Odefsey is the second tenofovir alafenamide-based regimen to be approved by the FDA

Although the man's HIV strain is resistant to multiple drugs, doctors have still found a way to treat him.

But scientists were quick to point out the case was "rare" and an exception to the high efficacy of the drug. According to Gilead, results of two large placebo-controlled trials of the drug for pre-exposure prophylaxis, or PrEP show that there were no new adverse reactions to Truvada were identified from the iPrEx and Partners PrEP trials and the incidence and types of side effects were consistent with Truvada's safety and tolerability profile when used as an HIV treatment.

Additionally, Gilead is working closely with the ADAP Crisis Task Force, as the company has done for each of its other HIV medications, to provide discounts to state AIDS Drug Assistance Programs (ADAPs) that will help ensure access to Odefsey for patients who receive medications through these programs.

What does this mean for people who are taking the drug? Odefsey is also indicated as a replacement for a stable antiretroviral regimen in patients who are virologically suppressed (HIV-1 RNA of less than 50 copies per mL) for at least six months, with no history of treatment failure and no known substitutions associated with resistance to the individual components of Odefsey.

Canada has formally approved the use of PrEP by HIV negative gay men, in order to better protect them from contracting the virus.

Truavada has been approved for PrEP use in the US since 2012.

"Reaching the nation's treatment goal of ensuring 80 percent of all of those diagnosed with HIV achieve viral suppression (that is, keeping their virus under control and at a level that dramatically reduces the risk of transmission) alone would prevent an estimated 168,000 infections over the next five years", the federal agency reported on its website. "It's also the effective thing to do", Dr. Isaac Bogoch, an infectious disease expert who runs one of Canada's biggest HIV prevention clinics out of Toronto General Hospital, told Global News.

Gilead Sciences has added another new product to its HIV franchise following FDA approval of Odefsey, a three-drug regimen taken as a single small tablet once a day.

It was the first drug to be approved by the U.S. Food and Drug Administration to reduce the risk of HIV infection in high-risk populations.