Protocol. This trial protocol has been provided by the authors to give readers additional information about their work.

Transcription

1 Protocol This trial protocol has been provided by the authors to give readers additional information about their work. Protocol for: Hemmelgarn BR, Moist LM, Lok CE, et al. Prevention of dialysis catheter malfunction with recombinant tissue plasminogen activator. N Engl J Med 2011;364:

2 Prevention of Catheter Lumen Occlusion with rt-pa versus Heparin (Pre-CLOT): A Double Blind Randomized Trial Previous Versions Original Protocol - August 27, 2004 Amendment #1 - November 22, 2004 Current Version Amendment #2 March 2, 2005 Dr. Nairne Scott-Douglas University of Calgary th Street N.W. Calgary, Alberta T2N 2T9 Protocol Approved By: Approval Date: Dr. Nairne Scott-Douglas, M.D., PhD, FRCPC Clinical Assistant Professor (dd-mmm-yyyy) This protocol is contains confidential information belonging to the University of Calgary and is intended for use in this clinical trial. This protocol may not be disclosed to parties not associated with the clinical study or used for any purpose without the prior written consent of the University of Calgary.

3 Protocol Signature Page Title: Prevention of Catheter Lumen Occlusion with rt-pa versus Heparin (Pre-CLOT): A Double Blind Randomized Trial. Protocol Amendment #2: March 2, 2005 Investigator: Signature Date (dd-mmm-yyyy) Printed Name The above signed confirms that you have thoroughly read and understood the information contained in this protocol and attached appendices and agree to conduct the study as outlined in this protocol, in accordance with applicable regulatory requirements and Good Clinical Practice (26). Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL i

4 Table of Contents Protocol Signature Page... i Table of Contents... ii Protocol Synopsis... vi Summary Introduction Study Rationale Primary Prevention of Catheter Malfunction in Hemodialysis Catheters Risk of Heparin Lock-Related Bleeding Tissue Plasminogen Activator (rt-pa) as a Thrombolytic Frequency of Instillation & Dose of rt-pa in the Primary Prevention of Catheter Malfunction Safety of rt-pa Treatment of Catheter Malfunction in Non-Dialysis Catheters Treatment of Catheter Malfunction in Hemodialysis Catheters Summary... 6 Plan of Investigation Study Objectives & Hypothesis Primary Objective Secondary Objectives Study Design & Duration Design Duration Study Population Number of Patients Patient Selection Criteria Inclusion Criteria Exclusion Criteria Patient Identification, Randomization & Intervention Patient Identification Randomization Study Treatment Outcome Measures Primary Outcome Secondary Outcome Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL ii

5 8. Data Collection Web-Based System and the Electronic Case Report Forms (ecrf) Baseline Data Data from Each Hemodialysis Session Monthly Laboratory Data Predicting Dialysis Catheter Malfunction Follow-Up Ongoing Patient Review Hospitalizations Primary Outcome Secondary Outcome Study Completion Catheter Follow-up Discontinuing Study Drug Treatment Non-Administration of Study Drug Treatment or Heparin Protocol Violations Study Withdrawal Statistical Analysis Sample Size Calculations Interim Analyses: Role of the Data Safety Monitoring Board Material & Supplies Study Drug Allocation, Accountability & Storage Study Blinding Procedure Patient Emergency Information Other Considerations Cointerventions Prohibited Medications Allowable Concomitant Medications Safety Reporting Adverse Events Serious Adverse Events Life-Threatening Adverse Event Initial Hospitalization Prolongation of Hospitalization Disability Expected Adverse Events Unexpected Adverse Events Adverse Event Documentation Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL iii

6 16.6 Adverse Event Reporting Adverse Event Follow-up Data & Study Management Data Safety Monitoring Board & Steering Committee Data Base Lock Protocol Violations Clinical Trial Monitoring & Auditing Source Documents & Record Retention Ethical Considerations & Informed Consent Institutional Review Board (IRB) Obtaining Patient Informed Consent Maintenance of Patient Confidentiality Serious Adverse Events Confidentiality Funding Indemnity Publications, Reports & Sub-Studies Appendix 1 - Study Schedule References Cost Effectiveness Analysis Background Objectives Primary Objective Secondary Objectives Design & Methods: Patient Population & Costing Time Period Costs Considered Hospitalization Outpatient Infections Diagnostic Imaging The Cost of Treating Catheter Malfunction Statistical Analysis Primary Analysis Decision Analysis Accordance with Economic Evaluation Guidelines Sensitivity Analysis Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL iv

