The Los Angeles Times on Thursday profiled HIV-positive patients who were treated in the early 1990s using monotherapy, or single-drug treatment, and who often are resistant to antiretroviral combination therapies because they previously have taken one of their components. Monotherapy -- which was used before combination therapy was initiated in 1996 -- gave HIV "only one obstacle to mutate past," and has created a "virtually insurmountable mutational challenge" for researchers to develop effective HIV/AIDS-related therapies, the Times reports. According to the Times, an estimated 40,000 HIV-positive "veterans of monotherapy" in the U.S. are "playing a fearsome waiting game" while researchers "repeatedly improvise with existing medications" to develop "salvage therapy," a "last resort" treatment for monotherapy patients. Salvage therapy "is a machine of many moving parts" because a patient's resistance to a certain drug often means that they are resistant to all other drugs in its class, according to the Times. HIV-positive patients with resistance await new combinations and new classes of drugs such as integrase inhibitors that might offer the chance of a viable treatment (Ricci, Los Angeles Times, 1/19).