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Title HAART in HIV-1 infected children : 10 years of clinical experience
Author H.J. Scherpbier
Faculty Faculty of Medicine
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HAART in HIV-1-infected children: 10 years of clinical experience
Cover artwork: Armand Avril
Copyright © 2006 Henriëtte J. Scherpbier
Lay-out: Chris Bor, Academic Medical Centre, & Kor L. Hacket
Photo: Maurice Boyer
Printed by Buijten & Schipperheijn, Amsterdam, The Netherlands
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HAART in HIV-1-infected children:
10 years of clinical experience
ter verkrijging van de graad van doctor
aan de Universiteit van Amsterdam, op gezag van
de Rector Magnificus prof. mr. P.F. van der Heijden
ten overstaan van een door het college voor promoties ingestelde commissie,
in het openbaar te verdedigen in de Aula der Universiteit
op woensdag 18 oktober 2006, te 10.00 uur
Henriëtte Jacqueline Scherpbier
geboren te Winschoten
Prof. dr. T.W. Kuijpers
Prof. dr. M.L. Newell
Prof. dr. P. Reiss
Prof. dr. P. Speelman
Prof. dr. H. Schuitemaker
Dr. T.F.W. Wolfs
Faculteit der Geneeskunde
Financial support for the publication of this thesis was gratefully acknowledged from
Abbott BV, Boehringer Ingelheim BV, Bristol-Myers Squibb, GlaxoSmithKline BV, Pfizer BV,
Roche BV, UCB Pharma-Gilead Sciences
Voor Anna en Charlotte
1 Introduction 11
2 Long-term experience with combination antiretroviral therapy that contains
nelfinavir for up to 7 years in a pediatric cohort 25
3 Once-daily HAART in HIV-infected children: safety and efficacy of an efavirenz-
containing regimen 39
4 Therapeutic immune reconstitution in HIV-1-infected children is independent of
their age and pretreatment immune status 55
5 Persistent, humoral immune defect in HAART-treated children: loss of specific
antibodies against attenuated vaccine strains and natural viral infection 69
6 Viral dynamics after starting first-line HAART in HIV-1-infected children 83
7 The pharmacokinetics of nelfinavir in HIV-1 infected children 95
8 Population pharmacokinetics and pharmacodynamics of nelfinavir and its active
metabolite M8 in HIV-1-infected children 105
9 Liver failure in a child receiving highly active antiretroviral therapy and
HAART in HIV-1 infected children: 10 years of clinical experience -
Summary and discussion 125
Nederlandse samenvatting 147
Curriculum vitae 158
In the early 1980´s nobody could foresee the tremendous impact of a new clinical entity,
now known as `acquired immunodeficiency syndrome´ (AIDS). A large spectrum of
clinical manifestations, previously rarely observed, was seen: opportunistic infections,
malignancies (Kaposi sarcoma, malignant lymphomas) and neurological disorders
(dementia, encephalopathy) (1). In the early days AIDS was predominantly restricted to
homosexuals, but subsequently also in hemophiliacs, recipients of other blood products
and intravenous drug users and their sex partners. Later on also children, born to mothers
with or at risk of the syndrome, were described (2-4). The first patients were seen in the
United States of America, but subsequently patients were identified in sub-Saharan Africa.
The major symptoms were weight loss and diarrhea and people in rural Uganda called it ‘
In 1983 the causative agent was identified as a virus belonging to the genus Lentivirus of
the Retroviridae (5,6). This virus is now called HIV-1 (Human Immunodeficiency Virus
type 1). In 1986 another human homologous virus was identified, nowadays called HIV-2
(7). We will use the word HIV for HIV-1 unless stated otherwise.
Since the Eighties, a pandemic has emerged all over the world, especially in the
developing world, where poverty, poor health care systems and limited resources for
prevention and care fuel the spread of the virus. A disproportional burden has been placed
on women and children, who in many settings continue to experience high rates of new
HIV infections and of HIV-related illness and death (8).
At the end of 2005 the Joint United Nations Program on HIV/AIDS (UNAIDS) / World
Health Organization (WHO) Epidemic Update reported that an estimated 38.6 million
adults (17.3 million women) and 2.3 million children (< 15 years of age) are now living
with HIV, about 4.1 million became newly infected, and an estimated 2.8 million people
died of AIDS (8,9) [Table 1]. This is more than 50% higher than the figures projected by
the WHO in 1991.
