US approves Gilead's twice-yearly injection to prevent HIV

Despite the impressive results, optimism may be tempered by the drug's cost. [AFP]

Drugs to prevent HIV transmission, known as pre-exposure prophylaxis or PrEP, have existed for more than a decade. But because they typically require taking a daily pill, they have yet to make a significant dent in global infections.

"This is a historic day in the decades-long fight against HIV," Gilead chairman and chief executive Daniel O'Day said in a statement.

Lenacapavir, marketed under the brand name Yeztugo, has been shown to reduce the risk of HIV transmission by more than 99.9 percent in adults and adolescents -- making it functionally akin to a powerful vaccine.

The company conducted two large clinical trials. The first, involving more than 2,000 women in sub-Saharan Africa, resulted in a 100 percent reduction in infections and demonstrated superiority over the daily oral pill Truvada.

In the second trial, involving over 2,000 men and gender-diverse individuals, only two infections were recorded - a 99.9 percent prevention rate, again surpassing Truvada.

Reported side effects included injection site reactions, headache, and nausea.

Results from both trials were published in The New England Journal of Medicine, and the journal Science named lenacapavir its 2024 "Breakthrough of the Year."