Descovy for PrEP® (FTC/TAF)

Non-Daily Dosing

This document is a summary of available data regarding non-daily dosing of Descovy for PrEP® (emtricitabine/tenofovir alafenamide [FTC/TAF] for HIV-1 pre-exposure prophylaxis) and includes content from or references to clinical practice guidelines. The inclusion of information from the guidelines should not be interpreted as a treatment recommendation or an endorsement of the guidelines by Gilead Sciences.

Some data may be outside of the US FDA-approved Prescribing Information. In providing this data, Gilead Sciences, Inc. is not making any representation as to its clinical relevance or to the use of any Gilead product(s). For information about the approved conditions of use of any Gilead drug product, please consult the FDA approved prescribing information.

The full indication, important safety information, and boxed warnings are available at: www.gilead.com/-/media/files/pdfs/medicines/hiv/descovy/descovy_pi.

Summary

Product Labeling1

The dosage of FTC/TAF for HIV-1 PrEP is one tablet (containing 200 mg of FTC and 25 mg of TAF) once daily taken orally with or without food in HIV-1 uninfected adults and adolescents weighing ≥35 kg and with a CrCl ≥30 mL/min, excluding individuals at risk from receptive vaginal sex.

Clinical Practice Guidelines on Non-Daily Dosing of FTC/TAF2

Non-daily dosing should not be prescribed with FTC/TAF because its use for pericoital dosing has not been approved by the FDA. The “2-1-1” regimen (also called event-driven, intermittent, or “on-demand”) is a non-daily PrEP regimen that times oral FTC/TDF doses in relation to sexual intercourse events.

Clinical Data on Non-Daily Dosing of FTC/TAF

The CHAPS study evaluated the efficacy of several on-demand drug and dosing regimens for PrEP (including FTC/TAF) as well as the PK and PD parameters in males who were eligible for VMMC. PK and PD data from participants enrolled from South Africa and Uganda are available.3,4

• For all dose regimens evaluated, PrEP with FTC/TAF resulted in higher TFV‑DP levels in foreskin explants and PBMCs than did PrEP with FTC/TDF.3
• 2 + 1 PrEP dosing tended to result in higher TFV-DP levels in foreskin explants than a single dose of 2 tablets.3
• A double dose of either FTC/TDF or FTC/TAF given once either 5 or 21 hours before ex vivo HIV-challenge provided protection of foreskin tissue.3

Clinical Data - CHAPS Study

Study Design

A phase 2, open-label, randomized controlled study evaluated the efficacy of several on-demand PrEP drug and dosing regimens for HIV-negative males between 13 and 24 years of age who were eligible for VMMC (Figure 1). The study was conducted in Uganda and South Africa. Efficacy was assessed using p24 antigen concentrations. PK and PD assessments, including TFV-DP and FTC-TP concentrations and a parallel evaluation in isolated PBMCs, were also performed.3 PK and PD data from enrolled participants have been summarized by Herrera et al.3,4

Figure 1. Study Design3

Note: Sixteen participants were recruited for each randomization arm.

Table 1. Randomization Arms4

Results3,4

There was no clear superiority of TAF to TDF in protecting foreskin against HIV acquisition. However, PrEP with FTC/TAF resulted in higher TFV-DP levels in foreskin explants and PBMCs than did PrEP with FTC/TDF, which suggests that protection may be of longer duration, or that the dosing requirements for on-demand FTC/TAF are somewhat lower than for FTC/TDF. Participants receiving a 2+ 1 regimen also had higher TFV-DP levels in foreskin than a single dose of 2 tablets. p24 concentrations in foreskin explants and PBMCs at Day 15 were similar in participants regardless of whether they had additional ex vivo exposure to their initial PrEP agent 20 hours later. The study authors concluded that ex vivo 2 + 1 tablet dosing confers similar protection of foreskin tissue against acquisition of HIV-1 as a single double dose PrEP and that the protection is sustained to at least 21 hours after ingestion of the last PrEP dose.

References

1. Enclosed. Gilead Sciences Inc, DESCOVY® (emtricitabine and tenofovir alafenamide) tablets, for oral use. U. S. Prescribing Information. Foster City, CA.

2. Centers for Disease Control and Prevention (CDC). US Public Health Service: Preexposure Prophylaxis for the Prevention of HIV Infection in the United States—2021 Update: Clinical Providers' Supplement. 2021. December.

3. Herrera C, Serwanga J, Else L, et al. Dose finding study for on-demand HIV pre-exposure prophylaxis for insertive sex in sub-Saharan Africa: results from the CHAPS open label randomised controlled trial. EBioMedicine. 2023;93:104648.

4. Herrera C, Serwanga J, Else L, et al. Dose finding study for on-demand HIV pre-exposure prophylaxis for insertive sex in sub-Saharan Africa: results from the CHAPS open label randomised controlled trial [Supplement]. EBioMedicine. 2023;93:104648.

Abbreviations

FTC=emtricitabine
FTC-TP= emtricitabine-triphosphate
PBMC=peripheral blood mononuclear cells
PD=pharmacodynamic(s)
PK=pharmacokinetic(s)
PrEP=pre-exposure prophylaxis
TAF=tenofovir alafenamide fumarate
TDF=tenofovir disoproxil fumarate
TFV-DP=tenofovir diphosphate
VMMC=voluntary medical male circumcision

Product Label

For the full indication, important safety information, and boxed warning(s), please refer to the Descovy US Prescribing Information available at:                                       www.gilead.com/-/media/files/pdfs/medicines/hiv/descovy/descovy_pi

Follow-Up

For any additional questions, please contact Gilead Medical Information at:                     ☎1‐866‐MEDI‐GSI (1‐866‐633‐4474) or   www.askgileadmedical.com

Adverse Event Reporting

Please report all adverse events to:

Gilead Global Patient Safety ☎ 1-800-445-3235, option 3 or 8 www.gilead.com/utility/contact/report-an-adverse-event

FDA MedWatch Program by ☎ 1-800-FDA-1088 or MedWatch, FDA, 5600 Fishers Ln, Rockville, MD 20852 or 8  www.accessdata.fda.gov/scripts/medwatch

Data Privacy

The Medical Information service at Gilead Sciences may collect, store and use your personal information to provide a response to your medical request.  We may share your information with other Gilead Sciences colleagues to ensure that your request is addressed appropriately.  If you report an adverse event or concern about the quality of a Gilead or Kite product, we will need to use the information you have given us in order to meet our regulatory requirements in relation to the safety of our medicines.

It may be necessary for us to share your information with Gilead’s affiliates, business partners, service providers and regulatory authorities located in countries besides your own.  Gilead Sciences has implemented measures to protect the personal information you provide.  Please see the Gilead Privacy Statement (www.gilead.com/privacy-statements) for more information about how Gilead handles your personal information and your rights.  If you have any further questions about the use of your personal information, please contact privacy@gilead.com.

DESCOVY, DESCOVY for PrEP, GILEAD, and the GILEAD logo are registered trademarks of Gilead Sciences, Inc., or its related companies.
© 2025 Gilead Sciences, Inc