In 2005 globally more than 540,000 children younger than 15 years became infected,
about 90% of these infections occurring in sub-Saharan countries being babies born to
HIV-positive mothers. The epidemic has left behind 15 million orphans, vulnerable to
poverty, exploitation and themselves becoming infected with HIV. In Sub-Saharan Africa,
the region with the largest AIDS burden, 2.0 million adults and 330.000 children died of
AIDS in 2005.
The HIV incidence rate (annual number of new infections as a proportion of previously
uninfected persons) has peaked in some countries (Kenya, Tanzania, Zimbabwe), but in
southern Africa the epidemic is still expanding (Botswana, Namibia, Swaziland, South
Africa). Women and children are the most vulnerable with a female-male ratio of about 3:1.
11 Chapter 1
In Northern America, Western and Central Europe 2.0 million people are living with HIV
in 2005, among them 15.000 children younger than 15 years of age. However, in Eastern
Europe an estimated 220,000 people were infected with HIV in 2005. Especially in the
Ukraine and the Russian Federation epidemics are expanding, forming the biggest AIDS
epidemic of Europe. Unsafe intravenous drug practice is the major risk factor in these
In Asia around 8.3 million people are living with HIV − more than two-thirds of
them living in India. In China, Indonesia, Vietnam, Bangladesh and Pakistan the HIV
prevalence is rising.
In Latin America an estimated 1.6 million people are now living with HIV, among them
32,000 are children younger than 15 years of age.
Most infected children acquired their infection from mother-to-child-transmission
(MTCT), which can occur during pregnancy, and more often during labor and delivery or
during breastfeeding (10-12). In the absence of any intervention the risk of MTCT is 15-
30% in non-breastfeeding populations; breastfeeding by an infected mother increases the
risk with 15-20% to a total of 30-45% (12).
In 1994 a breakthrough in prevention strategies came by the ACTG 076 study, a placebo-
azydothymidine (AZT, zidovudine) controlled study in pregnant HIV-positive women
and 6 weeks AZT in their non-breastfed off-spring. AZT reduced the transmission rate by
67%: i.e. transmission rates were observed of 22.6 % in the placebo group and 7.6% in the
AZT-treated group (13). The ACTG 076 regimen was rapidly introduced in the Western
world, but was too expensive for low-and middle-income countries. Shorter and simpler
antiretroviral regimens have subsequently been evaluated in trials in these countries (14-24).
TABLE 1 Regional HIV and AIDS statistics and features, 2005 by UNAIDS (8)
Region Adults (15+) & children
living with HIV*
Adults (15+) &
infected with HIV
Adults (15+) & child
death due to AIDS
Sub-Saharan Africa 24.5 million/2.0 million*2.7 million6.1 2.0 million
North Africa and
440000 / 3100064000 0.2 37000
Asia 8.3 million / 176000930000 0.4600000
Oceania 78000 / 30007200 0.3 3400
Latin America 1.6 million / 320001400000.559000
Caribbean 330000 / 2200037000 1.627000
Eastern Europe and
1.5 million / 6900 2200000.8 53000
Western Europe and
2.0 million / 1500065000 0.5 30000
TOTAL 38.6 million / 2.3 million 4.1 million1.02.8 million
Antiretroviral therapy and also HAART is now given to HIV-infected pregnant mothers
in high-income countries, where the MTCT rate has declined to about 1% (25). In the
Women and Infants Transmission Study Group (WITS) levels of HIV RNA at delivery
and prenatal antiretroviral therapy were independently associated with transmission (25).
Recently, concerns have been raised about potential teratogenic effects. The National
Study of HIV in Pregnancy in United Kingdom and Ireland showed between 1990
and 2003 no statistically significant association between the prevalence of congenital
abnormalities and exposure to ART overall: 3.4% (90 of 2657 pregnancies) in exposed
pregnancies and 2.2% (10 of 463 pregnancies) in non-exposed pregnancies (p=0.17);
prevalence was similar whether or not exposure to whatever type of ART had occurred in
the first trimester (p=0.48) (26).
HAART before and during pregnancy has been associated with prematurity, pre-eclampsia
and gestational diabetes (27-32). Women may already be at increased risk of nevirapine-
associated hepatotoxicity, especially those with CD4+ T cells > 250 cells/mm3 (31).
Elective cesarean section (ECS) is an efficacious intervention for the prevention of MTCT
among HIV-1-infected women not taking antiretrovirals or taking only zidovudine, but the
risk of postpartum mortality with ECS is higher than that associated with vaginal delivery,
yet lower than with non-ECS (33-35).
