The Plasma Large-Volume Exchange RCT (PLEX-RCT)

April 16, 2013 updated by: Dr William F Clark, London Health Sciences Centre

The Plasma Large-Volume Exchange Randomized Controlled Trial (PLEX-RCT)

Thrombotic thrombocytopenia purpura / hemolytic uremic syndrome (TTP/HUS) is a rare, life-threatening disorder. TTP/HUS causes multiple blood clots to form, which prevents blood from reaching the brain and kidneys. TTP/HUS affects 3-5 people per million per year. Anyone can develop TTP/HUS, but it is most common among 30-40 year olds, and women are twice as likely as men to acquire the condition. TTP/HUS sometimes develops as a result of medication use, pregnancy or cancer; however, for the majority of patients (80%) the cause of TTP/HUS is unknown. In 1991, researchers discovered that plasma exchange was superior to plasma infusion in treating idiopathic TTP/HUS. During plasma exchange the patient's blood plasma is removed and replaced with healthy blood plasma. Without plasma exchange, the survival rate for TTP/HUS is extremely low, with fewer than 5% of patients surviving. Treating TTP/HUS with plasma exchange improved the survival rate to 80%. Although this represents a dramatic improvement, researchers are still searching for methods to improve survival. No major advances in treating TTP/HUS have occurred in the past 20 years. Recent research suggests that high-dose plasma exchange may improve the survival of TTP/HUS patients. The investigators will conduct a randomized controlled trial to test whether treating TTP/HUS patients with high-dose versus standard-dose plasma exchange improves the treatment response. The investigators will recruit 150 patients with TTP/HUS from 9 centres across Canada over three years. The investigators will evaluate whether high-dose plasma exchange improves the treatment response, survival, and whether it reduces the number and volume of plasma exchange procedures and duration of hospital stay.

Study Overview

Detailed Description

Background: Thrombotic thrombocytopenia purpura / haemolytic uremic syndrome (TTP/HUS) is a rare blood disorder with a high mortality rate of >95% when left untreated. In 1991, researchers discovered that treating TTP/HUS with plasma exchange vs. plasma infusion dramatically improved the survival rate, from 60% to 80%.The optimal plasma dose for treating TTP/HUS is unknown; however, recent research suggests that high-dose plasma exchange may improve survival in patients with TTP/HUS.

Hypothesis: Treatment of TTP/HUS with high-dose vs. standard-dose plasma exchange will significantly decrease the composite outcome of 1) treatment failure at day 5 and/or 2) non-response or death at 2 weeks.

Methods: The investigators will conduct a multi-centre, parallel group randomized controlled trial. The investigators anticipate recruiting 150 eligible patients with idiopathic TTP/HUS from 9 centres across Canada over 2.25 years. Patients will be randomized to receive high-dose plasma exchange (125 ml/kg/day up to 10 L/day plasma volume) or standard-dose plasma exchange (50-75 ml/kg/day; approximately 1-1.5 plasma volume). The primary composite outcome includes treatment failure at day 5 or non-response or death from any cause at 2 weeks. Secondary outcomes include the individual components of the primary outcome, non-response or death from any cause at month 1 and month 6, days to remission, duration of hospital stay, number and volume of plasma exchange treatments, and cost minimization.

Research Team: Our multi-centre team is part of the Canadian Apheresis Group, which was established in 1980 and currently operates in 30 centres across Canada. Collectively, the Canadian Apheresis Group treats 150 TTP/HUS patients each year. Our team includes experienced haematologists, nephrologists, epidemiologists and a biostatistician. The investigators have successfully collaborated on several projects and have an excellent publication record (>50 publications across more than 15 journals including the New England Journal of Medicine).

Timeline and Budget: Because TTP/HUS is a relatively rare disorder (an orphan disease), the investigators will recruit patients over 2.25 years from across Canada to achieve a sufficiently large sample size. A cost minimization study will be carried out in conjunction with the RCT to provide insight into potential costing.

Future Directions: If the investigators can demonstrate that high-dose plasma exchange significantly improves the primary outcome, the investigators will pursue a multi-national collaboration with American, Chinese and European Centres to investigate other important outcomes including optimal dosing, cost-effectiveness and survival.

Implications: This study has the potential to be the first major advancement in treating TTP/HUS in twenty years.

Study Type

Interventional

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Ontario
      • London, Ontario, Canada, N6A 4G5
        • Central Facility

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. Age > 18 year-old
  2. First presentation of TTP/HUS
  3. Meet all of the following diagnostic criteria:

    • Platelet count < 150 x 109 /L
    • Microangiopathic haemolytic anaemia (blood film with presence of red blood cell fragmentation)
    • LDH > 1.25 X the upper limits of normal
    • No alternative diagnosis

Exclusion Criteria:

  1. Secondary TTP/HUS
  2. Relapsing TTP/HUS
  3. Hypersensitivity to blood product
  4. Patient has received 2 or more plasma exchange treatment since symptom started over the last 1 week
  5. Received medication, including cyclosporine, cyclophosphamide, rituximab for treatment of TTP/HUS
  6. Other causes of thrombocytopenia than TTP/HUS

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: TREATMENT
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: NONE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
ACTIVE_COMPARATOR: Standard-dose plasma exchange
50-75 ml/kg/day
Plasma exchange is a blood purification technique that removes plasma from the blood and replaces it with donor plasma.
EXPERIMENTAL: High-dose Plasma Exchange
125 ml/kg/day up to 10 L/day
Plasma exchange is a blood purification technique that removes plasma from the blood and replaces it with donor plasma.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
treatment failure at day 5 and/or 2) non-response or death at 2 weeks
Time Frame: baseline to two weeks
LDH >1.25 x the upper limit of normal at Day 5 and <50% decrease from initial value, or Initial platelet count <50 x 109/L with <100% rise at Day 5, or Initial platelet count 50-99 x 109/L with <50% rise at Day 5, or Initial platelet count 100-150 x 109/L with Day 5 <150x 109/L, or LDH >1.25 x the upper limit of normal at 2 weeks, or Platelet count <150 x 109/L at 2 weeks, or Persistent or new neurological symptoms at 2 weeks
baseline to two weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
All-cause mortality
Time Frame: 1 month; 6 months,
all-cause mortality at 1-month and 6-months after treatment initiation
1 month; 6 months,

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2012

Primary Completion (ANTICIPATED)

December 1, 2014

Study Completion (ANTICIPATED)

March 1, 2015

Study Registration Dates

First Submitted

September 9, 2011

First Submitted That Met QC Criteria

September 12, 2011

First Posted (ESTIMATE)

September 13, 2011

Study Record Updates

Last Update Posted (ESTIMATE)

April 17, 2013

Last Update Submitted That Met QC Criteria

April 16, 2013

Last Verified

April 1, 2013

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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