March 25 (Reuters) - The U.S. Food and Drug

Administration on Tuesday approved GSK's drug for a

common type of urinary tract infection (UTI) in women and

adolescent girls, one of five new approvals the British

drugmaker has been expecting this year.

The antibiotic, branded as Blujepa, is approved for women

aged 12 years and older to treat uncomplicated UTIs, which are

bacterial infections affecting the lower urinary tract in

otherwise healthy individuals.

GSK is banking on new drugs in its infectious diseases

portfolio, including its recently launched respiratory syncytial

virus vaccine, to make up for lost revenues from its

best-selling medicines and looming patent losses for its HIV

treatments.

Over half of all women will experience uncomplicated UTIs in

their lifetime, and around 30% will suffer at least one

recurrent episode, according to GSK.

The drug chemically known as gepotidacin is designed to

target the most common UTI-causing bacteria such as E. coli, the

company said.

The drug acts on a different part of the bacteria compared

to most other antibiotics, making it effective against organisms

resistant to current treatments, according to GSK.

The bacteria is also less likely to develop resistance to

the drug, as it would need to mutate in both the enzymes that

gepotidacin targets, according to GSK.

Antimicrobial resistance, where bacteria withstand the drugs

designed to kill them, results in over 2.8 million infections

annually in the United States, according to the CDC.

The approval was based on data from two late-stage trials

showing the drug was superior to nitrofurantoin, the

standard-of-care medication introduced in the 1950s.

In one of GSK's studies, gepotidacin achieved complete

disease resolution in 58.5% of patients compared with 43.6% for

nitrofurantoin.

The drug's development was partly funded by multiple U.S.

government grants, GSK said.

The FDA in October last year approved another oral

antibiotic, Orlynvah, developed by Irish biotech firm Iterum

Therapeutics ( ITRM ), for the treatment of certain types of bacterial

UTIs in adult women.