Experimental HIV Treatment Models Highlight Successes and Pinpoint Obstacles to Expanding Care in African Countries

Researchers in developing countries with high burdens of HIV infection are developing promising new strategies to advance towards global HIV treatment targets, the 21st International AIDS Conference in Durban South Africa has heard.

The UNAIDS fast track strategy seeks to ensure that 90 percent of HIV-positive people know their status, 90 percent are able to access antiretroviral treatment (ART), and 90 percent of those on treatment attain viral suppression, by the year 2020. Studies on treatment expansion in several southern and East African countries presented at AIDS 2016 provide new insights on how to acheive the 90-90-90 objectives, while also identifying some critical obstacles to overcome.

Anton Pozniak, Clinical Service Director of the HIV Unit at the Chelsea and Westminster Hospital in London and Treasurer of the International AIDS Society, highlighted the scope of the task by referring to statistics from the UNAIDS Prevention Gap Report, which estimate that 57 percent of people living with HIV know their status currently, 46 percent of all people living with HIV have access to ART, and only 38 percent of people living with HIV have achieved viral suppression.

"The limited success of efforts to provide broader access to treatment are reflected in unacceptable mortality rates and a decreasing momentum in the reduction of new HIV infections globally," commented Pozniak. "The research reported here offers valuable insight into the opportunities and the challenges we face in gearing up delivery systems to meet our HIV treatment goals."

Two studies presented here focus on the impact of the 'test and treat' approach to ARV therapy on expanding treatment access and improving retention in care. Under the test and treat model, the administration of ARVs begins as soon as possible after individuals learn they are HIV-positive, without regard to CD4 counts.

"Interim results from the SEARCH study, conducted in 164 communities in rural Kenya and Uganda, showed a significant advance toward achieving the UNAIDS 90-90-90 target among adults living with HIV," said Maya L. Petersen, Associate Professor of Biostatistics and Epidemiology, Berkeley School of Public Health. "The study employed a community-based multi-disease approach to HIV testing combined with a patient-centred 'test and treat' model of ART. At the start of SEARCH, 45 percent of the HIV-positive population had viral loads below 500 copies/ml. Two years later, following the study intervention, 81 percent were virally suppressed."

In contrast, a study in 22 rural South African communities found little difference in viral suppression between those offered therapy through the test and treat approach, and those provided with standard ART according to national guidelines. Nine of 10 patients in both groups achieved viral suppression. But the study identified a weakness in the middle of the 90-90-90 cascade -- only one in three individuals newly diagnosed as HIV-positive was linked to treatment clinics within six months of testing.

The challenge of ensuring linkage to care after HIV testing was addressed in another study, conducted in Swaziland. A combination of interventions -- such as CD4 count testing immediately after receipt of HIV test results, use of mobile phones to remind patients of their appointments, and non-cash financial incentives -- resulted in a 50 percent increase in prompt linkage to care and retention in the treatment programme.

Two studies presented here highlighted commonly-encountered challenges for treatment programmes in developing countries:

The high proportion of people with HIV who seek treatment at an advanced stage of infection, when the immune system is severely affected and the risk of mortality is high.
A growing number of adolescents who have been on ART for prolonged periods and show declining viral suppression.

The REALITY trial, spanning Kenya, Malawi, Uganda, and Zimbabwe, compared mortality rates when two different models of care were provided to adults and children who presented for ART with severely compromised immunity (CD4
REALITY demonstrated that enhanced prophylaxis saved lives. In the first 24 weeks of treatment, there were 108 deaths in the group receiving standard care, compared to 80 among those receiving enhanced prophylaxis. Within 48 weeks the respective figures increased to 127 and 98 deaths, respectively.

"Providing enhanced prophylaxis at the start of ART reduced early mortality by 25 percent among patients with advanced HIV disease," said James Hakim, Professor of Medicine at the University of Zimbabwe College of Health Sciences. "When the gains are spread across the entire treatment programme, we are looking at saving three lives for every 100 patients we treat. Policy-makers should consider introducing this low-cost broad infection package for all HIV-positive patients presenting with very low CD4 counts."

Researchers analysing records from South Africa's National Health Laboratory Service (NHLS) found that the number of children and adolescents receiving ART in the country increased tenfold between 2004 and 2011, and twentyfold between 2012 and 2014, leading to the existence of a 'youth treatment bulge.' The bulge is mainly due to historic deficiencies in the prevention of mother-to-child transmission of HIV in the country, which resulted in substantial numbers of babies being born with HIV, but surviving due to ART. Now that PMTCT is universally available in South Africa, the bulge is expected to shrink over the coming decade.

The study also found that viral suppression among young people decreased with age. While 71 percent of children aged five to nine years were virally suppressed, the rate among those aged 10 to 14 years dropped to 65 percent, and only 61 percent of those in the 15-19-year age group achieved viral supression.

"The number of adolescents accessing HIV care is increasing, yet this group experiences poorer treatment outcomes than other age groups," said Mhairi Maskew, Senior Researcher in the Health Economics and Epidemiology Research Office, Faculty of Health Sciences at Wits University. "Programs prioritizing this key population require investment at the national level."