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The Efavirenz (EFV) Central Nervous System Exposure Sub-study of Encore1 (ENCORE1-CNS)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01451333
Recruitment Status : Completed
First Posted : October 13, 2011
Last Update Posted : May 13, 2013
Imperial College London
Information provided by (Responsible Party):
Kirby Institute

Brief Summary:
Persistent HIV infection in the central nervous system (CNS) compartment may put subjects at risk of developing HIV-related brain disease. Important factors associated with the development of HIV-related brain disease include therapeutic concentrations of antiretroviral drugs in the CNS. Conflicting evidence regarding the CNS exposure of the antiretroviral drug used for the encore1 study, efavirenz (EFV) have been described in related studies. There were recent study of two small series assessment of EFV exposure in the cerebral spinal fluid (CSF); one group reported small detectable EFV concentrations, while another observed undetectable EFV exposure in the CSF. Also, in a larger reported series comprising of 80 subjects on EFV-containing antiretroviral therapy, a CSF to plasma concentration suggested that there is limited movement of EFV out of the CSF. In HIV-1 infected subjects at steady state, EFV plasma level parameters are dose proportional following 200mg, 400mg, and 600mg daily doses. The CNS exposure of EFV at different daily dosing has not been described.

Condition or disease Intervention/treatment Phase
HIV Infection Drug: Efavirenz Phase 3

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 32 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Treatment
Official Title: The EFV Central Nervous System Exposure 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
Study Start Date : September 2011
Actual Primary Completion Date : October 2012
Actual Study Completion Date : February 2013

Resource links provided by the National Library of Medicine

MedlinePlus related topics: HIV/AIDS
Drug Information available for: Efavirenz

Arm Intervention/treatment
Experimental: Reduced dose Efavirenz arm
Patient's on main study that was randomised to receive TDF (300mg qd)/FTC (200mg qd) + EFV (400mg qd; 2 x 200mg + 1 x 200mg placebo qd).
Drug: Efavirenz
400mg qd; 2 x 200mg

Active Comparator: Normal Efavirenz dose arm
Patient's on main study randomised to receive tenofovir (TDF) (300mg qd)/emtricitabine (FTC) (200mg qd) + EFV (600mg qd; 3 x 200mg qd)
Drug: Efavirenz
600mg qd; 3 x 200mg qd

Primary Outcome Measures :
  1. comparison of mean CSF concentration of EFV from both doses after week 24. [ Time Frame: 24 weeks ]
    measure the CSF exposure of EFV when dosed at 400mg and 600mg daily. Efavirenz plasma and CSF concentrations will be analysed and CSF:plasma ratios will be compared. Associations between plasma and CSF concentrations and relationship to study clinical parameters will be assessed.

Secondary Outcome Measures :
  1. CSF EFV exposure and plasma exposure (CSF:plasma ratio) using statistical analysis [ Time Frame: 24 weeks ]
    The relationship between CSF EFV exposure and plasma exposure (CSF:plasma ratio), both for protein bound and free plasma EFV exposure.

  2. The relationship between CSF EFV exposure and neuropsychiatric side effects using questionnaires and medical assessments [ Time Frame: 24 weeks ]
  3. The relationship between CSF EFV exposure and other study parameters such as race and sex. [ Time Frame: 24 weeks ]
  4. The number of subjects with EFV CSF exposure greater than the postulated CSF IC50 for wild type virus (0.51ng/mL) [ Time Frame: 24 weeks ]
  5. CSF HIV RNA measurement after 12 - 24 weeks of study therapy [ Time Frame: 24 weeks ]
  6. Relationship between plasma HIV RNA and CSF HIV RNA [ Time Frame: 24 weeks ]
  7. CSF biomarker analysis after 12 - 24 weeks of study therapy [ Time Frame: 24 weeks ]
  8. comparison between magnetic resonance (MR) spectroscopy findings and CSF HIV RNA and EFV concentration [ Time Frame: 24 weeks ]

Information from the National Library of Medicine

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Ages Eligible for Study:   16 Years and older   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • All subjects entering into the main study protocol at participating centres will be eligible to enter this sub-study.

Exclusion Criteria:

  • Existing neurological disease which in the opinion of the investigator would be a contra-indication to lumbar puncture examination
  • CNS opportunistic infections in the past 12 weeks of randomisation
  • Bacterial or viral meningitis in the past 12 weeks of randomisation
  • Head injury requiring medical assessment in the past 12 weeks of randomisation

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01451333

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Medical Group Practice
Berlin, Germany, 10777
HIVNAT Research Collaboration
Patumwan, Bangkok, Thailand, 10330
Khon Kaen University
Khon Kaen, Thailand, 40002
United Kingdom
Imperial College, St. Mary's Hospital
Clinical Trials Centre, Winston Churchil Wing, London, United Kingdom, W2 1NY
Chelsea and Westminster Hospital
HIV/GUM laboratory 5th floor St. Stephen Centre, London, United Kingdom, SW10 9NH
Sponsors and Collaborators
Kirby Institute
Imperial College London
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Principal Investigator: Alan Winston, Dr. Imperial College London
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Responsible Party: Kirby Institute Identifier: NCT01451333    
Other Study ID Numbers: NCHECR-ENCORE1-CNS
First Posted: October 13, 2011    Key Record Dates
Last Update Posted: May 13, 2013
Last Verified: May 2013
Keywords provided by Kirby Institute:
Central Nervous System (CNS)
Lumbar puncture
Dose reduction
Additional relevant MeSH terms:
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HIV Infections
Lentivirus Infections
Retroviridae Infections
RNA Virus Infections
Virus Diseases
Sexually Transmitted Diseases, Viral
Sexually Transmitted Diseases
Immunologic Deficiency Syndromes
Immune System Diseases
Reverse Transcriptase Inhibitors
Nucleic Acid Synthesis Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Anti-Retroviral Agents
Antiviral Agents
Anti-Infective Agents
Cytochrome P-450 CYP2C9 Inhibitors
Cytochrome P-450 Enzyme Inhibitors
Cytochrome P-450 CYP2C19 Inhibitors
Cytochrome P-450 CYP2B6 Inducers
Cytochrome P-450 Enzyme Inducers
Cytochrome P-450 CYP3A Inducers