managed by alternate 
drugs (see below). If not confirmed, the participant will resume RAS blockade at their usual dose and have a 
repeat lab check one week later. These same steps will be taken if hyperkalemia develops during the trial. 
Participants will continue to take any other antihypertensive drug that they may have been taking before study 
entry (except for other RAS blockers, aldosterone blockers, and renin inhibitors).  Participants will be provided with 

PERL Protocol Version 6.0 
 
Page 19 of 38 
a blood pressure monitoring device (if they do not already have access to one), will be trained on its use, and will 
be instructed to periodically monitor their blood pressure at home and to record the results into a BP diary, and to 
communicate them to study personnel if values are abnormal.  If hypotension develops (SBP<100 or significant 
lightheadedness), the dosage of non-RAS antagonist antihypertensive drugs will be progressively reduced until 
discontinuation, followed by a reduction of RAS blockers to half the dose and their discontinuation if the problem 
persists.  If BP is found to be elevated (>130/80 mm Hg) on three consecutive occasions, the dosage of existing 
non-RAS antagonists antihypertensive drugs will be maximized, followed, if necessary, by the introduction of 
antihypertensive drugs of a different class. These will be chosen by the study site physicians from a restricted 
menu of approved medications at recommended dosage, following the general protocol that was used in RASS33.  
The same menu and protocol will be used to start antihypertensive treatment in participants who have persistently 
high BP levels and were not on antihypertensive therapy prior to study entry.  If the goal of BP <130/80 is not 
achieved with these drugs, a Drug Monitoring Committee conference call will be convened to consider the 
possibility of causes of hypertension other than diabetic nephropathy and discuss alternative therapeutic 
approaches.  BP will continue to be monitored and the anti-hypertensive therapy to be adjusted in a similar way 
throughout the study. 
 
After 2 weeks of run-in, participants will come in for Visit 3 during which they will undergo the following 
procedures: 
 
Obtain interval medical history. 
 
Review concomitant medications and AEs 
 
Review and adjust BP therapy. 
 
Measure weight and vital signs. 
 
Collect samples for clinical laboratory assessments as outlined in Figure 1. 
 
Perform pregnancy test in women of childbearing potential. 
 
Provide a container and instructions for an overnight urine collection to be made immediately before Visit 
4. 
 
After 6 weeks of run-in, participants will come in for Visit 4 during which they will undergo the following 
procedures: 
 
Obtain interval medical history. 
 
Conduct a physical exam (if deemed to be required by the study physician) 
 
Review concomitant medications and AEs 
 
Review and adjust BP therapy. 
 
Measure height, weight and vital signs. 
 
Perform ECG. 
 
Collect samples for clinical laboratory assessments (including HLA B*5801) as outlined in Figure 1. 
 
Perform pregnancy test in women of childbearing potential. 
 
Measure iohexol GFR.  
 
If normal blood pressure control is not achieved at Visit 4, the run-in period may be extended for two more weeks 
after which participants will be examined as in Visit 4 (Visit 4A).  In this event, the GFR measurement scheduled for 
Visit 4 will be conducted at Visit 4A.  Participants whose SBP is >140 or whose DBP is >90 mmHg at the end of the 
run-in period will be discontinued from the study (prior to randomization). 
 
8.4. Enrollment in the Study and Randomization (Visit 5) 
 
At the end of the run-in period, eligibility will be re-assessed based on the BP measures obtained at Visits 4 
or 4A (if applicable) and HLA-based genetic susceptibility to allopurinol skin reactions36,37 (tested at Visit 4).  
Participants who are eligible for randomization based on those measures (SBP ≤ 140 and DBP ≤90 mmHg) and a 
negative HLA B*5801 test will be asked to come in for Visit 5 during which they will undergo the following 
procedures: 
 
Obtain interval medical history. 
 
Collect family history information. 
 
Confirm inclusion/exclusion criteria are met. 
 
Complete Personal Locator Form. 
 
Review concomitant medications and AEs 
 
Review and adjust RAS and BP therapy to achieve study goals (see 7.3). 
 
Measure weight and vital signs. 

PERL Protocol Version 6.0 
 
Page 20 of 38 
 
Inspect for skin rash. 
 
Collect samples for clinical laboratory assessments as outlined in Figure 1 and for storage for later 
biomarker research. 
 
Perform pregnancy test in women of childbearing potential. 
 
Randomization to allopurinol or placebo. 
 
Discuss how the study medication should be taken and its potential side effects. 
If the participant is positive for HLA-based genetic susceptibility to allopurinol skin reactions, he/she will be 
discontinued from the study prior to randomization. 
 
Immediately after Visit 5, participants will be mailed the first batch of study medication by the research 
pharmacy along with written instructions on how to take it. Participants will be instructed to notify the study 
personnel by phone and start taking the study medication as soon as they receive it. 
 
8.5. Treatment Period (Visits 6 to 15) 
 
During the treatment period, the following procedures will be completed at each visit for each participant: 
 
Obtain interval medical history. 
 
Review of concomitant medications and AEs. 
 
Review and adjust RAS and BP therapy 
 
Measure height (Visits 7 and 11), weight and vital signs. 
 
Inspect for skin rash. 
 
Conduct a physical exam (Visits 7 and 11). 
 
Update Personal Locator (Visits 7 and 11). 
 
Perform ECG according to the schedule outlined in Figure 1 (Visits 7 and 11). 
 
Collect samples for clinical laboratory assessments as outlined in Figure 1 and for storage for later 
biomarker research. 
 
Perform pregnancy test in women of childbearing potential. 
 
Measure GFR by means of plasma disappearance of non-radioactive iohexol, iGFR (Visits 7 and 11).  
 
Provide a container and instructions for an overnight urine collection whenever an AER measurement is 
scheduled at the following visit. 
 
In the days immediately after each visit, upon completion of serum creatinine measurements, participants will 
receive a new batch of study medication by mail from the research pharmacy.  Upon receipt of the new tablets, 
participants will be instructed to immediately mail the pill bottles with the tablets remaining from the previous 
prescription to the study center for drug accounting and compliance assessment (see 6.1.2). A pre-stamped and 
addressed envelope will be provided to participants for this purpose. 
 
8.6. End of Intervention (Visit 16) 
 
At the end of the treatment period (Visit 16), the following procedures will be completed for each 
participant: 
 
Obtain interval medical history. 
 
Review of concomitant medications and AEs. 
 
Review and adjust RAS and BP therapy. 
 
Collect unused study medication and document compliance. 
 
Measure height, weight and vital signs. 
 
Inspect for skin rash. 
 
Conduct a physical exam. 
 
Update Personal Locator. 
 
Perform ECG. 
 
Collect samples for clinical laboratory assessments as outlined in Figure 1 and for storage for later 
biomarker research. 
 
Perform pregnancy test in women of childbearing potential. 
 
Measure iGFR. 
 
Provide containers and instructions for 2 overnight urine collections to be made immediately before Visit 
17. 
 
Participants will be instructed to stop taking the study medication and to mail the pill bottles with the tablets 

PERL Protocol Version 6.0 
 
Page 21 of 38 
remaining from the last prescription to the study center if they did not already bring the unused study medication 
at the visit.  The RAS and BP therapy will be continued as before until the closing visit (Visit 17). The importance of 
coming back in 8 weeks for the closing visit (Visit 17) will be emphasized. 
 
8.7. End of Wash-out Period (Visit 17) 
 
After the end of the treatment period, participants will enter an 8-week wash-out period at the end of 
which the following procedures will be completed: 
 
Obtain medical history. 
 
Review of concomitant medications and AEs. 
 
Measure height and weight and vital signs. 
 
Inspect for skin rash. 
 
Collect samples for clinical laboratory assessments as outlined in Figure 1 and for storage for later 
biomarker research. 
 
Perform pregnancy test in women of childbearing potential. 
 
Measure iGFR. 
 
8.8. RAS blocking and anti-hypertensive therapy after completion of the study 
 
When the participant completes the study, control of the RAS-blocking and anti-hypertensive therapy will 
be relinquished to the participants’ physicians, who will decide whether or not to continue the therapy established 
during the study. Participants will continue the anti-hypertensive therapy established during the study until they 
see their physicians. 
 
8.9. Future biomarker studies 
Plasma, serum, and urine specimens and DNA will be stored the Advanced Research and Diagnostics 
Laboratory at the University of Minnesota and the NIDDK Central Repository for possible future studies of biomarkers 
of kidney disease in diabetes or other diabetic complications.  One 2.5 ml aliquot of plasma, one 2.5 ml aliquot of 
serum, and one 6 ml aliquot of urine will be stored at each visit, with the exception of Visits 4, 7, 11, 16, and 17 at 
which three aliquots of plasma, three aliquots of serum, and three aliquots of urine will be banked.  Twenty ml of 
whole blood will be obtained during an early visit when smaller aliquots are obtained.  This will be used for white 
blood cell DNA extraction and subsequent storage. Altogether, the stored plasma and serum aliquots will 
correspond to about 300-320 ml of blood collected for this purpose over the entire duration of the study.  
Participants will be allowed to elect to participate in the study while not having any or one or more of these 
samples stored, if so they choose. 
 
8.10. Early Withdrawal  
Unless the participant withdraws consent, all randomized participants will be followed for the full study 
period (through week 164) and all data will be collected as scheduled.   
 
9. SAFETY ASSESSMENTS 
9.1. Demographic Data/Medical History 
After collecting a detailed medical history at Visit 1, this information will be updated at each visit through a 
structured interview, with a special emphasis on skin symptoms and signs such as rash, itching and exfoliation and 
on pregnancy in females. Participants will be instructed to communicate any change in their health status and 
intervening hospitalizations to the study coordinator in-between visits.  In particular, they will be instructed to 
discontinue study medication and immediately contact the study coordinator if they develop a skin rash of any 
kind, swelling of the lips or mouth, arthralgias, and/or jaundice, which may indicate a hypersensitivity reaction to 
allopurinol.  Fever and chills should also be reported but would not require cessation of medication prior to 
discussion with study personnel. 
   
9.2 Skin exam 
At each visit study on and after Visit 5, the skin of study participants will be examined for the presence of 
any kind of rash.  Suspicion of drug allergy or Stevens-Johnson Syndrome SJS would require immediate 
discontinuation of study medication and dermatologic consultation. 
 
 
 

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9.3. Vital Signs 
 
Blood pressure and heart rate will be recorded at each visit. 
 
9.4. Clinical Laboratory Tests    
 
Serum ALT, creatinine and K+, and CBC will be monitored and a pregnancy test, if a female of child 
bearing potential, performed at each visit (except Visit 2). Participants who are started for the first time on RAS 
blockers as part of this study will have their serum K+ and creatinine measured at a local laboratory after 1 week of 
treatment.  HbA1c will be measured at Visits 1, 5 and 7, and 8-17. An ECG will be performed at Visits 1, 4, 7, 11, 
and 16. 
 
9.5. Management of Uric Acid Levels 
Study participants and study personnel, other than the DCC and the study pharmacists, will be masked as 
to the uric acid levels obtained during the study.  The patients' physicians will receive written requests to refrain 
from measuring uric acid levels during the time of the patients' participation in the study, except as is mandatory 
for the patient's wellbeing, e.g., in the treatment of malignancy or diagnosis of a clinical syndrome highly likely to 
represent gout.  If gout is diagnosed, open-label treatment with allopurinol will become indicated.  In such case, 
the study drug will be discontinued but the patient will remain in the study and will continue to be followed as if 
he/she was taking the study medication.  If uric acid lowering for malignancy treatment is required, the patient will 
receive open-label treatment until such time as return to study drug is deemed clinically reasonable by their 
physician. 
 
10. ADVERSE EVENT REPORTING 
10.1. Definitions 
An Adverse Event (AE) is any untoward medical occurrence in a participant administered an investigational 
medicinal product regardless of relationship to study treatment.  A treatment-emergent AE is an adverse event 
occurring during the period between the first dose and 30 days after the final dose of the study medication. A 
Serious Adverse Event (SAE) is any untoward medical occurrence that results in death, is life-threatening, requires 
hospitalization or prolongation of an existing hospitalization, results in persistent or significant disability, or is a 
congenital anomaly/birth defect.  Important medical events that do not fall into the above categories may also be 
considered an SAE when, based on medical judgment, such events may jeopardize the patient’s safety and require 
medical/surgical intervention to prevent one of the outcomes listed in the SAE definition.  The term SAE is not 
intended as a measure of severity or intensity. 
A Suspected Adverse Reaction is any adverse event for which there is a reasonable possibility that the drug 
caused the adverse event. For the purposes of IND safety reporting, "reasonable possibility" means there is 
evidence to suggest a causal relationship between the drug and the adverse event. Suspected adverse reaction 
implies a lesser degree of certainty about causality than adverse reaction, which means any adverse event caused 
by a drug.  An Unexpected Adverse Event or Unexpected Suspected Adverse Reaction is an adverse event or 
suspected adverse reaction that is not listed in the investigator brochure or is not listed at the specificity or severity 
that has been observed; or, if an investigator brochure is not required or available, is not consistent with the risk 
information described in the general investigational plan or elsewhere in the current application, as amended. For 
example, under this definition, hepatic necrosis would be unexpected (by virtue of greater severity) if the 
investigator brochure referred only to elevated hepatic enzymes or hepatitis. Similarly, cerebral thromboembolism 
and cerebral vasculitis would be unexpected (by virtue of greater specificity) if the investigator brochure listed only 
cerebral vascular accidents. “Unexpected”, as used in this definition, also refers to adverse events or suspected 
adverse reactions that are mentioned in the investigator brochure as occurring with a class of drugs or as 
anticipated from the pharmacological properties of the drug, but are not specifically mentioned as occurring with 
the particular drug under investigation.  An Expected Adverse Event or Expected Adverse Reaction is any adverse 
experience that has been identified in nature or severity in the current investigator brochure and/or protocol. 
 
10.2. Adverse Events Reporting 
All AEs will be reported on the Adverse Events form that will be completed by the study staff, who are 
masked as to study treatment assignment, at each regular follow-up visits.  This will insure that AEs are 
ascertained in an unbiased manner using the same standardized methodology for participants in both treatment 
arms.  Forms will include standardized questions relating to specific events of import in diabetic patients on either 
of the study treatment arms as well as any significantly abnormal physical finding identified on examination and 

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any significantly abnormal laboratory results obtained on the patient between visits or at the time of the visit.  AEs 
reported or ascertained between clinic visits will be captured and reported at the time of the next schedule visit.  
Pre-existing conditions (that is, conditions present prior to randomization) will not be considered or recorded as 
AEs unless the condition worsens in intensity or frequency after randomization.  Likewise, continuing AEs will not 
be reported as AEs at subsequent visits unless they increase in severity or frequency between visits, they results in 
criteria for a SAEs, and/or they resolve between visits.  Each site will be responsible for reporting all AE's to their 
IRB according to its AE reporting policy and procedures.   
 
10.3. Assessment of Causality and Severity 
The seriousness of adverse events will be ascertained by the study staff according to the criteria listed in 
10.1 and the need for further evaluation, follow-up, or referral.  The relationship between study participation and 
AEs will be determined according to the following criteria:  
A. 
Not related – temporal relationship of the onset of the event, relative to study participation, is not 
reasonable or another cause can by itself explain the occurrence of the event. 
B. 
Possibly related – temporal relationship of the onset of the event, relative to study participation, is 
reasonable but the event could have been due to another, equally likely cause. 
C. 
Probably related – temporal relationship of the onset of the event, relative to study participation, is 
reasonable and the event is more likely explained by the study treatment than by another cause. 
D. 
Definitely related – temporal relationship of the onset of the event, relative to study participation, is 
reasonable and there is no other cause to explain the event. 
 
10.4. Serious Adverse Events Reporting 
See Section 15 – Data and Safety Monitoring Plan 
 
11. STATISTICAL ANALYSIS 
11.1. Analysis Population 
An intention to treat (ITT) analytical approach will be employed.  Accordingly, the population for statistical 
analysis will consist of all study participants considered in their original randomization group, regardless of 
treatment discontinuation or loss to follow-up. 
 
11.2. Initial Data Analysis 
The initial data analysis will be performed to detect any differences in distributions of characteristics 
measured at baseline, 4, 20, 36, and 38 months (0, 16, 84, 156, and 164 weeks, respectively) between study 
groups. The number of patients screened, enrolled, and completing the study will be summarized within and across 
study centers. Measures of central tendency (means, medians) and variability (standard deviations, ranges) will be 
estimated from the data for continuous variables. Frequency distributions will be provided for categorical data. This 
preliminary analysis step will provide us with insight into data, distributions of the variables considered, and will 
allow us to find additional invalid values not detected earlier during data validation.  
 