7 Appendix 2 - Costing Methodology References Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL v

8 Title Primary Objective Secondary Objectives Protocol Synopsis Prevention of Catheter Lumen Occlusion with rt-pa versus Heparin (Pre-CLOT): A Double Blind Randomized Trial To determine if substituting rt-pa for heparin (1 mg per lumen) once per week as a catheter locking solution, will decrease the incidence of catheter malfunction compared to locking with heparin alone, after each dialysis session. To determine if substituting rt-pa for heparin (1 mg per lumen) once per week as a catheter locking solution will decrease the incidence of catheter-related bacteremia, compared to locking with heparin alone after each dialysis session. An economic evaluation of rt-pa versus heparin in the primary prevention of catheter malfunction will be done. Specifically, the objectives of this economic component will be to assess the cost required to avoid placement of a new dialysis catheter for patients treated with rt-pa compared to heparin, and to determine which locking solution is the most cost effective strategy in preventing the requirement of a new dialysis catheter. The details of this economic evaluation are discussed in a separate section of this protocol. Study Design Phase III multi-centre double-blind randomized trial involving 340 patients (170 per arm), being conducted at approximately 14 sites in Canada. Duration Study Population The study period will be six months in duration. Patients who have a functioning catheter at the end of the six month period, patients who have reached a primary outcome and patients who have been withdrawn early, will be followed for an additional month. One-hundred and seventy hemodialysis patients with newly inserted permanent, tunnelled hemodialysis catheters will be randomized to each arm of the study. Patients will be enrolled from approximately 14 sites across Canada. Patients will be stratified by study centre and virgin (first hemodialysis catheter ever) versus non-virgin (use of hemodialysis catheter at some point in the past) catheter status. Inclusion Criteria 1. ESRD patients with newly inserted permanent, tunnelled, duallumen catheters 2. Naïve to study but not naïve to catheters (both virgin and nonvirgin catheters will be included) 3. Expected to use catheter, and to dialyze at study centre, for at least six months 4. Frequency of hemodialysis 3 times per week 5. If indication for new catheter insertion was for line related infection, then patients are eligible when: the infection has been treated and the patient has been off Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL vi

9 Inclusion Criteria (cont d) Exclusion Criteria Primary Outcome Secondary Outcome antibiotics for 3 hemodialysis sessions. 6. Patient or legal representative able to provide written consent 7. Eighteen years of age or older 8. Baseline INR Baseline platelet count /L 1. Use of systemic anticoagulation (if indication for anticoagulation is for catheter patency then patients may be eligible for inclusion if the systemic anticoagulation is discontinued and baseline INR is 1.3) 2. Insertion of a new permanent hemodialysis catheter by a guidewire exchange procedure 3. Insertion of a new permanent hemodialysis catheter into the femoral vein 4. Current use of antibiotics for catheter-related bacteremia 5. Major hemorrhage within pervious 4 weeks, defined as bleeding resulting in a drop in hemoglobin of greater than 20 g/l or bleeding requiring transfusion of packed red blood cells with other clinical evidence or suspicion of bleeding 6. History of intra-cranial bleed in the prior 4 weeks 7. Intra-cranial or intra-spinal neoplasm (current) 8. Allergy or intolerance to rt-pa or heparin or its constituents 9. Active pericarditis defined by the presence of a pericardial rub 10. Weight 30 kg 11. Patient pregnant or lactating 12. Child bearing potential (i.e. pre-menopausal female who is not using a reliable method of contraception) 13. Major surgery in past 48 hours (CABG, organ biopsy, puncture of non-compressible vessels), or scheduled for major surgery during the study period 14. Involvement in another randomized drug trial 15. Presence of a fever as defined by a temperature of >38.2 C The primary outcome of the study will be catheter malfunction. A secondary study outcome will be the incidence of catheter-related bacteremia, defined according to the Canadian definitions for catheter-related infections. Investigational Product The study treatment will be locking of the catheter lumen with rt-pa at a dose of 1.0 mg per lumen once per week. To ensure that the rt- PA is administered to the catheter tip where the site of thrombus formation is, it will be instilled down each lumen first, followed by Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL vii

10 Investigational Product (cont d) Electronic Case Report Forms (ecrf) Screening Randomization Study Assessments normal saline at a volume adequate to fill the entire luminal volume of the hemodialysis catheter. Patients in the control arm, will receive heparin 5,000 units/ml, luminal volume. In order to ensure blinding of the patients and study personnel, the solutions for locking the catheter lumens will be prepared and dispensed by the pharmacy on the patient s treatment day. For patients who dialyse on a Monday/Wednesday/Friday schedule, the treatment day will be Wednesday, while for patients who dialyse on a Tuesday/Thursday/Saturday schedule their treatment day will be Thursday. Heparin and rt-pa have a similar appearance, and will be dispensed in identical syringes. The lumens will be tagged indicating a study drug of either heparin or rt-pa is contained in the lock. Heparin (5,000 units/ml, luminal volume), will be prepared and administered by the Hemodialysis Nurse for the non-treatment days (Monday and Friday for the Monday/Wednesday/Friday patients and Tuesday and Saturday for the Tuesday/Thursday/Saturday patients). Thus pharmacy dispensing of the locking solutions will occur only on the treatment days of Wednesday and Thursday. A unique feature of this trial is the use of a web-based system for both data entry and ongoing communication and documentation. The web-based system will be accessible to all study staff using a standard web browser, allowing messaging (electronic communication between study staff), tracking of serious adverse events, and monitoring of study progress (patient recruitment etc). After written informed consent is obtained, the Study Coordinator will screen the patients for study eligibility using the inclusion/exclusion criteria defined in section 5.2 of this protocol. Written Informed Consent will be obtained before any study specific procedure is conducted. Information will be collected and recorded from interviews with the patient and/or caregiver and by reviewing the patient s medical chart. Lab results from the patient s monthly blood work will also be collected. Information about the patient s dialysis session will be recorded. The hemoglobin, platelets, albumin, Kt/V and urea reduction ratio will be recorded from the patient s usual monthly blood work. No additional blood work will be required. The patient will be assessed at each dialysis session for the 6 month study period to determine if they have experienced a catheter malfunction or bacterial infection. Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL viii

