GlaxoSmithKline Plc (NYSE:GSK) is betting on a new two-drug regimen to treat HIV, a move that if successful could see it surge ahead of its rival Gilead Sciences, Inc. (NASDAQ:GILD). Traditionally, a three-med approach is used to treat HIV, which results in increased sides effects alongside increased financial burden for patients. Glaxo’s two-med treatment regimen is centered on Tivicay, the latest pill from Glaxo’s ViiV Healthcare unit.

Glaxo has already embarked on a number of clinical trials to demonstrate the use of Tivicay with just one other HIV-fighter to get the job done. In one of the studies, the British Pharma giant is testing Tivicay with Edurant from Johnson & Johnson’s Janssen. In another, the company is collaborating with long-used generic med 3TC. The company also has more drugs on the way.

GSK has already established that the use of Tivicay with Edurant is proving as effective as a three-drug medley in patients whose disease has been suppressed by a lead-in period of triple therapy. The company is currently planning to launch a late-stage trial fusing an injectable version of Tivicacy and Edurant. Glaxo’s Chief Executive Andrew Witty has already vouched for the trial noting that it would be a game changer, because taking fewer pills has financial and health benefits.

Rochelle Walensky, an associate professor of medicine at Harvard estimates that just by switching a quarter of patients currently on triple therapy to dolutegravir plus 3TC, an older generic HIV drug would reduce the cost of treating HIV by more than $3 billion in a five year period. The cost saving that would result from GlaxoSmithKline’s two-med would probably be higher.

However, in case Glaxo’s two drug vision doesn’t pan out, Gilead is working on a Tivicay competitor of its own, and could keep on moving with successful triple therapies. Also, even if GSK comes with a two-med therapy, doctors may not feel the pressure to switch most of their patients away from Gilead’s meds, now that the company has a new line of improved trios on the market. These products are less toxic than their predecessors.