11.3. Primary Efficacy Analysis.   
For the primary endpoint (iGFR at the end of the 2-month wash-out period following the 3-year 
intervention), we will follow the recommendations by Carpenter et al38,39 and perform the analysis by means of a 
linear model for correlated errors with general/unstructured covariance matrix using all available iGFR measures 
(including those at baseline, 4, 20, 36, and 38 months [i.e., 0, 16, 84, 156, and 164 weeks, respectively]) as the 
dependent variable. By conditioning on the baseline iGFR measure we will also effectively use this variable as a 
covariate. Treatment group, study center, stratifying variables, baseline AER, time, and time by treatment 
interaction will be included as covariates in the model. Three features make this analytical approach especially 
attractive:  
1. If there is no dropout (a very unlikely case), the estimate of the treatment effect at the end of the 2-month 
wash-out period following the 3-year intervention and its precision obtained using this approach will be 
exactly the same as those based on a classical approach employing an analysis of covariance (ANCOVA) 
model with treatment group, study center, iGFR and AER/ACR measured at baseline included as covariates.  
2. If the iGFR measure at the end of the wash-out period is missing, we will be able to efficiently use the 
information contained in the intermediate iGFR measurements obtained at 4, 20, and 36 months, by virtue 
of them being correlated with the GFR measurement at washout. Estimate of the treatment effect obtained 

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this way is valid under the missing at random (MAR) assumption. This is in contrast to the ANCOVA 
approach, which would lead to the loss of this information and would require a more stringent assumption 
about the mechanism of data missingness, i.e. a missing completely at random (MCAR) mechanism.  
3. The underlying analytical framework allows the use of all post-randomization data and is well suited to 
investigate the reason for withdrawal, for example to study whether participants having low iGFR values 
are more likely to withdraw. 
Calculations will be performed using SAS PROC/MIXED. Results of the analysis will be expressed in terms of 
point estimate and its corresponding 95% confidence interval for the treatment effect at the end of the 2-month 
wash-out period following the 3-year treatment and will be accompanied by the corresponding p value.  
 
11.4. Secondary Efficacy Analyses.  
1. The effect of treatment on the iGFR at 4 months after randomization will be evaluated using the same 
analytical approach employed for the primary outcome. 
2. The effect of treatment on the iGFR at the end of the 3-year treatment period (before the washout) will be 
evaluated using the same analytical approach employed for the primary outcome. 
3. The iGFR and eGFR time trajectories, estimated from periodical iGFR measures and quarterly serum 
creatinine and cystatin C measurements using the CKD-EPI SCr and the CKD-EPI SCr-SCysC equations34,35, 
respectively, will be analyzed using linear mixed-effects models.40-42 The main objective of the analysis will 
be to construct confidence interval for the effect of the intervention over three years of observation 
(treatment main effect) and investigate whether the effect of the intervention changes with time (time by 
treatment interaction).  
4. Time to serum creatinine doubling or ESRD in the two treatment groups is subject to censoring due to 
dropouts or reaching the end of study before the participant experiences the event.  Survival time will be 
defined as the time from randomization to the event (the first of serum creatinine doubling from baseline 
or occurrence of ESRD, defined as eGFR < 15 ml/min/1.73 m2, hemodialysis, or kidney transplant) or, for 
participants who did not experienced an event, to the last study visit.  Data will be summarized by means 
of Kaplan-Meier survival curves and by providing the proportions of participants surviving without events at 
1, 2, 3 years, and at the end of the wash-out period along with their 95% CIs. Given the potentially small 
number of events, differences between study groups will be tested by means of the log rang test or by 
means of simple Cox regression models including a limited number of predictors in addition to treatment 
group.  
5. The effect of treatment on the AER at the end of the wash-out period, based on the geometric mean of 
two AER measured at this time point and adjusted for the geometric mean of AER at baseline (Visit 3 and 
4), will be investigated in a linear regression model framework as in the case of the primary outcome. 
6. The effect of treatment on the AER at the end of the treatment period, based on the geometric mean of 
the AER measures at visit 15 and 16 adjusted for the geometric mean of AER at baseline (Visit 3 and 4) will 
be investigated as in #5. 
7. Time to fatal or non-fatal cardiovascular events will be analyzed as proposed for time to serum creatinine 
doubling or ESRD. 
 
 11.5. Incomplete Data.  
Missing values represent a potential source of bias. Efforts will be made to keep all participants in the 
study. If this is not feasible, at least some information regarding the status at the end of the trial will be obtained. 
For randomized patients, the number of completing and dropouts will be summarized. This procedure will help to 
compare characteristics of the participants’ groups who drop out from the study with those who completed the 
study by treatment group, within and across study centers. The models considered in the proposal allow for a 
missing at random (MAR) mechanism. MAR means that the missing values mechanism can be explained by 
observed data and does not depend on the unobserved values of outcome measures. The differences in 
distributions between characteristics of the groups may indicate potential sources of bias due to missing values. For 
instance some patients may dropout from the study due to unobserved factors related to the intervention itself. If 
we suspect such bias is present, the methods discussed in this section, assuming (MAR), are not applicable. We will 
incorporate plausible missing values mechanism into the model as discussed in Little43 and investigate how such 

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mechanism may affect the estimates of treatment effect.  To this end, sensitivity analyses will be conducted 
involving selection and/or pattern-mixture models44 with an appropriate submodel used to describe dropout. 
 
11.6. Pilot participants. 
All pilot participants who were already randomized to allopurinol or placebo during the pilot will be included 
in the final analysis of the pivotal trial.  Those who do not consent to the pivotal trial will be treated as having 
dropped from the study at a time corresponding to their last pilot visit.  Sensitivity analyses will be performed to 
investigate whether results may be potentially affected by the roll-over of pilot subjects in the pivotal trial.  
 
11.7. Model assumptions and alternative analyses 
Model assumptions will be thoroughly checked for individual and systematic departures, using informal, 
e.g. inspection of residuals, and formal methods such as score test for extra parameter or methods based on 
likelihood displacement. If individual outliers are detected, their influence will be evaluated using influence 
diagnostics methods based on comparing estimates from models fitted to data with and without outlying values. 
Whenever we are not successful in fitting the parametric model (linear or non-linear), then non-parametric 
analyses and/or transformation of the variables involved in the analysis will be considered. To investigate the 
potential hemodynamic influence of allopurinol on treatment effect, in addition to the aforementioned analyses, we 
will consider models including the post-randomization measure of GFR at 4 months as an additional covariate. To 
investigate the possible presence of heterogeneity in the response to allopurinol, subgroup analyses will be 
performed by age groups (≤40 and >40 yrs), gender, racial/ethnic group, HbA1c (≤7.8 and >7.8%), serum uric 
acid (≤6.0 and > 6.0 mg/dl), baseline GFR (≤70 ml/min and >70 ml/min/1.73m2), and AER (≤300 and >300 
mg/24 hr).  These additional analyses will be considered as strictly exploratory. 
 
11.8. Safety Analyses 
Adverse events will be independently reviewed by an independent data safety monitoring board (DSMB, 
see Sections 15 and 16). All safety data will be available in data listing in the clinical protocol report. Data will be 
described in terms of descriptive statistics and presented by treatment group. Presentation will include graphs 
(scatterplots, boxplots, histograms), measures of central tendency (mean, median) and variability (confidence 
intervals) for continuous variables and frequency tables for categorical variables. 
 
11.9. Interim Analysis  
No formal interim analyses of efficacy to stop for benefit or futility are planned, given the timing of the 
primary endpoint. 
 
11.10. Sample Size. 
 
 
Since a variance-covariance matrix for the iGFR measures is not available and this matrix is essential in order 
to perform formal power calculations for a model with correlated errors, we performed alternative power 
calculations based on an intent-to-treat analysis within an ANCOVA framework. Specifically, we assumed that the 
primary hypothesis is tested in the following model: 
 
 
M1: iGFR at washout = iGFR at baseline + treatment group  
 
 
Compared to the model that will be used in the primary analysis, model M1 is simplified in two aspects. First, 
it does not use information from iGFR values measured at intermediate time points. Second, it does not include 
covariates such as the stratifying variables (HbA1c and UA) or other GFR predictors such as baseline AER.  Both of 
these aspects may lead to loss of precision of the treatment effect estimate. Consequently, our sample size 
calculations should be considered as conservative.   
 
 
The hypothesis being tested, i.e. the effect of treatment on iGFR at washout, corresponds to testing whether 
the treatment group factor in Model M1 is significant.  The choice of the ANCOVA model for the purpose of power 
calculations is sensible, as residuals from a univariate model involving baseline iGFR as covariate fitted to data from 
RASS study conform to normal distribution. Sample size calculations were performed based on Cohen45 and making 
the following assumptions: 
1. Postulated effect on iGFR at washout () = 3 ml/min/1.73 m2.  We deem this effect to be clinically 
meaningful and attainable. It is clinically meaningful because it would translate on average into a 10-year 
delay in the progression to ESRD. It is attainable because it is smaller than the difference in 3-year GFR 
that we observed in the JKS between subjects with serum UA ≥ 4.5 mg/dl compared to those with levels 

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below this value. The postulated effect was based on the following changes in GFR levels in the two 
treatment groups: 
a. Untreated group = 3 ml/min/1.73 m2 per year.  This estimate is based on data from the Joslin Kidney 
Study (JKS), in which the median GFR loss among 43 subjects meeting the above criteria was 3.1 
ml/min/1.73 m2 per year, with 70% of subjects having a GFR loss >1.5 ml/min/1.73 m2 per year.  Also, 
among 116 subjects from Steno who met the albuminuria and GFR criteria, but for whom serum uric 
acid values were not available, the median GFR loss was 3.3 ml/min/1.73 m2 per year, with 71% of 
subjects having a GFR loss >1.5 ml/min/1.73 m2 per year. 
b. Treated group = 2 ml/min/1.73 m2 per year. The average GFR loss in the JKS subjects with serum UA 
<4.5 mg/dl was 1.5 ml/min per year.  On this basis, we conservatively assumed that the allopurinol 
treatment, if effective, would decrease the GFR loss to 2 ml/min per year (a 33% decrease compared to 
the untreated group).  
2. Standard deviation (SD) of residual error = 10.1 ml/min/1.73 m2.  This was estimated based on the root-
mean-squared error from a regression model with eGFR at 3 yrs as the dependent variable and baseline 
eGFR as the independent variable fitted to data concerning T1D patients from the Joslin Kidney Study 
meeting the PERL inclusion criteria.  
 Assuming a two-sided alpha error equal to 0.05, the effective sample size needed to detect the pre-specified 
treatment effect ( = 3 ml/min/1.73 m2) at washout adjusted for baseline iGFR with 80% power is equal to n=180 
per group. To take into account the anticipated overall dropout rate (up to 5%/yr or 15% over the entire duration 
of the study) and drug discontinuation or non-compliance in the treatment group (up to 2%/yr or 6% over the 
entire duration of the study), and to maintain the desired power of at least 80%, it will be necessary to recruit 
n=240 subjects per group. In Table 1, we show the power of the proposed sample size for Model M1 under  
different dropout and non-compliance scenarios.  We also provide the 
corresponding power for a model (Model M2)  
including the two stratifying variables (Hb1Ac and UA) and baseline 
AER as covariates to illustrate the effect of adding these variables to 
Model M1. In this analysis, we assumed that adding these covariates 
reduces the residual  
variance by 10%, which corresponds to these covariates explaining 
merely 4% of the total iGFR variation over and above the variability 
explained by iGFR at baseline. As shown in Table 1, once these 
covariates are accounted for, power is expected to exceed the 
conservative estimates provided by Model M1 and reach almost 90% 
for 15% dropout and 6% non-compliance rates.  
 
12. DATA COLLECTION AND QUALITY ASSURANCE 
Comprehensive data coordinating center (DCC) functions for 
this clinical trial, including clinical monitoring, database development, web-based data entry and management, as 
well as the creation and export of study reports for the DSMB will be provided by the University of Michigan 
Statistical Analysis of Biomedical and Education Research (SABER) group.  Housed in the top nationally ranked 
Department of Biostatistics, SABER, in its 13-year existence, has served as the DCC for over 50 studies, including 
multiple NIH-sponsored networks.   
The DCC will use OpenClinica® (OpenClinica Clinical Trial Software; OpenClinica, LLC, Waltham, MA), a 
clinical trial software platform for electronic remote (i.e., site-based entry) data capture and clinical data 
management, as the basis for our custom-designed data entry and management system. We expect that the 
majority of data will be collected via Case Report Forms (CRFs); however, other data sources, such as laboratory 
data from the central laboratory, may be used. In these circumstances, the DCC will also utilize electronic data 
transfer. Protocols for the transfer of data, with careful attention to data integrity, will be written by experienced 
programmers and stored in the OpenClinica database or data mart.   
The DCC has established a set of standard operating procedures (SOPs) governing the processes used to 
ensure patient privacy and data confidentiality, including the use of anonymous participant IDs on CRFs and in 
reports. In addition to clinical study databases, the UM DCC has also incorporated MEDdra® 
[www.meddramsso.com/] and WHODD® [www.who-umc.org/] databases into our systems to have the capacity to 
Table 1. Power to detect treatment effect for 
two ANCOVA models under different drop-out 
and non-compliance scenarios. 
Overall 
Dropout 
(%) 
Non-
compliance 
(%) 
Model 
M1 
M2 
9 
0 
.87 
.92 
12 
0 
.86 
.91 
15 
0 
.85 
.90 
 
 
 
 
9 
6 
.83 
.89 
12 
6 
.82 
.88 
15 
6 
.80 
.87 

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code adverse events and illnesses by body organ system, respectively.  OpenClinica® enables compliance with 
Good Clinical Practice (GCP) and regulatory requirements by providing differentiated user roles and privileges, 
password and user authentication security, electronic signatures, SSL encryption, and comprehensive auditing to 
record and monitor access and data changes. 
 
12.1. Case Report Forms 
Study information will be collected for each participant by study staff using standardized electronic Case 
Report Forms (CRFs).  CRFs will be developed by the DCC, modeling their formats on the CRFs developed for the 
RASS clinical trial33, to which the study group has access through Dr. Mauer.  CRFs will not report information 
about treatment assignment, in order to maintain blinding of study site.  Forms will be stored at a secure location 
at the clinical sites.   
 
12.2. Quality Control and Quality Assurance 
DCC staff will prepare data management and clinical monitoring plans. The clinical monitoring plan will 
detail procedures to assess accuracy of the database relative to source documents, as well as site adherence to 
regulatory and study procedures. Emphasis will be placed on the process of consenting subjects, compliance with 
regulatory requirements and study protocol, values of key endpoints, and identification of SAEs that may not have 
been reported. The data management plan will describe the front-and back-end edit checks, as well as forms 
tracking procedures, that will be implemented to ensure timely and high-quality data collection.  It will also define 
the periodic reports that will be shared with site coordinators and PIs that summarize site performance.  The 
clinical monitoring and data management procedures will be consistent with the International Conference on 
Harmonisation (ICH E6) standards for Good Clinical Practice (GCPs).46  
 
12.2.1. Clinical monitoring.   
During trial conduct, the DCC will conduct periodic monitoring visits to ensure that the protocol and GCPs 
are being followed.  The monitors may review source documents to confirm that the data recorded on CRFs is 
accurate.  The investigator and institution will allow DCC monitors direct access to source documents to perform 
this verification.  It is important that the investigator(s) and their relevant personnel are available during the 
monitoring visits and that sufficient time is devoted to the process. 
Clinical monitoring will be conducted through approximately yearly on-site visits by qualified personnel. In 
the first year, site initiation  visits will be conducted to review the protocol, verify that the Site Director and his/her 
collaborators receive all necessary trial documents for a proper trial conduct, and review the procedures related to 
CRFs completion and query resolution. Investigators will be instructed about the importance of recording accurate 
and clean data, avoiding protocol violations, and retaining participants in the study. Follow-up monitoring visits will 
involve the verification of source documents and reporting of adverse events. Monitors will also verify that an 
informed consent form is on file for each subject screened, with appropriately dated signatures and all pages 
present, that all of the inclusion and exclusion criteria were met for each subject enrolled into the study, and that 
all the withdrawals and dropouts of enrolled participants from the trial are reported and explained in the 
appropriate CRFs. Accrual and retention rates will also be monitored and if these fall appreciably below the 
projected levels, attempts will be made to identify the reasons. At the end of each monitoring visit, a clinical 
monitoring report will be prepared by the DCC Clinical Monitor and sent to the site PI and to a NIDDK 
representative with recommendations to correct problems and/or improve the trial quality.  
12.2.2. Statistical monitoring.  
Clinical monitoring will be complemented by statistical central monitoring, as described by Venet et al.47. 
Such a statistical approach to central monitoring relies on assessing the clinical data for departures from expected 
patterns (e.g., baseline variables in our randomized trial should be comparable between treatment arms for each 
site; visit days should be randomly distributed over the week), and assessment of a greater number of data values 
than those associated with site performance metrics.  The statistical monitoring plan will be incorporated into the 
larger data management plan, and will identify the specific descriptive statistics, graphical presentations, and 
formal hypothesis tests to be performed and at what frequency.  Pattern recognition may require a sufficient 
number of participants followed for a sufficient amount of time in order to be valid.   
12.2.3. Laboratory quality monitoring.  
The Central Laboratory at the U. of Minnesota uses internal quality control methods to assess assay 
precision and drift as well external quality control (e.g., proficiency testing)  to assess accuracy.  The laboratory is 
well versed in both aspects and adheres to rigid performance standards.  For all analytes, enough commercial 

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lyophilized control material is typically purchased prior to beginning the study, so that a single control pool lot can 
be used throughout.  Control pool mean and between-day SD’s for each analyte are routinely established at a 
minimum of two different analyte concentrations on a minimum of one hundred different analytical batches.  In the 
unlikely event that a new control pool lot becomes necessary during the study, both the new and old control pool 
lots will be run for a minimum of 20 days to establish a target mean for the new pool.  The target SD’s are not 
changed if the new and old lots of control material are the same “matrix” (e.g., lyophilized human serum).  An in-
house control pool is also typically prepared from the exact same specimen type (e.g., 0.5-mL aliquots of pooled 
serum or EDTA-plasma from several individual donors), kept at -70°C, and incorporated as an internal control in all 
analytical batches throughout the study.  This sort of control is very useful since occasionally the commercial pools 
of lyophilized serum have matrix effects that make assessment of the true accuracy of the given assay difficult to 
assess. Accuracy is assessed by comparison of external quality control proficiency testing results.  For most of the 
assays, the laboratory participates in either the College of American Pathologists’ Surveys Program (uric acid, 
creatinine, ALT, glycosylated hemoglobin, urine albumin, urine creatinine) or by sample exchange in a survey 
program with another laboratory (iohexol). The laboratory is CLIA certified.  
 