11 Study Assessments (cont d) Statistical Considerations Safety Summary Steering Committee The patient will also be observed for episodes of bleeding complications. At anytime during the follow-up period if the attending nephrologist determines the patient has met the criteria for catheter malfunction, they will be withdrawn from the study. The patient will continue to be followed for one month in order to determine the natural history of the catheter. Data will be collected during this time period for an economic evaluation to help determine the costs versus benefits between heparin and rt-pa. Analysis of the primary and secondary outcomes will be based on the intention-to-treat principle. The time from randomization until catheter malfunction will be analyzed and Kaplan-Meier estimates of the probability of event-free survival will be calculated for the control and treatment arms. Cox proportional hazards analysis will also be used to compare event-free survival in the rt-pa and heparin groups, controlling for clinical risk factors and including stratification variables. The proportion of patients in each treatment arm achieving the secondary outcome measure, catheter-related bacteremia, will also be recorded, as will the number of infections per 1000 catheter-days. Differences in proportions will be assessed using the Fisher s exact test and the number of infections per 1000 catheter days using the exact binomial test. All serious adverse events, regardless of treatment group or suspected relationship to study drug must be reported immediately by telephone to the University of Calgary or its representatives within 24 hours of their occurrence or knowledge by the Investigator or his/her study staff. All such reports will be reviewed urgently by the Sponsor (or delegate) blind to treatment allocation, with any necessary additional information sought. Such events will then be reported promptly to the Chair of the Data Safety Monitoring Board (DSMB). In order to assess safety, all patients will be followed for 30 days by the investigative site after receiving their last dose of study medication. The Steering Committee will be responsible for providing overall guidance and support to the University of Calgary on the study protocol, the scientific merit of the data and the execution of the study, the review of recommendations from the DSMB and the oversight of study publications. Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL ix

12 Interim Analysis & Data Safety Monitoring Board (DSMB) Sponsor Project Funding An independent committee consisting of three members with expertise in nephrology and/or clinical epidemiology will be assembled prior to study commencement. Safety data will be periodically received. The DSMB will participate in the conduct of the planned efficacy interim analyses. The DSMB will advise the Steering Committee and study sponsor on finding that may impact the conduct of the study, and communicate recommendations based on the results of the efficacy interim analysis. The University of Calgary Hoffmann - La Roche Ltd. Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL x

13 Summary For many patients with end-stage kidney disease a permanent dual lumen hemodialysis catheter may be their only remaining option for access for dialysis, while for others this may be a temporary solution. Regardless of the indication, an increasing number of hemodialysis patients are managed with permanent dual-lumen catheters. Unfortunately most hemodialysis catheters fail within one year of insertion, with up to two-thirds due to thrombosis. A limited amount of research has been conducted regarding measures to prevent catheter-related thrombosis. The current standard of practice, based on little evidence, is to lock the catheter with heparin for the interdialytic period. However preliminary data would suggest that locking the catheter with rt-pa may be a safe and effective primary prevention strategy. We propose a randomized clinical trial to compare rt-pa versus heparin in the primary prevention of catheter malfunction. This study will involve approximately 14 sites across Canada, and include 170 patients randomized to each arm of the trial. The study population will consist of hemodialysis patients with a newly inserted permanent duallumen catheter. Patients who have had a permanent catheter inserted for the first time, as well as those who have had a temporary or permanent catheter in the past, will be eligible. Patients will be randomized to either a locking solution of rt-pa, 1 mg per lumen, administered once per week with heparin being used for the remaining two sessions or to heparin 5,000 units per ml after each dialysis session (which will serve as the control arm). The study treatment period will be six months. The primary outcome will be catheter malfunction, based on mean blood flow parameters while on dialysis, with the secondary outcome of catheter-related bacteremia. A cost-effectiveness analysis will be undertaken to assess the cost of maintaining a hemodialysis catheter using rt-pa as a locking solution, compared to the use of heparin. A practical and cost-effective strategy to reduce the incidence of catheter malfunction would have a significant impact both on the resources associated with chronic hemodialysis therapy as well as the patients quality of life. Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 1

