An editorial published in Clinical Pharmacology & Therapeutics describes the progress made in combating human immunodeficiency virus (HIV) and addresses barriers that continue to prevent eradication.
Since the first clinical observation of HIV/AIDS in 1981, some 35.4 million people have died from AIDS-related illnesses. New antiretroviral therapies (ART) for HIV continue to be approved, yet despite their availability, roughly 1 million people died from AIDS-related illnesses in 2017.
This level of mortality, the authors noted, demonstrates a crucial need for new therapies and novel means of prevention. They point to combination antiretroviral therapies (cART), which make it possible to tailor and optimize treatment, as a major win. The approval earlier this year of Trogarzo (ibalizumab-uiyk; Theratechnologies), a treatment for multidrug-resistant HIV-1 infection in heavily treatment-experienced patients who have previously failed other regimens, is yet another advance. However, none of these therapies are a cure, and as with most individuals who initiate ART, treatment is required for life and viral rebound is likely to occur if it is stopped. “This rebound is largely attributed to persistent HIV reservoirs, which may result from latently infected resting CD4+ T-cells or inadequate penetration of ART drugs into sites of viral replication or sanctuary sites,” the authors explained.
Regarding prevention, a boosted bivalent form of the HIV viral protein, Env gp120 has shown some short-term promise as a potential vaccine, but long-term immune responses remain the goal. With no vaccine, condom use remains the main preventive measure for transmission. In addition, the implementation of pre-exposure prophylaxis therapy (PrEP) has led to reductions in new infections.
According to the authors, drug adherence remains a significant barrier to success in developed countries. “Although confounding factors, such as mental illness or substance abuse, are known to impact ART adherence, the stigma associated with HIV/AIDS is cited as a major culprit of nonadherence.” Poor adherence to PrEP has also affected assessments of efficacy in clinical trials (Brooks and Anderson, 2018). In addition, lack of treatment access continues to be an obstacle for HIV-infected individuals living in third world countries.
While significant advances have been made in the fight against HIV, barriers such as virus characteristics (ie, mutations, immune evasion, drug resistance), as well as global population issues (ie, limited drug access, corruption, nonadherence), continue to be obstacles to prevention and eradication. The authors concluded by stating that “Future development of strategies to overcome physiological, psychological, and economic barriers as well as enhanced efforts to optimize preventative approaches will require collaborative efforts across all disciplines of our society ranging from drug development, governmental regulation, and implementation policies.”
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