12.3. Study Record Retention 
The source documents will be stored for at least 10 yrs after the study ends.  
 
12.4. Data and Biosample Archiving in the NIDDK Central Repository. 
 
In agreement with NIDDK’s policy on the sharing of data from large, NIDDK-sponsored, multi-site studies, 
the data and biosamples collected in the course of the trial will be archived in anonymized form in the NIDDK 
Central Repository for future distribution to the scientific community.  All samples and data transferred to the 
Repository will be under the custodianship of the NIDDK, although the study’s Steering Committee will have 
proprietary control of and exclusive access to the sample and data for an agreed-upon period of time before these 
are made available to the wider scientific community.    
 
13.  PROTECTION OF HUMAN SUBJECTS 
 
13.1. Characteristics of the study population  
 
Participants will be patients who have had T1D for 8 years or more and who will be 18-65 years old at 
entry into the study.  We anticipate that there will be approximately an equal number of males and females.  There 
will be no selection criterion based on race, although most patients will be of Western background and European 
extraction, given the demographics of the cities in which the centers are located and the fact that T1D is 30-40% 
less common among Blacks and Hispanics than among Whites.  Inclusion and exclusion criteria are as noted above.  
Female patients of child-bearing potential will be included in the study but only if pregnancy is not planned during 
the time frame of the study.  Women who become pregnant after randomization will be discontinued from the 
study medication until pregnancy and breast feeding are complete; iGFR will not be obtained during or for 6 
months after pregnancy is completed.  Individuals younger than 18 will not be included since kidney complications 
are rare before this age.  Patients will be tested for HLA-based genetic susceptibility to Stevens-Johnson Syndrome 
and excluded if this is found. 
 
13.2. Sources of research material 
a. Specimens on patients obtained specifically for research purposes. 
1. Renal function studies requiring multiple blood specimens drawn from an indwelling IV over 4-6 
hours for measurement of glomerular filtration rate at yearly intervals. 
2. Collection of urine for measurement of urinary albumin and creatinine at 3-6 month intervals. 
3. Blood for measurement of serum UA, creatinine, and liver enzymes, and WBC at quarterly 
intervals. 
b. Specimens or measures obtained quarterly as component of routine patient care 
1. HbA1c 
2. Blood pressure 
3. Height and weight 
c. Patient and family medical information. 
All study participants will be assigned a unique study identifier and in no publications or public 
presentations will information be available which could identify individual study participants or their families. 

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13.3. Plans for recruitment of subjects and consent procedures. 
Potential participants will be sought (1) from among the patients attending the study centers (including the 
satellite centers) involved in the study and (2) by placing advertisements at other health care facilities and in local 
newspapers or other media.  At each clinical site, potential candidates will be identified and contacted according to 
the procedures established by the local IRBs in compliance with local laws protecting patient confidentiality. 
Invitation letters to patients attending the study centers will clearly offer the possibility to opt out of any further 
contacts with the study.  Patients who agree to participate will be screened by means of a telephone or in-person 
interview to determine whether exclusion criteria apply. Subjects who respond to advertisements will undergo the 
same screening interview. Subjects who pass this initial screening will be given or mailed an informed consent form 
and will be invited to come to the clinic for a screening visit (Visit 1) during which a final eligibility determination 
will be made on the basis of a detailed medical history and laboratory tests. Written consent will be obtained on 
that occasion from all subjects undergoing the screening visit after explaining again the purpose and procedures of 
the study. In the initial contact and again at the time of the screening visit, study subjects will be encouraged to 
ask questions and they will be reassured that they may withdraw from the study at any time.  The consent form 
will again be reviewed and consent affirmed at the visit prior to randomization (Visit 4). 
 
13.4. Potential Risks 
13.4.1. Risks associated with screening procedures and blood tests 
 
After participating in the screening tests and procedures, or after the run-in period, subjects may find out 
that they are not eligible to participate in the study. In that case, they will be told the reasons for their ineligibility 
and will be given the results of clinically approved tests such as serum UA, serum creatinine, urinary 
albumin/creatinine ratio, and ALT.  The results of the test for genetically increased risk of allopurinol-induced SJS 
will also be given to their physician, if the subject agrees with this.  Thus, they may learn about as yet unknown 
health problems such as anemia or liver disease, more advanced kidney disease, or the need for allopurinol 
avoidance. This and/or the exclusion from the study may cause psychological distress. The drawing of blood 
samples may cause some pain and discomfort and hematoma formation at the site of venipuncture. The total 
amount of blood taken for the entire study will be about 700 mL (26 ml at Visits 1, 3, 5-6, 8-10, and 12-15; 67 ml 
at Visits 4, 7, 11, 16, and 17).  At the dose used in the study, there are no known risks to the infusion of the 
substance used for the measurement of renal function other than the very small risk of allergic reactions (<0.5%), 
diminished by the exclusion of patients with a history of iodine allergy and by having appropriate treatment drugs 
for allergic reactions on hand.  
 
13.4.2. Risks associated with allopurinol treatment 
Allopurinol has been used for several decades for the long-term therapy of symptomatic gout. The risks 
associated with its use are low and include: 
a. Skin rashes, usually pruritic maculopapular skin eruptions, sometimes scaly or exfoliative, are the most 
commonly reported adverse effect of allopurinol. Skin reactions were observed in the past in up to 3% of 
treated patients, but more recent data suggest that their frequency is now less than 1% 
(www.drugs.com/pro/allopurinol.html) perhaps more likely due to changes in the filler compounds rather 
than the actual drug. Rashes may be followed by more severe hypersensitivity reactions such as exfoliative 
lesions and the Stevens-Johnson syndrome (erythema multiforme major), which can be fatal.  Although 
such occurrence is very rare, in the order of 1 in 10,00048, treatment with allopurinol will be immediately 
discontinued if a rash develops and will not be reinstated. As noted, those with HLA-based genetic 
susceptibility to allopurinol-related SJS will be screened out. About 0.7% of Whites and 2-3% of African 
Americans and Asians are carriers of such genetic susceptibility. 
b. An increased frequency of acute gout attacks has been reported during the early stages of allopurinol 
administration, possibly resulting from the mobilization of urates from tissue deposits causing fluctuations 
in serum UA levels. Early studies estimated the risk of such events to be about 6%, but an analysis of 
current usage suggests that the risk has now decreased to less than 1% (www.drugs.com/pro/ 
allopurinol.html).  The risk is expected to be even lower in this study population since individuals with a 
previous history of gout will be excluded and UA levels will be on average lower than in patients usually 
taking allopurinol for elevated UA levels. 

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c. Reversible liver damage as well as asymptomatic rises in liver enzymes has been observed in 1-2% of 
patients taking allopurinol. Some very rare cases of irreversible liver damage have been observed in the 
context of the Stevens-Johnson syndrome.  
d. Bone marrow depression has been reported in patients receiving allopurinol, most of whom received 
concomitant drugs with the potential for causing this reaction. Bone marrow depression has been rarely 
observed in patients receiving allopurinol alone.  
e. Experience with allopurinol during human pregnancy is limited because women of reproductive age rarely 
require this treatment.  Given this paucity of data, the study will consider it unsafe for the fetus or the 
mother to receive this drug.  Allopurinol has been found in the milk of a mother on this drug and, 
therefore, will not be taken by nursing mothers. 
 
13.4.3. Risks associated with RAS blocker treatment. 
Treatment with RAS blockers (either ACE inhibitors such as ramipril or angiotensin receptor blockers such 
as irbesartan) is currently the standard of care for diabetic individuals who have micro- or macroalbuminuria.  The 
risk associated with the use of these drugs during the trial will not be greater than the risks participants would face 
outside the trial by being treated with these agents. These risks include allergic reactions, hyperkalemia, 
hypotension, increased serum creatinine, persistent cough (with ramipril), liver damage, and bone marrow 
depression.  The occurrence of these adverse events will be monitored during the trial.  
 
13.5. Procedures for protecting against and minimizing potential risks 
a. General 
The patients are under constant medical supervision.  They are told that the data which are collected will 
be used for scientific report, but they will not be identified in such reports. 
 
b. Specific  
1. Regular pregnancy tests and education regarding fetal risk of the study drug will be provided to female 
patients of child bearing age.   
2. Quarterly measures of liver enzyme and white blood cell count will allow for early detection of liver injury 
or leucopenia potentially representing drug toxicity.  
3. Quarterly measures of serum creatinine will allow titration of allopurinol in relation to kidney function to 
avoid excessive dosage of the medication.  
4. IV's for kidney function studies will be placed by trained skilled clinical research nurses or technicians or by 
experienced physicians.   
5. Blood drawing for laboratory studies will be performed by trained skilled phlebotomy personnel at the 
respective institutions, thus limiting the risk of discomfort or local hematoma formation. 
6. Participants will be advised not to donate blood throughout the time they are in the study. 
7. Regarding possible drug toxicity: 
a. To avoid fetal risks from the study drug, patients planning pregnancies will not be included.  
Sexually active female patients will be instructed to immediately discontinue study drugs if a 
menstrual period is missed by more than two weeks and, if found to be pregnant, the study 
medication will be discontinued and not resumed until pregnancy and nursing are completed.  
Pregnancy tests will be done quarterly on all women in the study.  
b. Subjects with known allergy to xanthine-oxidase inhibitors will be excluded from the study. 
Patients will be instructed to immediately report skin reactions and allergic symptoms and to 
immediately stop the study medication should these occur. Patients will be given antihistamines for 
symptom relief.  A small supply of antihistamines to be used in such an event will be supplied to 
each patient.  Should an allergic reaction or skin rash occur, the study drug will be permanently 
discontinued. 
c. To minimize the risk of gout attacks, subjects with a gout history will be excluded from the study 
and the allopurinol dosage in those enrolled in the study will be gradually increased over several 

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weeks. Should a gout attack occur, this will be treated with colchicine or anti-inflammatory agents 
according to current standards of care by study personnel. Study uric acid levels <2.0 mg/dl will be 
flagged by the DCC and reported to the appropriate study pharmacist who will initiate a 50% dose 
reduction in study drug at the next quarterly visit.  In order to avoid gout attacks, if uric acid levels 
exceed 12 mg/dl this will be flagged by the DCC and the center informed  and open-label 
allopurinol will be started and titrated with the goal of bringing and keeping serum uric acid below 
7.0 mg/dl.  Participants will continue to be followed according to the study protocol and will be 
analyzed according to their blinded treatment groups.    
d. Primary care physicians will be notified (with the participants’ permission) of the patients’ 
participation in the trial, so that they avoid the prescription of drugs interacting with allopurinol or 
notify the study personnel that treatment with such drugs is necessary.  
e. Participants will be reminded at each visit to immediately to notify the study personnel if they start 
a new drug, so that possible interactions with allopurinol can be identified at once and appropriate 
precautions can be taken including discontinuation of the study drug.  
f. 
Subjects taking drugs known to interact with allopurinol in causing bone marrow depression will be 
excluded from the study.  White blood cell counts will be done before the study drugs are 
prescribed, and quarterly thereafter and the study drug discontinued should evidence of bone 
marrow depression (WBC<3500/mm3) develop.  The Drug Monitoring Committee will review each 
case and decide whether a referral to a hematologist is warranted and whether study treatment 
can be reinstated after blood values have returned to normal. If drugs potentially causing bone 
marrow depression in combination with allopurinol are begun after entry into the trial, observations 
for this side effect will be intensified or, if recommended by the Drug Monitoring Committee, study 
drug may be interrupted. 
g. To minimize the risk of allergic reactions during the iGFR measurement, subjects with a history of 
iodine allergy will be excluded from the study. 
h. To minimize the risk of liver injury, subjects with clinically significant hepatic disease and/or 
elevated liver enzymes above 2.5 x the upper limit of normal at the screening visit will be excluded 
from the study. In those subjects that are enrolled in the study, liver enzyme levels will be 
monitored at each follow-up visit. If levels are abnormal, the measurement will be repeated and if 
values are confirmed to be elevated the study drug will be discontinued. The Drug Monitoring 
Committee will review each case and decide whether a referral to a hepatologist is warranted and 
whether study treatment can be reinstated after enzyme values have returned to normal on the 
recommendation of a hepatologist. 
i. 
To minimize the impact of blood draws, participants with low hemoglobin levels (<11 g/dL in 
males, <10 g/dl in females) will be excluded.  Subjects will be advised not to donate blood while 
participating in the study and for two months after their participation has ended. If they have just 
donated blood, their screening for the study will be delayed by 3 months. Hemoglobin levels will be 
monitored quarterly. 
j. 
Most of the participants will already be on an ACE inhibitor. Thus, switching them to another drug 
of the same class (ramipril) should not pose significant risks.  In the remaining participants (taking 
an Angiotensin Receptor Blocker [ARB] or not taking any RAS Blockers), risks will be minimized by 
not prescribing RAS Blockers to participants who have contraindications to these drugs and by 
prescribing an ARB (irbesartan) whenever ACE inhibitors are contraindicated.  If adverse events 
develop that are deemed to be related to the use of RAS blockers, the dose of these drugs will be 
decreased, followed by their discontinuation if the problem persists (see 8.2. Run-in period), thus 
adhering to current standards of care.  If receiving discontinuation of RAS blockade becomes 
necessary, BP will be managed by alternate drugs as described above.  
k. Blood pressure will be measured quarterly with the goal of maintaining BP <130 mmHg systolic 
and <85 mmHg diastolic. If elevated a recheck will be performed within 2 weeks and if still 
elevated additional antihypertensive non-RAS blockers will be added from a limited menu of agents 
as prescribed in the MOO. Failure to achieve satisfactory BP control within 2 months would lead to 
a Drug Monitoring Committee conference call. The patient’s physicians would be asked to 

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relinquish BP management to PERL personnel in order to achieve uniformity of goals, but the 
patient’s physicians would be informed of any BP medication changes. 
l. 
Participants with a decrease in both iGFR (meeting the R2 criterion described in 7.1.2) and eGFR 
from one measurement to the following one corresponding to a GFR decline >20% per year will be 
referred to a nephrologist to investigate the causes of such rapid loss of kidney function.  If a 
decrease of such magnitude is observed for the iGFR but is less than a 20% decline per year for 
the eGFR, the iGFR measurement will be repeated. If the >20% per year iGFR decrease is 
confirmed, the participant will be referred to a nephrologist for further evaluation. In this case, the 
first iGFR value will be used for the analysis of the primary outcome. If the >20% per year iGFR 
decrease is not confirmed, the participant will not be referred to a nephrologist.  The first iGFR test 
will be reviewed to verify whether medical conditions that should have prompted a test 
postponement, such as dehydration or recent use of NSAID (see 7.1.1.3), were present. In that 
case,  the repeated iGFR value will be used for the primary outcome analysis. Otherwise, the first 
iGFR value will be used. 
m. Data monitoring will be performed on a regular basis.  Data entry computers will be programmed 
to flag any parameters outside clinically acceptable ranges.   
 
c. Protection of confidentiality 
All data, forms, and specimens will be labeled with each study participant’s unique study identifier.  All data 
transferred to the Data Coordinating Center for accumulation in the central database or to the NIDDK Central 
Repository will identify study participants only with their unique study identifier. Each study center will maintain a 
file on each study participant that includes personal identifiers, linking name and contact information to the unique 
study ID. These data will not be entered into the study data management system. Participants’ names and 
addresses will be shared with the Pharmacy along with selected laboratory results (serum creatinine and, if 
needed, uric acid) for the purpose of adjusting the dosage and mailing the study medication. Identifiers may also 
be shared with the local laboratories if required by the laboratory ordering procedures.  Study participants’ files will 
be kept in secure locations and the clinical center will be responsible for taking every other reasonable measure 
(those set by the state, the site, and the study) to ensure and maintain record confidentiality and patient privacy. 
Participants will be given the opportunity to decide whether or not the clinical information gained from the study 
should be shared with their health care providers.  Participants will be made aware that, despite these measures, 
confidentiality cannot be totally ensured. Each site will adhere as required by law to regulatory oversight by federal 
and state agencies that have authority over the conduct of clinical research such as the Department of Health and 
Human Services, the Food and Drug Administration, the National Institutes of Health, the Office of Human 
Research Protection, the Department of Social Services and the Data Safety Monitoring Board.  
 
d. Risk-benefit ratio 
If urate-lowering therapy is demonstrated to be effective in preventing or slowing early GFR decline, the 
reduction in morbidity and mortality resulting from the prevention or delay of ESRD would have a major impact on 
the lives of T1D patients as well as on society at large, significantly reducing the human suffering and financial 
costs associated with this condition.  Also, demonstrating a causal link between serum UA and kidney damage in 
T1D would prompt further research on the molecular mechanisms responsible for this link, which could lead to the 
development of further interventions to prevent renal disease in T1D.  Overall, the risks to study participants are 
deemed reasonable in relation to the anticipated benefit of identifying an effective therapy for early GFR loss in type 1 
diabetes. 
 
