Glaxo, through its ViiV Healthcare joint venture, has been looking for simpler ways to control the virus, with the hope that fewer drugs will lead to fewer side effects.
Over the course of a year, patients taking Dovato, a tablet containing dolutegravir and lamivudine, once a day were able to maintain viral suppression after switching from a cocktail of at least three drugs previously.
The results will give GSK a boost in its bid to topple US drugmaker Gilead Sciences, the current leader in the HIV treatment market.
“When we developed the TANGO study, we asked if virally suppressed people living with HIV could reduce the number of medicines in their HIV treatment regimen while maintaining viral suppression,” said Kimberly Smith, the head of global research at ViiV Healthcare.
“These Week 48 data clearly indicate that they can - individuals who are already on treatment can maintain viral suppression if they switch from a 3-drug, TAF-containing regimen to a 2-drug regimen of dolutegravir plus lamivudine.”
Last week, the treatment was approved by European regulators, following on from the approval given by the US Food and Drug Administration earlier in the year.
At the end of 2017, another one-pill, two-drug HIV treatment, called Juluca, was approved by US regulators.
GSK shares were broadly flat at 1,638.4p on Wednesday morning.