(Reuters) – GlaxoSmithKline PLC’s unit ViiV Healthcare said on Monday its two-drug regimen to treat HIV was as effective in patients given the treatment every two months, as when administered once a month.

The drug, Cabenuva, the long-acting injectable two-drug regimen of antiviral compounds cabotegravir and Johnson & Johnson’s rilpivirine, met the main goal at the end of 48 weeks.

“This two-drug regimen may provide an opportunity for people living with HIV to break the cycle of taking a daily pill and reduce their total treatment dosing days from 365 to six,” Kimberly Smith, head of research and development, said.

ViiV, in which Pfizer and Shionogi & Co Ltd have small stakes, was testing Cabenuva in adults with HIV-1 infection for whom the number of viral particles in the bloodstream was suppressed and were not resistant to cabotegravir and rilpivirine.

The U.S. Food and Drug Administration in December declined to approve https://reut.rs/2xiL4qZ the once-monthly treatment, Cabenuva, questioning the treatment’s chemistry, manufacturing and controls process, but not its safety.

Smith declined to comment on how long it would take to address FDA’s requests from the December complete response letter, but said there would still likely be a staggered launch even after the drug has been approved.

“It’s most likely that we would still get the four week approval first and the eight week approval would follow,” said Smith, adding the delay between them could be as much as 10 months.

The drug, which is a monthly injection to suppress the virus that causes AIDS, is aimed as an alternative to daily pills.

GlaxoSmithKline’s once-a-day pill, Dovato, also a two-drug combination, won U.S. market approval in 2019.

(Reporting by Ludwig Burger in Frankfurt and Trisha Roy in Bengaluru; Editing by Shinjini Ganguli)