13.6. Incentives/remuneration. 
If allowed by local regulations, participants will receive $740 ($20 for each visit completed at the clinic not 
involving the kidney function test and $100 for each visit completed at the clinic involving the kidney function test) 
as a reimbursement for the time and discomfort associated with participating in this study. Payments will be made 
at each visit. Participants with financial hardships deriving, for example, from loss of income or child care costs, 
may be reimbursed for such costs on a case by case basis. Participants who do not complete the whole study will 
only be reimbursed for the visits they completed. Parking will be paid by vouchers on the days participants are 
asked to come in for a study visit. For participants who do not drive, public transportation costs may be reimbursed 
up to the same costs of parking.  If this study should result in the development of any marketable product, profits 
will not be shared with participants. 
 

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13.7. Institutional Review Board 
The protocol and informed consent forms and subsequent modifications will be reviewed and approved by 
the Human Subject Committees at all the centers involved in the study for compliance with applicable 
standards/regulations. 
 
14. DATA AND SAFETY MONITORING PLAN 
The Data and Safety Monitoring Plan for this study includes the following elements: 
1. A Data Safety Monitoring Board (DSMB), including outside experts in the design and conduct of clinical 
trials and in diabetic nephropathy, will be established by NIH.  The purpose of the DSMB is to assure 
independent review as to whether study patients are exposed to unreasonable risk because of study 
participation, and to monitor study progress and integrity The DSMB will receive detailed data from the 
Data Coordinating Center as frequently as deemed appropriate by the board, including summary 
tabulations and narratives of adverse events, and will meet periodically with the Study Investigators and 
the Data Coordinating Center personnel. They will have full access to all data, and their recommendations 
and input will be given high priority and will be incorporated into the study protocol.  To this end, the 
DSMB will meet separately, “in camera” (Closed Sessions), with the Co-Director of the Data Coordinating 
Center, Dr. Andrzej Galecki, to review all adverse event data in relation to the randomized treatment 
groups in order to detect any increased frequency of significant adverse events which could be study drug 
related, and decide whether continuation of the trial is warranted. 
2. 
IRB monitoring will be in place from: 
 Joslin Diabetes Center 
 University of Minnesota 
 University of Colorado 
 University of Michigan 
 Northwestern University 
 University of Toronto 
 Albert Einstein College of Medicine 
 Steno Diabetes Center 
 
3. 
SAE reporting.  
All adverse events are reported to the DCC by completion of the Adverse Events Form.  All SAEs as defined 
previously will require expedited event notification within 72 hours of occurrence or identification to the 
DCC.  The DCC will promptly notify the study PIs, who may convene a Drug Monitoring Committee (DMC) 
conference to acquire further information about the event and take appropriate actions concerning the 
study medication (see Section 15.1).     
An independent physician not involved in the study will serve as the Medical Safety Officer, reviewing all 
SAEs promptly after being reported in the database by the clinical sites.  Based on the clinical site report 
and any additional input from the DMC, the Medical Safety Officer will prepare a preliminary SAE narrative 
report (in cases where the SAE is not resolved) for each SAE which will be distributed to the PIs, NIDDK 
Program Director, DSMB Chair, clinical site director, and appropriate DCC staff.  Once the SAE is resolved, 
a final SAE narrative report is generated by the Medical Safety Officer. This report will be sent to the 
clinical site PI to review for accuracy and completeness. Following review by the clinical site PI, the Medical 
Safety Officer will send the final SAE narrative report to the PIs, NIDDK Program Director, DSMB Chair, 
clinical site director, and appropriate DCC staff. All SAE narrative reports, both preliminary and final, will be 
reviewed by the DSMB during their regularly scheduled meetings or on an expedited basis as determined 
by the NIDDK Program Director, who will solicit the input of the Chair of the DSMB as needed. The FDA 
definitions and requirements for expedited reporting will be used to determine if any individual SAE 
warrants notification to the FDA and to the IRBs of all participating PERL clinical sites. 
The clinical site at which the SAE occurred is responsible for expedited reporting of the SAE to their 
respective IRB. Each site is responsible to report all AE’s to their IRB according to its AE reporting policy 
and procedures. 
On behalf of the NIDDK, the Data Coordinating Center will submit an expedited safety report to the FDA 
for all serious unexpected suspected adverse reactions (SUSARs).  That is, when the SAE is unexpected 
and may be related to the study drug based on evidence of causality. This report will include information 

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on frequency of similar events along with a narrative of similar events to provide context for the individual 
report.  Copies of the expedited safety report will be provided to the PIs, NIDDK, DSMB, and site 
investigators. 
4. 
When collecting data on participants, adequate safety levels will be set for flagging test results. When 
these levels are reached, the Data Coordinating Center will notify the appropriate clinic that an abnormal 
result has been received. Detailed follow-up procedures will be set in the Manual of Operations that will be 
followed by the clinic when any abnormal results are received. 
5. 
Monthly conference calls will be scheduled for the Steering Committee (SC) and the Trial Coordinators. 
Subject participation and compliance will be discussed in detail during these calls. A clinical psychology 
expert in the behavioral and compliance aspects of clinical trials, Dr. William Robiner from the University of 
Minnesota, will be included in the Trial Coordinator calls when discussing participant compliance issues.    
6. 
A Drug Monitoring Committee (DMC) consisting of the PERL Center Directors and PIs, a research 
pharmacist, and the Project Manager will hold conference calls regarding any serious medication related 
problem that a participant has.  Changes in study medication dose, medication discontinuation and 
medication re-institution will be discussed during these calls. 
7. 
Twice a year, the Study Group will meet face-to-face with the Data Coordinating Center personnel for a 
1½ day meeting to discuss the study in detail and any problems that may have occurred. The Trial 
Coordinators will hold a separate ½ day meeting with the Data Coordinating Center prior to the SC 
meeting and any issues needing discussion will be presented at that time and carried from and to the main 
Study Group meeting for discussion and resolution.    
 
15. STUDY ADMINISTRATION 
15.1. Organization 
 
The major organizational components of the study are: 
 
The Study Group is composed of all investigators and study staff from the Clinical Sites, the Data 
Coordinating Center, and the Central Laboratory. The Study Group is responsible for the conduct of the 
study. 
 
The Steering Committee is responsible for the design of the study and provides guidance to its execution.  
Members are the co-Chairs of the PERL Consortium (Drs. Mauer and Doria), the Directors of the Clinical 
Sites (Drs. Caramori, Goldfine, Maahs, Perkins, Pop-Busui, Molitch, Crandall, and Rossing), the Directors of 
the Data Coordinating Center (Drs. Galecki and Spino), and the Director of the Central Laboratory (Dr. 
Eckfeldt), and the NIH program officer (TBD). 
 
The Executive Committee will consist of the two PIs, Drs Doria and Mauer, the DCC leaders, Drs Galeki and 
Spino, the Project Manager, and the Lead Clinical Coordinator. The EC will have at least monthly 
conference calls to discuss the overall conduct of the study and set the agendas for the Clinical 
Coordinators and Steering Committee conference calls. The EC will be responsible for the overall quality of 
the study, the setting of broad policy directions, and will address major budgetary issues, including, if 
necessary, reallocation of funds based on developed parameters of need and performance. 
 
The Drug Monitoring Committee is responsible for the oversight of the study drug administration as well as 
the RAS blocking and antihypertensive therapy during the trial. Members are Dr. Doria, Dr. Mauer, the PIs 
of the clinical sites, the Project Manager, the Lead Clinical Coordinator, and a research pharmacist. The 
participation of one of the PIs and 5 of the 8 Center Directors will be sufficient for making decisions. 
 
The Clinical Sites are located at the Joslin Diabetes Center, the University of Minnesota, the University of 
Colorado (Barbara Davis Center for Childhood Diabetes), the University of Michigan, Northwestern 
University, Albert Einstein College of Medicine, the University of Toronto and the Steno Diabetes Center 
(Denmark) are responsible for recruiting study participants and implementing the protocol. 
 
The Data Coordinating Center (DCC), based at the University of Michigan, is directed by Drs. Galecki and 
Spino is responsible for managing the trial on a day-to-day basis, monitoring enrollment, retention, and 
protocol adherence and for collecting, monitoring, editing, and analyzing data from the Clinical Sites. 

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 
The Central Laboratory, located at the University of Minnesota, is directed by Dr. Eckfeldt, and is 
responsible for all blood and urine tests. 
 
The Data Safety Monitoring Board (DSMB) will be composed of to-be-named outside experts in the design 
and conduct of clinical trials and in diabetic nephropathy.  The board will be responsible for reviewing the 
study documents, monitoring study progress and participant safety. 
Monthly conference calls will be scheduled for the Steering Committee and the trial coordinators to discuss 
subject participation and compliance. Twice a year, the Steering Committee, the Data Coordinating Center, and the 
trial coordinators will meet for two days to discuss the study progress. Dr. Robiner, the study psychologist, will 
attend this meeting annually.   
 
A study website will be maintained where all study meetings and phone call minutes will be maintained and 
where an updated version of the Manual of Operations will be available. 
 
15.2. Protocol Deviations, Violations, and Amendments. 
 
A Protocol Deviation is defined as any change, divergence, or departure from the approve study protocol 
that does not affect the participant’s safety, rights, welfare or the integrity of the study and its resultant data. A 
Protocol Violation is defined as a protocol deviation that may affect the participant's rights, safety, or wellbeing 
and/or the completeness, accuracy, and reliability of the study data.  Deviation will be reported to the IRB at the 
time of continuing review whereas violations will be reported as soon as study personnel are aware of the event. 
The PI will keep an internal protocol deviation and violation log that will be forwarded to the IRB at the time of 
continuing review.  Adoption of protocol amendments will require three-fifths majority approval by members of the 
Steering Committee. The amended protocol is resubmitted to the IRB. 
 
15.3. Financial Disclosure 
On an annual basis or whenever there is a significant change in status, participating investigators will be 
required to disclose any financial or related interest that could present an actual conflict of interest or could be 
perceived as presenting a conflict of interest. The Steering Committee will determine 1. if the disclosed interest 
could directly and significantly affect the performance of study responsibility and, 2. the management, reduction, or 
elimination of the conflict.  
 
15.4. Publications 
It is anticipated that this research may lead to oral and written presentations including one or more jointly-
authored publications. The contribution of investigators will be acknowledged in accordance with scientific custom 
in all published and oral communications concerning this study and its results. 
 
16. References 
 
1. Krolewski AS, Warram JH. Epidemiology of late complications of diabetes: A basis for the development and 
evaluation of preventive program. in Joslin's Diabetes Mellitus. Lippincott, Williams & Wilkins, New York 
(2005). 
2. U S Renal Data System. USRDS 2010 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage 
Renal Disease in the United States.National Institutes of Health, National Institute of Diabetes and 
Digestive and Kidney Diseases, Bethesda, MD (2010). 
3. de Boer IH, Rue TC, Hall YN, Heagerty PJ, Weiss NS, Himmelfarb J. Temporal trends in the prevalence of 
diabetic kidney disease in the United States. JAMA 305, 2532-2539, 2011. 
4. Rosolowsky ET, Skupien J, Smiles AM, Niewczas M, Roshan B, Stanton R, Eckfeldt JH, Warram JH, 
Krolewski AS. Risk for ESRD in type 1 diabetes remains high despite renoprotection. J Am Soc Nephrol 22, 
545-553, 2011. 
5. Caramori ML, Fioretto P, Mauer M. Low glomerular filtration rate in normoalbuminuric type 1 diabetic 
patients: an indicator of more advanced glomerular lesions. Diabetes 52, 1036-1040, 2003. 

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6. Perkins BA, Ficociello LH, Ostrander BE, Silva KH, Weinberg J, Warram JH, Krolewski AS. Microalbuminuria 
and the risk for early progressive renal function decline in type 1 diabetes. J Am Soc Nephrol 18, 1353-
1361, 2007. 
7. Premaratne E, MacIsaac RJ, Finch S, Panagiotopoulos S, Ekinci E, Jerums G. Serial measurements of 
cystatin C are more accurate than creatinine-based methods in detecting declining renal function in type 1 
diabetes. Diabetes Care 31, 971-973, 2008. 
8. Ficociello LH, Rosolowsky ET, Niewczas MA, Maselli NJ, Weinberg JM, Aschengrau A, Eckfeldt JH, Stanton 
RC, Galecki AT, Doria A, Warram JH, Krolewski AS. High-normal serum uric acid increases risk of early 
progressive renal function loss in type 1 diabetes: results of a 6-year follow-up. Diabetes Care 33, 1337-
1343, 2010. 
9. Jalal DI, Rivard CJ, Johnson RJ, Maahs DM, McFann K, Rewers M, Snell-Bergeon JK. Serum uric acid levels 
predict the development of albuminuria over 6 years in patients with type 1 diabetes: findings from the 
Coronary Artery Calcification in Type 1 Diabetes study. Nephrol Dial Transplant 25, 1865-1869, 2010. 
10. Rodrigues TC, Maahs DM, Johnson RJ, Jalal DI, Kinney GL, Rivard C, Rewers M, Snell-Bergeon JK. Serum 
uric acid predicts progression of subclinical coronary atherosclerosis in individuals without renal disease. 
Diabetes Care 33, 2471-2473, 2010. 
11. Hovind P, Rossing P, Tarnow L, Johnson RJ, Parving HH. Serum uric acid as a predictor for development of 
diabetic nephropathy in type 1 diabetes: an inception cohort study. Diabetes 58, 1668-1671, 2009. 
12. Iseki K, Ikemiya Y, Inoue T, Iseki C, Kinjo K, Takishita S. Significance of hyperuricemia as a risk factor for 
developing ESRD in a screened cohort. Am J Kidney Dis 44, 642-650, 2004. 
13. Domrongkitchaiporn S, Sritara P, Kitiyakara C, Stitchantrakul W, Krittaphol V, Lolekha P, Cheepudomwit S, 
Yipintsoi T. Risk factors for development of decreased kidney function in a southeast Asian population: a 
12-year cohort study. J Am Soc Nephrol 16, 791-799, 2005. 
14. Zhang L, Zuo L, Xu G, Wang F, Wang M, Wang S, Lv J, Liu L, Wang H. Community-based screening for 
chronic kidney disease among populations older than 40 years in Beijing. Nephrol Dial Transplant 22, 1093-
1099, 2007. 
15. Kang DH, Nakagawa T, Feng L, Watanabe S, Han L, Mazzali M, Truong L, Harris R, Johnson RJ. A role for 
uric acid in the progression of renal disease. J Am Soc Nephrol 13, 2888-2897, 2002. 
16. Mazzali M, Hughes J, Kim YG, Jefferson JA, Kang DH, Gordon KL, Lan HY, Kivlighn S, Johnson RJ. Elevated 
uric acid increases blood pressure in the rat by a novel crystal-independent mechanism. Hypertension 38, 
1101-1106, 2001. 
17. Johnson RJ, Segal MS, Srinivas T, Ejaz A, Mu W, Roncal C, Sanchez-Lozada LG, Gersch M, Rodriguez-Iturbe 
B, Kang DH, Acosta JH. Essential hypertension, progressive renal disease, and uric acid: a pathogenetic 
link? J Am Soc Nephrol 16, 1909-1919, 2005. 
18. Mazzali M, Kanellis J, Han L, Feng L, Xia YY, Chen Q, Kang DH, Gordon KL, Watanabe S, Nakagawa T, Lan 
HY, Johnson RJ. Hyperuricemia induces a primary renal arteriolopathy in rats by a blood pressure-
independent mechanism. Am J Physiol Renal Physiol 282, F991-F997, 2002. 
19. Desco MC, Asensi M, Marquez R, Martinez-Valls J, Vento M, Pallardo FV, Sastre J, Vina J. Xanthine oxidase 
is involved in free radical production in type 1 diabetes: protection by allopurinol. Diabetes 51, 1118-1124, 
2002. 
20. Pacher P, Nivorozhkin A, Szabo C. Therapeutic effects of xanthine oxidase inhibitors: renaissance half a 
century after the discovery of allopurinol. Pharmacol Rev 58, 87-114, 2006. 

