Baseline PI susceptibility by HIV-1 Gag-protease phenotyping and subsequent virological suppression with PI-based second-line ART in Nigeria

Objectives

Previous work showed that gag-protease-derived phenotypic susceptibility to PIs differed between HIV-1 subtype CRF02_AG/subtype G-infected patients who went on to successfully suppress viral replication versus those who experienced virological failure of lopinavir/ritonavir monotherapy as first-line treatment in a clinical trial. We analysed the relationship between PI susceptibility and outcome of second-line ART in Nigeria, where subtypes CRF02_AG/G dominate the epidemic.

Methods

Individuals who experienced second-line failure with ritonavir-boosted PI-based ART were matched (by subtype, sex, age, viral load, duration of treatment and baseline CD4 count) to those who achieved virological response (‘successes’). Successes were defined by viral load <400 copies of HIV-1 RNA/mL by week 48. Full-length Gag-protease was amplified from patient samples for in vitro phenotypic susceptibility testing, with PI susceptibility expressed as IC₅₀ fold change (FC) relative to a subtype B reference strain.

Results

The median (IQR) lopinavir IC₅₀ FC was 4.04 (2.49–7.89) for virological failures and 4.13 (3.14–8.17) for virological successes (P = 0.94). One patient had an FC >10 for lopinavir at baseline and experienced subsequent virological failure with ritonavir-boosted lopinavir as the PI. There was no statistically significant difference in single-round replication efficiency between the two groups (P = 0.93). There was a moderate correlation between single-round replication efficiency and FC for lopinavir (correlation coefficient 0.32).

Conclusions

We found no impact of baseline HIV-1 Gag-protease-derived phenotypic susceptibility on outcomes of PI-based second-line ART in Nigeria.

A3 Molecular epidemiology of HIV-1 in Nigeria

Nigeria has been reported to have the highest number of AIDS-related deaths in the world. In this study, we aimed to use molecular epidemiology to investigate the HIV-1 diversity and phylodynamics in Nigeria. We analyzed 1,442 HIV-1 pol sequences collected from 1999 to 2014 from seven geopolitical zones in Nigeria. The main circulating strains, CRF02_AG (44.1% of the analyzed sequences), Subtype G (8.3%), and CRF43_02G (16.4%), were introduced to Nigeria in the 1960s, 1970s, and 1980s, respectively. The number of effective infections decreased in Nigeria after the introduction of free antiretroviral treatment in 2006. We also found a significant number of unique recombinant forms (22.7%), the majority of which were recombinants between the two or three of the main circulating strains described above. In addition, phylogeographic analysis indicates multiple occasions of HIV-1 transmission between Lagos and Abuja (two of the main cities in Nigeria). Our results may be relevant for HIV-1 intervention and contribute in making informed decisions in strategies aiming at reducing further spread of HIV-1 in Nigeria.

Delay in the Provision of Antiretroviral Therapy to HIV-infected TB Patients in Nigeria

Background

Nigeria has a high burden of HIV and tuberculosis (TB). To reduce TB-associated morbidity and mortality, the World Health Organization recommends that HIV-positive TB patients receive antiretroviral therapy (ART) within eight weeks of TB treatment initiation, or within two weeks if profoundly immunosuppressed (CD4<50 cell/μL).

Methods

TB and HIV clinical records from facilities in two Nigerian states between October 1^st, 2012 and September 30^th, 2013 were retrospectively reviewed to assess uptake and timing of ART initiation among HIV-positive TB patients. Healthcare workers were qualitatively interviewed to assess TB/HIV knowledge and barriers to timely ART.

Results

Data were abstracted from 4,810 TB patient records, of which 1,249 (26.0%) had HIV-positive or unknown HIV status documented, and the 574 (45.9%) HIV-positive TB patients were evaluated for timing of ART uptake relative to TB treatment. Among 484 (84.3%) HIV-positive TB patients not already on ART, 256 (52.9%, 95% CI: 45.0-60.8) were not initiated on ART during six months of TB treatment. 30.0% of 273 patients with a known CD4≥50cells/μL started ART within eight weeks, and 14.8% of 54 patients with a known CD4<50cells/μL started within the recommended two weeks. Only 42% of health workers interviewed reported knowing to interpret guidelines on when to initiate ART in HIV-positive TB patients based on CD4 cell count results. CD4 cell count significantly predicted timely ART uptake.

Conclusion

A large proportion of HIV-positive TB patients were not initiated on ART early or even at all during TB treatment. Retraining of staff, and interventions to strengthen referral systems should be implemented to ensure timely provision of ART among HIV-positive TB patients in Nigeria.