Antiretroviral therapy has allowed more patients with HIV to live into their 60s and even 70s, but HIV medications are typically toxic for the people who take them. Drugmakers are therefore seeking to make medications that subdue the illness without wreaking havoc on aging bodies, and minimize the risk of harmful drug interactions for people on multiple medications. GlaxoSmithKline is now working on two-drug combinations, rather than traditional combination therapies. In 2013, Glaxo introduced a new treatment that scientists say is less toxic than older formulas and which makes it hard for the virus to evolve resistance. The drive to simplify treatment could restructure the competitive landscape: UBS says that if Glaxo’s dual regimens prove effective, the company could capture one-half of the market by 2023, up from 17% today. In addition, Gilead this year received FDA approval for an upgraded version of emtricitabine; tenofovir disoproxil fumarate (Truvada)—the preferred basis of therapy for nearly a decade—that replaces the ingredient connected to kidney and bone problems with a formulation that causes fewer adverse events.