Gilead Study (GS-US-380-5578)

A Phase 1b Study to Evaluate the Safety and Pharmacokinetics of Bictegravir/Emtricitabine/Tenofovir Alafenamide (B/F/TAF) in Neonates Exposed to HIV-1

Overview

The Gilead Study (GS-US-380-5578) is a Phase 1b clinical study evaluating the safety, tolerability and pharmacokinetics (PK) of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in full-term newborns who have been exposed to HIV-1 but are not infected. The study is investigating B/F/TAF as a tablet-for-oral-suspension (TOS) formulation, administered alongside one antiretroviral medicine used as standard-of-care postnatal prophylaxis. The study aims to generate evidence on how the medicines are absorbed, distributed and eliminated in newborns and to assess whether this formulation may be suitable for use in this population.

Rationale

The availability of appropriate antiretroviral formulations for newborns exposed to HIV remains more limited than for older children and adults. Neonates have unique physiological characteristics that can affect how medicines are processed by the body, making it important to establish appropriate safety and pharmacokinetic data before new antiretroviral formulations can be considered for this population. B/F/TAF is a complete antiretroviral regimen with established use in adults and paediatric populations. Its tablet-for-oral-suspension formulation provides an option for infants and young children who are unable to swallow tablets. This study will contribute important evidence on the use of B/F/TAF in the neonatal period, including its safety profile, pharmacokinetics and acceptability.

Primary Objectives

The study aims to:

• Evaluate the safety of B/F/TAF TOS administered alongside one antiretroviral medicine used as standard-of-care postnatal prophylaxis in full-term neonates.
• Evaluate the plasma pharmacokinetics of bictegravir (BIC) in full-term neonates exposed to HIV-1 but uninfected.

Secondary Objectives

The study will:

• Evaluate the plasma pharmacokinetics of emtricitabine (FTC), tenofovir alafenamide (TAF) and tenofovir (TFV).
• Assess the acceptability and palatability of the B/F/TAF tablet-for-oral-suspension formulation in full-term neonates exposed to HIV-1 but uninfected.

Study Population

The study population comprises full-term neonates who are exposed to HIV-1 but uninfected, with a birth weight of at least 2.5 kg, and who are receiving one antiretroviral medicine as standard-of-care postnatal prophylaxis at study enrolment. Their mothers also participate in the study.

Investigators

Dr Faeezah Patel – Principal Investigator
Prof Lee Fairlie – Sub-Investigator
Dr Elizea Horne – Sub-Investigator
Dr Mrinmayee Dhar – Sub-Investigator
Dr Jeanne Coetzee – Sub-Investigator

Latest Update: March 2026

For more information, please email rhicomms@wrhi.ac.za