Abstract
The public health problem of HIV and access issues related to ARVs
Despite the fact that new HIV infections and AIDS-related deaths have decreased by almost one third since the early 2000s, HIV/AIDS remains a substantial global health problem. In 2012, there were 35.3 million people living with HIV (PLWH). Low- and middle-income countries had 98% of the AIDS-related deaths, with sub-Saharan Africa bearing a disproportionate burden, accounting for 70.8% of all PLWH. Access to appropriate antiretroviral therapy (ART) is vital to prevent HIV morbidity and mortality, and high ART coverage also promotes HIV prevention by lowering the amount of virus circulating in people within a particular setting or population. The World Health Organization (WHO) released new treatment recommendations in June 2013 that raise the CD4 cell count threshold for ART initiation for most people (from 350 to 500 cells/mL) and expand the number of populations that should receive treatment irrespective of their immune status. These changes have substantially increased the number of people eligible for ART. At the end of 2012, almost 10 million people were receiving ART in low- and middle-income countries, or about 34% of the total eligible population under the 2013 WHO treatment guidelines (28.6 million). The access level in children was falling behind at an estimated 20% of the total paediatric population in need of ART; while 647 000 children were receiving ART as of December 2012, an additional 2.6 million children were eligible for ART under current WHO treatment guidelines, but not receiving it. In addition, access to second-line treatment remains limited, estimated by WHO at 4% where data from countries having access to viral load suggest much greater needs, with 14% of patients failing first-line treatment in South Africa within five years.
Antiretroviral (ARV) technology landscape
Emerging ARVs could play a key role for treatment in resource-limited settings. Integrase inhibitors (INIs) are a new class of ARVs with the potential to simplify treatment regimens, although their optimal role in the management of HIV is still being determined. The INI dolutegravir (DTG), approved by the United States Food and Drug Administration (FDA) in August 2013, is a well-tolerated compound with a very high barrier to resistance and high potential for all age groups with production costs that may be lower than other treatment options due to relatively low dose (50 mg, once-daily dosing). A combination is in the pipeline with DTG and abacavir + lamivudine (ABC+3TC); other potentially beneficial combinations need to be considered as well, including a combination with tenofovir: tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide fumarate (TAF). Studies of DTG with ritonavir (RTV)-boosted darunavir (DRV/r) are under discussion that could prove their role in second-line therapy and potentially co-formulated as a single full-regimen tablet. A number of paediatric trials are under way or planned and a granule formulation is in development.
