The US Food and Drug Administration has designated the Bristol-Mayers Squibb experimental HIV drug BMS-663068 as a breakthrough treatment, which could accelerate its approval.

The US drugmaker is currently running late-stage clinical tests with the drug, intended to be used with other antiretroviral drugs in adults who have already developed resistance to several other types of HIV treatments.

According to the National Institutes of Health, there are six classes of HIV drugs, and patients are typically treated with drugs from at least two different classes at any given time, but if they develop resistance to several types of drugs, their doctors may not be able to assemble an effective treatment regimen.

The company is studying BMS-663068 in patients who have two or fewer drug classes left to them. The new development, which the company said does not fit into the six current classes of HIV therapy, is designed to stick to HIV cells and stop them from binding to a type of white blood cell.