Clinical trials have shown that six-monthly injections of lenacapavir are almost 100 percent protective against becoming infected with HIV. But big questions remain over the drug’s affordability.

The Food and Drug Administration approved the preventative use of lenacapavir, made by Gilead Sciences, on Wednesday. Experts say lenacapavir is easier to administer, and each dose lasts longer compared to other medications.

Gilead’s Yeztugo will offer an alternative to treatments such as daily pills and every-other-month injections.