The Intensive Pharmacokinetics Sub-study of Encore1 (ENCORE1-PK)

May 10, 2013 updated by: Kirby Institute

The Intensive Pharmacokinetics Sub-study of Encore1: A Randomised, Double-blind, Placebo-controlled, Clinical Trial to Compare the Safety and Efficacy of Reduced Dose Efavirenz (EFV) With Standard Dose EFV Plus Two Nucleotide Reverse Transcriptase Inhibitors (N(t)RTI) in Antiretroviral-naïve HIV-infected Individuals Over 96 Weeks

Safety and efficacy are key issues in antiretroviral therapy (ART) selection. Efavirenz (EFV) is an important component of combination ART in treatment naive individuals. Like many drugs, there are inter-individual differences in the efficacy and tolerability of EFV. The Encore1 study provides an opportunity to examine the pharmacokinetics (PK)(processes by which a drug is absorbed, distributed, metabolized, and eliminated by the body) of EFV in blood samples collected over a 24-hour dosing interval in participants receiving either standard 600 mg or reduced 400 mg dose EFV once daily.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This sub-study will investigate the relationships between dosage, EFV plasma concentrations, toxicity and virological efficacy. EFV concentrations in dried blood spots and matched plasma and will be evaluated to determine the utility of dried blood spot measurements in measuring EFV plasma concentrations. Measurements dried blood spots could potentially be a cheap and easy alternative to measurements in plasma. Dried blood spots can be easily collected from venous blood or fingerprick, do not need plasma separation and potentially need less stringent storage conditions during shipment.

Study Type

Interventional

Enrollment (Actual)

40

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

  • Argentina
      • Buenos Aires, Argentina
        • Hospital J.M. Ramos Mejia
  • South Africa
      • Cape Town, South Africa
        • Desmond Tutu HIV Foundation
  • Thailand
      • Bangkok, Thailand
        • Thai Red Cross-AIDS Research Centre, HIV-NAT Research Collaboration
  • United Kingdom
      • London, United Kingdom
        • Chelsea and Westminister Hospital

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

16 years and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

All participants enrolled into the main Encore1 study at participating sub-study sites will be eligible to participate.

Participants must meet the following additional inclusion criteria prior to intensive pharmacokinetic assessment. Inclusion Criteria:

  • provide written sub-study consent at or before week 0
  • taken randomized study drugs for at least 4 weeks but less than 8 weeks
  • taken EFV in the evening for at least 7 days
  • taken all EFV doses over the 3 preceding days.

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: Screening
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Reduced dose Efavirenz arm
Participants randomized in main study to receive EFV (400 mg once daily; 2 x 200 mg + 1 x placebo once daily) plus tenofovir/emtricitabine (300/200 mg) fixed-dose combination once daily
Drug: Efavirenz
600 mg once daily; given as 3 x 200 mg once
Drug: Efavirenz
400 mg once daily; given as 2 x 200 mg + 1 x placebo
Active Comparator: Normal Efavirenz dose arm
Patients randomized in the main study to receive EFV (600 mg once daily; 3 x 200 mg once daily) plus tenofovir/emtricitabine (300/200 mg) fixed-dose combination once daily
Drug: Efavirenz
600 mg once daily; given as 3 x 200 mg once
Drug: Efavirenz
400 mg once daily; given as 2 x 200 mg + 1 x placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
To compare the pharmacokinetic parameters of EFV determined from blood collected over a 24-hour dosing interval in blinded samples from participants taking either 600 mg or 400 mg once daily in combination with Truvada.
Time Frame: 48 weeks
48 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
To compare the safety and tolerability of EFV 400 mg versus 600 mg given once daily.
Time Frame: 48 weeks
48 weeks
To investigate the correlation between EFV concentration measurements from dried blood spots and concentration measured in matched plasma samples.
Time Frame: 48 weeks
48 weeks

Collaborators and Investigators

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

Sponsor

Kirby Institute

Collaborators

Chelsea and Westminster NHS Foundation Trust

Investigators

  • Principal Investigator: Marta Boffito, Dr., Chelsea & Westminster Hospital

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

September 1, 2011

Primary Completion (Actual)

May 1, 2013

Study Completion (Actual)

May 1, 2013

Study Registration Dates

First Submitted

January 5, 2011

First Submitted That Met QC Criteria

January 5, 2011

First Posted (Estimate)

January 7, 2011

Study Record Updates

Last Update Posted (Estimate)

May 13, 2013

Last Update Submitted That Met QC Criteria

May 10, 2013

Last Verified

November 1, 2012

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NCHECR-ENCORE1-PK

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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