['hiv']
['efavirenz', 'tenofovir /emtricitabine', 'tenofovir/lamivudine', 'lamivudine/zidovudine']

        Inclusion Criteria:

          1. Evidence of a personally signed and dated informed consent document indicating that
             the participant has been informed of all pertinent aspects of the study.

          2. HIV-1-infected pregnant female, stable on two nucleos/tide analogues
             (tenofovir/emtricitabine or tenofovir/lamivudine or zidovudine/lamivudine) and
             efavirenz 600mg once daily for more than 12 weeks and willing to take efavirenz 400 mg
             once daily at gestational age of 28 weeks +/- 3 weeks.

          3. Undetectable viral load (by local assay).

          4. CD4 count > 100 cells/mm3.

          5. Aged between 18 to 45 years, inclusive.

        Exclusion Criteria:

          1. Viral load ≥ 50 copies/mL (or detectable by local assay).

          2. Evidence of organ dysfunction or any clinically significant deviation from normal in
             physical examination, vital signs, ECG or clinical laboratory determinations.

          3. Positive blood screen for chronic hepatitis C (if available locally) or hepatitis B.

          4. Current or recent (within 3 months) gastrointestinal disease.

          5. Clinically relevant alcohol or drug use (positive urine drug screen) or history of
             alcohol or drug use considered by the Investigator to be sufficient to hinder
             compliance with treatment, follow-up procedures or evaluation of adverse events.

          6. Exposure to any investigational drug or placebo within 3 months prior to first dose of
             study drug.

          7. Use of any other drugs, including over-the-counter medications and herbal
             preparations, within two weeks prior to first dose of study drug, unless
             approved/prescribed by the Principal Investigator as known not to interact with study
             drugs.
      