Abacavir: a safe first line drug for children

Adverse events associated with abacavir use in HIV-infected children and adolescents: a systematic review and meta-analysis.

Jesson J, Dahourou DL, Renaud F, Penazzato M, Leroy V. Lancet HIV. [1] 2016 Feb;3(2):e64-75. doi: 10.1016/S2352-3018(15)00225-8. Epub 2015 Dec 7.

Background: Concerns exist about the toxicity of drugs used in the implementation of large-scale antiretroviral programmes, and documentation of antiretroviral toxicity is essential. We did a systematic review and meta-analysis of adverse events among children and adolescents receiving regimens that contain abacavir, a widely used antiretroviral drug.

Methods: We searched bibliographic databases and abstracts from relevant conferences from Jan 1, 2000, to March 1, 2015. All experimental and observational studies of HIV-infected patients aged 0-18 years who used abacavir, were eligible. Incidence of adverse outcomes in patients taking abacavir (number of new events in a period divided by population at risk at the beginning of the study) and relative risks (RR) compared with non-abacavir regimens were pooled with random effects models.

Findings: Of 337 records and 21 conference abstracts identified, nine studies (eight full-text articles and one abstract) collected information about 2546 children, of whom 1769 (69%) were on abacavir regimens. Among children and adolescents taking abacavir, hypersensitivity reactions (eight studies) had a pooled incidence of 2.2% (95% CI 0.4-5.2); treatment switching or discontinuation (seven studies) pooled incidence was 10.9% (2.1-24.3); of grade 3-4 adverse events (six studies) pooled incidence was 9.9% (2.4-20.9); and adverse events other than hypersensitivity reaction (six studies) pooled incidence was 21.5% (2.8-48.4). Between-study inconsistency was significant for all outcomes (p<0.0001 for all inconsistencies). Incidence of death (four studies) was 3.3% (95% CI 1.5-5.6). In the three randomised clinical trials with comparative data, no increased risk of hypersensitivity reaction (pooled RR 1.08; 95% CI 0.19-6.15), grade 3 or 4 events (0.79 [0.44-1.42]), or death (1.72 [0.77-3.82]) was noted for abacavir relative to non-abacavir regimens. None of the reported deaths were related to abacavir.

Interpretation: Abacavir-related toxicity occurs early after ART initiation and is manageable. Abacavir can be safely used for first-line or second-line antiretroviral regimens in children and adolescents, especially in sub-Saharan Africa where HLA B5701 genotype is rare.

Abstract access [1]

Editor’s notes: Abacavir is a nucleoside reverse transciptase inhibitor (NRTI), available as a paediatric formulation. Abacavir in combination with lamivudine is the preferred NRTI backbone for children aged three to ten years and for adolescents weighing under 35 kilograms. It is thus part of both first- and second-line antiretroviral therapy (ART) regimens recommended for children by World Health Organization (WHO), American and European guidelines.  

In the context of implementation of large-scale ART programmes where abacavir is recommended as the NRTI of choice, understanding its toxicity is crucial. In adults the main concern is the increased risk of hypersensitivity reactions, particularly among people with the HLA B5701 genotype, and of myocardial infarction. Children have specific characteristics that affect both the pharmacokinetic profiles of drugs, and also drug tolerability in the short and the long term. Despite the widespread use of abacavir, there has been no systematic evaluation of the toxicity profile of abacavir in children. 

This systematic review of nine studies conducted between 2000 and 2015 demonstrates that there is a low risk of hypersensitivity reactions, especially for children living in sub-Saharan Africa, where 90% of children with HIV live. This is consistent with studies in adults which illustrates that the frequency of the HLAB5701 allele genotype in African populations is low, estimated to be less than two percent.

Other adverse events such as gastrointestinal symptoms and laboratory abnormalities were common. Rates of adverse events should be interpreted with caution as these could depend on factors such as other drugs in the regimen, adherence and so on. Furthermore, data on adverse events were obtained from cohort studies that were not blinded and selection or recall bias cannot be excluded.

Notwithstanding this, most adverse events occurred early after initiation of abacavir, were no more common than with other NRTI regimens, and were manageable. Importantly, there were no deaths associated with abacavir in any of the reported studies. This study supports the use of abacavir as a preferred drug in the NRTI backbone for treatment of children living with HIV. 

HIV Treatment [3]
Africa [4], Europe [5], Latin America [6]
Belgium [7], Brazil [8], France [9], Germany [10], Ghana [11], Ireland [12], Italy [13], Netherlands [14], Panama [15], Portugal [16], South Africa [17], Spain [18], Uganda [19], United Kingdom [20], United States of America [21], Zimbabwe [22]
  • [23]