PERL Protocol Version 6.0 
 
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21. Siu YP, Leung KT, Tong MK, Kwan TH. Use of allopurinol in slowing the progression of renal disease 
through its ability to lower serum uric acid level. Am J Kidney Dis 47, 51-59, 2006. 
22. Goicoechea M, de Vinuesa SG, Verdalles U, Ruiz-Caro C, Ampuero J, Rincon A, Arroyo D, Luno J. Effect of 
allopurinol in chronic kidney disease progression and cardiovascular risk. Clin J Am Soc Nephrol 5, 1388-
1393, 2010. 
23. Sanchez-Lozada LG, Tapia E, Soto V, Avila-Casado C, Franco M, Wessale JL, Zhao L, Johnson RJ. Effect of 
febuxostat on the progression of renal disease in 5/6 nephrectomy rats with and without hyperuricemia. 
Nephron Physiol 108, 69-78, 2008. 
24. Becker MA, Schumacher HR, Jr., Wortmann RL, MacDonald PA, Eustace D, Palo WA, Streit J, Joseph-Ridge 
N. Febuxostat compared with allopurinol in patients with hyperuricemia and gout. N Engl J Med 353, 2450-
2461, 2005. 
25. Feig DI, Soletsky B, Johnson RJ. Effect of allopurinol on blood pressure of adolescents with newly 
diagnosed essential hypertension: a randomized trial. JAMA 300, 924-932, 2008. 
26. Schumacher HR, Jr., Becker MA, Wortmann RL, MacDonald PA, Hunt B, Streit J, Lademacher C, Joseph-
Ridge N. Effects of febuxostat versus allopurinol and placebo in reducing serum urate in subjects with 
hyperuricemia and gout: a 28-week, phase III, randomized, double-blind, parallel-group trial. Arthritis 
Rheum 59, 1540-1548, 2008. 
27. Noman A, Ang DS, Ogston S, Lang CC, Struthers AD. Effect of high-dose allopurinol on exercise in patients 
with chronic stable angina: a randomised, placebo controlled crossover trial. Lancet 375, 2161-2167, 2010. 
28. Gibson T, Rodgers V, Potter C, Simmonds HA. Allopurinol treatment and its effect on renal function in gout: 
a controlled study. Ann Rheum Dis 41, 59-65, 1982. 
29. Ettinger B, Tang A, Citron JT, Livermore B, Williams T. Randomized trial of allopurinol in the prevention of 
calcium oxalate calculi. N Engl J Med 315, 1386-1389, 1986. 
30. Gaspari F, Perico N, Matalone M, Signorini O, Azzollini N, Mister M, Remuzzi G. Precision of plasma 
clearance of iohexol for estimation of GFR in patients with renal disease. J Am Soc Nephrol 9, 310-313, 
1998. 
31. O'Reilly PH, Brooman PJ, Martin PJ, Pollard AJ, Farah NB, Mason GC. Accuracy and reproducibility of a new 
contrast clearance method for the determination of glomerular filtration rate. Br Med J (Clin Res Ed ) 293, 
234-236, 1986. 
32. Gaspari F, Perico N, Remuzzi G. Measurement of glomerular filtration rate. Kidney Int Suppl 63, S151-S154, 
1997. 
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Gubler MC, Klein R. Renal and retinal effects of enalapril and losartan in type 1 diabetes. N Engl J Med 361, 
40-51, 2009. 
34. Levey AS, Stevens LA, Schmid CH, Zhang YL, Castro AF, III, Feldman HI, Kusek JW, Eggers P, Van LF, 
Greene T, Coresh J. A new equation to estimate glomerular filtration rate. Ann Intern Med 150, 604-612, 
2009. 
35. Stevens LA, Coresh J, Schmid CH, Feldman HI, Froissart M, Kusek J, Rossert J, Van Lente F, Bruce RD, III, 
Zhang YL, Greene T, Levey AS. Estimating GFR using serum cystatin C alone and in combination with 
serum creatinine: a pooled analysis of 3,418 individuals with CKD. Am J Kidney Dis 51, 395-406, 2008. 
36. Lonjou C, Borot N, Sekula P, Ledger N, Thomas L, Halevy S, Naldi L, Bouwes-Bavinck JN, Sidoroff A, de TC, 
Schumacher M, Roujeau JC, Hovnanian A, Mockenhaupt M. A European study of HLA-B in Stevens-Johnson 

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107, 2008. 
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HLA-B58 can help the clinical decision on starting allopurinol in patients with chronic renal insufficiency. 
Nephrol Dial Transplant 26, 3567-3572, 2011. 
38. Carpenter J, Pocock S, Lamm CJ. Coping with missing data in clinical trials: a model-based approach 
applied to asthma trials. Stat Med 21, 1043-1066, 2002. 
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National Institute for Health Research Publication RM03/JH17/MK, 2008. 
40. Laird NM, Ware JH. Random-effects models for longitudinal data. Biometrics 38, 963-974, 1982. 
41. Verbeke, G. & Molenberghs, G. Linear mixed models for longitudinal data 1-568 Springer Verlag, New York, 
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softwareChapman & Hall/CRC Press,(2007). 
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44. Molenberghs, G. & Kenward, M. G. Missing Data in Clinical StudiesWiley & Sons, Inc., New York (2007). 
45. Cohen, J. Statistical power analysis for the behavioral sciencesErlbaum, Hillsdale, NJ (2013). 
46. ICH. Guideline for Good Clincial Practice in International Conference on Harmonisation of Technical 
Requirements for Registration of Pharmaceutical for Human Use.  (1996). 
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Legrand C, Buyse M. A statistical approach to central monitoring of data quality in clinical trials. Clin Trials 
9, 705-713, 2012. 
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333, 1600-1607, 1995. 
 
  

1 
 
 
Summary of Changes to PERL Protocols 
 
NOTE. Version 6 of the protocol (dated December 17, 2013) is the first protocol version under which participants were enrolled in the PERL pivotal 
trial. As such, this version is considered as the “original version” against which subsequent versions are compared.  Protocol versions before v6 were 
for study design purposes only.  
 
# 
Location 
Change 
Rationale 
List of changes to Version 7.0 Amendment 2 July 14, 2014 
p.1 
Title page  
 
Change version and date Version 7.0 Amendment 2 July 14, 2014                         
 
Updates to title page 
 
 
Program Officers  
Teresa Jones, MD 
Division of Diabetes, Endocrinology, & Metabolic Diseases 
NIDDK, National Institutes of Health 
6707 Democracy Blvd. Room 609 
Bethesda, MD   20892-5460 
Phone: (301) 435-2996 
Fax: (301) 480-3503 
jonester@mail.nih.gov 
New Project Officer 
p.3 
General Information 
Sponsor for IND #115313 
Alessandro Doria, MD PhD MPH  
Joslin Diabetes Center and Harvard Medical School 
One Joslin Place 
Boston, MA 02215 
Phone (617) 309-2406 
Fax (617) 309-2667 
alessandro.doria@joslin.harvard.edu 
Identify new Sponsor 
p.3 
Directors of Clinical Sites 
 
Mount Sinai Hospital 
Room L5-210, Mail Box 16 
60 Murray St. 
Toronto, ON 
Canada, M5G 1X5 
Phone: (416) 586-8763 
Fax: (647) 826-1528 
bruce.perkins@mtsinai.ca 
Change of information 

2 
 
# 
Location 
Change 
Rationale 
p.3 
Directors of Clinical Sites 
 
Rodica Pop-Busui, MD PhD 
Associate Professor of Internal Medicine Metabolism, Endocrinology and 
Diabetes 
University of Michigan 
5329 Brehm Tower 
1000 Wall Street 
Ann Arbor MI 48105 
Phone: (734) 763-3056 
rpbusui@umich.edu 
Change of information 
p.4 
Directors of Clinical Sites 
 
Janet McGill, MD 
Washington University School of Medicine 
660 S. Euclid, Campus Box 8127 
St. Louis, MO  63110 
Phone: (314) 362-8681 
Fax: (314) 362-4833 
hmcgill@dom.wustl.edu 
 
New Investigator  
p.4  
Global Clinical 
Coordinator 
Debbie Conboy, RN CDE  
 
Revise listing 
p.6 
PROTOCOL SUMMARY 
Inclusion Criteria 
Criteria 4:                                                                                                                  
Increase upper age limit to 70 years. 
 
 
 
 
 
Criteria 5: 
Increase screening urinary albumin excretion rates [AERs] or albumin 
creatinine ratios [ACRs] 30-5000 mg/24 hr (20-
-5000 mg/g 
range, if not on RASB agents 
OR 
18-5000 mg/24 hr (12-
-5000 mg/g range, if on RASB 
agents  
 
Clarify that creatinine measurement is derived from serum 
Age limit raised to include 
patients diagnosed with T1D at 
an age older than 35, who may 
now be in the study based on 
the previous amendment. 
 
The Steering Committee 
considered 2500 mg/g overly 
restrictive. 
 
 
 
 
 
 
May increase the eligible 

3 
 
# 
Location 
Change 
Rationale 
 
Criteria 6: 
Decrease Estimated GFR (eGFR) based on serum creatinine to between 40 and 
99.9 ml/min/1.73 m2 at screening 
population.  
p.7.  
PROTOCOL SUMMARY 
Exclusion Criteria 
Criteria 9: 
Increase:  SBP>150 or DBP>95 mmHg at the end of the run-in period. 
Raising the BP criterion at the 
end of the run-in period will 
facilitate retention in the study 
p.8 
PROTOCOL SUMMARY 
Study Duration 
Increase:  acceptable BP 140/90 mmHg 
 
p.8 
PROTOCOL SUMMARY 
Date of Protocol 
Change: July  7, 2014 
 
 
p.12 
4. PARTICIPATING 
CENTERS  
 
Increase: in number of centers to nine 
Add: Washington University (St. Louis, MO)  
 
New site assist to enhance 
recruitment 
p.13. 
4. PARTICIPATING 
CENTERS 
4.1 Location of study 
visits 
Delete: (Visit 2 and all the visits including an iohexol-GFR measurement, i.e., 
V4, V11, V16, V17, will always be done “In-person”). 
Delete: Study procedures that require physical interactions (e.g., BP 
measurement) will be carried out at PCPs’ offices, health care facilities, and/or 
clinical laboratories close to where participants live (hereby referred to as 
“Remote Visits”) 
 
Insert: Blood draws and urine collections scheduled at the time of Phone Visits 
will be performed at local facilities close to where participants live (hereby 
referred to as “Remote Biospecimen Collections”).  For any given study visit to 
be conducted remotely, a Phone Visit and a Remote Biospecimen Collection 
will be both required. 
 
Delete: For any given study visit to be conducted remotely, a Phone Visit and a 
Remote Visit will be both required 
 
Insert: Phone Visits and Remote Biospecimen Collections 
 
Insert: Study Site  
 
Delete: for these Remote Visits. 
 

4 
 
# 
Location 
Change 
Rationale 
p.14 
4. PARTICIPATING 
CENTERS 
4.1 Location of study 
visits 
Insert: Following a Phone Visit, participants may be invited to an In-Person 
Visit at the Study Site, at their PCP’s office, or at other local healthcare 
facilities if procedures that require physical interactions are deemed to be 
necessary (e.g., BP measurement to confirm the self-report of elevated BP 
values, physical exam to confirm the self report of skin rash). Sites for remote 
in-person visits will be chosen by the Study Site based on the participant’s 
preference, logistic and financial considerations, and site’s qualifications. Study 
personnel will discuss study requirements with the remote site health providers 
and operators and will provided with written instructions on how to carry out 
the procedures that will be conducted at their locations and report the results to 
the Study Site.   
 
Revised structure of Remote 
Visits  
p.14 
4. PARTICIPATING 
CENTERS 
4.1 Location of study 
visits 
Delete: Remote Visits text as follows 
Remote Visits will be scheduled as close as possible to the 
corresponding Phone Visit and within the same time window as outlined in 
Section 8.1 
Remote Visits will take place only after a signed copy of the ICF has 
been received by the study site (see Point #2 under Phone Visits). 
Sites for Remote Visits will be chosen by the Study Site based on the 
participant’s preference, logistic and financial considerations, and site’s 
qualifications.  More than one remote site may be selected for a given visit if 
different procedures must be carried out at different facilities (e.g., if the PCP 
office and Clinical Laboratory are not part of the same structure or institution). 
Study personnel will discuss study requirements with the remote site 
health providers and operators and will provided be with written instructions on 
how to carry out the study procedures that will be conducted at their locations. 
Procedures that may be carried out at the remote site (PCP’s office, other 
healthcare facilities, clinical laboratories) will include: 
Weight and height measurements. 
Heart rate and blood pressure measurements. 
ECG. 
Physical exam. 
Skin assessment. 
Blood draws for local lab tests (serum creatinine, K, and ALT, CBC, pregnancy 
tests). 
Revised structure of Remote 
Visits 

5 
 
# 
Location 
Change 
Rationale 
Blood draw for central lab tests (serum creatinine, Cystatin C, uric acid, and 
HbA1c). 
Collection of urine samples from first morning voids (Visit 1) or overnight 
collections (Visits 3, 9, 13, and 15).  
Data (#5a-5e above) will be collected on forms provided by the Study Site and 
will be transmitted back to the Site by fax or other secure methods 
p.14 
4. PARTICIPATING 
CENTERS 
4.1 Location of study 
visits 
Insert: Remote Biospecimen Collections 
Local sites for Remote Biospecimen Collections will be chosen by the 
Study Site based on the participant’s preference, logistic and financial 
considerations, and site’s qualifications. 
Revised procedure for Remote 
Visits specimen collection, 
handling and shipping. 
p.15 
4. PARTICIPATING 
CENTERS 
4.1 Location of study 
visits 
Revise: text related to Remote Biospecimen Collection as follows  
Specific instructions will be provided for presentation to the local lab 
sites for specimen collection, handling and tube labeling for specimens 
requiring shipment to the Study Main site Central Laboratory.  Pre-addressed 
shipping containers will also be provided for these Remote Visits along with a 
labeled an inventory sheet for each shipping container will also be provided 
faxing to the Study Main Site or Central Laboratory and inclusion with the 
shipment. 
Blood samples for local lab tests (serum creatinine, K, and ALT, CBC, 
pregnancy tests) will be processed and analyzed at the remote site  facilties 
where samples are collected or shipped to commercial laboratories for testing. 
Results will be transmitted to the Study Site by fax or other secure methods. 
Blood and urine samples for central lab tests (serum creatinine, Cystatin 
C, uric acid, HbA1c, urinary ACR and AER) will be mailed by the Remote Site 
to the Central Lab a commercial lab or to the Main Study Site where they will 
be processed, aliquoted, and forwarded to the Central Lab.  Blood tubes and 
urine containers will be provided by the Study Site. 
 
Revised procedure for specimen 
of Remote Visits collection, 
handling, shipping. 
p.15 
5. SUBJECT 
SELECTION 
Inclusion Criteria  
Text revised to be consistent with changes identified in the Protocol Summary 
Subject Population Inclusion Criteria 
Consistency 
p.16 
5. SUBJECT 
SELECTION 
Exclusion Criteria 
Text revised to be consistent with changes identified in the Protocol Summary 
Subject Population Exclusion Criteria  
Consistency 
p.20 
7. STUDY OUTCOMES   Correct spelling:  insulin  
 

6 
 
# 
Location 
Change 
Rationale 
7.1. Primary outcome 
 
p.23-
24 
8. STUDY 
PROCEDURES Figure 1.  
Schedule of Events 
Revised to reflect protocol changes in study evaluations and footnotes  
The schedule has been revised 
to incorporate the protocol 
changes. 
 
p.25 
8. STUDY 
PROCEDURES 
8.2 Screening and 
Enrollment in the Run-in 
Period (Visit 1) 
Revised text: 
Subjects who have a confirmed history of micro- or macroalbuminuria (at least 
two out of three consecutive urinary AER or ACR in micro- or 
macroalbuminuria range as defined in Section 5.1) will not need to bring a 
sample of urine to Visit 1 (if the evidence of micro- or macroalbuminuria dates 
back to more than two years before screening, evidence of ongoing GFR 
decline should be gathered, see Section 5.1). Subjects who have incomplete 
evidence of micro- or macroalbuminuria (one of the last two urinary AER or 
ACR in the micro- or macroalbuminuria range), 
 
p.25-
26 
8. STUDY 
PROCEDURES 
8.3 Screening and 
Enrollment in the Run-in 
Period (Visits 2,3,4) 
RAS antagonist treatment will be standardized, and BP, if elevated (>1430/90 
mm Hg), normalized.  Letters will be written to the participants’ physicians 
informing them about the study and notifying them of the study's protocol RAS 
blocker requirements and blood pressure goals. The letter will propose active 
participation of the participants’ physicians in blood pressure management with 
the availability of advice from the PERL site physicians and, if needed, the 
PERL Drug monitoring Committee for out of range blood pressure values 
during the course of the study. Letters will be written to the participants’ 
physicians informing them about the study and notifying them that study 
physicians will be assuming control of the participants’ antihypertensive 
therapy.  The run-in period will start at Visit 2.  If a participant is already on a 
RAS Blocker, its dose will be increased adjusted, if necessary, to make it at 
least equivalent to ramipril 10 mg (if on ACE inhibitor [ACEI]) or irbesartan 
300 mg (if on an angiotensin receptor blocker [ARB]), if acceptable to the 
patient’s primary physician, if tolerated and if not contraindicated (see 
below).  Participants who were not taking a RAS Blocker will be prescribed and 
instructed to start taking 10 mg of ramipril daily or 300 mg of irbesartan daily 
(if ramipril is contraindicated or has side effects) or another ACE inhibitor or 
ARB at equivalent doses if there are impediments to the use of ramipril or 
irbesartan. Participants who have contraindications to RAS blockers (e.g., 
Antihypertensive therapy 
should now be managed jointly 
by the study physicians and the 
participants’ personal 
physicians. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

7 
 
# 
Location 
Change 
Rationale 
SBP<100 mmHg, K+>5.5 mEq) or are normoalbuminuric and normotensive 
and are not currently treated with RAS blockers, will not be treated with these 
drugs, as this represents the standard of care.  
p26-27 
8. STUDY 
PROCEDURES 
8.3 Screening and 
Enrollment in the Run-in 
Period (Visits 2,3,4) 
Revised text:  
If BP is found to be elevated (>1430/980 mm Hg) on three consecutive 
occasions, the dosage of existing non-RAS antagonists antihypertensive drugs 
will be maximized, followed, if necessary, by the introduction of 
antihypertensive drugs of a different class. These will be chosen by the study 
site physicians in collaboration with the other health care providers that are 
involved in managing the participant’s anti-hypertensive therapy. from a 
restricted menu of approved medications at recommended dosage, following the 
general protocol that was used in RASS33.  The same menu and protocol will 
be used to start antihypertensive treatment in participants who have persistently 
high BP levels and were not on antihypertensive therapy prior to study entry.  If 
the goal of BP (>1430/980 mm Hg) is not achieved with these drugs, a Drug 
Monitoring Committee conference call will be convened to consider the 
possibility of causes of hypertension other than diabetic nephropathy and 
discuss alternative therapeutic approaches.  BP will continue to be monitored 
and the anti-hypertensive therapy to be adjusted in a similar way throughout the 
study.      
 
