Background: Nevirapine is the only nonnucleoside reverse transcriptase inhibitor currently available as a paediatric fixed-dose-combination tablet and is widely used in African children. Nonetheless, the number of investigations into pharmacokinetic determinants of virological suppression in African children is limited, and the predictive power of the current therapeutic range was never evaluated in this population, thereby limiting treatment optimization.
Methods: We analysed data from 322 African children (aged 0.3–13 years) treated with nevirapine, lamivudine, and either abacavir, stavudine, or zidovudine, and followed up to 144 weeks. Nevirapine trough concentration (Cmin) and other factors were tested for associations with viral load more than 100 copies/ml and transaminase increases more than grade 1 using proportional hazard and logistic models in 219 initially antiretroviral treatment (ART)-naive children.
Results: Pre-ART viral load, adherence, and nevirapine Cmin were associated with viral load nonsuppression [hazard ratio = 2.08 (95% confidence interval (CI): 1.50–2.90, P < 0.001) for 10-fold higher pre-ART viral load, hazard ratio = 0.78 (95% CI: 0.68–0.90, P < 0.001) for 10% improvement in adherence, and hazard ratio = 0.94 (95% CI: 0.90–0.99, P = 0.014) for a 1 mg/l increase in nevirapine Cmin]. There were additional effects of pre-ART CD4+ cell percentage and clinical site. The risk of virological nonsuppression decreased with increasing nevirapine Cmin, and there was no clear Cmin threshold predictive of virological nonsuppression. Transient transaminase elevations more than grade 1 were associated with high Cmin (>12.4 mg/l), hazard ratio = 5.18 (95% CI 1.95–13.80, P < 0.001).
Conclusion: Treatment initiation at lower pre-ART viral load and higher pre-ART CD4+ cell percentage, increased adherence, and maintaining average Cmin higher than current target could improve virological suppression of African children treated with nevirapine without increasing toxicity.
aDivision of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
bMRC Clinical Trials Unit at University College London, London, United Kingdom
cDepartment of Paediatrics and Child Health, University Teaching Hospital, Lusaka, Zambia
dJoint Clinical Research Centre
eBaylor College of Medicine Bristol Myers Squibb Children's Clinical Centre of Excellence, Kampala, Uganda
fGulu Regional Centre of Excellence, Gulu, Uganda
gDepartment of Pharmacy, Radboud University Medical Centre, Nijmegen, The Netherlands.
*Ann S. Walker and Helen McIlleron contributed equally to the article.
Correspondence to Helen McIlleron, PhD, Groote Schuur Hospital, Observatory, K45 Old Main Building, Cape Town 7925, South Africa. Tel: +27 21 406 6292; fax: +27 21 448 1989; e-mail: firstname.lastname@example.org
Received 14 October, 2016
Revised 5 December, 2016
Accepted 5 December, 2016
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