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Objectives: No data are available on bone metabolism in infants exposed to tenofovir during breastfeeding. We investigated bone metabolism markers in the first year of life in infants from mothers who received tenofovir, lamivudine and efavirenz during pregnancy and 12 months of breastfeeding in a national Option B+ programme in Malawi.Methods: Serum samples collected at 6 and 12 months in tenofovir-exposed infants and in a small sample of tenofovir-unexposed infants from the same clinical centre were analysed in batches for levels of bone-specific alkaline phosphatase (BAP; marker of bone formation) and of C-terminal telopeptide of type I collagen (CTX; marker of bone resorption).Results: Overall, 136 tenofovir-exposed infants were evaluated. No infant had at either timepoint CTX values above the upper normal limit, while most of them had at 6 and 12 months levels of BAP above the upper normal limit for the age range. Levels of bone markers showed no differences by gender and no association with growth parameters. Tenofovir-unexposed and -exposed children had similar mean levels of bone markers at 6 months (CTX: 0.62 versus 0.55 ng/mL, P = 0.122; BAP: 384 versus 362 U/L, P = 0.631).Conclusions: No significant association between treatment with tenofovir and CTX or BAP levels was found. The high levels of BAP, coupled to the normal levels observed for CTX, might reflect primarily skeletal growth. Potential negative effects of prolonged exposure to tenofovir through breastfeeding cannot however be excluded and longitudinal studies that evaluate bone mineralization status in children enrolled in Option B+ programmes are warranted. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate antiretroviral drug concentrations in mothers and infants enrolled under the Option B-Plus approach for the prevention of HIV mother-to-child transmission in Malawi and to assess the maternal virological response after 1 year of treatment.Patients and Methods: Forty-seven women and 25 children were studied. Mothers were administered during pregnancy a combination of tenofovir, lamivudine and efavirenz and continued it during breastfeeding (up to 2 years) and thereafter. Drug concentrations were evaluated in mothers (plasma and breast milk) at 1 and 12 months post-partum and in infants (plasma) at 6 and 12 months of age. Drug concentrations were determined using an LC-MS/MS validated methodology.Results: In breast milk, tenofovir concentrations were very low (breast milk/maternal plasma ratio = 0.08), while lamivudine was concentrated (breast milk/plasma ratio = 3) and efavirenz levels were 80% of those found in plasma. In infants, median levels at 6 months were 24 ng/mL tenofovir, 2.5 ng/mL lamivudine and 86.4 ng/mL efavirenz. At month 12, median levels were below the limit of quantification for the three drugs. No correlation was found between drug concentrations and laboratory parameters or indices of growth. HIV-RNA >1000 copies/mL was seen at month 1 in 15% of the women and at month 12 in 8.5%. Resistance was found in half of the women with detectable viral load.Conclusions: Breastfeeding infants under Option B-Plus are exposed to low concentrations of antiretroviral drugs. With this strategy, mothers had a good virological response 1 year after delivery. [ABSTRACT FROM AUTHOR]