Gilead Sciences’ first human trial of its investigational capsid inhibitor, called GS-6207, yielded promising results. GS-6207 is a long-acting antiretroviral that can be injected subcutaneously (under the skin) and may provide a new option for those with multidrug-resistant virus. In an ongoing Phase Ib trial, 24 people with HIV who had not previously been treated with a capsid inhibitor received one subcutaneous injection of either a 50 milligram, 150 mg or 450 mg dose of GS-6207 or a placebo. Ten days later, those who received the drug experienced an average maximum reduction in viral load of 98.4% to 99.3% (1.8 to 2.2 log10)—reductions that were significantly greater than those seen among people who received the placebo. None of the participants experienced serious adverse health events or dropped out of the study because of adverse events.