Revised Visit Procedures list:  
After 2 weeks of run-in, participants will come in for Visit 3 during which they 
will undergo the following procedures: 
Review RASB and adjust BP therapy. 
Measure weight and vital signs. 
After 6 weeks of run-in, participants will come in for Visit 4 during which they 
will undergo the following procedures: 
Review RASB and adjust BP therapy 
If normal blood pressure control is not achieved at Visit 4, the run-in period 
may be extended for two more weeks after which participants will be examined 
as in Visit 4 (Visit 4A).  In this event, the GFR measurement scheduled for 
Visit 4 will be conducted at Visit 4A.  Participants whose SBP is >15040 or 
whose DBP is >9590 mmHg at the end of the run-in period will be discontinued 
from the study (prior to randomization). 
 
Antihypertensive therapy 
should now be managed jointly 
by the study physicians and the 
participants’ personal 
physicians. 
 
 
 
 
 
 
 
 
 
 
The procedure schedule has 
been revised to incorporate the 
protocol changes. 
 

8 
 
# 
Location 
Change 
Rationale 
p.28 
8. STUDY 
PROCEDURES 
8.5 Treatment Period 
(Visits 6-15)  
Revise procedures list: 
Obtain interval medical history (with special emphasis on BP control and CVD 
events). 
Review of concomitant medications and AEs.   
Review and adjust RASB and BP therapy. 
Measure height,  (Visits  and 11) weight, and vital signs according to the 
schedule outlined in Figure 1 
Inspect for skin rash  (Visit 11) 
The procedure schedule has 
been revised to incorporate the 
protocol changes. 
p.28  
8. STUDY 
PROCEDURES 
8.6  End of Intervention 
(Visit 16)  
Revise procedure list:  
Review RASB and adjust BP therapy. 
 
  
The procedure schedule has 
been revised to incorporate the 
protocol changes. 
 
p.30 
9. SAFETY 
ASSESSMENTS 
9.2 Skin Exam 
Revised text: 
At each visit study on and after Visit 4, The skin of study participants will be 
examined for the presence of any kind of rash at each in-person visit.  
Participants will be instructed to carry-out periodical skin self-exams. If skin 
abnormalities are reported to the study personnel during the phone visits or on 
any other occasion, participants will be asked to immediately report to the study 
site, their PCP’s office, or other local healthcare facilities for an in-person skin 
exam. 
Reflect change in remote visit 
schedule. 
p.30 
9. SAFETY 
ASSESSMENTS 
9.3 Vital Signs 
Revised text: 
Blood pressure and heart rate will be recorded at each in-person visit.  BP 
readings at home will be reviewed during each phone visits; if abnormal values 
are reported, participants will be asked to visit the study site, their PCP’s office, 
or other local healthcare facilities to have their BP measured 
Antihypertensive therapy 
should now be managed jointly 
by the study physicians and the 
participants’ personal 
physicians 
p.42 
13.  PROTECTION OF 
HUMAN SUBJECTS 
13.5.b.k. Procedures for 
protecting against and 
minimizing potential risks   
b. Specific 
 
 
Revised text: 
Blood pressure will be measured quarterly with the goal of maintaining BP 
≤130140mmHg systolic and ≤8590 mmHg diastolic. If elevated, a recheck will 
be performed within 2 weeks and if still elevated additional antihypertensive 
non-RAS blockers will be added in collaboration with the participants’ 
physicians from a limited menu of agents as prescribed in the MOO.  Failure to 
achieve satisfactory BP control within 2 months would lead to a Drug 
Monitoring Committee conference call. The patient’s physicians would be 
asked to relinquish BP management to PERL personnel in order to achieve 
uniformity of goals, but the patient’s physicians would be informed of any BP 
Reflects change related to 
acceptable BP level 

9 
 
# 
Location 
Change 
Rationale 
medication changes. 
List of Changes in PERL Protocol Version 8.0 November 18, 2014 
p.1 
Title page  
 
Change version and date Version 8.0 Approved by the DSMB November 18, 2014       
 
Version date changed to date of 
DSMB approval 
p.2-4 
Table of Contents  
Page numbers 8-49 changed 
Page numbers shifted. 
p.7 
Directors of Clinical Sites 
Ronald J. Sigal, MD, MPH 
Cumming School of Medicine, University of Calgary 
1820 Richmond Road SW 
Calgary, Alberta, Canada T2T 5C7 
Phone: (403) 955-8327 
Fax: (403) 955-8249 
rsigal@ucalgary.ca 
New Investigator 
p.7 
Directors of Clinical Sites 
 
Peter Senior, MD 
Alberta Diabetes Institute 
2-004 Li Ka Shing Center for Health Research Innovation 
Edmonton, Alberta, Canada T6G2E1 
Phone: (780) 407-1480 
Fax: (780) 492-9555 
petersenior@ualberta.ca 
New Investigator 
p.7-8 
Directors of Clinical Sites 
 
Guillermo E. Umpierrez, MD 
Emory University School of Medicine 
101 Wodruff Circle, 1st Floor, RM 1311 
Atlanta, GA 30322 
Phone: (404) 778-1663 
geumpie@emory.edu 
New Investigator 
p.8 
Directors of Clinical Sites 
 
Irl B. Hirsch, MD 
University of Washington Medical Center – Roosevelt 
4245 Roosevelt Way, NE, 3rd floor, Box 354691 
Seattle, WA  98105 
Phone:  (206) 598-4884 
Fax:  (202) 598-4976 
ihirsch@uw.edu 
New Investigator  
p.9  
PROTOCOL SUMMARY 
Subject Population  
Inclusion/Exclusion Criteria 
Revised Text: 
The upper and the lower limits should be decreased by 1 ml/min/1.73 m2 for each 
year over age 60 (with a lower limit of 35 ml/min/1.73m2) and by 10 ml/min/1.73 m2 
for strict vegans. 
Change in Inclusion criteria to 
reflect changes of eGFR with age 

10 
 
# 
Location 
Change 
Rationale 
 
p.11 
PROTOCOL SUMMARY 
Study Duration 
Revised Text: 
9-week run-in period, during which RAS inhibition will be introduced and/or 
standardized, if indicated, and BP normalized, if elevated above 140/90 mmHg, 
followed by a 3-year treatment period and then by a 2-month wash-out period. 
 
Modification of visit schedule to 
acknowledge that some patients 
enter without the need for RAS 
treatment 
p.11 
PROTOCOL SUMMARY 
Date of Protocol 
Revised Text: 
November 18. 2014 
Date approved by DSMB 
p.16 
Participating centers 
New Text: 
University of Calgary (Calgary, Alberta, Canada) 
Alberta Diabetes Institute (Edmonton, Alberta, Canada) 
Emory University (Atlanta) 
University of Washington Medical Center (Seattle) 
New sites added to enhance 
recruitment 
p.18 
5. SUBJECT SELECTION 
Inclusion Criteria 
Revised Text: 
The upper and the lower limits should be decreased by 1 ml/min/1.73 m2 for each 
year over age 60 (with a lower limit of 35 ml/min/1.73m2) and by 10 ml/min/1.73 m2 
for strict vegans. 
Change in inclusion criteria to 
reflect changes of eGFR with age 
p.22 
6. STUDY TREATMENTS 
6.1.2  Dosage 
New text: 
4. At some sites the study medication may be dispensed directly to the study 
participant at a relevant in person study visit or by mail from the site following a 
relevant in-person or phone study visit. 
Change in study medication 
dispensing 
p.26 
8. STUDY PROCEDURES  
Figure 1.  Schedule of 
Events 
Revised Figure 1:                                                                                                                  
To reflect protocol changes in study evaluations and footnotes  
The schedule has been revised to 
incorporate the protocol changes. 
 
p.27 
8. STUDY PROCEDURES 
8.3 Run-in Period (visits 2, 3 
and 4) 
Revised Text: 
Starting at Visit 2, eligible subjects who agree to participate in the study will enter a 
run-in period of 9 weeks (see note at the end of this section for exceptions to this 
duration).  During this visit, subjects will undergo the following procedures: 
Reference to modification of 
number of run-in study visits  and 
consequent duration of run-in 
period 
p.28 
8. STUDY PROCEDURES 
8.3 Run-in Period (visits 2, 3 
and 4) 
Revised Text: 
RAS antagonist treatment will be standardized, and BP, if elevated (>140/90 mm Hg), 
normalized.  Letters will be written to the participants’ physicians informing them 
about the study and notifying them of the study's protocol RAS blocker requirements 
and blood pressure goals. The letter will propose active participation of the 
Further clarify the use of anti-
hypertensive therapy 

11 
 
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participants’ physicians in blood pressure management with the availability of advice 
from the PERL site physicians and, if needed, the PERL Drug monitoring Committee 
for out of range blood pressure values during the course of the study. The run-in period 
will start at Visit 2.  If a participant is already on a RAS Blocker, its dose will be 
increased, if necessary, to make it at least equivalent to ramipril 10 mg (if on ACE 
inhibitor [ACEI]) or irbesartan 300 mg (if on an angiotensin receptor blocker [ARB]), 
if acceptable to the patient’s primary physician, if tolerated and if not contraindicated 
(see below).  Participants who were not taking a RAS Blocker will be prescribed and 
instructed to start taking 10 mg of ramipril daily or 300 mg of irbesartan daily (if 
ramipril is contraindicated or has side effects) or another ACE inhibitor or ARB at 
equivalent doses if there are impediments to the use of ramipril or irbesartan. 
Participants who have contraindications to RAS blockers (e.g., SBP<100 mmHg, 
K+>5.5 mEq) or do not have evidence or history of micro- or macroalbuminuria 
(as defined in 5.1.4), are normotensive, and are not being treated with RASB or 
other anti-hypertensive agents will not be treated with these drugs, as this represents 
the standard of care. 
 
p.28 
8. STUDY PROCEDURES 
8.3 Run-in Period (visits 2, 3 
and 4) 
Revised Text: 
After 2 weeks of run-in, participants will come in for Visit 3 during which they will 
undergo the following procedures: 
Obtain interval medical history (with special emphasis on CVD events). 
Review concomitant medications and AEs 
Review RASB and BP therapy. 
Collect samples for clinical laboratory assessments as outlined in Figure 1. 
Perform pregnancy test in women of childbearing potential. 
Be provided with a container and instructions for an overnight urine 
collection to be made immediately before Visit 4. 
 
Delete Text: 
(including HLA B*58.01) in collection of samples for clinical laboratory assessments 
procedures list  
Modification of visit procedure 
list, to exclude collection of HLA 
B*58.01 at this visit 
p.29 
8. STUDY PROCEDURES 
8.3 Run-in Period (visits 2, 3 
and 4) 
Revised Text: 
After 6 weeks of run-in, participants will come in for Visit 4 during which they will 
undergo the following procedures: 
• 
Obtain interval medical history (with special emphasis on CVD events). 
• 
Conduct a physical exam (if deemed to be required by the study physician) 
• 
Review concomitant medications and AEs 
• 
Review BP therapy. 
Modification of visit procedure list 
to include collection of HLA 
B*58.01 

12 
 
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• 
Review the fetal risks of RAS blockade.  
• 
Measure height, weight and vital signs. 
• 
Perform ECG. 
• 
Collect samples for clinical laboratory assessments (including HLA B*58:01)   
as outlined in Figure 1. 
• 
Perform pregnancy test in women of childbearing potential. 
• 
Measure iohexol GFR. 
 
p.29 
8. STUDY PROCEDURES 
8.3 Run-in Period (visits 2, 3 
and 4) 
New Text: 
If normal blood pressure control is not achieved at Visit 4, the run-in period may be 
extended for two more weeks after which participants will be examined as in Visit 4 
(Visit 4A).  In this event, the GFR measurement scheduled for Visit 4 will be 
conducted at Visit 4A.  Participants whose SBP is >150 or whose DBP is >95 mmHg 
at the end of the run-in period will be discontinued from the study (prior to 
randomization). 
 
IMPORTANT: Visit 2 and Visit 3 can be skipped, i.e., a participant can move 
directly from Visit 1 to Visit 4, if the following criteria are met at Visit 1: 
The participant is eligible based on the results of Visit 1 assessments, including 
laboratory values; 
Blood pressure is <140/90 mmHg; 
AND 
The participant meets one of the following criteria: 
Has been treated with a RASB for at least two months at a dose at least equivalent 
to Ramipril 10 mg or Irbesartan 300 mg;  
Has contraindications to RASB; 
Does not have evidence or history of micro- or macroalbuminuria (as defined in 
5.1.4) and is not being treated with RASB or other anti-hypertensive agents. 
If the above criteria are met and Visits 2 and 3 are skipped, Visit 4 will be 
scheduled 3 weeks after Visit 1 with a window of 2 weeks before and 3 weeks after 
the target date. The collection of medical history and the physical exam scheduled 
at Visit 2 will be conducted at Visit 4. 
 
Modification of visit schedule to 
reduce number of run-in study 
visits  and consequent duration 
of run-in period for participants 
who qualify 
p.29 
8. STUDY PROCEDURES 
8.4. Enrollment in the Study 
and Randomization (Visit 5) 
Revised Text: 
• 
At the end of the run-in period, eligibility will be re-assessed based on the BP 
measures obtained at Visits 4 or 4A (if applicable), HLA-based genetic susceptibility 
to allopurinol skin reactions36,37 (tested at Visit 4), and a valid baseline iGFR 
measurement.  Participants who are eligible for randomization based on those 
measures (SBP ≤ 150 and DBP ≤95 mmHg) and a negative HLA B*58:01 test will be 
Modification of visit schedule 
 
 
 
 
 

13 
 
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telephoned by the study coordinator to discuss how the study medication should be 
taken and its potential side effects. 
 
Deleted Text: 
(tested at vVisit 3) 
 
 
 
 
 
P.30 
8. STUDY PROCEDURES 
8.5. Treatment Period (Visits 
6 to 15) 
Revised Text: 
During the treatment period, the following procedures will be completed at each visit 
for each participant: 
Obtain interval medical history (with special emphasis on BP control and CVD 
events). 
Review of concomitant medications and AEs.   
Review RASB and BP therapy. 
Measure height, weight, and vital signs according to the schedule outlined in Figure 1 
Inspect for skin rash. (Visit 11) 
Conduct a physical exam (Visit 11). 
Perform ECG according to the schedule outlined in Figure 1 (Visit 11). 
Collect samples for clinical laboratory assessments and for storage of serum, plasma 
and urine for later biomarker research according to the schedule outlined in Figure 1. 
Perform pregnancy test in women of childbearing potential. 
Measure GFR by means of plasma disappearance of non-radioactive iohexol, iGFR at 
Visit 11.  
Provide a container and instructions for an overnight urine collection whenever an 
AER measurement is scheduled at the following visit. 
Modification of visit procedure list 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
P.30 
8. STUDY PROCEDURES 
8.5. Treatment Period (Visits 
6 to 15) 
New Text: 
At some sites the study medication may be dispensed directly to the study 
participant at a relevant in person study visit or by mail from the site following a 
relevant in-person or phone study visit. 
 