14 1. Introduction In Canada approximately 15-70% of the hemodialysis patients dialyse via indwelling central venous catheters. A catheter may be used as a long term access if the patient has exhausted all other access sites, or as temporary access while awaiting graft or fistula surgery or maturation. The major limitations of central venous catheters as dialysis access include infection, thrombosis and poor blood flow. Unfortunately approximately fifty percent of these catheters will fail within one year of insertion (1, 2) and up to two-thirds will be thrombosis related (3, 4). A limited amount of research has been conducted regarding measures to prevent catheterrelated thrombosis, as well as the most efficacious means of treating the thrombus once it has developed. Studies which are available are fraught with methodological limitations. While most hemodialysis centres use heparin as a solution to lock their hemodialysis catheters between hemodialysis sessions, questions regarding the optimal concentration and volume of heparin to use, the systemic effects of heparin, and use the of locking solutions other than heparin remain unanswered. Catheter malfunction may have a significant impact on the dialysis schedule and adequacy if patients hemodialysis sessions are suboptimal because of low blood flow or cut short or cancelled while patients are sent to radiology for catheter stripping or new line placement. This impacts on the patients quality of life, and adds additional costs to the already high costs of chronic hemodialysis therapy. Unfortunately, there is little evidence in the literature to guide us in terms of prevention and treatment of catheter malfunction due to thrombosis. Given the lack of an effective therapy to treat catheterrelated thrombosis, it would seem inherent that emphasis and research should focus on the prevention of catheter thrombosis. 2. Study Rationale 2.1 Primary Prevention of Catheter Malfunction in Hemodialysis Catheters Hemodialysis catheters are commonly locked with a concentrated or diluted heparin solution to prevent their thrombosis between hemodialysis sessions. The amount of solution instilled is typically based upon the catheter priming volume (5). Unfortunately the evidence to support the use of specific locking solutions, including the strength and amount of solution, is extremely limited. Even the National Kidney Foundation Dialysis Outcomes Quality Initiative (K-DOQI) guidelines for vascular access do not include recommendations for the filling of catheters to prevent their thrombosis during the interdialytic period (6). The critical care and oncology literature have provided some evidence for the use of prophylactic anticoagulants to decrease central-venous catheter-related thrombosis. A recent meta-analysis of 14 randomized, controlled trials suggests prophylactic heparin administration reduces thrombus formation among patients who had central venous and pulmonary artery catheters (7). Prophylactic heparin, decreased the risk of catheter thrombus or fibrin sheath by 44% (relative risk 0.66, 95% CI ) (7). However the heparin dose used was extremely variable, ranging from 5,000 units every 12 hours to a continuous infusion of 1 unit/ml of TPN (7). The generalizability Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 2

15 of these results being applied to hemodialysis catheters, which are much larger in size, utilized for longer periods of time, and require a solution to remain in-situ for up to 72 hours, remains questionable. It would appear, based on the critical care and oncology literature, the use of heparin as a locking solution in hemodialysis catheters has become the accepted standard of practice. To the best of our knowledge there have been no published studies assessing whether heparin as a locking solution is superior to placebo in maintaining the patency of hemodialysis catheters. A few small and poorly designed trials have attempted to determine if citrate and heparin have equal efficacy in maintaining hemodialysis catheter patency (8-10). These studies are limited by their small sample sizes, short follow-up durations and surrogate outcome measures of catheter thrombosis prone to considerable measurement error. Conclusions regarding superiority, or even equivalency, of heparin and citrate can not be made based on the available evidence. More recently, rt-pa, has been used in the treatment of catheter-related thrombosis, and has also been considered as a possible hemodialysis catheter locking solution. Using a randomized crossover design with only 12 patients, Schenk and colleagues (11) demonstrated the instillation of 2 mg of rt-pa in each catheter lumen at the end of each dialysis run was superior to the conventional practice of locking each lumen with 2000 units of heparin. After four months, 20% of the heparin locked catheters had a thrombotic event versus 0% in the rt-pa group. The rt-pa group maintained significantly greater blood flow and arterial pressures and lower venous pressures compared to the heparin group. The results of this study are encouraging with respect to rt-pa as a potential catheter locking solution. Unfortunately, the cost of using rt- PA after each dialysis session is high and may make the overall cost of this protocol if applied to every patient with a catheter prohibitive. Further research is needed to determine if a more cost-effective means of using rt-pa as a locking solution, such as once per week, results in a decreased incidence of catheter related thrombosis compared to the regular use of heparin. 2.2 Risk of Heparin Lock-Related Bleeding The use of heparin as a locking solution is not without its risks, with several anecdotal reports suggesting an increased risk of bleeding. Surprisingly, little has been published in the literature regarding the possible systemic effects of heparin when administered as a catheter locking solution. Karaaslan et al (12) undertook an observational study of 20 patients to assess the degree of anticoagulation induced by heparin locking of the hemodialysis catheter. Catheter lumens were locked with 2 ml heparin (5000 units/ml), with a PTT measured 10 minutes after locking in all patients, and every 30 minutes for 6 hours in one patient. The results were expressed as a ratio, patient/control (for values > 3.75, the blood was not coagulable) (12). At 10 minutes, all patients had a PTT ratio of > 3.75 (uncoagulable blood) (12). This hypocoagulable state lasted more than two hours. However, when the catheters were locked with an estimate of the luminal volume rather than the standard 2 ml instillation, only one patient had a PTT ratio of > 3.75 at 10 minutes. The effect of an increased lock volume on specific patient outcomes, including both the incidence of bleeding as well Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 3

