Women were well-represented in studies of Truvada for PrEP. (The drug had been in use since 2004 as a form of treatment for people who already have HIV infections.) With between 20 and 52 percent cisgender women, the successful PrEP trials were strong enough to establish its effectiveness and enable its broad approval.
And in May, promising results emerged from a clinical trial for a long-lasting injectable form of PrEP that also works by blocking an enzyme the virus needs to replicate. Cabotegravir is made by ViiV, a pharmaceutical company that is majority-owned by GlaxoSmithKline. An independent panel of experts overseeing the cabotegravir study, known as a data and safety monitoring board, ended the trial early after it showed the injectable was at least as protective as Truvada for men and transgender women. (In fact, there were 12 new HIV infections in the cabotegravir group versus 38 in the