Safety of combination antiretroviral prophylaxis in high-risk HIV-exposed newborns: a retrospective review of the Canadian experience

Introduction: The optimal management of infants born to HIV-positive mothers who are untreated or have detectable viral load prior to delivery remains controversial. Despite the increasing use of combination antiretroviral therapy (cART) for post-exposure prophylaxis (PEP) of neonates at high risk of HIV infection, there is little safety and pharmacokinetic data to support this approach. The objective of this study was to evaluate the safety and tolerability of cART for PEP in HIV-exposed neonates.

Methods: Retrospective study on 148 cART and 145 Zidovudine (ZDV) monotherapy-exposed infants identified from four Canadian centres where cART for PEP has routinely been prescribed in high-risk situations. Physician-reported adverse events and clinical outcomes were extracted by chart review. Haematological and growth parameters at birth, one and six months of age were compared between cART and ZDV-exposed infants using multivariate mixed effects modelling.

Results: Non-specific signs and symptoms were reported in 10.2% of cART recipients versus none of the ZDV recipients. Treatment was discontinued prematurely in 9.5% of cART recipients versus 2.1% of ZDV recipients (p=0.01). In the multivariate model, cART recipients had lower mean haemoglobin (decrease of 2.07 g/L) over the 6-month period compared with ZDV recipients (p=0.04), but no effect was seen on absolute neutrophil count. cART recipients had lower weight and smaller head circumference at birth and one month of age compared with ZDV-exposed infants; these differences were no longer significant at six months of age.

Conclusions: cART administered at treatment doses for PEP in neonates was generally well tolerated, though a higher incidence of non-specific signs and symptoms and early treatment discontinuation occurred among cART recipients.