16 as prevention of thrombosis, was not assessed. Further research is needed to assess not only the systemic effects of heparin when used as a catheter locking solution, but also the basic pharmacologic viability of heparin as a locking solution. 2.3 Tissue Plasminogen Activator (rt-pa) as a Thrombolytic Thromboembolic disease can be treated using agents that activate the conversion of plasminogen to plasmin, a serine protease that hydrolyzes fibrin and dissolves clots. Streptokinase and Urokinase were the first thrombolytic agents to be approved, however they cause a systemic fibrinolytic state which can lead to bleeding problems (13). Tissue plasminogen activator (rt-pa) preferentially binds to fibrin and thus activates plasminogen in close proximity to the clot. This confines fibrinolysis to the formed thrombus and, in theory, avoids systemic activation. In patients with acute myocardial infarction, studies have shown that rt-pa is rapidly cleared from the plasma, with an initial half life of less than 5 minutes (14). Clearance is mediated primarily by the liver (14). 2.4 Frequency of Instillation & Dose of rt-pa in the Primary Prevention of Catheter Malfunction Only the study done by Schenk et al (11), has explored the use of rt-pa as a potential catheter locking solution. The dose used, was 2 mg (information regarding luminal volume was not provided), with frequency of instillation being each run. It may be possible that a smaller dose, such as 1 mg per lumen, or less frequent administration, such as once every week, may result in a decreased incidence of catheter malfunction when compared to the standard instillation of heparin. 2.5 Safety of rt-pa The minimum dose of rt-pa required as a catheter locking solution to prevent thrombosis, or as a treatment for catheter-related thrombosis is unknown. The dose of rt-pa most extensively studied to date for the treatment of catheter-related thrombosis is a bolus of 2 mg, and was empirically derived based on dosing for Urokinase. The FDA approved dose of Urokinase for catheter clearance is 5,000 IU, which is approximately 2% of the FDA approved dose for systemic treatment of pulmonary embolism. Thus 2% of the approved dose of rt-pa for coronary thrombosis (100 mg) is 2 mg, the dose most commonly used in current studies. The systemic effects of rt-pa are more likely to occur at higher doses. It has been reported that at doses of 2-4 mg systemic fibrinogen levels remain unchanged (15). At this same dose of 2-4 mg, it has also been shown that platelet count, plasminogen level, fibrin degradation products, INR and PTT results all remain unchanged (16). Two of the largest studies to date, of rt-pa use in non-dialysis central venous catheters (CVC s), which included over 1,000 patients, reported no cases of death, major bleeding episodes, or embolic events attributable to treatment (17, 18). The dose of rt-pa in these studies was 2 mg with a dwell time of up to 2 hours, with a second 2 mg dose administered if function was not restored (17, 18). Thus at low doses rt-pa appears to have relatively few adverse effects. Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 4

17 2.6 Treatment of Catheter Malfunction in Non-Dialysis Catheters Several studies have been published, looking at the treatment of thrombosis related catheter malfunction in non-dialysis catheters. The COOL-1 (17) and COOL-2 (18) trials were placebo controlled trials looking at the safety and efficacy of rt-pa for restoring function to occluded non-dialysis catheters. In COOL-1, patients with CVCs (n=150) were randomized to two treatment arms consisting of: placebo, rt-pa, rt-pa or rt-pa, rt-pa, placebo. The dwell time was two hours for each arm, with a second dose instilled only if function was not restored (defined as inability to withdraw blood). After the first dose, function was restored in 73.9% of patients treated with rt- PA, versus 17% of those treated with placebo (17). Successful restoration of function was achieved in 77% of patients who received placebo as the first treatment and rt-pa as the second. Restoration of function was also increased to 89.9% if two doses of rt- PA were used (17). In COOL-2 (18), a phase III open-label single-arm trial, 995 patients with occluded non-dialysis catheters received a 2 mg dose of rt-pa that was allowed to dwell for minutes. If the catheter remained obstructed at 120 minutes, a second dose of rt- PA was allowed to dwell for minutes. Flow was restored in 52% and 78% of catheters at 30 and 120 minutes after one dose, and 84% and 87% at 30 and 120 minutes after a second dose, respectively (18). This again, demonstrates an increased success rate with longer dwell times and sequential doses of rt-pa. The primary limitations of this study are the lack of a control group. Perhaps use of placebo and rt- PA may have been just as effective as subsequent doses of rt-pa. The 30 day catheter patency rate in COOL-2 was 65% (18). 2.7 Treatment of Catheter Malfunction in Hemodialysis Catheters A number of observational studies have attempted to determine the effectiveness of rt-pa in the treatment of hemodialysis catheter malfunction. Unfortunately, these studies are fraught with limitations, not the least of which are the lack of a control group and small sample sizes. One such study by Little et al (19) explored the repeated use of rt-pa in hemodialysis catheter malfunction among 336 patients corresponding to 570 episodes of malfunction. The median time to first catheter malfunction was 135 days, with thrombolytic use required in 2.77 catheters/100 dialysis sessions. The additional catheter survival advantage gained by repeated use of rt-pa was small, with a median survival time to next intervention of 27 days, and then less than 20 days for each additional episode. Daeihagh et al (20) studied the effect of rt-pa in re-establishing adequate blood flow in 22 consecutive hemodialysis patients. After a dwell time of 2 to 96 hours (median 24 hours) rt-pa was effective in establishing adequate blood flow rates in 87.5% of cases. The primary patency rate was 75% at 9 days, 50% at 24 days, and 25% at 61 days. Only one observational study has explored the effect of an rt-pa infusion in hemodialysis catheter malfunction. Savader et al (21) looked at a low dose rt-pa infusion for the treatment of catheter associated fibrin sheaths. A total of 5 mg of rt- PA was infused over 3 hours with success defined as ability to aspirate and flush the Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 5