Modification of study drug 
dispensing 
P.33 
10. ADVERSE EVENT 
REPORTING 
10.1. Definitions 
New Text: 
An Adverse Event (AE) is any untoward medical occurrence in a study participant 
regardless of its relationship to study treatment.  A treatment-emergent AE is an 
adverse event occurring during the period between the first dose and 30 days after the 
final dose of the study medication. A Serious Adverse Event (SAE) is any untoward 
medical occurrence that results in death, is life-threatening, requires hospitalization or 
prolongation of an existing hospitalization, results in persistent or significant disability, 
Clarification of the AE reporting 
period 

14 
 
# 
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Change 
Rationale 
or is a congenital anomaly/birth defect.  Important medical events that do not fall into 
the above categories may also be considered an SAE when, based on medical 
judgment, such events may jeopardize the patient’s safety and require medical/surgical 
intervention to prevent one of the outcomes listed in the SAE definition.  The term 
SAE is not intended as a measure of severity or intensity. All AE’s/SAE’s that occur 
after the time of informed consent will be reported. 
P.33 
10. ADVERSE EVENT 
REPORTING 
10.2 Adverse Event 
Reporting 
Revised Text: 
All AEs will be reported on the Adverse Events form that will be completed by the 
study staff, who are masked as to study treatment assignment, at each regular follow-
up visits.  This will insure that AEs are ascertained in an unbiased manner using the 
same standardized methodology for participants in both treatment arms.  Forms will 
include standardized questions relating to specific events of import in diabetic patients 
on either of the study treatment arms as well as any significantly abnormal physical 
finding identified on examination and any significantly abnormal laboratory results 
obtained on the patient between visits or at the time of the visit.  AEs reported or 
ascertained between clinic visits will be captured and reported at the time of the next 
schedule visit.  Pre-existing conditions (that is, any conditions that was known to be 
present prior to  the signing of informed consent or was identified during the 
screening procedures at Visit 1) will not be considered or recorded as AEs unless the 
condition worsens in intensity or frequency after Visit 1.  Likewise, continuing AEs 
will not be reported as AEs at subsequent visits unless they increase in severity or 
frequency between visits, they results in criteria for a SAEs, and/or they resolve 
between visits.  Each site will be responsible for reporting all AE's to their IRB 
according to its AE reporting policy and procedures 
Clarification of AE’s 
p.46 
14. DATA AND SAFETY 
MONITORING PLAN      
2. IRB Monitoring 
New Text: 
• 
Joslin Diabetes Center 
• 
University of Minnesota 
• 
University of Colorado 
• 
University of Michigan 
• 
Northwestern University 
• 
University of Toronto 
• 
Albert Einstein University 
• 
Washington University 
• 
Steno Diabetes Center 
• 
University of Calgary 
• 
Alberta Diabetes Institute 
• 
Emory University 
• 
University of Washington 
 
New clinical sites 

15 
 
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p.47 
15. STUDY 
ADMINISTRATION             
15.1. Organization 
 
Revised Text: 
 
The Steering Committee is responsible for the design of the study and provides 
guidance to its execution.  Members are the co-Chairs of the PERL Consortium (Drs. 
Mauer and Doria), the Directors of the Clinical Sites (Drs. Caramori, Goldfine, Maahs, 
Perkins, Pop-Busui, Molitch, Crandall, Rossing, Sigal, Senior, Umpierrez and 
Hirsh), the Directors of the Data Coordinating Center (Drs. Galecki and Spino), and 
the Director of the Central Laboratory (Dr. Eckfeldt), the NIH program officers (Drs. 
Jones and Flessner), and the JDRF program officer (Dr. Nickerson). 
 
Revised Text: 
The Clinical Sites are located at the Joslin Diabetes Center, the University of 
Minnesota, the University of Colorado (Barbara Davis Center for Childhood Diabetes), 
the University of Michigan, Northwestern University, Albert Einstein College of 
Medicine, Washington University (St. Louis), the University of Toronto the Steno 
Diabetes Center (Denmark), the University of Calgary (Calgary, Alberta, Canada), 
Alberta Diabetes Institute (Edmonton, Alberta, Canada), Emory University and 
the University of Washington Medical Center (Seattle) are responsible for 
recruiting study participants and implementing the protocol. 
 
New site directors added 
 
 
 
 
 
 
 
 
 
New clinical sites added 
List of Changes in PERL Protocol Version 9.0 August 16, 2016 
p.1 
Title page  
 
Change version and date Version 9.0 Approved by the DSMB August 16, 2016            
 
Version date changed to date of 
DSMB approval 
p.2-4 
Table of Contents  
Page numbers 8-49 changed 
Page numbers shifted. 
p.5 
Program Officers 
Revised Text: 
Marlon Pragnell, PhD 
Senior Scientist, Translational Development 
Juvenile Diabetes Research Foundation 
26 Broadway 
New York, NY 10004 
Phone: (212) 479-7690 
Fax: (212) 785-9609 
mpragnell@jdrf.org  
 
Deleted Text: 
Helen Nickerson 
Scientific Program Manager: Complications 
Hnicjerson 
New Program Officer 

16 
 
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p.6 
Directors of Clinical Sites 
Revised Text: 
Sarit Polsky, MD, MPH 
Barbara Davis Center for Diabetes  
University of Colorado at Denver - Anschutz Medical Campus  
1775 Aurora Court, Mail Stop A140  
Aurora, CO 80045 P 
Phone: (303) 724-8575 
Fax: (303) 724-6784 
sarit.polsky@ucdenver.edu  
 
Deleted Text: 
David Maahs PhD 
david.maahs@ucdenver.edu 
New Investigator 
p.6-7 
Directors of Clinical Sites 
 
New Text: 
Ronnie Aronson, MD 
LMC Diabetes and Endocrinology 
1929 Bayview Avenue, Suite 107 
Toronto, ON Canada M4G 3E8 
Ph: (416) 646-2929 
Fax: (416) 645-2930 
Email: Ronnie.Aronson@LMC.CA 
Additional Investigator 
p.8 
Directors of Clinical Sites 
 
New Text: 
Ildiko Lingvay, MD, MPH, MSCS 
University of Texas Southwestern Medical Center  
5323 Harry Hines Blvd., U9.134E  
Dallas, TX 75390-9302  
Phone: (214) 648-2779 
Fax: (214) 648-2885 
ildiko.lingvay@utsouthwestern.edu 
New Investigator 
p.8 
Directors of Clinical Sites 
 
New Text: 
Katherine R. Tuttle, MD 
Providence Medical Research Center  
104 W. 5th Avenue, Suite 350E  
Spokane, WA 99204  
Phone: (509) 474-4345 
Fax: (509) 474-4325 
katherine.tuttle@providence.org 
New Investigator 

17 
 
# 
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p.8 
Directors of Clinical Sites 
 
New Text: 
Tom Elliott MBBS, FRCPC 
BC Diabetes  
4102-2775 Laurel Street  
Vancouver, BC V5Z 1M9  
Phone: (604) 683-3734 ext. 1001  
Fax: (604) 628-3821 
telliott@bcdiabetes.ca 
New Investigator  
p.9 
Central Laboratory 
Revised Text: 
Advanced Research and Diagnostics Laboratory 
Director:  Amy Karger, MD, PhD  
University of Minnesota  
Mayo Mail Code 609, Room Mayo D211  
420 Delaware Street, SE  
Minneapolis, MN 55455  
Ph: (612) 624-2150 
Fax: (612) 625-1121 
karge026@umn.edu 
 
Deleted Text: 
John Eckfeldt 
New Director 
p.10 
PROTOCOL SUMMARY 
Participating centers 
New Text: 
University of Washington (Seattle)  
University of Calgary (Calgary)  
University of Alberta (Edmonton)  
Emory University (Atlanta)  
Washington University (St. Louis)  
University of Texas Southwestern (Dallas)  
Providence Medical Research Center (Spokane)  
BC Diabetes (Vancouver).   
New sites added to enhance 
recruitment 
p.12 
PROTOCOL SUMMARY 
Statistical methods 
Revised Text: 
The majority of data analyses, including the primary analysis, will be performed 
according to an intention-to-treat approach.   
Change in the analysis plan 
p.12 
PROTOCOL SUMMARY 
Date of Protocol 
Revised Text: 
July 13, 2016 
Date approved by DSMB 
 
 
 
 

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p.15 
1. INTRODUCTION 
 
Revised Text: 
It is very important to note that, in that study, the UA levels shortly after the onset of 
T1D was a significant independent predictor of macroalbuminuria 18 years later 
(hazard ratio 1.90 per mg/dl increase in UA level; p=0.04)11, this being suggestive of 
a pathogenetic role. 
Grammar clarification 
p.16 
1. INTRODUCTION 
 
New text: 
To test this hypothesis, we have established a consortium of investigators from 
academic centers where large rosters of T1D patients are available along with long-
standing expertise in the study of diabetic complications, especially DN, and in DN 
clinical trials. Included in this initiative are the Joslin Diabetes Center, the Universities 
of Minnesota, Colorado, Toronto, Michigan, Washington (Seattle), Texas 
Southwestern, Calgary, and Alberta Northwestern University, Washington 
University (St. Louis), Emory University, Albert Einstein College of Medicine, BC 
Diabetes, Providence Medical Research Center, and the Steno Diabetes Center in 
Copenhagen, Denmark. The Consortium, led by Dr. Alessandro Doria from the Joslin 
Kidney Study, and by Dr. Michael Mauer, who recently led the Renin Angiotensin 
System Study (RASS) clinical trial, has been named PERL (Preventing Early Renal 
Function Loss in Diabetes) to emphasize the Consortium’s focus on intervening early 
in the course of kidney disease, when renal damage is most likely to be able to be 
arrested or reversed and interventions are more likely to be effective. 
Addition of new centers 
p.16-17 
4. PARTICIPATING 
CENTERS 
Revised /New Text:                                                                                        
The study will involve 16 centers that are part of the PERL Consortium: 
Joslin Diabetes Center (Boston) 
University of Minnesota (Minneapolis) 
University of Colorado (Barbara Davis Center for Childhood Diabetes, 
Denver) 
University of Michigan (Ann Arbor) 
University of Toronto (Toronto) 
Northwestern University (Chicago) 
Albert Einstein College of Medicine (New York) 
Steno Diabetes Center (Copenhagen, Denmark) 
Washington University (St. Louis, MO)  
University of Calgary (Calgary, Alberta, Canada) 
University of Alberta (Edmonton, Alberta, Canada) 
Emory University (Atlanta) 
University of Washington (Seattle) 
University of Texas Soutwestern (Dallas) 
Providence Medical Research Center (Spokane) 
This section has been revised to 
update the number of sites, add 
new sites and clarification of the 
name of an existing center for 
consistency 
 

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BC Diabetes (Vancouver) 
  
p.18 
4. PARTICIPATING 
CENTERS 
4.1 Location of Study Visits 
New Text: 
• 
Blood samples for local lab tests (serum creatinine, K, and ALT, CBC, 
pregnancy tests) will be processed and analyzed at the facilities where samples are 
collected or shipped to commercial laboratories or to the Central Laboratory for 
testing. Results will be transmitted to the Study Site by fax or other secure methods. 
Reflects the ability of the Central 
Laboratory to analyze remote local 
lab specimens, in the event a lab in 
the subject’s local area is unable to 
be identified. 
p.21 
5. SUBJECT SELECTION 
5.5.1 Reasons for 
discontinuation 
Revised Text: 
The study drug will be temporarily discontinued if a participant: 
Has clinically significant persistent changes from baseline based on laboratory 
safety assessment results (the response to discontinuation will be monitored to assess 
whether the drug can be re-instituted, see next paragraph on permanent 
discontinuations).  
Requires treatment with allopurinol or medications that make allopurinol 
contraindicated (see 5.5.2 and 9.5). 
Becomes pregnant or breastfeeding (see 5.5.2)   
Whenever the reason for temporary discontinuation of the study drug ceases to 
exist, the study medication will be resumed with the consensus of the drug 
monitoring committee, according to the following procedures: 
If the study medication was discontinued because of a suspected drug reaction or 
the participant was off-medication for 3 months or longer, the study drug will be 
re-started at a dosage of 100 mg for 4 weeks, which will then be increased to the 
full dosage appropriate for the eGFR. (see 6.1.2)  
If the study medication was not discontinued because of a drug reaction and the 
participant was off-medication for less than 3 months, the study medication will 
be re-started, at the full dosage appropriate for the eGFR.  
The study drug will be permanently discontinued if a participant: 
Experiences an SAE related to the study drug or an intolerable AE such as a 
persistent allergy or rash. 
Has clinically significant persistent changes from baseline based on laboratory 
safety assessment results which do not respond to temporary 2-week discontinuation of 
study drug and re-institution of drug at ½ of the initial dose. 
Develops end-stage renal disease (eGFR ≤15 ml/min/1.73 m2, institution of 
chronic dialysis treatment or kidney transplantation) or iGFR decreases by 50% from 
one measurement to the next or serum creatinine levels double over any 12-month 
interval in the post-randomization period.  If these renal function changes prove to 
be temporary, the study medication could be resumed as described above with the 
consensus of the drug monitoring committee. 
Further clarify the resuming of 
study drug after discontinuation 

20 
 
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p.23 
6. STUDY TREATMENTS 
6.1.2. Dosage 
Revised Text: 
All participants, whether they are randomized to allopurinol or placebo, will be given 
four tablets per day to be taken orally following breakfast.  Tablets will be provided in 
four vials (A, B, C, and D) or in blister packs, in which each blister contains the 
four tablets for a given day. If the medication is provided in bottles, participants 
randomized to allopurinol will receive a dosage of 100 mg as a 100 mg tablet (from 
vial A) plus three placebo tablets (from vials B, C, D), 200 mg as two 100 mg (from 
vials A and C) and two placebo tablets (from vials B and D), 300 mg as three 100 mg 
(from vials A, B, C) and one placebo tablet (from vial D), 400 mg as four 100 mg 
tablets (from vials A, B, C, D). Subjects randomized to placebo will be given four 
placebo tablets (from vials A, B, C, D). If the medication is provided in blister 
packs, each blister will contain the four tablets for a given day, with the same 
proportion of active and placebo tablets described above for each allopurinol 
dosage and for placebo. 
The dose adjustment will be carried out as follows: 
At each follow-up visit, a study drug requisition will be sent by the clinical site 
to the research pharmacy indicating the study ID, name, and address of the participant, 
the most recent eGFR value (CKD-EPI), calculated using a recent local lab creatinine 
value, and the number of days to be covered by the drug supply.  
At the pharmacy, a clinical pharmacist will determine the allopurinol dose 
(ranging from 0 to 400 mg) that should be given at that time according to the study 
protocol given the participant’s treatment assignment and the most recent eGFR value 
(CKD-EPI) calculated using a recent local lab serum creatinine value. 
The research pharmacy will mail the new batch of study medication directly to 
the study participant.  
At some sites the study medication may be dispensed directly to the study 
participant at a relevant in person study visit or by mail from the site following a 
relevant in-person or phone study visit. 
Participants will be instructed to immediately inform the clinical site upon 
receipt of the new tablets and mail the pill bottles or blister packs with the tablets 
remaining from the previous prescription in a provided pre-addressed mailer, to the 
clinical site for drug accounting and compliance assessment. 
Addition of ability to provide 
study medication in blister packs 

21 
 
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p.23-24 
6. STUDY TREATMENTS 
6.1.3. Compliance and 
Accountability 
Revised Text: 
Skills will be taught and reinforced at each visit with regard to scheduling and 
administration of pills at home and while traveling.  Methods (e.g. record-keeping) will 
be taught to help participants monitor tablet usage and enhance compliance. To 
complement the regular compliance interventions at the scheduled visits, study 
information and motivational materials (postcards, newsletters, etc.) will be mailed. In 
addition, at midpoint between clinic visits, participants will be phoned by the clinic 
staff to review pill-taking. Patients will be provided with random but known numbers 
of excess medications, providing extras in case of pill loss. Adherence will be 
monitored by instructing participants to expect extra pills and to mail the pill bottles or 
the blister packs with the tablets remaining from the previous prescription to the study 
center upon receipt of a new batch of tablets. The number of extra pills included in 
each supply of medications will be decided by the pharmacist, who will keep a record 
of it and will transmit this information to the Study Site.  Personnel at the Study Site 
will enter this information in the appropriate electronic Case Report Form along with 
the expected number of pills used during the period covered by the supply and the 
number of unused pills returned by the participant.  These data will be used to analyze 
compliance. If poor adherence is noticed, measures will be taken to increase 
compliance, such as explaining the purpose of the study again, providing pill 
reminders, and more frequently contacting the study subject by phone. Participants at 
each visit will be asked about their perceived compliance and about any difficulties 
with taking the study medications, but the individualized strategies to improve 
compliance will not be openly linked to the pill counts, i.e. participants will not be 
informed of the results of pill counting. Participants showing poor compliance will not 
be withdrawn from the study. 
Addition of ability to provide 
study medication in blister packs 
p.26 
8. STUDY PROCEDURES 
8.1. Schedule of Events 
New Text: 
Outcome variables (plasma iohexol, serum creatinine and cystatin C, urinary AER), 
HbA1c, and serum uric acid will be measured by the Central Laboratory at the 
University of Minnesota, directed by Dr. Amy Karger 
 
Deleted Text: 
John Eckfeldt 
Adding new central lab director 
p.29 
8. STUDY PROCEDURES 
8.1. Schedule of Events 
Revised Text: 
Note:  (x) indicates an optional assessment; For “BP and Measurements”, (x) 
indicates an optional assessment only if the patient is NOT seen in-person. 
Clarification as to when the BP 
measurement is truly optional 
P.31 
8. STUDY PROCEDURES 
8.5. Treatment Period (Visits 
6 to 15) 
Revised Text: 
In the days immediately after each visit, upon completion of serum creatinine 
measurements, participants will receive a new batch of study medication by mail from 
the research pharmacy.  Upon receipt of the new tablets, participants will be instructed 
Addition of ability to provide 
study medication in blister packs  
 
 

22 
 
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to immediately mail the pill bottles or the blister packs with the tablets remaining 
from the previous prescription to the study center for drug accounting and compliance 
assessment (see 6.1.2). A pre-stamped and addressed envelope will be provided to 
participants for this purpose. 
 
