Renal tubular dysfunction with tenofovir-based HAART in four vertically infected adolescents

A poster authored by Onyeador and coworkers from Imperial College and St Mary’s Hospital, London described renal tubular dysfunction in four adolescents receiving tenofovir-based HAART.

This was a retrospective case note review of children <18 years old who have ever received tenofovir. In this clinic, all children receiving tenofovir undergo prospective screening by annual renal ultrasound scanning (USS), three monthly serum electrolytes and urine Ca/Cr, albumin/Cr or protein/Cr and retinal binding protein.

In this cohort of 139 HAART experienced, vertically infected children, 51 (37%) had received tenofovir. Four (8%) patients, all female, had documented renal tubular leak at a median age of 16.9 years (range 12.3-18 years). The children’s ethnicity was: black african (2), caucasian (1) asian/caucasian (1). None of the children had hepatitis B/C coinfection, prior renal disease, family history of renal disease or hypertension.

Their median duration of HAART prior to tenofovir-based HAART was 9 years (range 9-14 years), in three regimens (range 2-8 regimens). The tenofovir-based HAART was started at a median CD4 count of 335 cells/mm³ (range 20-1360 cells/mm³) and median viral load 77,000 copies/mL (~range 1,200-172,000 copies/mL).

The children all received the adult tenofovir dose of 300 mg once daily, at initial weights of 32, 33, 36 and 59 kg with a dose range of 5.1-9.4 mg/kg for a median duration of 37 months (range 18-54 months) prior to stopping tenofovir. All children were asymptomatic, identified on screening, with biochemical resolution within 4 months of tenofovir cessation.

The authors wrote: “Although unlicensed, tenofovir is widely used in HAART experienced paediatric cohorts resulting in cases of renal tubular dysfunction. Paediatric formulations and pharmacokinetic studies are currently recruiting with results eagerly awaited.”

Onyeador N, Patel D, Lyall H et al. Renal tubular dysfunction associated with tenofovir based HAART in perinatally acquired HIV: the need for paediatric formulations and pharmacokinetic studies. 14th Annual BHIVA Conference, Dublin, 2008, HIV Medicine, 9 (Suppl. 1). P61.