PURPOSE 1 which stands for Phase 3, Double- Blinded, Multicenter, Randomized Study to Evaluate Safety and Efficacy of Twice Yearly Long- Acting Subcutaneous Lenacapavir, and Daily Oral Emtricitabine/ Tenofovir Alafenamide for Pre- Exposure Prophylaxis in Adolescent Girls and Young Women at Risk of HIV Infection started in 2022 and has the main objective of evaluating the efficacy of lenacapavir (LEN) and emitricitabine/ tenofovir alafenamide (F/TAF) in preventing the risk of HIV-1 infection relative to the background HIV-1 incidence rate. 

The PURPOSE 1 study includes a cross-sectional study which has the Incidence phase, the Randomized phase a LEN Open Label Extension phase and Pharmacokinetic Tail Phase.
The PURPOSE I study in partnership with Gilead Sciences, Inc. is based in approximately 25 centers in South Africa and Uganda. In Uganda there are three sites that work on the PURPOSE study namely; Makerere- Kalangala, AMBSO and MUJHU with each site recruiting a total number of 250 cisgender Adolescent Girls and Young Women at risk of acquiring HIV-1 infection from the age of 16 to 25 years.

The study objectives are;

• The primary objective of the Incidence phase of the study is to estimate the HIV-1 background incidence rate.
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The primary objective of the Randomized phase of the study is;

• To evaluate the efficacy of LEN for HIV-1 pre-exposure prophylaxis (PrEP) in Adolescent girls and Young Women at risk of HIV-1 infection
• To evaluate the efficacy of F/TAF for HIV-1 PrEP in AGYW at risk of HIV-1 infection.