18 port without resistance (21). Immediate technical success was 100% and patency rates were 67% at 30 days and 51% at 90 days (21). However, this protocol required radiographic diagnosis of a fibrin sheath with the infusion being administered in the radiology outpatient department. The adequacy of blood flow rates at the next dialysis session were not reported. Finally, only one randomized controlled trial has been conducted comparing two modalities of rt-pa administration on patency of dialysis catheters. MacRae et al (22) randomized 76 episodes of catheter malfunction (61 catheters) to a short one hour dwell of rt-pa versus a longer dwell (48 to 72 hours). The short dwell time of one hour with 2 mg rt-pa per port achieved an immediate success rate (QB >250 ml/min) of 65% (22). The longer dwell time of 48 to 72 hours achieved a success rate of 80% success (p=0.19). However, the median time to the next thrombotic event was 14 days and 18 days with the short and long dwell respectively (22). 2.8 Summary Clearly the evidence to guide the use of rt-pa in both the prophylaxis and treatment of catheter-related malfunction is limited. While preliminary data (11) would suggest rt-pa may be an effective catheter locking solution, the optimal dose and frequency of administration are unknown. Based on the limited evidence available we have designed a double blind, randomized trial to compare the use of recombinant tissue plasminogen activator (rt-pa) versus heparin in the primary prevention of dialysis catheter malfunction. This is a multi-centre trial involving approximately 14 study sites across Canada, and will include approximately 340 dialysis patients with a newly inserted permanent dialysis catheter. Patients will be randomized to a locking solution of rt-pa administered once per week (with heparin being used for the remaining two sessions) versus heparin alone after each dialysis session. Patients will be followed for a duration of six months, with a primary outcome being catheter malfunction, and a secondary outcome being catheter-related bacteremia. See Appendix 1 Study Schedule for an overview. Finally, a cost-effectiveness analysis will be undertaken to assess the costs associated with the use of rt-pa to maintain catheter patency. Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 6

19 Plan of Investigation 3. Study Objectives & Hypothesis 3.1 Primary Objective To determine if substituting rt-pa for heparin (1 mg per lumen) once per week as a catheter locking solution will decrease the incidence of catheter malfunction compared to locking with heparin alone after each dialysis session. 3.2 Secondary Objectives To determine if substituting rt-pa for heparin (1 mg per lumen) once per week as a catheter locking solution will decrease the incidence of catheter-related bacteremia, compared to locking with heparin alone after each dialysis session. A secondary objective of this study is an economic evaluation of rt-pa versus heparin in the primary prevention of catheter malfunction. Specifically the objectives of this economic component are to assess the cost required to avoid placement of a new dialysis catheter for patients treated with rt-pa compared to heparin, as well as to determine which locking solution is a less expensive strategy in preventing the requirement for a new dialysis catheter. The details of this economic evaluation are discussed in a separate section of this protocol. 4. Study Design & Duration 4.1 Design The current standard of practice in most dialysis centres is to lock the catheter lumen after each dialysis session with unfractionated heparin at a concentration of 1,000-10,000 units/ml, and a volume equal to the luminal volume. This standard of care, with a heparin concentration 5,000 units/ml (luminal volume) administered after each dialysis session will serve as the control arm. The intervention will be to lock both the arterial and venous catheter lumen with rt-pa at a dose of 1.0 mg once per week, with heparin 5,000 units/ml used as a locking solution for the other two dialysis sessions. Rt-PA will be administered into each lumen initially, with saline added to top-up the lock to the full luminal volume. The rt-pa locking solution will be instilled after the Wednesday session for patients who dialysis Monday/Wednesday/Friday, and after the Thursday session for patients who dialyze Tuesday/Thursday/Saturday. The set intervention days will ensure an equivalent dwell time of no more than 48 hours. 4.2 Duration The study period will be six months in duration. The primary outcome will be catheter malfunction, as defined below, with a secondary outcome of catheter-related bactermia. Hemorrhagic complications will also be monitored and reported. Patients will be stratified by study centre and virgin (first hemodialysis catheter ever) versus non-virgin (use of hemodialysis catheter at some point in the past) catheter status. Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 7

20 5. Study Population 5.1 Number of Patients One-hundred and seventy hemodialysis patients with a newly inserted permanent tunnelled hemodialysis catheter will be randomized to each arm of the study. Patients will be enrolled from approximately 14 sites across Canada. 5.2 Patient Selection Criteria Inclusion Criteria 1. End-Stage Renal Disease (ESRD) patients with newly inserted permanent, tunnelled, dual-lumen catheters 2. Naïve to study but not naïve to catheters (both virgin and non-virgin catheters will be included) 3. Expected to use catheter, and to dialyze at study centre, for at least six months (see text below for details) 4. Frequency of hemodialysis 3 times per week 5. If indication for new catheter insertion was for line related infection, patients will be eligible when (see text below for details): the infection has been treated and the patient has been off antibiotics for 3 hemodialysis sessions 6. Patient or legal representative able to provide written consent 7. Eighteen years of age or older 8. Baseline INR Baseline platelet count /L Eligible patients are hemodialysis patients with a newly inserted permanent tunnelled catheter. Both patients who have had a catheter inserted for the first time, and those who have had either a temporary or permanent catheter at some point in the past will be eligible for inclusion. Given the potential for a higher one-year primary patency rate for virgin versus non-virgin catheters (19), patients will be stratified by virgin (first catheter ever) versus non-virgin (catheter at any point in the past) catheter status. To decrease the drop-out rate only patients who are expected to use their catheter for at least six months will be eligible. In addition, patients who are expected to move to a satellite dialysis unit within six months of the catheter line insertion will be eligible only if that satellite unit is able to receive pharmacy dispensing of the study drug. Patients who are expected to move to a satellite unit within six months, where distance precludes delivery of the pharmacy dispensed medication, will not be eligible for inclusion. Given our secondary outcome of catheter-related bacteremia, patients who have had a hemodialysis catheter replaced for a catheter-related infection must Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 8

