June 20 (Reuters) - Gilead Sciences ( GILD ) said on

Thursday a late-stage study showed its injectable drug,

lenacapavir, showed superior efficacy in preventing HIV

infection in women compared to the company's existing daily pill

Truvada.

There were zero incident cases of HIV infection among women

who received lenacapavir, Gilead said.

Lenacapavir was well-tolerated with no significant or new

safety concerns in the study, the company said, adding that more

detailed data would be presented at a future conference.

About 1.2 million people in the United States have HIV,

according to the CDC.

Truvada, which combines the medicines tenofovir and

emtricitabine, is used to treat HIV and also in a prevention

regimen known as pre-exposure prophylaxis (PrEP).

PrEP can lower the risk of getting HIV from sex by about

99%, according to the CDC.

Lenacapavir, branded as Sunlenca and given twice a year,

gained U.S. approval in 2022 as a long-acting treatment option

for heavily pre-treated patients infected with HIV and who have

become resistant to multiple drugs.

In the study, which had more than 5,300 cisgender women and

adolescent girls aged 16-25, participants received either

lenacapavir, Descovy or Truvada.

Cisgender refers to people who identify as the sex assigned

to them at birth, while transgender is an umbrella term for

those who do not, and non-binary is for those who do not

identify exclusively as a man or woman, according to the Human

Rights Campaign.

A once-daily pill, Descovy was approved in 2019 to reduce

the risk of sexually acquired HIV infection in men and

transgender women who have sex with men.

Gilead said it expects results from another late-stage trial

testing lenacapavir for PrEP among men who have sex with men,

transgender men, transgender women and gender non-binary

individuals who have sex with partners assigned male, in late

2024 or early 2025.

The studies are part of a program comprising of five

late-stage HIV prevention trials being conducted around the

world.