In just six months between January and June, an additional 1 million HIV-infected people gained access to lifesaving treatment, according to figures announced in advance of World AIDS Day on Thursday.

The news came as several promising studies of drugs that could hasten the elimination of the disease are headed toward preliminary human trials.

According  to the United Nations Program on AIDS, huge progress has been made since 2000 and millions of lives have been saved, “but there are still important milestones to reach, barriers to break and frontiers to cross,” the agency said.