21 meet specific criteria before they are eligible for inclusion. First of all, a course of antibiotic therapy must have been completed, and secondly, the patient must have completed three hemodialysis sessions since completing the antibiotics. These restrictions may delay randomization for several weeks following the catheter insertion, during which time centre specific catheter management will take place. Details regarding delayed randomization will be recorded. Before any study specific procedure is performed, written informed consent for participation in the study must be obtained from either the patient themselves or a legal representative. Only patients 18 years of age and older will be included Exclusion Criteria 1. Use of systemic anticoagulation (if indication for anticoagulation is for catheter patency then patients may be eligible for inclusion if the systemic anticoagulation is discontinued and baseline INR is 1.3) 2. Insertion of a new permanent hemodialysis catheter by a guide-wire exchange procedure 3. Insertion of a new permanent hemodialysis catheter into the femoral vein 4. Current use of antibiotics for catheter-related bacteremia 5. Major hemorrhage in the prior 4 weeks, defined as bleeding resulting in a drop in hemoglobin of greater than 20 g/l or bleeding requiring transfusion of packed red blood cells with other clinical evidence or suspicion of bleeding 6. History of intra-cranial bleed in the prior 4 weeks 7. Intra-cranial or intra-spinal neoplasm (current) 8. Allergy or intolerance to rt-pa or heparin or its constituents 9. Active pericarditis defined by the presence of a pericardial rub 10. Weight 30 kg 11. Patient pregnant or lactating 12. Child bearing potential (i.e. pre-menopausal woman who is not using a reliable method of contraception) 13. Major surgery in past 48 hours (CABG, organ biopsy, puncture of noncompressible vessels), or scheduled for major surgery during the study period 14. Involvement in another randomized drug trial 15. Presence of a fever as defined by a temperature >38.2 C Patients who are on systemic anticoagulation either for atrial fibrillation, previous thrombosis, or genetic hypercoagulable states, will be excluded. Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 9

22 However if the indication for the systemic anticoagulation is catheter patency then these patients will be eligible for inclusion if their anticoagulation is discontinued prior to randomization. Given the secondary outcome of catheter-related bacteremia, patients currently on antibiotics for a catheter-related bacteremia are not eligible for inclusion until they satisfy the criteria defined above (section 5.2.1). Patients who have had a new catheter inserted using a guide-wire exchange procedure are also not eligible as the potential for re-inserting the catheter into a previously formed fibrin sheath may be higher with this technique. Bleeding complications associated with rt-pa in this setting are reported to be extremely low. Never-the-less, to avoid these potential complications we will exclude patients with a recent major hemorrhage, as well as patients with intra-cranial bleeds in the prior 4 weeks or current intra-cranial or intra-spinal neoplasm. 6. Patient Identification, Randomization & Intervention 6.1 Patient Identification The Study Coordinator will check with the interventional radiology department and the hemodialysis units on a daily basis to identify patients who have had a tunnelled catheter inserted. Note: sources of patient identification may vary depending on the investigational site. Eligible patients will be invited to participate. After written informed consent is obtained, the Study Coordinator will screen the patients for study eligibility using the inclusion/exclusion criteria defined in section 5.2 of this protocol. Written informed consent will be obtained before any study related procedure is performed. Patient recruitment will occur over approximately a two week period following catheter insertion, during which time centre specific catheter management (with respect to the locking solution) will take place. The patient will be eligible for randomization after the fourth hemodialysis session, if sessions three and four were successful (defined as a mean blood flow of 300 ml/min). Randomization will occur on the day preceeding the first treatment day (Wednesday or Thursday), depending on the patients dialysis schedule, following the fourth successful run. The approximate two week eligibility period is included for two reasons. First of all, the risk of local bleeding following catheter insertion may be slightly increased using a locking solution of heparin 5,000 units/ml. Therefore to decrease this risk catheter management during the initial time period following catheter insertion will be at the discretion of the study centre. Secondly, catheter malfunction which occurs within two weeks of insertion is more likely due to a mechanical cause rather than thrombosis. Randomization will be delayed for patients who have had a new catheter inserted for a catheter-related infection, as discussed in section 5.2. These patients will be eligible for randomization if hemodialysis sessions two and three OFF antibiotics are successful (defined as a mean blood flow of 300 ml/min). Randomization will occur Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 10

