What if people at risk of HIV could protect themselves without taking a daily pill? In a landmark clinical trial in Uganda, researchers found that a twice-yearly injectable prevention method was highly effective. The study was led by CARTA fellow Flavia Matovu Kiweewa – part of a growing network of African researchers supported by the CARTA leading high-impact, policy-relevant research.

Adolescent girls and young women in Uganda continue to face a disproportionate risk of HIV/AIDS: according to the Uganda AIDS Commission 2025 report, they account for roughly four out of five new infections among young people. While daily oral pre-exposure prophylaxis (PrEP) can prevent HIV, persistent barriers such as stigma, pill fatigue, and inconsistent access to medication, often limit its effectiveness. 

Amid this persistent challenge, African-led research is generating the evidence needed to shape more effective HIV prevention strategies. The clinical trial led by Flavia evaluated innovative approaches among cisgender women and directly contributed to the approval of lenacapavir, a long-acting injectable HIV prevention medicine. This treatment offers a new and effective option for people at risk—particularly adolescent girls and young women and marks an important milestone in expanding HIV prevention choices globally.

The Clinical Trial 
The study, “Twice-Yearly Lenacapavir or Daily F/TAF for HIV Prevention in Cisgender Women”, dubbed PURPOSE 1, is part of the broader PURPOSE clinical trial programme, a series of global studies evaluating long-acting lenacapavir for HIV prevention across different populations. PURPOSE 1 was a phase 3 (final large-scale, pre-approval) multi-center, randomized, double-blind clinical trial conducted at 28 sites – three in Uganda and 25 in South Africa. In Uganda, Flavia led the Makerere University–Johns Hopkins University Research Collaboration to carry out the study across Mityana, Mubende, Kassanda, greater Masaka, and the Kalangala islands.

Flavia served as Uganda’s national Principal Investigator (PI) as well as for the Mityana site. She coordinated closely with her Ugandan colleagues, including investigators at Makerere University (Professor Noah Kiwanuka) and the Africa Medical and Behavioural Sciences Organization (Dr. Godfrey Kigozi), to ensure scientific and ethical rigor. She also actively engaged the Uganda Ministry of Health, the National Drug Authority,  local policymakers and community stakeholders to maintain participant safety and relevance of the findings to national HIV prevention strategies.

The trial compared twice-yearly injectable lenacapavir with daily oral PrEP. Early results suggested extremely high protection among women receiving lenacapavir. Updated results from the PURPOSE 1 trial, presented at the Conference on Retroviruses and Opportunistic Infections (CROI) in February 2026, confirmed that twice-yearly subcutaneous lenacapavir is highly effective, with an incidence of just 0.07 infections per 100 persons among cisgender adolescent girls and young women in sub-Saharan Africa. In contrast, w0men using daily oral PrEP experienced about 2 infections per 100 women each year. 

The drug was generally well-tolerated and safe in pregnancy, with reactions in the site of injection such as nodules or redness rarely severe enough to lead to discontinuation. A sister study – PURPOSE 2, expanded the evidence base to include a global cohort of cisgender men, transgender women, transgender men, and non-binary individuals who have sex with men. PURPOSE 2 mirrored the high efficacy seen in PURPOSE 1. There were only two infections per 1000 persons per year. This represented 96% reduction in HIV incidence. 

From Local Evidence to National Policy
The evidence generated by the Ugandan sites in PURPOSE 1 study contributed directly to submissions to the Uganda National Drug Authority to inform the approval of the use of lenacapavir in the country. This locally generated evidence complemented global clinical data and helped accelerate the review process, reducing the standard timeline of 210 days to 120 days. On January 5, 2026, Uganda officially authorized lenacapavir for use as pre-exposure prophylaxis, marking a major milestone in HIV prevention in Uganda. The Global Fund has committed $1.14 million worth of the drug, with approximately 36,000 doses expected to reach nine health facilities in the first quarter of 2026.

Toward a Comprehensive Prevention Toolbox
While lenacapavir represents a major step forward, it is part of a broader effort to expand HIV prevention options for women. Researchers are now exploring multi-purpose prevention technologies that can protect against both HIV and unintended pregnancy, as well as easier-to-use options such as the investigational once-monthly oral drug, MK-8527. The long-term goal is to create a prevention toolbox that gives women real choices, between daily pills, monthly tablets, or twice-yearly injections—based on what works best for their lives. 

CARTA’s Role in Strengthening African Research Leadership
Flavia’s leadership in this landmark study reflects CARTA’s long-term investment in strengthening African research leadership and ensuring that locally generated evidence informs health policy and practice. She reflects:

“Leading this trial was both a challenge and a privilege. CARTA gave me the training and confidence to manage a study of this scale, from coordinating with international partners to engaging local policymakers. It taught me not just to conduct research, but to ensure that the evidence we generate actually informs national HIV prevention strategies globally.”

Through CARTA, Flavia expanded her research portfolio, strengthened her collaborations with African scholars, and secured competitive grants such as the National Institute of Health (NIH) Research Project Grant (R01). This support allowed her to gain international visibility and opened doors to high-level global collaborations, which have since accelerated advancements in HIV prevention policy and practice in Uganda and beyond. 

Flavia’s leadership in this landmark study reflects a broader shift—where African researchers are not only contributing to global science, but leading it across disciplines and sectors. Supported by initiatives like CARTA, African-led research continues to redefine what is possible – advancing knowledge, informing policy, and delivering real-world impact across communities and sectors.