Long-term effects of maternal HAART in non-infected HIV-exposed children have been
observed as well. Bunders et al found alterations in hematological parameters, which may
persist for a long period (36). To date, the clinical implications remain uncertain.
A French group described neurological involvement in HIV-and ART-exposed infants,
possibly associated with mitochondrial disease (37). This association has not been
confirmed in other large cohorts in the US or by the European Collaborative Study on
In resource-constrained settings much effort focuses on the implementation of HIV-
testing and counseling during pregnancy and introduction of more effective antiretroviral
regimens, starting during the third trimester in HIV-infected pregnant women (38,39).
However, in 2005 only 9% of the pregnant women received ART (39). Although
reducing MTCT assessed at 4-6 weeks post-partum to 2-4%, infants remain at risk when
the mothers continue breastfeeding (39). Research is ongoing to evaluate several new
approaches to prevent HIV transmission during breastfeeding (39,40).
The reverse side of this is an unjustified or half-hearted use of ART. As a consequence,
viral resistance may emerge on large scale and limit future treatment options for both
mothers and children (41,42).
Diagnostic tests in pediatric HIV and immunophenotyping
Early diagnosis of HIV-infection in vertically HIV-exposed children is hampered by trans-
placental maternal HIV antibodies. Virological assays, including PCR tests to detect HIV
RNA (or DNA) or to quantify the viral load, can be used to determine the presence of HIV
or rule out infection in infants less than 18 months of age. Serologic diagnostic methods,
including HIV-specific ELISA, immunofluorescence, and western blot assays, can be
used to diagnose HIV in infants over 18 months of age, when maternal antibodies have
disappeared completely from HIV-exposed infants (43).
The challenge of the early and accurate diagnosis of perinatally HIV-exposed infants
is the use of new assays to detect different HIV subtype infections that are prevalent in
developing countries. Rapid, simple, and inexpensive serologic and virologic assays are
being developed for worldwide use (43).
Dried paper blood spots have already been used with PCR tests for HIV RNA and have been
shown to be very reliable. Recently, a quantitative p24 antigen test has been developed using
dried paper spots of blood drops, which showed similar sensitivity and specificity to tests
using blood plasma, has the potential to further simplify testing and improve health care
delivery to HIV-affected individuals in resource-constrained countries (44).
Immunophenotyping is performed by flowcytometry and routinely used to count the T
cells (subdivided into the major subsets of CD4+ T helper cells and cytotoxic CD8+ T
cells), CD19+(CD20+) B cells and NK cells. We believe that it is better to use absolute
CD4+ T cell counts in pediatric studies on T cell repopulation during HAART, since
CD4+ T cells as percentages of total T-cell counts are influenced by the major changes in
the number of CD8+ T cells, a condition often encountered in HIV-infected patients.
In the pediatric population we meet the problem that CD4+ T cell counts change with
age. Reference values are much higher in infants and young children than in older ones.
Therefore, the absolute CD4+ T-cell counts were calculated as percentage of normal
absolute values resulting in an independent age-adjusted parameter for the degree of T cell
Natural history and classification of disease
Before HAART the natural history of HIV/AIDS in children showed a much more rapid
progression with a high viral load, a more profound immune deficiency (depletion of
CD4+ T cells) and impaired growth characteristics. Around 23% of HIV-infected infants
developed AIDS before the age of 1 year, and nearly 40% by 4 years of age. Ten percent
died in their first year of life and almost 30% before reaching the age of 5 years (47).
Barnhart described the natural history of pediatric HIV infection, using five progressive
stages using the clinical categories in the CDC 1994 pediatric HIV classification system
(48): stage N, no signs or symptoms; stage A, mild signs or symptoms; stage B, moderate
signs or symptoms; stage C, severe signs or symptoms; and stage D, death.
A total of 2,148 perinatally HIV-infected children, born between 1988 and 1993, were
included in the analysis. The estimated mean times spent in each stage were: N, 10
months; A, 4 months; B, 65 months; and C, 34 months. The authors estimated that a child
born with HIV infection has a 50% chance of severe signs or symptoms developing by 5
years of age and a 75% chance of surviving to 5 years of age. For a child in stage B, there
is a 60% chance of severe signs or symptoms developing within the next 5 years and a
65% chance of surviving 5 more years. The estimated mean time from birth to stage C
was 6.6 years (95% CI, 5.7-7.5 years), and the estimated mean survival time was 9.4 years
(95% CI, 8.1-10.7 years) (49).