23 on the day preceeding the first treatment day (Wednesday or Thursday), depending on the patients dialysis schedule, following the third successful run off antibiotics. 6.2 Randomization Following informed consent, patients will be eligible for randomization on the day preceeding the first treatment day (Wednesday or Thursday) after their fourth successful hemodialysis session (with a successful run defined as a mean blood flow of 300 ml/min), or the third successful session off antibiotics for patients with a new catheter insertion for catheter-related infection. Patients will continue centre specific catheter management until their first treatment day. Patients will be randomized in blocks of four and stratified by study centre and virgin versus non-virgin catheter status. They will be assigned a randomization identification number and a treatment allocation by a centrally administered webbased computing system. The pharmacy departments at each study site will receive the randomization number and treatment allocation via , and will prepare and dispense the drug accordingly. 6.3 Study Treatment The study treatment, locking of the catheter lumen with rt-pa at a dose of 1.0 mg per lumen, will take place once per week. To ensure that the rt-pa is administered to the catheter tip, the site of thrombus formation, it will be instilled down each lumen first, followed by saline at a volume adequate to fill the entire luminal volume. Thus each patient will be dispensed four syringes (two syringes per lumen consisting of rt-pa and saline). To ensure blinding, patients in the control arm will also be dispensed four syringes, all of which will contain heparin 5,000 units/ml. A concentration of heparin 5,000 units/ml will be obtained by diluting heparin 10,000 units/ml with an equal volume of normal saline. The volume of heparin used as the locking solution will be equal to the luminal volume. All syringes will be labelled and numbered as to the order of instillation by the pharmacy. In order to ensure blinding of the patients and study personnel, the solutions for locking the catheter lumens will be prepared and dispensed by the pharmacy on the patient s treatment day. For patients who dialyse on a Monday/Wednesday/Friday schedule the treatment day will be Wednesday, while for patients who dialyse on a Tuesday/Thursday/Saturday schedule their treatment day will be Thursday. The pharmacy will have a record of the luminal volume of each patient s arterial and venous catheter lumens, and will administer a volume of drug equal to the luminal volume, divided into four syringes as described above. Heparin and rt-pa have a similar appearance, and will be dispensed in identical syringes. The lumens will be tagged indicating that a study drug of either heparin or rt-pa is contained in the lock. Heparin (5,000 units/ml, luminal volume), will be prepared and administered by the Hemodialysis Nurse, as per usual standard of care, for the non-treatment days (Monday and Friday for the Monday/Wednesday/Friday patients and Tuesday and Saturday for the Tuesday/Thursday/Saturday patients). Thus pharmacy dispensing of the locking solutions will occur only on the treatment days of Wednesday and Thursday. Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 11

24 7. Outcome Measures 7.1 Primary Outcome The primary outcome of the study will be catheter malfunction. This will be defined by one or more of the following events occurring after attempts to re-establish patency have been undertaken as per a pre-defined protocol (including flushing with a 10 cc syringe, repositioning the patient and reversal of lines): 1. Peak blood flow 200 ml/min for 30 minutes during an ongoing dialysis treatment (with maximum arterial and venous pressure limits of -250 mmhg and +250 mmhg respectively) 2. Mean blood flow 250 ml/min during two consecutive dialysis sessions, calculated as the blood processed in millilitres divided by the time on dialysis in minutes (with maximum arterial and venous pressure limits of -250 mmhg and +250 mmhg respectively) 3. Inability to initiate dialysis According to the recent K/DOQI guidelines an extracorporeal blood flow of 300 ml/min is required to maintain adequate dialysis (6). A peak blood flow of 200 ml/min for 30 minutes, or a mean blood flow of 250 ml/min during two consecutive dialysis sessions, were therefore chosen to define catheter malfunction. The blood flow must be maintained with a maximum venous pressure of +250 mmhg and arterial pressure of -250 mmhg, to ensure higher blood flows are not achieved at the expense of excessive pressures. A blood flow which cannot be maintained with venous and arterial pressures of 250 mmhg, should be investigated for catheter malfunction. Mean blood flow will be calculated as the blood processed, in millilitres, divided by the time on dialysis in minutes. Reversal of dialysis catheter lines may be required to initiate or maintain dialysis during some dialysis sessions. However, dialysis with a reversal of lines over several dialysis sessions, may lead to inadequate dialysis due to increased re-circulation of blood. The need for ongoing reversal of catheter lines to maintain dialysis would suggest potential catheter malfunction, and indicate further treatment or investigation of the dialysis catheter be undertaken. A strategy regarding dialysis catheter line reversal will therefore be implemented to ensure that ongoing reversal of dialysis lines is not undertaken at the expense of inadequate dialysis. The strategy to follow regarding dialysis catheter line reversal will include: Dialysis catheter lines may be reversed in an attempt to re-establish patency and initiate/maintain dialysis Dialysis catheter lines may be reversed for no more than three consecutive dialysis sessions After three consecutive dialysis sessions with reversed lines the next two consecutive dialysis sessions must be run without a reversal of lines, during which time a patient is eligible for the primary outcome if any of the primary outcome criteria listed above are met Amendment #2 - March 2, 2005 PROPRIETARY & CONFIDENTIAL 12