Impact of Early Initiation of Combination Antiretroviral Therapy on Measures of Virus in Peripheral Blood of Vertically HIV-1-Infected Children Jason Brophy 1 , Tae-Wook Chun 2 , Lindy Samson 1 , Fatima Kakkar 3 , Hugo Soudeyns 3 , Mario Ostrowski 4 , S. Mujib 5 , John Kim 6 , Paul Sandstrom 6 , Richard Harrigan 7 , Stanley E. Read 8 , Ari Bitnun 8 1. Children’s Hospital of Eastern Ontario, University of Ottawa; 2. National Institute of Allergy & Infectious Diseases, National Institutes of Health, U.S.A.; 3. CHU Sainte- Justine, Université de Montréal; 4. Department of Immunology and Medicine, University of Toronto, 5. University of Toronto, Institute of Medical Sciences, Department of Medicine; 6. National HIV & Retrovirology Laboratories, Public Health Agency of
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Early Combination Antiretroviral Therapy in Infants
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Impact of Early Initiation of Combination Antiretroviral Therapy on Measures of Virus in Peripheral Blood of Vertically HIV-1-Infected
Children
Jason Brophy1, Tae-Wook Chun2, Lindy Samson1, Fatima Kakkar3, Hugo Soudeyns3, Mario Ostrowski4, S. Mujib5, John Kim6, Paul Sandstrom6, Richard Harrigan7, Stanley E. Read8, Ari Bitnun8
1. Children’s Hospital of Eastern Ontario, University of Ottawa; 2. National Institute of Allergy & Infectious Diseases, National Institutes of Health, U.S.A.; 3. CHU Sainte-Justine, Université de Montréal; 4. Department of Immunology and Medicine, University of Toronto, 5. University of
Toronto, Institute of Medical Sciences, Department of Medicine; 6. National HIV & Retrovirology Laboratories, Public Health Agency of Canada; 7. University of British Columbia, British Columbia
Centre for Excellence in HIV/AIDS; 8. Hospital for Sick Children, University of Toronto
Early Combination Antiretroviral Therapy in Infants
The “Mississippi baby” received early cART – experienced a 2-year “viral remission” after stopping treatment until a recent viral rebound raises the possibility of this as an intervention to limit
reservoir establishment and enable “viral remission” Triple cART as HIV-post exposure prophylaxis has
been routinely administered to newborns at high risk for HIV infection in our centres for many years SickKids (Toronto), CHEO (Ottawa), and CHU Ste-Justine
(Montreal)
Objectives To investigate HIV-1 reservoirs in peripheral blood of
HIV-1-infected children with SVS following initiation of cART within 72 hours of birth
SVS: defined as absence of detectable virus in standard viral load (VL) assay subsequent to having achieved an undetectable VL (< 50 copies/mL)
Methods Retrospective review at our 3 centres of all children
born to HIV-infected mothers who received triple cART within 72 hours of birth
Evaluation of HIV reservoir, immune responses, and genetic characteristics in those infected children with SVS after cART
Results – Retrospective Review
136 infants received triple cART HIV infection in 12 (8.8%) In utero infection probable in at least 50% (n=6; HIV PCR
positive within 48 hours of birth) Timing uncertain in 50% (n=6) as testing done after 48 hrs
Four HIV-infected children achieved SVS (Cases 1-4) Eight HIV-infected children did not achieve SVS
6 of 8 did not achieve virologic suppression due to poor adherence
2 of 8 initially suppressed for 2-3 years, then experienced viral rebound after poor adherence (one during the course of our study – Case 5)
Reservoir Evaluation of 4 Early-Treated, HIV-Infected Children
Cases 1 to 4 had SVS from 2-7 years
All 4 remained on their original cART regimen of zidovudine, lamivudine, and nevirapine
‡ Limit of detection: 1.5 copies/mL; each assay performed on 6 mL of whole blood; § Limit of detection: 1.5 g RNA; performed in duplicate; ¶ Limit of detection; 20 copies/ml; ¥ HLA-B variation at positions associated with better virologic control (lower set-point) and specific protective amino acid substitutions are indicated in bold
Case 5 – Prior to Treatment Interruption
Initial findings before TI Case 5
Age/Sex/Clade 3 years/M/Clade B
Serology (ELISA & WB) Negative
Plasma viremia ‡ < 1.5 copies/mL
Cell-associated proviral DNA < 2.6 copies/g
Cell-associated RNA § 149 copies/1.5g RNA
HIV RNA in stimulated T-cells Not detected (6.7 million cells)
Discussion Absence of detectable HIV DNA and absent/very low levels
of replication-competent virus in peripheral blood and lack of HIV-specific immune responses demonstrated in a subgroup of children initiated on cART <72 hours of birth
Suggests early cART initiation can greatly reduce HIV reservoir size
Genetic factors may also play an important role - protective HLA genotypes were found in 3 of 4 children HLA B*58 Sequence variation at HLA-B positions 67, 70 and 97 (associated with
superior control of HIV replication) The child with replication competent virus did not have these
protective genotypic features International HIV Controllers Study, Science 2010Lazaryan, J Virology 2006; Lazaryan, J Virology 2010
Discussion Our 5th case with rapid viral rebound after interruption of
therapy despite limited reservoir size demonstrates that early cART will not be effective in all patients
Multiple factors may have influenced this patient’s outcome Baseline NNRTI resistance, sub-optimal initial regimen Low-level detectable VL after initial suppression
This, along with late relapse of viral replication in Mississippi baby, underscore the need for better understanding of contributing factors to reservoir & viral control Host and viral genetics Timing and completeness of initial viral suppression Selection of components of cART regimen in infants
Conclusions Based on our study findings and other reports, early cART
for HIV-infected infants clearly limits size of viral reservoir Additional non-blood reservoir sites require investigation The clinical significance and benefit of this remain to be seen
Accurate estimation of size of HIV viral reservoir in children is significantly impacted by limitations in collection of adequate blood volumes in children compared with adults
A prospective multi-centre observational study (EPIC4) is underway in Canada to determine the impact of early versus later treatment on reservoir size and HIV control in children
Acknowledgments The children and parents who agreed to participate in this
study The Canadian Institutes for Health Research, Canadian
Association for AIDS Research, and the International AIDS Society for funding to carry out EPIC4 study
QUESTIONS?
Reservoir, Immunologic Responses and Genetics
Level of cell-associated HIV-1 DNA in CD4+ T cellsreal-time PCR
Level of cell-associated HIV RNACobas Ampliprep/Cobas Taqman HIV 1 assay‐
Residual plasma viremiamodified Cobas Ampliprep/Cobas Taqman HIV 1 assay‐
Presence of replication competent viruslevel of virion-associated HIV RNA in culture supernatant after mitogenic stimulation
Not detected 0.1 infectious units/10^6 CD4 T-cells
Not detected Not done
‡ Limit of detection: 1.5 copies/mL; each assay performed on 6 mL of whole blood; § Limit of detection: 1.5 g RNA; performed in duplicate; ¶ Limit of detection; 20 copies/ml; ¥ HLA-B variation at positions associated with better virologic control (lower set-point) and specific protective amino acid substitutions are indicated in bold