 
P.32 
8. STUDY PROCEDURES 
8.6. End of Intervention 
(Visit 16) 
New Text: 
Participants will be instructed to stop taking the study medication and to mail the pill 
bottles or the blister packs with the tablets remaining from the last prescription to the 
study center if they did not already bring the unused study medication at the visit.  The 
RAS and BP therapy will be continued as before until the closing visit (Visit 17). The 
importance of coming back in 8 weeks for the closing visit (Visit 17) will be 
emphasized. 
 
Addition of ability to provide 
study medication in blister packs 
P.33 
9. SAFETY 
ASSESSMENTS 
9.1. Demographic 
Data/Medical History 
 
New Text: 
After collecting a detailed medical history at Visit 1, this information will be updated 
at each visit through a structured interview, with a special emphasis on skin symptoms 
and signs such as rash, itching and exfoliation and on pregnancy in females. 
Participants will be instructed to communicate any change in their health status and 
intervening hospitalizations to the study coordinator in-between visits.  In particular, 
they will be instructed to discontinue study medication and immediately contact the 
study coordinator if they develop a suspicious skin rash, swelling of the lips or mouth, 
arthralgias, and/or jaundice, which may indicate a hypersensitivity reaction to 
allopurinol.  Fever and chills should also be reported but would not require cessation of 
medication prior to discussion with study personnel. 
 
Deleted Text: 
Of any kind 
Clarification of skin rash 
triggering discontinuation of study 
drug 
P.35 
11. STATISTICAL 
ANALYSIS 
 
New Text: 
This section presents a summary of the planned statistical analyses. A statistical 
analysis plan (SAP) will be written for the study that contains detailed 
descriptions of the analyses to be performed. The SAP will be written prior to 
database lock. 
Clarification of statistical analysis 
p.35 
11. STATISTICAL 
ANALYSIS 
11.1. Analysis Population 
New Text: 
For most of the analyses, including the primary efficacy analysis described in 
section 11.3, an intention to treat (ITT) analytical approach will be employed.  
Accordingly, the population for statistical analysis will consist of all randomized study 
participants considered in their original randomization group, regardless of treatment 
discontinuation or loss to follow-up. 
Selected secondary efficacy analyses will be performed using a per-protocol 
Revised analysis plan 

23 
 
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analytical approach. In this case, the analysis population will consist of the ITT 
population excluding data points which 1. had cumulative exposure to the study 
medication from randomization that was less than 80% of the theoretical full 
exposure; or 2. during major protocol deviations (e.g., treatment with prohibited 
medications), which could affect primary outcome. 
 
p.35 
11. STATISTICAL 
ANALYSIS                        
11.3. Primary Efficacy 
Analysis 
 
New Text: 
 
For the primary endpoint (iGFR at the end of the 2-month wash-out period following 
the 3-year intervention), we will follow the recommendations by Carpenter et al38,39 
and perform the analysis by means of a linear model for correlated errors with 
general/unstructured covariance matrix using all available iGFR measures (including 
those at baseline, 80, 156, and 164 weeks, respectively) as the dependent variable. By 
conditioning on the baseline iGFR measure we will also effectively use this variable as 
a covariate. Treatment group, study center, stratifying variables, albuminuria status 
(subjects who qualified by ACR or AER or were albuminuric at baseline vs. 
subjects who did qualified by eGFR slope and were normoalbuminuric at 
baseline), baseline AER, time, and time by treatment interaction will also be included 
as covariates in the model. Three features make this analytical approach especially 
attractive:  
Revised analysis plan 
p.37 
11. STATISTICAL 
ANALYSIS 
11.4. Secondary Efficacy 
Analyses 
New Text: 
We will perform a per-protocol analysis (as defined in 11.1) for the primary 
efficacy endpoint (iGFR at the end of the 2-month wash-out period following the 
3-year intervention). 
Revised analysis plan 
p.37-38 
11. STATISTICAL 
ANALYSIS 
11.7. Model assumptions 
and alternative analyses 
New Text: 
Model assumptions will be thoroughly checked for individual and systematic 
departures, using informal, e.g. inspection of residuals, and formal methods such as 
score test for extra parameter or methods based on likelihood displacement. If 
individual outliers are detected, their influence will be evaluated using influence 
diagnostics methods based on comparing estimates from models fitted to data with and 
without outlying values. Whenever we are not successful in fitting the parametric 
model (linear or non-linear), then non-parametric analyses and/or transformation of the 
variables involved in the analysis will be considered. To investigate the potential 
hemodynamic influence of allopurinol on treatment effect, in addition to the 
aforementioned analyses, we will consider models including the post-randomization 
measure of GFR at 4 months as an additional covariate.  To investigate the possible 
presence of heterogeneity in the response to allopurinol, subgroup analyses (based on 
the primary efficacy analysis described in section 11.3, with the inclusion of an 
interaction term of the treatment group by the subgroup variable) will be 
performed by age groups (≤40 and >40 yrs), gender, racial/ethnic group, HbA1c (≤7.8 
Revised analysis plan 

24 
 
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Rationale 
and >7.8%), serum uric acid (≤6.0 and > 6.0 mg/dl), baseline iGFR (≤70 ml/min and 
>70 ml/min/1.73m2), AER at baseline (≤300 and >300 mg/24 hr), and albuminuria 
status (subjects who qualified by ACR or AER or were albuminuric at baseline 
vs. subjects who did qualify by eGFR slope and were normoalbuminuric at 
baseline). To investigate possible influence of using selected covariates on the 
treatment effect estimate in the models considered in Section 11, we will perform 
appropriate sensitivity analyses. These additional analyses will be considered as 
strictly exploratory. 
p.45 
13.  PROTECTION OF 
HUMAN SUBJECTS 
13.5. Procedures for 
protecting against and 
minimizing potential risks, 
b. specific 
New Text: 
Subjects taking drugs known to interact with allopurinol in causing bone marrow 
depression will be excluded from the study.  White blood cell counts will be done 
before the study drugs are prescribed, and quarterly thereafter. The study drug should 
be temporarily discontinued should evidence of bone marrow depression 
(WBC<3500/mm3) be present and confirmed. WBC should be repeated two weeks 
after study drug discontinuation.  If WBC recovers, consider re-challenging and 
repeating WBC two weeks after drug re-introduction. In addition, if WBC is 
confirmed to be <2500/mm3 and/or ANC is <1000/mm3, the event also needs to be 
reported as an AE.   The Drug Monitoring Committee will review each case and 
decide whether a referral to a hematologist is warranted and whether study treatment 
can be reinstated after blood values have returned to normal. If drugs potentially 
causing bone marrow depression in combination with allopurinol are begun after entry 
into the trial, observations for this side effect will be intensified or, if recommended by 
the Drug Monitoring Committee, study drug may be interrupted. 
 
Deleted Text: 
develop 
Additional details directing follow 
up and reporting of possible bone 
marrow depression 
p.45 
13.  PROTECTION OF 
HUMAN SUBJECTS 
13.5. Procedures for 
protecting against and 
minimizing potential risks, 
b. specific 
New Text: 
Blood pressure will be measured quarterly with the goal of maintaining BP 
≤140mmHg systolic and ≤90 mmHg diastolic. If elevated, a recheck will be performed 
within 2 weeks and if still elevated additional antihypertensive non-RAS blockers will 
be added in collaboration with the participants’ physicians. Failure to achieve 
satisfactory BP control within 2 months would lead to a case review by the Drug 
Monitoring Committee.  
 
Deleted Text: 
Conference call 
 
Allows flexibility to discuss cases 
via e-mail or means other than a 
call 

25 
 
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p.47 
14. DATA AND SAFETY 
MONITORING PLAN 
New Text: 
IRB monitoring will be in place from: 
Joslin Diabetes Center 
University of Minnesota 
University of Colorado 
University of Michigan 
Northwestern University 
University of Toronto 
Albert Einstein University 
Washington University 
Steno Diabetes Center 
University of Calgary 
University of Alberta 
Emory University 
University of Washington 
University of Texas Southwestern 
Providence Medical Research 
BC Diabetes 
 
Deleted Text: 
Alberta Diabetes Institute 
 
Addition of new centers, and 
clarifying the name of an existing 
center for consistency 
p.48 
 
 
 
14. DATA AND SAFETY 
MONITORING PLAN 
Revised Text: 
A Drug Monitoring Committee (DMC) consisting of the PERL Center 
Directors and PIs, a research pharmacist, and the Project Manager will discuss any 
serious medication related problem that a participant has.  Changes in study medication 
dose, medication discontinuation and medication re-institution will be included in 
these discussions.  
 
Deleted text: 
hold conference calls  
discussed during these calls 
 
Allows flexibility to discuss cases 
via e-mail or means other than a 
call 
p.49 
15. STUDY 
ADMINISTRATION 
15.1. Organization 
Revised Text: 
The Steering Committee is responsible for the design of the study and provides 
guidance to its execution.  Members are the co-Chairs of the PERL Consortium (Drs. 
Mauer and Doria), the Directors of the Clinical Sites (Drs. Caramori, Goldfine, Maahs, 
Perkins, Pop-Busui, Molitch, Crandall, Rossing, Sigal, Senior, Umpierrez, Hirsch, 
Adding new site directors, a 
change in central lab director, and 
correction to a name spelling error 

26 
 
# 
Location 
Change 
Rationale 
Lingvay, Tuttle, Aronson and Elliott), the Directors of the Data Coordinating Center 
(Drs. Galecki and Spino), and the Director of the Central Laboratory (Dr. Karger), the 
NIH program officers (Drs. Jones and Flessner), and the JDRF program officer (Dr. 
Pragnell) 
 
Deleted Text: 
Hirsh, Eckfeldt and Pragnell 
p.49 
15. STUDY 
ADMINISTRATION 
15.1. Organization 
Revised Text: 
The Drug Monitoring Committee is responsible for the oversight of the 
study drug administration as well as the RAS blocking and antihypertensive therapy 
during the trial. Members are Dr. Doria, Dr. Mauer, the PIs of the clinical sites, the 
Project Manager, the Lead Clinical Coordinator, and a research pharmacist. The 
participation of one of the PIs and 5 of the 16 Center Directors will be sufficient for 
making decisions. 
 
Deleted Text: 
8 
Correcting current number of sites 
p.49 
15. STUDY 
ADMINISTRATION 
15.1. Organization 
Revised Text: 
The Clinical Sites are located at the Joslin Diabetes Center, the University of 
Minnesota, the University of Colorado (Barbara Davis Center for Childhood Diabetes), 
the University of Michigan, Northwestern University, Albert Einstein College of 
Medicine, Washington University (St. Louis), the University of Toronto, the Steno 
Diabetes Center (Denmark), the University of Calgary (Calgary, Alberta, Canada), 
University of Alberta (Edmonton, Alberta, Canada), Emory University, the University 
of Washington (Seattle), University of Texas Southwestern, Providence Medical 
Research, and BC Diabetes are responsible for recruiting study participants and 
implementing the protocol. 
Addition of new centers, and 
clarifying the name of an existing 
center for consistency 
p.49 
15. STUDY 
ADMINISTRATION 
15.1. Organization 
Revised Text: 
The Central Laboratory, located at the University of Minnesota, is directed by Dr. 
Karger, and is responsible for all blood and urine tests. 
 
Deleted Text: 
Eckfeldt 
Adding new central laboratory 
director 
List of Changes in PERL Protocol Version 10.0 March 6, 2018 
p.1 
Title page 
Change version and date Version 10.0 Approved by the DSMB March 6, 2018 
Version date changed to date of 
DSMB approval 

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p.2-4 
Table of Contents 
Page numbers 8-49 changed 
Page numbers shifted. 
p.5 
GENERAL 
INFORMATION 
Program Officers 
Revised Text: 
Afshin Parsa, MD, MPH 
Program Director, Clinical Kidney Genomics, PKD and CKD NIDDK/NIH 
6707 Democracy Blvd. Room 6139 
Bethesda, MD 20892-5460 
Tel: (301) 827-1375 
New Program Officer 
 
 
afshin.parsa@nih.gov 
 
 
 
Deleted Text: 
Michael Flessner, MD, PhD 
Division of Kidney, Urologic, & Hematologic Diseases NIDDK, National Institutes of Health 
Building 2DEM, Room 641 6707 Democracy Blvd. 
Bethesda, MD 20817 
Phone: (301) 451-4901 
flessnermf@mail.nih.gov 
 
p.6 
GENERAL 
INFORMATION 
Directors of Clinical Sites 
Added Text: 
S. Michael Mauer, MD University of Minnesota 2450 Riverside Ave. East Building, MB681 
Minneapolis, MN 55454 
Mobile: (612) 703-5884 
Added mobile phone number 
p.6-7 
GENERAL 
INFORMATION 
Directors of Clinical Sites 
New Text: 
Sylvia Rosas, MD 
Joslin Diabetes Center and Harvard Medical School One Joslin Place 
Boston, MA 02215 
Phone: (617) 309-2477 
Fax: (617) 309-3403 
Sylvia.Rosas@joslin.harvard.edu 
Deleted Text: 
Allison Goldfine, MD 
Joslin Diabetes Center and Harvard Medical School One Joslin Place 
Boston, MA 02215 
Phone: (617) 309-2643 
Fax: (617) 309-3403 
allison.goldfine@joslin.harvard.edu 
Change in Director of Clinical Site 
p. 8 
GENERAL 
INFORMATION 
Directors of Clinical Sites 
New Text: 
Ian de Boer, MD, MS 
University of Washington Medical Center Box 359606 
325 9th Avenue, Room 3NJ357 Seattle, WA 98104 
New Director of clinical Site 

28 
 
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Phone: (206) 616-5403 
Fax: (206) 685-9399IDeBoer@Nephrology.washington.edu 
Deleted Text: 
Irl B. Hirsch, MD 
University of Washington Medical Center – Roosevelt 4245 Roosevelt Way, NE, 3rd floor 
Box 354691 
Seattle, WA 98105 
Phone: (206) 598-4884 
Fax: (202) 598-4976 
ihirsch@uw.edu 
p. 12 
Protocol Summary 
Revised Text: 
February 22, 2018 
 
p. 21 
Discontinuation of study 
drug 
Reasons for Discontinuation 
New Text: 
Develops end-stage renal disease (confirmed eGFR ≤15 ml/min/1.73 m2 in the absence 
of acute kidney injury [AKI], institution of chronic dialysis treatment or kidney 
transplantation) or iGFR decreases by 50% from one measurement to the next or serum 
creatinine levels double over any 12 month interval in the post-randomization period. 
If any of these renal function changes prove to be temporary, the study medication 
could be resumed as described above with the consensus of the drug monitoring 
committee. 
 
Revised Text: 
Develops end-stage renal disease (eGFR ≤15 ml/min/1.73 m2, institution of chronic 
dialysis treatment or kidney transplantation) or iGFR decreases by 50% from one 
measurement to the next or serum creatinine levels double over any 12-month interval 
in the post-randomization period. If these renal function changes prove to be 
temporary, the study medication could be resumed as described above with the 
consensus of the drug monitoring 
Committee. 
Clarification of wording for 
developing ESRD and drug 
discontinuation. 
p. 22 
Discontinuation of study 
drug Handling of study drug 
discontinuation 
New/Revised Text: 
Unless a participant withdraws consent all participants that are permanently 
discontinued from study drug or who discontinue study medication on their own will 
be followed for the full study period (i.e., 164 weeks, including the washout period) 
and all data will be collected as scheduled. 
 
Deleted Text: 
Or develop ESRD as defined above under 5.5.1 
Wording clarification. 

29 
 
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p. 22 
Discontinuation of study 
drug Handling of study drug 
discontinuation 
New Text: 
If a participant reaches ESRD as defined above under 5.5.1, he/she will be permanently 
discontinued from the study and invited to participate in a study close-out call or visit 
to be held within three months from the occurrence of ESRD. Data collection at this 
call or visit will be limited to standard adverse event reporting. In addition, sites should 
continue to contact participants who have reached end-stage renal disease to determine 
their final status until 3 years and 2 months after randomization. Major attempts will be 
made to schedule an end-of-study assessment for all participants who are lost to 
follow-up during the course of the study. 
New text was added to clarify 
handling of study drug 
discontinuation and data collection 
for specific scenario in which 
participant reaches ESRD. 
p. 35 
Statistical Analysis 
Analysis Population 
Revised Text: 
Selected secondary efficacy analyses will be performed using a per-protocol analytical 
approach. In this case, the analysis population will consist of the ITT population 
excluding data points which 1. Had cumulative exposure to the study medication from 
randomization that was less than 80% of the theoretical full exposure; or 2. during 
major protocol deviations (e.g., treatment with prohibited medications), which could 
affect primary outcome. 
 
Deleted Text: 
all iGFR measurements/ did incur 
Grammar clarification. 
p. 49 
Study Administration 
Revised Text: 
The Steering Committee is responsible for the design of the study and provides 
guidance to its execution. Members are the co-Chairs of the PERL Consortium (Drs. 
Mauer and Doria), the Directors of the Clinical Sites (Drs. Caramori, Rosas, Polsky, 
Perkins, Pop-Busui, Molitch, Crandall, Rossing, Sigal, Senior, Umpierrez, De Boer, 
Lingvay, Tuttle, Aronson and Elliott), the Directors of the Data Coordinating Center 
(Drs. Galecki and Spino), and the Director of the Central Laboratory (Dr. Karger), the 
NIH program officers (Drs. Jones and Parsa), and the JDRF program officer (Dr. 
Pragnell). 
 
Deleted Text: 
Goldfine, Maaha, Hirsch, Flessner